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BIOL 202 Concept Map

CC

Chloe Calinescu

Transcript

BIOLOGY 202 CONCEPT MAP

Unit 3:

Unit 7:

Unit 6:

Chromosomes

DNA

&

Biotechnology

CELLS

DNA

&

Biotechnology

ENERGY

Inheritance

ENERGY

Unit 9:

Unit 10:

Unit 8:

Species

Diversification

Animal Diversification

EVOLUTION

Species

Diversification

CELLS

  • Smallest unit of life

  • Can function independently

  • Performs all necessary functions of life, including reproducing itself

CELLS

Cell Theory

All living things are made of cells

Every new cell is made from division of preexisting cell

Cell Theory

Plant vs. Animal Cell Components

PLANT

ANIMAL

Centriole

Chloroplasts

Cell Wall

Vacuole

(rare exceptions)

Plant Cells

vs

Animal Cells

Nucleus

Plasma Membrane

Ribosomes

Mitochondria

Rough & Smooth endoplasmic reticulum

Cytoplasm

Cytoskeleton

Golgi Apparatus

Lyosome

Chloroplasts

  • Two surrounding membranes, one internal membrane network (thylakoid stacks)

  • Thylakoid stacks are "pancaked" on top of each other to create stack of membrane discs (granum)

  • Chloroplasts contain ribosomes

  • Site of photosynthesis: conversion of light into chemical energy

  • Light is collected by chlorophyl molecules within thylakoid sacks

  • Converted into sugar (glucose)

Cell Wall

  • Provides plant cell with structural strength

  • Increased water resistance

  • Protection from insects and other animals

  • Made of cellulose, which is indigestible to humans

  • Water and other particles can pass between cells through plasmodesma

Vacuoles

  • Stores nutrients

  • Retains and degrades waste products

  • Accumulates poisonous materials

  • Contains pigments allowing plants to attract birds and insects to help plant reproduce

  • Provides physical support

  • Mainly found in plant cells, occasionally in animal cells (protists)

Prokaryotes (Prokaryotic Cell)

Does not have a nucleus, DNA simply resides in middle of cell

Prokaryotic Cells

Eukaryotes (Eukaryotic Cell)

Has a central control structure called nucleus, which contains cell's DNA

Eukaryotic Cells

Has various organelles with specialized functions

Important Landmarks Distinguishing Eukaryotic Cells

Important Landmarks Distinguishing Eukaryotic Cells

Organelles in Eukaryotic Cells

Ribosomes

Complexes of RNA and protein that carry out protein synthesis

Multi subunit enzymes

Ribosomes

Cytoskeleton

Network of protein fibers that carry out many different functions:

cell support, cell movement, movement of structures within cell

Each type of cytoskeleton fibre has a specific structure & function

Cytoskeleton

Microtubules

  • Attachment site for flagella/cilila

  • Plays many important roles within cell

Microtubules

Intermediate Filaments

Offers mainly structural support and rigidity, provides tension to cell and maintain shape

Intermediate Filaments

Microfilaments

Ex. When contracting muscle cells, your body uses microfilaments

(made of proteins actin and myosin)

that interlock and pull together to contract muscle

Microfilaments

Nucleus

  • Defining organelle of eukaryotic cells

  • Surrounded by the nuclear envelope (double membrane made of two lipid bilayers)

  • Nuclear envelope controls passage of molecules between nucleus and cytoplasm

  • DNA is stored in nucleus, wrapped around proteins, called chromatins

Nucleus

The Nucleolus

Nucleolus

Area in nucleus where ribosomes are assembled

Mitochondria

  • Where we convert energy into usable form (ATP)

  • Found in almost all eukaryotes including plants

  • Has two membranes- the highly folded inner membrane, and the outer membrane

  • Actively pushes H+ ions from matrix to intermembrane space, storing potential energy

Mitochondria

Lysosomes

  • Garbage disposal for cells

  • Digests and recycles cellular waste products and consumed material, breaking it down into smaller molecules

  • Contains over 40 digestive enzymes that can breakdown almost anything, and contains an acidic pH level

  • Cell takes in molecules and brings them to lysosome for digestion, digested parts are then used for various functions

Cilia and Flagella

Cilia & Flagella

  • Attached to microtubules

  • Can be found in both eukaryotic and prokaryotic cells

  • Flagella are tail-like strucures found on the end of some cells (ex. sperm) allowing it to swim and move itself

  • Cilia are hair-like strucures found on cell surface allowing it to move fluids past cells (ex. fallopian tubes)

Endomembrane System

  • Produces and modifies molecules to transport them to other parts of organism

  • Breaks down toxic chemicals and cellular by-products

  • Made up of key components:

Endoplasmic Reticulum

  • Vast network of membrane-covered tubes/sacks that serve as transport system throughout cell

  • Extends from nuclear envelope

Endoplasmic Reticulum

Smooth Endoplasmic Reticulum

  • Site of lipid production (fatty acids, phospholipids, steroids

  • Detoxifies molecules (alcohol in liver cells, drugs, metabolic waste products)

Smooth Endoplasmic Reticulum

Rough Endoplasmic Reticulum

  • Studded with ribosomes that make proteins

  • Modifies proteins that will be shipped to other locations inside/outside of cell

  • Factory of cell

Golgi Apparatus

  • Processes and packages molecules received from endoplasmic reticulum into transport vesicles

  • Ships vesicles to desired location

Golgi apparatus

Typical Eukaryotic vs. Prokaryotic Cells

Key Differences?

  • DNA in cytoplasm

  • Internal structures not compartmentalized

  • Much smaller
  • DNA in nucleus

  • Contains special structures called organelles

  • Up to 10x larger

Plasma Membrane of Cell

Structure & Function of Cell Membrane

Basic Functions:

  • Get rid of waste products

  • Takes in all food and nutrients

  • Helps build and export molecules

  • Regulates heat exchange

  • Regulates flow of materials in and out cell

  • "Gatekeeper" of cell

Phospholipid Bi-layer

  • Is amphipathic (hydrophic and hydrophillic)

Made of Phospholipids

  • Boundary between external environment and cell's cytoplasm

Cell Membrane is Semi-Permeable

Permeable to:

hydrophobic molecules, small polar molecules (like water), and gases

Impermeable to:

large polar molecules (like glucose) and other hydrophilic substances (like ions)

Permeability

(How molecules travel across cell membrane)

Various ways that molecules may travel through cell membrane:

Diffusion

(simple)

Simple Diffusion

  • Solute: what is being dissolved
  • Solvent: what it's being dissolved into

  • Solute naturally moves along the concentration gradient (high concentration - low concentration)

  • Molecular collisions: molecules bumping off of each other

  • Molecular collisions cause molecules to expand and move away from each other, until they're evenly distributed (equilibrium)

Simple diffusion is an example of Passive Transport

Osmosis

Water diffuses across membrane to equalize the concentration of water inside and outside of cell

Water will always move towards region with higher concentration of solutes

Osmosis

Osmosis is an example of Passive Transport

Hypertonic Solution

Concentration of solutes is higher outside of cell, and lower inside of cell.

As a result, water flows out of the cell in an effort to make concentrations equal

Hypertonic Solution

water always moves towards area of high concentration

Hypotonic Solution

Concentration of solutes is lower outside of cell, and higher inside of cell.

As a result, water flows into the cell in an effort to make concentrations equal

Hypotonic Solution

Animal cells may explode because they don't have a cell wall to limit cellular expansion

Isotonic Solution

Concentration of solutes in water and cell are equal and therefore are balanced

Water flows both in and out of cell equally in order to maintain this state

Isotonic Solution

Facilitated Diffusion

Larger molecules that would otherwise be impermeable to the cell membrane can move through transport proteins

Transport proteins act as a channel, carrier, or pump to provide a passageway for many larger hydrophilic molecules to enter cell (Glucose)

They can also push solute out/in against the natural concentration grain

Facilitated Diffusion

Facilitated Diffusion is an example of Passive Transport

Active Transport

Pushing solute out/in against natural concentration gradient (low concentration to high concentration)

Requires ATP (Adenosine Triphosphate), main energy carrier within cells

Active Transport

Endocytosis

This is another method in which large molecules can enter the cell

There are 3 types of endocytosis:

Endocytosis

Phagocytosis

Cell Eating

  • Cell engulfs large particles, creating a pocket-like vesicle around particle

  • Cell encloses around vesicle, particle is transported into cell

Phagocytosis

Pinocytosis

Cell Drinking

Cell engulfs smaller particles and fluids into cell

Same method as phagocytosis, but vesicle is much smaller due to size of particles/fluids

Pinocytosis

Receptor Mediated Endocytosis

  • Cells engulf specific particles by binding to the receptor proteins on plasma membrane

  • Only works if proteins on particle and receptors on cell are compatible

Receptor Mediated Endocytosis

Exocytosis

Particles to exit the cell for use somewhere else in body

Vesicle moves to plasma membrane where it fuses and releases contents into body

Exocytosis

How do cells communicate?

Connections between cells hold them in place and allow them to communicate with eachother

Involves many kinds of protein and glycoprotein adhesion molecules

How do cells communicate?

The primary connections between animal cells are called junctions

There are 3 kinds:

Junctions

Tight Junctions

  • Form a water-tight seal between cells

  • Found in intestinal lining, holds cells together

  • Protects foreign particles from entering

Tight Junctions

Desmosomes

  • Acts like velcro to fasten cells together

  • Looser than tight junctions

  • Found in heart muscle cells, and all throughout body

Desmosomes

Gap Junctions

  • Particles can freely move across cell membrane into other cells

  • Secret passageways to pass signals/particles through body

  • Found all throughout body

Gap Junctions

ENERGY

Unit 4:

How energy is converted from sunlight to sugar (chemical energy)

Photosynthesis

Plants capture energy from sun (1%) with chloroplasts and store it in chemical bonds of sugars and other food molecules

Photosynthesis

Organisms release energy stored in bonds of food molecules they eat

(or sugar produced during photosynthesis) and use it as fuel

Photosynthetic Organisms

Not just plants!

Other photosynthetic organisms

(algae)

The Big Picture

Role of Water in Photosynthesis

  • Not just for hydration

  • Water provides electrons to plant

  • Light energy is captured in chloroplasts, electrons are moved from water molecules to other molecules, transferring energy

  • Photosynthesis cannot occur without water

Water

Light Energy

  • A type of kinetic energy

  • Made up of energy packets called photons

  • Different photons carry different amounts of energy, carried as waves

ELECTROMAGNETIC SPECTRUM:

  • Length of wave = amount of energy

  • Short wavelength: higher energy (x-rays, gamma rays, UV light)

  • Long wavelength: lower energy (radio waves, infrared)

  • In between: visible light spectrum (detectable by human eye)

Photosynthetic Pigments

  • Photosynthetic plant pigment (ex. chlorophyll)

  • Absorbs only certain wavelengths of energy (photons) from sun

  • Doesn't absorb green, visible green color of chlorophyll is because it is reflecting green wavelengths

  • Absorbed energy excites electrons

  • Plant pigments can only absorb specific wavelengths of energy

  • Plants produce several different types of light-absorbing pigments, and reflect specific wavelengths

Electron Excitation

  • Conversion of electromagnetic energy into chemical energy of bonds between atoms

  • Photons of specific wavelengths bump electrons up a quantum level into an excited state

  • Electrons are then returned to resting, unexcited state OR excited electrons are passed to other atoms

"Photo" part of photosynthesis:

Two main products: ADP and N A D P H

"Photo" and "Synthesis"

"Synthesis" part of photosynthesis:

Synthesis Part of Photosynthesis

The Calvin Cycle

  • Series of chemical reactions of making sugars

  • Occurs in soma

  • Enzymes are recycled

Calvin Cycle

Fixation

Enzyme rubiso plucks carbon atoms from CO2 molecules in the air, the carbon atom is attached to an organic molecule with 5 carbons, creating a molecule with 6 carbons

1. Fixation

Sugar Creation

2. Sugar Creation

Organic molecule is modified into a small sugar called G 3 P, by using energy from N A D P H and ATP

Some molecules of G 3 P are combined to form six carbon molecules such as glucose

Regeneration

Remainder of molecules of G 3 P are used to regenerate original organic molecule (with 5 carbons) using energy from ATP

3. Regeneration

N A D P H

  • An energy storing molecule similar to ATP, produced by "photo" reactions of light absorption

  • Electron carrying molecule

  • Energy stored among electrons in
  • N A D P H molecule

  • Excited electrons from water moved between molecules, eventually onto

N A D P H

N A D P H

Where does the mass come from?

Plants use energy from sun to take 6 carbon dioxide molecules, bond them together, to create glucose

Where does plant matter come from?

Bio fuels

Bio fuels

  • Both bio fuels (lipids) and traditional gasoline are made of hydrocarbons

  • Engine takes in hydrocarbons, and com busts and breaks apart bonds to generate energy

  • Bio fuels are more environmentally friendly:

cleaner burning, high octane, made from recycled ingredients (used fry oil) with zero carbon net output

  • Zero carbon net output - amount of carbon dioxide put into atmosphere will be taken in by plants that are used to cultivate bio fuels

  • Fundamentally the same type of energy we put into our bodies

Kinetic vs Potential

  • Energy stored in an object

  • ex: dam trapping water

  • Energy of objects in motion

  • ex: ball rolling down hill, combustion

Kinetic

vs.

Potential Energy

Energy is never generated or destroyed in a system, simply converted from one form to another

Energy Transformations

Kinetic energy to potential energy:

Light energy from sun is mostly (99%) transformed into heat, while rest is absorbed and stored as chemical energy in plants

Energy Transformations

Potential energy to kinetic energy:

Chemical energy in muscles & liver is partially transformed into heat energy, the rest will be released as waste

Food = Energy

Food

Food is full of chemical energy, within covalent bonds

Breaking apart bonds between atoms releases energy

Structure of Chloroplasts

Thylakoid sacs: location of "photo" reactions, where light is converted into chemical energy

Stroma: location of "synthesis" reactions, where chemical energy is used to synthesize sugars

Chloroplasts

How do cells directly fuel chemical reactions?

ATP

None of the light energy can be used directly

Must be captured in the bonds of ATP (adenosine triphosphate)

ATP

adenosine triphosphate

Adenine - nitrogen containing base

Ribose - sugar

Three phosphate groups - all negatively charged, bonds force them to stay together

Cell breaks bonds to use as energy, ATP loses a phosphate, producing ADP (adenosine diphosphate)

ATP

Cellular Respiration

  • Almost every cell undergoes cellular respiration

  • Requires fuel and oxygen

  • Opposite of photosynthesis

  • Potential energy stored in chemical bonds of sugar, protein, and fat molecules

  • Breaks bonds, release high-energy electrons captured in ATP

  • Oxygen is electron magnet

Cellular Respiration

First step of cellular respiration: Glycolysis

1. Glycolysis

  • Universal energy-releasing pathway

  • Glyco = sugar

  • Lysis = breaking it apart

  • Ten steps, three of which yield energy

  • Net result:
  • Each glucose molecule broken into two pyruvate molecules

  • ATP molecules produced

  • NADH molecules store high-energy electrons

Preparatory Phase to the Kreb's Cycle

2. Preparatory Phase to the Kreb's Cycle

  • As each pyruvate is broken down, a pair of electrons and a proton are passed to NAD+, producing NADH

  • A carbon and two oxygen atoms are released as carbon dioxide

  • Coenzyme A attaches itself to remaining molecule, creating acetyl-CoA

Kreb's Cycle

(citric acid cycle)

Kreb's Cycle

Happens over and over again

Electron Transport Chain

Transferring electrons from high energy carrier to low energy carrier

Two key features of mitochondria are essential to their ability to harness energy from molecules:

  • Mitochondrial "bag-within-a-bag" structure

(inter membrane space & mitochondrial matrix)

  • Electron carriers organized within the inner "bag" these molecules create an electron transport chain that enables ATP production

3. Electron Transport Chain

Oxygen is the final electron acceptor

Alternative Energy Sources

Alternative Sources of Energy

During strenuous activities, oxygen becomes limited within muscles, without oxygen electron transport chain stops

Glycolosis can occur without oxygen

Fermentation: cells produce lactic acid in order to provide energy for body

Ethanol (alcohol) is a by-product of cellular metabolism in the absence of oxygen

Learning Objectives:

  • How energy flows from sun and through life on earth

  • How photosynthesis uses energy from sunlight to make food

  • How cellular respiration converts food molecules into ATP (a universal source of energy)

  • Alternative pathways to energy acquisition

Learning Objectives

Energy can be transferred within cell in two ways:

Overall

  • Chemical energy (ATP)

  • Electron transfer (NADH)

Biotechnology

Unit 5:

DNA

DNA Structure

  • DNA is a nucleic acid

  • DNA is made of two strands, connected by base pairs to form double-helix structure

Structure & Function

Nucleotides

Each nucleotide has three components:

  • 5-Carbon Sugar (Deoxyribose)

  • Phosphate Group

  • Nitrogen-Containing Base

Nucleotides

Nitrogen-Containing Base

  • Changes between molecules, acts as a variable

  • Ex. Adenine, Thymine, Guanine, Cytosine

  • Complimentary Base Pairing:

  • Adenine always pairs with Thymine

(form 2 hydrogen bonds)

  • Guanine always pairs with Cytosine

(form 3 hydrogen bonds)

Chromosomes

Each person has 23 different types of chromosomes, half come from mother and other half from father

Chromosomes

Genes

A sequence of DNA with instructions on how to make a specific amino acid sequence

Genes

Alleles

Possible "versions" of genes

3 different possible alleles for human gene

(A, B, & O)

Phenotype (characteristics: color, blood type)

depends on combination of alleles

Ex. A allele from mom + B allele from dad = blood type AB

Alleles

Amount of DNA

An onion has 5x amount of DNA compared to humans, are onions more complex than us?

Amount of DNA is less important than amount of coding DNA

Not all DNA contains instructions for making proteins

Amount of DNA

Coding vs Non-Coding

In between genes, 75% of non-coding DNA are in-between genes, other 25% found within genes

Regions in-between genes that do not code for proteins are called intergenic DNA regions

Most DNA in eukaryotes (human cell) don't code for any proteins

Coding vs Non-Coding DNA

Central Dogma

The central dogma of molecular biology: information flows in one direction when genes are expressed

RNA viruses are exceptions to central dogma

Prokaryotes vs

Eukaryotes

In prokaryotes, DNA occurs in circular pieces, usually only one circular type of DNA

In eukaryotes, genome is divided among smaller, linear strands of DNA called chromosomes

DNA Transcription & Translation

Information coded in the sequence of nucleotide bases in DNA is passed to a sequence of nucleotide bases in RNA

The information in RNA can be passed onto polypeptides

Ex. Gene for insulin, the RNA codes how to make the polypeptide (insulin)

Transcription & Translation

Transcription

1st Step of Building Organism

A copy of gene's base sequence is made (in RNA language)

Occurs inside nucleus of cell, DNA is transcribed by cell in order to produce a messenger RNA (m RNA)

Contains four steps: 1. Recognize & Bind,

2. Transcribe, 3. Terminate, and 4. Capping & Editing

Transcription

RNA Polymerase

Enzyme that makes RNA

Recognizes promoter site in DNA, binds to one strand of DNA and reads gene's message (recognizing & binding)

As it travels down the strand of DNA, it unwinds the helix so it can be read, helix rewinds behind it

Builds a single strand copy of DNA (transcription)

When it reaches a code signaling the end of the gene (termination site), it stops transcribing releases m RNA transcript (termination)

RNA Polymerase

m RNA Transcript

messenger RNA

m RNA transcript

  • Final product of transcription

  • Made by RNA polymerase

  • It is the RNA version of DNA strand that has been transcribed (coding strand)

  • Contains Uracil instead of Thymine

Translation

m-RNA is used to direct production of protein/functional molecules

Translation

Ribosomes

The enzyme (catalyst) that makes a polypeptide

Made of proteins, and r RNA (ribosomal RNA)

Contains large & small ribosomal subunit

Ribosomes

Transfer RNA

"bridge" between m-RNA & amino acid

Translates the m-RNA code, linking specific bases on the m-RNA with specific amino acids that will be used to build a protein

Only one amino acid per t-RNA molecule

Transfer RNA

Codons & Anticodons

Codon is a sequence of three nucleotide bases, three bases are read at a time

Smallest unit of length that can code for all amino acids

All protein translation begins with a START codon (ATG/AUG) and ends with a STOP codon

Anticodon is simply the opposing base pairs of a codon (codon is ATT, anticodon will be TAA)

Each codon corresponds with certain amino acid

Codons

Phenotype/Genotype

Phenotype vs

Genotype

Genotype: All of the genes contained in organism, various alleles (AB, A)

Phenotype: Physical manifestations of the instructions

Mutations

Alteration of bases in DNA sequence can lead to changes in structure and function of the proteins produced

There is a wide range of possible effects

What causes mutations?

Differential Gene Expression

Not every cell is making all 30,00 proteins at once (skin cells don't make insulin, pancreas cells do)

Some genes are turned on and some are turned off - regulated by positive/negative control

Positive Control: cell receives signal to turn on gene (pancreas cells get signal of high blood sugar, make insulin)

Negative Control: stopping genes from being transcribed for no reason

Lac Operon

In E-Coli, for example

On/Off switches exist in bacteria as well

Lac operon turns on and begins making enzyme to metabolize lactose only when lactose is detected

Lac operon usually has the "brakes" on in the absence of lactose, and takes off the "brakes" when lactose is detected

Lac Operon

Breast Cancer

  • 2 human genes called BCRA1 and BCRA2

  • More than 200 different changes in the DNA sequences of these genes have been detected

  • Each of these changes results in a higher risk of developing breast cancer

  • Not everyone has same risk, because not everyone has same sequences of the genes

  • Depending on what sequence you have and what mutations may occur, can increase risk

  • P53 protein: "police " that makes sure cells don't divide uncontrollably

  • If P53 is mutated, the cells will uncontrollably make copies of itself, resulting in a tumor

Breast Cancer

At the level of the chromosome

Point Mutations

at level of the gene

Only one base is affected

Point Mutations

Nucleotide Substitution

One nucleotide is swapped with another, this is basis of sickle-cell anemia

Substitution

Nucleotide Insertion

Insertion

A single nucleotide is added,

completely shifts frame and changes every amino acid following it

Nucleotide Deletion

(or Gene Deletion if on the level of the chromosome)

A single nucleotide is removed,

completely shifts frame and changes every downstream amino acid

Deletion

Chromosomal Aberrations

at the level of the chromosome

Much larger impact than point mutations

Chromosomal Aberrations

Gene Duplication

Duplication

Gene is duplicated, multiple copies are now available

Too many of a certain protein can shift body's homeostasis

Gene Relocation

Entire gene is cut & pasted onto another chromosome, basis of leukemia/white blood cell cancers

Relocation

Gene Deletion

Entire gene is deleted, caused by mutagen

Deletion

Mutagens

Possible causes of mutations that can change our DNA

  • Chemicals (cigarette smoke)

  • UV-rays from sun

  • Radiation from X-rays

Mutagens

How can faulty enzymes lead to diseases?

Diseases

  • Mutated gene will code for non-functioning protein/enzyme

  • Why do people respond so differently to alcohol?

  • If enzyme for metabolizing alcohol is non-functioning, it can't catalyze reaction so the molecule that's supposed to be metabolized accumulates, and alcohol will build up in body.

Biotechnology

Biotechnology

Genetic Engineering

Adding, deleting or transplanting genes from one organism to another, altering organisms in useful ways

Genetic Engineering

Restriction Enzymes

Molecular Scissors

Enzymes that cleave/cut DNA at specific sites, recognize base sequences

Restriction Enzymes

Resistances in Genetic Modification

Resistance

Some plants (tomatoes) have been genetically modified to be more resistant to insects

Other crops are sprayed with herbicide-resistance genes from bacteria to prevent weed growth

Gene Therapy: Direct insertion of genes into living cell's DNA

Why doesn't it always work?

Difficulties of Gene Therapy

  • Difficulty getting working gene into specific cells where it's needed, or into enough cells at the right rate to have psychological effect

  • Difficulty arising if transfer organism gets into unintended cells

  • Difficulty regulating gene expression

Cloning

Ranging from genes to organs to individuals

  • Offers potential benefits in agriculture or medicine, but ethical questions still linger

Cloning

Ex. Dolly the sheep

DNA Fingerprinting

Amplifying DNA fragment containing each STR region using PCR

(polymerase chain reaction)

DNA Fingerprinting

Chromosomes

&

Replication

Chromosomes

Meiosis

(Eukaryotic)

  • In humans, each nucleus has 46 chromosomes

  • There are 23 different kinds of chromosomes

  • Each cell has two complete sets of 23 from each parent

Mitosis

(Eukaryotic)

Telomeres

A section of non-coding, repetitive DNA

  • "Protective cap" at end of DNA

  • Every time a cell divides, the telomere gets a bit shorter

Telomeres

Telomeres in Humans

  • Repeats of nucleotide sequence TTAGGG

  • About 200 repeats, 80-90 cell divisions

  • Telomeres too short?: Hutchinson-Gilford progeria syndrome, causes faster aging

Telomeres in Humans

How Do Prokaryotic Cells Divide?

Binary Fission

(Prokaryotic)

Prokaryotic cells divide through binary fission, the simplest form of cell division

  • Each strand of DNA creates identical copy of itself, resulting in 2 genetically identical circular chromosomes

  • Cell divides, the daughter cells will be clones of each other

Why Do Cells Divide?

Why Do Cells Divide?

1. Reproduction

2. Growth & Development

3. Tissue Renewal & Repair

Two Types of Cells

(in multicellular organisms)

Two Types of Cells

Somatic Cells: (all of the cells in body other than sex cells) Product of mitosis

These are the cells that form the body of the organism

Reproductive Cells: (sperm, egg) Product of Meiosis

These are the sex cells

Mitosis

Mitosis leads to production of two daughter cells, not for reproduction

(except in single celled organisms)

What are spindles?

Composed of proteins, mostly hollow tubes called micro-tubules

The spindle micro-tubules stretch across the cell between its two poles (ends)

In animal cells, the spindle fibers connect at each pole to a structure called the centriole

Spindles

Interphase

Interphase

3 Main Parts:

Interphase

Gap 1:

Cell's primary growth phase, normal cell functions take place (making proteins, ATP production & removing waste)

S Phase (DNA Synthesis):

The cell begins preparations for division. In process of replication (copying genetic information), chromosome creates an exact replica of itself resulting in 23 new duplicated chromosomes

Gap 2:

Second period of growth and preparation for cell division, spindle forms

Sister chromatids: two genetically identical strands of DNA held together at centromere

Mitotic Phase

(Consists of 2 main parts, shortest phase)

Mitotic Phase

Mitosis:

The parent cell's nucleus, with its duplicated chromosomes, divides

(Prophase, Metaphase, Anaphase, Telophase)

Cytokinesis:

The cytoplasm is divided into 2 daughter cells, which have a complete set of the parent cell's DNA and other cellular structures

Checkpoints

(Cell cycle control system)

When certain cells exit into G0 where they don't further divide

Checkpoints

Prophase

1st phase of mitosis

  • Centrioles are at opposite poles of cell

  • Nuclear membrane breaks down

  • Sister chromatids condense

  • Spindle organizes itself

Prophase

Metaphase

2nd phase of mitosis

Sister chromatids line up in single file at center of cell (metaphase plate)

Spindles are attached to both centrioles and centomeres

Metaphase

Anaphase

3rd phase of mitosis

  • Sister chromatid pairs are pulled apart at centromere by the spindle fibers

  • One full set of individual chromosomes goes to one side, and other identical set goes to the other

Anaphase

Telophase

4th phase of mitosis

  • The chromosomes begin to uncoil as nuclear membrane reassembles around them (opposite of prophase)

  • Cell begins to pinch into two

Telophase

Cytokenisis

After telophase when the cell is pinched, the membrane officially splits into two separate cells

Cytokenisis

Cancer

  • Defined as unrestrained cell growth & division, cells can't stop at checkpoints

  • Can damage adjacent tissues, some can metastasize leading to tumors

  • Malignant tumors can spread through circulatory system to other essential organs, or blocking blood vessels

  • Benign tumors are very similar, but don't have the ability to break apart and travel to other tissues

  • Chemotherapy can also damage healthy cells

How is mitosis involved with cancer?

Meiosis

  • Generates gametes (sperm & egg cells)

  • Starts with diploid cell (23 pairs of chromosomes)

  • Generates haploid cell (one set of 23 chromosomes)

  • If mitosis occurred instead of meiosis, number of chromosomes would double with each generation

  • Important outcomes of meiosis:

  • Reduces amount of genetic material in gametes

  • Produces gametes that all differ from each other with the combinations of alleles they carry (genetic variation)

Meiosis I ends, Meiosis II starts

Homology

Chromosomes from each parent contain same types of genes, but not the same versions of those genes are homologous to each other

Homology

Interphase

In preparation for meiosis, the chromosomes replicate

G1, S Phase, G2

(Same as mitosis interphase)

Interphase

Prophase I

  • Replicated chromosomes condense

  • Nuclear membrane disintegrates

  • Homologous pairs of sister chromatids come together and cross over (this part differs from mitosis)

Prophase I

Metaphase I

Each pair of homologous chromosomes move to equator of cell (unlike in mitosis, where they line up in single file to be pulled apart)

Metaphase I

Anaphase I

Homologous pairs are pulled apart towards opposite sides of cell (chromatids still attached)

Maternal and paternal sister chromatids are pulled to the ends of the cell in a random fashion called random assortment

Anaphase I

Telophase I & Cytokenisis

Chromosomes arrive at opposite poles of cell, nuclear membrane reassembles, chromosomes may slightly unwind

Cytoplasm begins to divide and pinches the cell to create 2 daughter cells

(Same concept as mitosis telophase)

Telophase I & Cytokenisis

Prophase II

(identical to prophase in mitosis)

  • Chromosomes in daughter cells condense

  • Nuclear membrane breaks down

  • Spindle forms

Prophase II

Metaphase II

(identical to metaphase in mitosis)

Sister chromatids line up in single-file at metaphase plate

Metaphase II

Anaphase II

(identical to anaphase in mitosis)

Sister chromatids are pulled apart by spindle fibers, breaking centromere, and moving to opposite poles

Anaphase II

Telophase II & Cytokenisis

(identical to telophase in mitosis)

Nuclear membrane reassembles, chromosomes may slightly unwind

Cytoplasm begins to divide and pinches the 2 daughter cells to into 4 unique haploid daughter cells

Telophase II

&

Cytokenisis

Gamete Development in Females

Gamete Development

One diploid starting cell gives rise to a single functional haploid gamete (egg)

Polar bodies are also produced in the process, but can't be fertilized by sperm

Three Main Causes of Genetic Variation

Genetic Variation

Law of Independent Assortment

Each pair is lined up at metaphase plate independently of the other, you will get various combinations in resulting daughter cells

Law of Independent Assortment

Sexual

vs Asexual

Reproduction

Sexual Reproduction

(humans, animals)

Sexual

Pros:

  • Genetic variation

Cons:

  • Only half of individual alleles will be passed on

  • Time & energy to find mate

  • Opportunities for mistakes

Asexual Reproduction

(Bacteria)

Pros:

Can reproduce very fast

Cons:

No genetic variability

Asexual

Sex Chromosomes

How Sex is Determined in Humans

Individuals have two copies of the sex chromosomes in every cell

Females have X X, Males have X & Y

How is Sex Determined?

How is Sex Determined in Animals?

Varies in many ways throughout different species...

In Animals?

Variations in Chromosomes

  • Additional or lacking of number of chromosomes

  • Can result in conditions such as down syndrome

  • Karyotypes reveal individual's entire chromosome set, allowing for diagnosis before birth

  • Correlation between mother's age and down-syndrome

Variations in Chromosomes

Down Syndrome vs Normal Karyotypes

NORMAL

DOWN SYNDROME

Karyotypes

People with Down Syndrome have a trisomy on chromosome 21, meaning they have an extra chromosome

(trisomy 21)

Caused by

Non-Disjunction

  • Non-disjunction is the unequal distributions of chromosomes during meiosis, can happen in females or males

  • Error in cell division that creates gametes with zero or two copies of a chromosome

  • Homologous pairs don't separate at Anaphase I, ending up with an unequal amount of chromosomes in gametes

How Does This Happen?

Only One X

Monosomy X

More Possible Syndromes

Trisomy X

Inheritance

On the level of the organism

Inheritance of Genes

Heredity: the passing of characteristics from parent to offspring via genes

Inheritance of Genes

Single vs Multiple Gene Traits

Single-Gene Traits

Some traits are determined by the instructions an organism carries on one gene

Single-Gene

Traits

Fish Odor Syndrome

Cats' Fur Length & Colour

Only determined by one single gene

Albinsim: individuals do not produce normal pigmentation

Cats' Fur

Multi-Gene Traits

Polygenetic Trait: The effects of alleles from multiple genes all contribute to the ultimate phenotype (ex. height, skin color)

Pleiotropy: One gene influences multiple, different traits (ex. sickle cell)

Multiple-Gene Traits

Parental (P) Generation

Dominant vs Recessive Traits

F 1 Generation

Mendel crossed a true-breeding purple plant with a true-breeding white plant, the first generation produced only purple plants, why?

Because in this case, purple is the dominant trait and white is the recessive trait

Dominant vs Recessive Traits

The recessive trait will only be observable if there is no dominant trait

Recessive

Two recessive alleles and no dominant alleles - recessive traits will be observable

The dominant trait masks the effects of the recessive trait

Dominant

One dominant allele and one recessive allele - only dominant characteristics will be observable

The Gene Locus

The Gene Locus

  • Diploid organisms possess two copies of each chromosome

  • Each gene occurs on a specific chromosome and is located at a specific site on chromosome

  • The specific site is called the locus

  • One locus exists for each gene, on each chromosome

Alleles

Alternative Versions of Genes

Alleles govern the same character, but do not necessarily contain the same information

Found at the same locus on the same kind of homologous chromosomes

Alleles

Dominant alleles (A)

mask the presence of recessive allele

recessive alleles (a)

presence is masked by Dominant allele

Dominant vs Recessive Alleles

Mendel's Discoveries

True-Breeding plants: always have same characteristics when bred

(they are homozygous P P or w w)

Mendel the Monk

Law of Segregation

You have two copies of each gene, but put only one copy in each sperm/egg

Phenotype

Genotype

w w

w P

P w

P P

Punnet Squares

Determines probability of an offspring having a particular genotype

Made by comparing all possible combinations of alleles

Rows represent possible gametes of one parent, columns represent possible gametes of another parent

Punnet Squares

Test-Crossing

Pedigrees

"Family Trees"

Pedigrees

Used to decipher and predict the inheritance pattern of genes

Sex-Linked Traits

Trait's mode of inheritance is not always obvious...

Types of Dominance

Some traits may not show complete dominance

Many traits are influenced by the environment

The effects of both alleles in a genotype can show up in the phenotype

Complete Dominance

Complete Dominance

The normal dominance of a certain allele

(purple pea plants)

3:1 proportion when two heterozygous organisms are crossed (Pw+Pw)

Incomplete Dominance

Incomplete Dominance

Hetero zygote appears to be an intermediate blend between the two homo zygotes

The genotype proportion will always be identical to the phenotype proportion

Co-dominance

Hetero zygote simultaneously expresses the phenotypes of both alleles:

  • When both alleles are dominant

  • When there is no dominant allele

  • Heterozygous person shows both alleles expressed equally (R R, R W)

Genotype is visibly distinguished

Blood Types

A, B, and O Alleles

A & B are both completely dominant to O

A & B are codominant to each other

Individuals can be one of four possible blood phenotypes: A, B, AB, or O

Antigens & Antibodies

Antigens & Antibodies

Universal Blood Donors/Acceptors?

Sex Chromosomes

X & Y

Sex Chromosomes

Sex-linked traits differ in their patterns of expression in males & females

There are other genes on the sex chromosomes not just related to primary/secondary sexual characteristics (hemophilia, color blindness), but only on X chromosome

SRY

Sex-determining Region on the Y chromosome is called the SRY - "the master switch"

Causes fetal gonads to develop as testes after fertilization (lack of SRY leads to ovaries)

Following the gonads' secretion of testosterone, other developmental changes occur

SRY

Why is color-blindness more common in males?

Color-Blindness

Sex-linked traits are carried on the X chromosome, women have two Xs and men have one X and one Y

Women need two recessive alleles, men only need one to have color-blindness

Genetic Linkage

Genes are close together on chromosome, and travel together in meisois

Ex. Red hair gene and freckle gene

Genetic

Linkage

EVOLUTION!

Hardy Weinburg Law

EVOLUTION

How Does It Happen?

Evidence?

4 Mechanisms That Give Rise to Evolution

How Does It Happen?

These three are random!

Natural Selection

Organisms adapt to their environments

  • Camouflage, "Eye Spots" make them look bigger ------------------->

  • NOT random

Natural Selection

Charles Darwin

Fruit Fly Natural Selection Experiment

If environment changes, alleles causing traits favoured by natural selection may change too

Factors preventing populations from progressing towards perfection:

1. Environments change quickly

2. Variation is needed as raw material of selection

3. Maybe be multiple different alleles for a trait, each causing individual to have same fitness

Does Not Lead to Perfect Organisms

Artificial Selection or selective breeding: Selecting certain desirable traits for future generations (ex. bigger petals)

Artificial Selection

Possible Outcomes of Artificial Selection

Directional Selection

Shift in one direction favoured

Directional Selection

Stabilizing Selection

Individuals with intermediate phenotypes are most fit

Stabilizing Selection

Disruptive Selection

Individuals with most extreme pheonotypes are most fit

Disruptive Selection

3 conditions

3 conditions must be satisfied for it to occur...

1. Must be genetic variation for the trait within

a population

2. Variation must be inheritable

3. Differential reproductive success

What Causes it to Occur?

Differential Reproductive Success

There are more organisms born than can survive

Organisms are constantly struggling for existence

Some organisms are more likely than others to win the struggle and survive & reproduce

Fitness

Measure of relative amount of reproduction of an individual with a particular phenotype

Individual's fitness is measured relative to other genotypes/phenotypes in population

Depends on specific environment in which organism lives (ex. fish fit in water, not land)

Also depends on organism's reproductive success compared to other organisms in population or same species

Complex Natural Selection

Mutations

  • Direct change in the DNA of an individual

  • Ultimate source of genetic variation

  • Random

Mutations

Genetic Drift

Random change in allele frequencies in a population over time

Reduces genetic variation in a population

Not related to allele's influence on reproductive success and survival

Much greater in smaller populations

Founder Effect

A small number of individuals leave population and become founding members of a new, isolated population

Founders of new population may have different allele frequencies than original "source" population, especially if small sample

Founder Effect

Bottleneck Effect

Large proportion of population

dies, new population dominated by

surviving members genetics

Migration

Gene flow into or out of a population may change allele frequencies

Migration

Hardy-Weinburg Law

Used to predict how common each genotype in population will be

Hardy Weinburg Law

If 'p' = frequency of dominant alelle (A)

If 'q' = frequency of recessive allele (a)

p + q = 1 (100%)

p2 = frequency of homozygous dominants (AA)

q2 = frequency of homozygous recessives (aa)

2pq = frequency of heterozygotes (Aa)

Evidence?

Evidence of Evolution?

Comparative Anatomy and Embryology

The Fossil Record

Older fossils have more stable isoptopes, because unstable isotopes will decay over time.

Increase in stability over the years, so we can date fossils based on how stable they are.

The Fossil Record

Geographic Patterns

Geographic patterns of species distributions reflect species' evolutionary histories

Similar animals in different regions have different physical characteristics based on type of environment (ex. wet vs dry environment)

Same concept as Darwin's finches

Convergent Evolution: Evolution of different types of organisms to have similar traits, because they have similar environments

Biogeography

Comparative Anatomy & Embryology

Reveal common evolutionary origins

Vestigial structures have no apparent function, residual parts from past ancestors (ex. Vampire bat's molars)

Molecular Biology

Reveals that common genetic sequences link all life forms

More related you are evolutionary wise, more we share at molecular level in common, in terms of DNA codes

Molecular clocks allow us to determine how closely related we are

Molecular Biology

Laboratory

& Field Experiments

Allow us to watch evolution in progress

Ex. Fruit Fly Experiment

Laboratory and Field Experiments

Species Diversification

Life on Earth Originated From Non-Living Materials

How is it possible to generate a cell from non-living materials/chemicals?

Origin of Life

Phase 1

Formation of Small Molecules containing Carbon and Hydrogen

Phase 1

Urey-Miller Experiment

Phase 2

Formation of self-replicating, information containing molecules

RNA was likely the first self-replicating information containing molecule (m RNA, t RNA, etc.)

RNA can catalyze reactions necessary for replication

Phase 2

Phase 3

The development of a membrane, enabling metabolism and creating first cells

Phase 3

Membrane establishes inside and outside of cells, maintains homeostasis

The first living cells were made from small chemical molecules (carbon, oxygen, etc.) and self replicating, information containing molecules (RNA), surrounded by a cell membrane

Therefore...

Biological Species Concept

Species are populations of organisms can that interbreed with one another

Are reproductively isolated from other groups (ex. humans can't breed with flowers)

Barriers prevent interspecies breeding:

Biological Species Concept

Some members of different species can be artificially bred with eachother, for example in captivity - "zorse"

Groups are only considered to be of same species if there is a possibility of natural breeding in the wild

Artificial Breeding

Postzygotic Barriers

Prezygotic Barriers

Either the individuals are physically unable to mate, or the sperm is unable to fertilize the egg

  • Long distance from one another

  • Different timing of mating seasons

  • Different mating rituals

  • Physical/biochemical factors (different sizes, genetics)

Postzygotic Barriers

Individuals are able to breed, but offspring is usually very frail and ill, often dies after fertilization

If offspring survives, usually infertile

(horse + donkey = infertile mule)

Postzygotic Barriers

3 s of life

How do we name organisms?

Scientific names consist of two parts:

Genus "first name"

Specific Epithet "last name"

ex: Equus Quagga (zebra),

or Homo Sapiens (humans)

Systema Naturae

The Biological Species Concept doesn't always work...

Not Always Easily Defined...

Ring Species

Population splits due to large geographical distance, when they meet after thousands of years of evolution, they can no longer breed

Hybridizing Species

Hybridization is the interbreeding of closely related species (ex. zorse)

Hybrid is usually infertile

Morphological Species Concept

Characterizes species based on size or shape

Useful for classifying asexual species

Morphological Species Concept

Speciation

How do new species arise?

When one species splits into two distinct species, occurs in two phases:

  • Reproductive isolation

Two populations (once the same) not able to breed

  • Genetic divergence

Populations accumulate independent genetic changes (mutations) over time

Speciation

Allopatric Speciation

Occurs when a geographic barrier isolates a group from the other

ex. Darwin's finches

Allopatric Speciation

Sympatric Speciation

Usually in plants

Does not require physical seperation of individuals in population

Can happen within a single population or between two different species

Sympatric Speciation

Evolutionary Trees

Help us conceptualize and categorize biodiversity

Systematics name and arrange species in a matter that indicates

  • the common ancestors that they share
  • the points at which they diverged from each other

Phylogeny

  • history of organism

You can compare organisms based on physical features, or on the DNA level

Evolutionary Trees

Humans are not "more advanced" evolutionarily than cockroaches or bacteria, simply more complex

Any group in which all of the members are more closely related to each other than to any individuals outside that group

Monophyletic Groups

Macro-Evolution

Gives rise to much larger and significant characteristics of evolution and diversity (evolution of wings, feathers)

Micro-evolution: A slight change in allele frequencies in a population over one or a few generations

Macro-evolution: Occurs at or above the level of the species, the result of micro-evolution taking place over many generations

Adaptive Radiations

Times of extreme diversification

When a small number of species diversifies into a much larger number of species, a result of large environmental changes

Adaptive Radiation

"Five"-Kingdom System

of Classification:

Monera: Prokaryotic Organisms

Plant, Animal, Fungi, Protists: 4 Kingdoms of Eukarya Domain

Kingdoms

Bacteria Are a Monophyletic Group

Bacteria

All bacteria ...

  • are single-celled organisms with no nucleus or organelles

  • have one or more circular molecules of DNA

  • have several methods of exchanging genetic information

  • are asexual organisms

Archaea

Many live in extreme environments

Very diverse, 5 groups:

Thermophiles love heat

Halophiles love salt

High and Low pH tolerant

High Pressure tolerant

Methanogens release methane

We're more closely related to archaea than bacteria!

Archaea

Animal

Diversification

Animal

Diversification

Animals are just one branch of the Eukarya Domain

Animal Diversification

Four Key Distinctions Divide Animals:

Does the animal have specialized cells that form defined tissues?

Does animal develop with radial or bilateral symmetry?

During gut development, does mouth or anus form first?

Does growth occur by molting, or by adding to the animal's body in a continuous manner?

What Defines an Animal?

All animals...

  • Eat other organisms (find food)

  • Can move (escape predators)

  • Are multicellular (can reproduce)

All living species

are successful!

Intervertebrates

Animals without a backbone

Interverbrates

  • Most diverse group of animals

  • 25% of all species on earth are beetles, an intervertebrate

  • 8 out of 9 phila are intervertebrates:

Sponges

  • No tissues or organs

  • Consists of a hollow tube or network of canals with pores in their walls

  • Feed by pumping in water, bacteria, algae and small particles of organic material through their pores

  • Baby sponges (larvae) can freely swim around, sessile as adults

  • Are hermaphrodites (both male and female reproductive organs)

  • Can also reproduce asexually

Over 5,000 kinds of sponges!

Polyp

Cnidarians

  • Has tissues, is radially symetrical

  • Have tentacles armed with rows of stinging cells (cnidocysts) to paralyze prey

  • Carnivores

  • Reproduce sexually and asexually

Medusa

Sea Anemones

Sea Anemones

  • Resemble flowers

  • Free-swimming as babies (larval stage)

  • Mostly sessile as adults

The Corals

  • Small, soft-bodied polyps

  • Live in large colonial groups

  • Secrete calcium carbonate

  • Stinging tentacles surrounding a mouth

  • Both sexual and asexual reproduction

Coral

Coral Bleaching

When sea temperatures rise even slightly, corals will eject algae (their photosynthetic partner), turn white, and likely die.

Phenomenon known as coral bleaching

1/3 of coral reefs are bleached due to global warming

Jellyfish

Jellyfish

  • Not a fish

  • Many different kinds, range widely in size, shape and colour

  • Some species are deadly

Worms

Worms!

Flatworms

  • Well defined head and tail regions

  • Hermaphroditic, sexual and asexual

  • Some have sinles opening which serves as mouth and anus

Members: Tapeworm and Fluke

Flatworms

Roundworms

  • Long, narrow, unsegmented body

  • Surrounded by strong, flexible cuticle

  • Must molt in order to get bigger

  • More than 9000 species!

Roundworms

Annelids

  • Segmented body

Members include: Earthworm, Leech, Polychaete Worm

Annelids

Mollusks

Most have a shell to protect soft body

Mantle: a tissue that forms the shell

Radula: a sandpaper-like tongue structure used during feeding, found in all mollusks except bivalves)

Members include:

  • Gastropods (slugs, snails)

  • Bivalves (giant clam)

  • Cephalopods (octopus, squid)

Mollusks

  • Tentacles used for capturing and/or stinging prey

  • "Cephalo" meaning head or brain

  • "Pod" meaning feet or tentacles

  • Very well developed head region/brain, octopuses are very smart and able to learn

Anthropods

Segmented body with a distinct head, thorax, and abdomen

Exoskeleton made of chitin and jointed appendages

Anthropods

Flight and metomorphisis produce the greatest adaptative radiation ever!

Metamorphisis

Echinoderms

Enclosed by hard skeleton of shiny plates

Larvae are bilaterally symmetrical and share some anatomical features with chordates

Adults are radially symmetrical

Undersides covered with tube feet that aid in moving and grasping

Members include: sea urchins, starfish, sand dollars, sea cucumbers

Vertebrates

Animals with a backbone/spine

Are members of the chordata phylum

Vertebrates differ from other two chordates because they have a backbone and a head

Vertebrates

Jaws and fins are the most important adaptive radiation in vertebrates.

They had parallel evolution, because they work together to capture prey

Chordates

All chordates possess 4 common body structures (present during specific life stages)

  • Notochord: beginning of backbone

  • Dorsal hollow nerve cord: spinal tissue

  • Phyrangeal slits: gills, tonsils

  • Post-anal tail: tail

Chordates

The chordata phylum mainly includes vertebrates, but also includes tunicates and lancelets, which do not have a backbone.

Jawed Fish

The movement onto land required lungs, a rigid backbone, four legs, and eggs that resist drying

Movement Onto Land

All terrestrial vertebrates are tetrapods (4 appedages)

All tetrapods are either amniotes or non-amniotes

Terrestrial Vertebrates

Amphibians are Non-Amniotic

Amphibians must reproduce in water and do not have dessication-proof amniotic eggs

Non-Amniotes

Amniotic Vertebrates

Lizards & Snakes, Turtles, Crocodiles, Birds & Dinosaurs, and Mammals

Can produce an amniotic egg (reptiles lay on land, mammals develop theirs internally)

Amniotes

Feathers and Scales

Reptiles vs Birds

Feathers and Scales

Reptiles' skin is covered in scales, and body temperature is controlled by external conditions such as air temperature (exothermic)

Birds have wings and feathers which provide insulation and flight, body temperature is maintained by internal heat from cellular respiration (endothermic)

Mammals

  • Have hair and produce milk

  • Viparity: mammals are viviparous, birth live babies (not eggs)

  • Exception: Monotremes lay eggs AND produce milk (platypus)

Mammals

Monotremes

  • Lay eggs, produce milk but don't have nipples - baby sucks from hairs on mother's chest

  • Platypus and four species of spiny animals called echidnas

Monotremes

Marsupials

Give birth after short period of development

Most species' females have a pouch where the baby completes their development

Marsupials

Placental Mammals

Have a placenta that provides oxygen and nutrients to embryo inside the uterus, egg does not have a shell

Placental Mammals

Three Major Anatomical Differences Between Humans and Chimps:

Humans

vs

Chimps

  • Humans are completely bipedial - conserves energy and allows multitasking

  • Humans are bigger

  • Humans have a brain 3x the size of a chimpanzee

Microbes

Can live almost anywhere!

Unit 11:

Microbes

Binary fission!

Bacteria

Most Diverse Organisms

  • Single celled organisms with no nucleus

Bacteria

Cocci: Spherical Bacteria

Bacilli: Rod-shaped bacteria (sausages)

Spirilli: Spiral-shaped bacteria

Classification and Structure

Bacteria Carry Genetic Information in Two Structures:

Genome

1. A circular DNA molecule called the chromosome (1 or more)

2. Circular DNA molecules called plasmids

  • Metabolic plasmids

  • Resistance plasmids

  • Virulence plasmids

Metabolic Diversity Among Bacteria is Extreme!

Wide range of modes of nutrition

Chemoorganotrophs: Feed on organic molecules

Chemolithotrophs: Feed on inroganic molecules

Photoautotrophs: Use energy from sunlight to pruduce glucose via photosynthesis

Metabolic Diversity

Oxygen Revolution

During earth's birth, majority of bacteria were autotrophs

Oxygen is a product of photosynthesis

Photoautotrophs input a large amount of oxygen into atmosphere

Bacteria can have harmful or beneficial effects on humans

Effects on Humans

Examples of Good Bacteria

Good Bacteria

E. Coli cells: normal, natural flora in GI tract

  • Produce Vitamin K

  • Populate Intestines, deter bad pathogens

Lactobacillus Acidophilus: a probiotic in dairy products

  • Release Lactic Acid

  • Populate Intestines, deter bad pathogens

Harmful Bacteria

Pathogens Can Cause Diseases

Bad Bacteria

Cholera outbreak:

  • Cholera is produced by vibrio cholerae bacteria

  • Deadly, can enter body

  • Found in contaminated water

Streptococcus:

  • Pyogenes are usually harmless

  • Some strains responsible for strep-throat

  • Other strains responsible for flesh-eating disease, destroys colagen

STD's

Bacterial infections (chlamydia, syphillis, gonnorhea) can be treated and cured with antibiotics

Virus infections (AIDS, Herpes, HPV) can not be cured, only treated with antiviral or antiretrovial medications

Sexually Transmitted Diseases

Antibiotic Resistance

How do bacteria and other microbes resist antibiotics?

Antibiotic Resistance

  • Pumping antibiotics out of their cell

  • Make proteins bind to antibiotic molecule and block lethal effect

  • Make enzymes that break down antibiotic molecules and use them as fuel to help bacteria grow faster

Archaea Domain

Can exploit very extreme habitats

More closely related to eukarya (humans)

than bacteria is

Resemble bacteria, but are profoundly different

Archaea

Differences between Bacteria vs Archaea:

  • Archaea have branched fatty acids in their plasma membranes

  • Archaea cell walls are not made of peptidoglycan

  • Significantly different flagellae

Difference between Bacteria & Archaea vs Eukarya:

  • Eukarya have nucleus, nuclear membrane, and other organelles, Bacteria and Archaea do not

Differences Among the Domains

Archaea are Extremophiles

Can live in extreme conditions

Types of Archaea

Halophiles: archaea that thrive in salt

Many extremophile archaea are helpful in bioengineering and environmental remediation (degrading the oil in oil spills)

Methanogens: archaea that produce methane

  • Live in our gastrointestinal tracts, break down certain carbohydrates (found in beans) that our bodies can't digest, and produce methane gas in the process (farts)

Protists

Part of the Eukarya Domain

  • Most are single-celled and microscopic

  • Acritarcs: ancient protists

  • Vary in size, but are generally larger than bacteria and archaea

  • Have organelles (like all eukarya)

Protists & Viruses

Cellular organelles are internal structures that carry out specific functions, an evolutionary innovation that occured first in protists

Organelles were likely first formed by fusion of folds of the plasma membrane:

  • Incorporated proteins that controlled the movement of molecules in/out of nucleus

  • Extended outwards from nucleus to form a folded membrane called the endoplasmic reticulum

Formation of Organelles

Some Protists Can Make You Very Sick

Cause Illnesses

A parasite lives in or on another organism, called a host, and damages it

A parasitic protist called Plasmodium, transmitted by mosquitos, is responsible for malaria

Diversity of Protists

Different Forms

Some Protists Are Multi-Cellular

Most aren't!

Multi-Cellular Protists?

Green and brown algae are multi-cellular protists

So are diatoms:

  • Important part of the food chain, eaten by krill and copepods, who are then eaten by large predators

  • Primary producers - are photosynthetic!

  • Different from algae, cell wall not made of cellulose, it is made of silicia (glass-like)

  • Can withstand huge amounts of pressure

VIRUSES

not a part of any domain

Can't replicate by themselves, require a host

All viruses have two things:

  • Genetic material of some sort (DNA or RNA based)

  • Protein capsid in which to store genetic material

Some viruses have an outer envelope that surrounds the capsid, which comes from the host cell infected by the virus

Some have glycoproteins on outer envelope (ex. coronavirus)

VIRUSES

Ex. influenza virus, coronavirus, HIV, herpes, HPV

Ex. polio virus, rhino viruses (common cold), adenovirus

Viral replication

Virus only needs to insert its genome into a host cell

Viral replication

hiv/aids

HIV/AIDS

HIV mutates very easily

It specifically targets "helper T cells", which are white blood cells, very important immune system cells

immune system collapses

Immune system collapse

HIV does not directly cause symptoms, it slowly breaks down immune system

Normally, all white blood cells work together to identify and destroy virus-infected cells

HIV kills the cells that hunt for viruses and bacteria, immune system collapses

Results in Acquired Immune Deficiency Syndrome (AIDS)

influenza

why do flu viruses change so quickly?

Influenza

RNA viruses such as the flu (coronavirus, HIV) mutate a lot faster, coded proteins change, which is why we need repeated vaccinations

This is because RNA polymerase is a faulty enzyme, and makes more mistakes than DNA polymerase does, leading to more mutations in RNA viruses

There are some other types of non-living infectious agents...

Prions: misfolded proteins, form plaques and misfold neighbouring proteins, acquired via ingestion of infected animal

ex. mad cow disease

zoonotic viruses can spread between animals & humans

zoonotic viruses

Animal

Physiology

Unit 12 & 13:

Physiology

and

Circulatory & Respiratory Systems

Homeostasis

Maintenance of a relatively constant internal chemical/physical environment, in the face of changing environmental factors

Disruptions such as hyperthermia/ hypothermia, levels of blood sugar & blood pH, and tissue concentrations of oxygen and carbon dioxide

Homeostasis

Negative and Positive Feedback Systems Influence Homestasis...

Negative/Positive Feedback Systems

Negative Feedback Loops

Perturbation away from set point results in a corrective action

Most common method used to maintain homeostasis in animals

Sensor detects stimuli (too hot or too cold), turns on an effector

Effector elicits the desired effect

Negative

Feedback Loops

Positive Feedback System

In some instances, perturbation can result in further movement away from set point, known as positive feedback

Change away from normal conditions, causes increase or acceleration of certain variable

Ex. blood clotting, stomach enzyme

activation, childbirth

Positive

Feedback Loops

Regulators vs Conformers

Not all organisms maintain a set internal environment

Regulators vs. Conformers

Regulators:

  • For some physiological variables, organisms have a set point and bodily functions maintain variable to stay within the ideal range

  • Organism's internal environment does not vary with external environment

Conformers:

  • For other physiological variables, organism has no set point, variable fluctuates based on environment

  • Organism's internal environment varies based on external environment

Organisms can regulate certain variables

while conforming to others

Thermoregulation

Temperature control is a classic

component of homeostasis

Thermoregulation

Endotherms vs Ectotherms

Endotherms "warm-blooded"

  • Animals that generate heat internally

  • Most mammals and birds

  • Metabolic rate increases as external temp decreases, maintaining body temp

Ectotherms "cold-blooded"

  • Animals that mainly get their heat from their environments (ex. the sun)

  • Intervertebrates, fish, reptiles, amphibian

  • Metabolic rate is constant regardless of

external temperature changes

Endotherms & Ectotherms

Homeotherms vs Heterotherms

Often interlinked with ectotherms and endotherms, but mean something different

Homeotherms & Heterotherms

Homeotherms maintain a constant internal body temperature (most are endotherms)

Heterotherms' body temperatures fluctuate with environment (most are ectotherms)

Ecto/endo refers to the source of heat,

homeo/hetero refers to the maintenance of body temperature or not

Mechanisms of Heat Exchange

Heat Exchange Mechanisms

Body heat is a combination of internal heat generation and exchange with the external environment, that occurs through four mechanisms:

Conduction

Heat transfer that occurs when objects of different temperatures come into contact

Ex. lose heat by leaning against a cool rock

Conduction

Convection

Object transmits heat to a medium such as water or air

Ex. steaming hot cup of tea, steam shows that heat is being transfered to the air

Convention

Radiation

Heat is transferred from warmer object to colder object, with no direct contact

Ex. warming up in the sun

Radiation

Evaporation

Loss of heat that occurs as a liquid substance

Ex. sweating to cool off

Evaporation

Body Temperature Regulation in Animals

Methods of Body Temp Regulation

Physical Methods

Walruses' thick layer of blubber insulates them

Behavioural Methods:

Squirrel shades himself with his tail

Physiological Methods:

Dog pants, loses heat through evaporation

Cellular Methods:

Human babies have brown fat that produces heat, not ATP, when broken down

Osmoregulation

Osmoregulation

The regulation of water content and dissolved solute concentrations by balancing water gain and loss

Gain water by drinking, eating, osmosis, or cellular respiration

Lose water by peeing, pooping, evaporation, or osmosis

Osmoregulatory Strategies

Living in air, salt water, and freshwater pose unique challenges, all organisms are either Osmoconformers or Osmoregulators

Osmoregulatory Strategies

Osmoregulatory Structures

Osmoregulatory Structures

Malpighian Tubes: Small tubes that regulate osmotic balance in insects by removing excess solutes from circulatory system

  • Insects don't have a closed circulatory system, instead they have hemolymph which is found all throughout their body plans

Kidneys: Complex organ that regulates osmotic balance in vertebrates by removing either excess solutes or excess water from circulatory system, depending on organism's external environment

Kidneys

Primary organ in vertebrates for regulating water balance and solute concentrations

Temporarily removes both good and bad stuff from blood, reabsorbs good stuff (proteins, glucose) back into circulatory system, filters out waste (water, salt, urea)

Function of Kidneys

FORM FOLLOWS FUNCTION

FORM FOLLOWS FUNCTION

Animals' body structures reflect their functions

STRuctures

and

Functions

Animals Are Mulitcellular Organisms

Multicellularity allows animals to become larger and develop greater physiological

complexity than single-celled organisms

Increased size & complexity brings benefits via specialization of cell and tissue functions

Most animal bodies are organized in a

hierarchy from cells to tissues, organs,

and organ systems

Mulitcellular Organisms

Tissues are grouped into organs or organ systems

Animal

Tissues

Organs: structures that serve specialized functions, and they can contain several (or all) types of tissue.

Organ systems: groups of organs that work together to accomplish related functions

There are FOUR TYPES OF TISSUES:

Connective Tissue

connective tissue

  • Made of cells dispersed throughout a matrix

  • Provides structure and support, anchors cells, and regulates communication between cells

  • Consists of:
  • Fibroblasts: Cells that produce collagen (glue) and elastin (elasticity of skin)
  • Present in every single connective tissue except blood

  • Matrix: Non-living, extracellular mass of protein fibers (collagen and elastin) and surrounding liquid, jelly-like or solid material

PROPER

SPECIAL

Connective Tissues Proper

Soft and flexible Extracellular Matrix

Bone

Cartilage

Loose

Loose Connective Tissue:

  • Semi-fluid, flexible, not tightlty packed matrix

  • Cushions, lubricates and insulates other tissue

  • Ex: soft padding under the skin, tissue surrounding most organs, and adipose tissue

Dense Connective Tissue:

  • Matrix is tighly packed with many collagen fibers

  • Connects bones to muscles or other bones

  • Ex: tendons and ligaments

Types of Connective Tissue

Blood

Dense

Special Connective Tissues

Liquid or Rigid Extracellular Matrix

Special Connective Tissues

Bone

  • Matrix is hardened with calcium into a solid material

  • Provides protection and structural support

Cartilage

  • Strong but flexible matrix rich in protein fibers

  • Provides structural support and cushioning for joints

Blood

  • Liquid matrix (plasma) consists mainly of water

  • Transports gases and other substances throughout body

Epithelial Tissue

Epithelium is a sheet-like tissue that searates different parts of the body, 3 main functions:

  • Protection:
  • Acts as a barrier between the inside and outside of an organism

  • Keeps fluid from leaking into or out of organism

  • Transport:
  • Regulates movement of nutrients and other molecules into and out of body tissues

  • Secretion:
  • Can form exocrine glands which secrete products such as saliva, sweat and mucus

  • Can form endocrine glands, which secrete hormones into the blood

Epithelial Tissue

Muscle tissue

Enables movements and contractions

3 types of muscle tissues:

Muscle tissue

Skeletal Muscle

  • Usually attached to bones and is responsible for generating most movement

  • Can be under conscious (voluntary) control or unconscious control

  • The individual skeletal muscle cells are called muscle fibers

Skeletal Muscle

Cardiac Muscle

  • Located only in the heart

  • Not under conscious control

cardiac

Muscle

smooth muscle

  • Found in the walls surrounding blood vessels, stomach and intestines, bladder, and other organs and internal tubes within the body

  • Not under conscious control

smooth Muscle

nervous tissue

  • Transmits information, 2 types

  • Neurons
  • Cells that receive and transmit signals

  • Made of dendrites, cell body, and axon

  • Glial cells (neuroglia)
  • Assist neurons by insulating, protecting, and regulating their chemical environment, holding them in place, destroying pathogens, and providing nutrients and oxygen

Nervous tissue

Organ Systems

Each organ system performs specific tasks

Tissues are organized into organs, which operate together in organ systems to achieve a common function

These systems interact to support the growth, development, maintenance, and reproduction of the entire organism

Organ Systems

Circulatory System

Transports nutrients and respiratory gases to the tissues and eliminates waste from the tissues

Heart & blood vessels

Circulatory System

Digestive System

Digestive System

Dissasembles and absorbs food so the body can acquire the nutrients it needs to function

Includes the mouth, esophagus, stomach small intestine, large intestine, liver, gallbladder, pancreas

Respiratory System

Provides a site for gas exchange between the external environment and an organism's circulatory system

Includes nasal cavity, trachea, bronchi, and lungs

Respiratory System

Nervous System

Control center of body: interprets, stores, and transmits information using electrical impulses and chemical signals

Includes all of central nervous system and peripheral nerves

Nervous System

Female

Reproductive System

Produces eggs and provides an environment that can nurture a developing embryo and fetus after fertilization

Includes uterus, fallopian tubes, cervix, ovaries

Female Reroductive System

Male

Reproductive System

Produces and delivers sperm to the female reproductive system, where fertilization may occur

Includes testes,

Male Reroductive System

Immune and Lymphatic System

Attacks pathogens that threaten the body and plays a supporting role in circulation by recycling fluid that leaks from the circulatory system

Includes white blood cells, lymphatic vessels, lymph nodes

Lymph is the fluid in found in nodes, vessels and tissue within body that is not blood

  • Gets rid of excess water and has a population of immune cells

Immune and Lymphatic System

Urinary/Execratory System

Purifies the blood by filtering out and transporting waste out of body via urine

Includes kidneys and bladder

Urinary/Execretory System

Endocrine System

Regulates bodily activities by releasing hormones that travel through vessels in circulatory system to reach target cells

Includes pituitary gland, thyroid gland, adrenal glands, ovaries and testes

Endocrine System

Integumentary System

Provides protection by creating a barrier between the inside and outside of an organism and can aid in the secretion and transport of molecules

Includes skin, hair, nails, teeth

Integumentary System

Muscular System

Generates force through contraction which enables movement of the body and of blood, food, and other substances throughout body

Muscles!

Muscular System

Skeletal System

Support and protects the body and internal organs, manufactures blood cells and provides a surface for muscle attachment, foundation for movement

Bones!

Skeletal System

Circulatory & Respiratory Systems

In Humans and Other Animals

Unit 13:

circulatory

and

respiratory systems

The

Circulatory

System

Circulatory System

Open vs Closed Circulatory Systems

Open

vs

Closed Systems

Open Circulatory Systems

No clear distinction between the circulating fluid and the interstitial fluid

The heart(s) pumps the fluid mixture -hemolymph- through the extracellular spaces inside the body

Ex. Arthropods/insects

open systems

Closed Circulatory Systems

Blood, Vessels, and Heart

Arteries don't always carry oxygen-rich blood, and veins don't always carry oxygen-poor blood

closed systems

Blood is contained within vessels that separate it from interstital fluid

A muscular heart pumps blood through vessels to tissues throughout body

Three types of blood vessels:

Arteries carry blood away from heart, towards capillaries

Capillaries are tiny and porous, bring blood close to tissue, enable diffusion of gas, nutrients and other molecules in & out of tissues

Veins carry blood away from capillaries, towards heart

Simple closed system, ex. fish

Purpose of four-chambered heart is to seperate oxygen-rich blood from oxygen-poor blood

Closed Circulatory System: Mammals and Birds

Mammals and birds have a four-chambered heart with two circuits of flow

pulmonary

vein

pulmonary artery

aorta

vena cava

Atria: where blood enters the heart

Mammals and Birds

Oxygen-poor blood travels out of left ventricle through the pulmonary artery, where it is sent to the lungs to be oxygenated

Once it has become oxygen-rich, it travels back into left atrium of heart via the pulmonary vein

Left ventricle pumps blood out through aorta into body tissues

Oxygen is used up in the tissues, oxygen-poor blood travels back into right atrium via vena cava

Ventricles: pump blood out of the heart

What is a Circulatory System, and Why is It Needed?

Purpose

& Functions

As body size increased, dedicated delivery and removal systems became a necessity

Some animals, such as jellyfish and other cnidarians don't need a circulatory system

They obtain oxygen & nutrients and get rid of waste through diffusion

Functions of The Circulatory System

Not just for nutrient and oxygen delivery...

Functions

The Human Heart

  • Deoxygenated blood comes into heart via vena cava, travels through right atrium into right ventricle

  • Pumped out through pulmonary arteries, gets oxygenated in the lungs, returns to heart through pulmonary veins

  • Moves into left ventricle, and pumped out via aorta

  • All of the blood on right side of heart is oxygen-poor

Human Heart

Heartbeat

The sound of a heartbeat comes from two sets of valves that keep blood flowing in the proper direction, not from a heart's contractions

Heart Contractions

Contractions

Heart is made of cardiac muscle tissue

Has the ability to contract and beat independent of the nervous system, is not controllable

1. The sinoatrial node (cluster of muscle fibers), sends electrical impulse to both atria

2. Atria contract and push blood through into ventricles

3. Ventricles contract and push blood out through pulmonary artery and aorta

EKGs measure rythmic heart contractions

SA Node

Initiates regular, rythmic heart contractions (pacemaker of the heart)

A heart contraction begins with an electrical impulse in the SA node in the right atrium.

The contraction spreads to the left atrium, passes down the center to the bottom of the heart, then moves upward, pushing blood from both ventricles out through the pulmonary arteries and aorta

Sinoatrial Node (SA Node)

Arteries don't have valves! Veins do.

All three have an endothelium layer!

Arteries, Capillaries, and Veins

Blood

Flow

What is Blood Made of?

Components

Plasma (55%)

  • 90% salty water

  • Variety of molecules including metabolites, wastes, salts, ions, and plasma proteins

Packed Cells (45%)

  • 95% red blood cells

  • White blood cells

  • Platelets (cell fragments)

Living, longer lasting

Not truly living, only last a few weeks

Constantly squeezing through capillaries, get damaged

Blood is a salty, protein-rich mixture of cells and fluid that transports:

(1) respiratory gases

(2) vitamins and minerals

(3) nutrients

(4) hormones

(5) components of the immune system

(6) metabolic wastes

Transportation

Blood Pressure

Blood pressure measurement gives important clues about an individual’s overall health, as well as potential for cardiovascular disease

Blood pressure readings consist of two measurements:

Systolic Pressure

  • The force that blood exerts on the artery walls when the heart contracts and pumps blood into the arteries
  • Normal range is between 90-140 mm Hg

Diastolic pressure

  • The force that blood exerts on the artery walls while the heart is between beats
  • Normal range is between 60 - 90 mm Hg

Hypertension = High Blood pressure

Cardiovascular Diseases

Cardiovascular Disease

Includes all diseases of the heart and blood vessels, including heart attacks and strokes, cardiovascular disease is the leading cause of death in the United States

How do Arteries Get Clogged?

Two Processes Work

Together to Clog Arteries:

Atherosclerosis:

  • Cholesterol circulating in the bloodstream forms a fatty plaque that reduces flow of blood

Arteriosclerosis:

  • Calcium is deposited in the plaque, hardening it

Clogged arteries often result in heart attacks, where there is an interruption in blood flow through one of the coronary arteries

Heart cells surrounding the malfunctioning artery die because they cannot receive oxygen and nutrients

Good vs Bad Cholesterol

Cholesterol is beneficial in small amounts, but too much is not healthy

The "density" of the cholesterol refers to how much protein there is in it (high-density=high protein and low-cholesterol)

Good

vs

Bad Cholesterol

Lymphatic System

Fluids drain from tissues of body into the circulatory system

Lymph nodes are clusters of lymphatic tissue, populated by white blood cells

Most food gets absorbed directly into bloodstream (simple carbs, amino acids)

Lipids (fats, fatty acids) get absorbed in lymphatic system in small intestine, become LDL/HDL particles

Lymphatic System

Phyla & Circulation

Animal Phyla

Respiratory System

Gas Exchange

In single-celled and very small multicellular organisms, gas exchange can occur by direct diffusion

In large multicellular organisms, gas exchange is a two-stage process

Gas Exchange

Exchange between the circulatory system and the cells involved in cellular respiration

Exchange between the external environment and the organism’s circulatory system, usually takes place in lungs, tracheae, or gills

Hemoglobin

Red blood cells are filled with hemoglobin, a protein that picks up oxygen in the lungs and transports it around the body

Hemoglobin releases its oxygen in organs and tissues, such as muscles, where it is needed for cellular respiration

Iron atom binds and unbinds to oxygen

Hemoglobin

Air Pressure and Partial Pressure

Structure

Respiratory systems of terrestrial vertebrates move oxygen-rich air into the lungs and carbon-dioxide-rich air out of the lungs

The conducting portion is responsible for getting air from external environment into the lungs, consists of the nose and mouth

The respiratory portion is responsible for transporting oxygen into and CO2 out of the blood, consists of the bronchi and bronchioles

Structure of Respiratory System

Alveoli

Alveoli are the delicate, thin-walled elastic sacs at the end of bronchioles where the air meets the blood vessels

Where gas exchange occurs

Low partial pressure of oxygen in the blood, and high partial pressure of oxygen in the alveoli

Oxygen moves from alveoli into blood via hemoglobin, and is delivered to tissues of body

Alveoli are surrounded by capillaries

Breathing Mechanics

Muscles contract and relax to allow changes in volume of lungs to occur

Mechanics of Breathing

Adaptations to Low Partial Pressure of Oxygen

Humans adapt to low-oxygen conditions by making more red blood cells, more hemoglobin, and increasing amount of mitchondria to increase cellular respiration

They also increase DPG, a molecule that makes hemoglobin more likely to release oxygen into tissues

Adaptations to Low Partial Pressure of Oxygen

Animal Phyla

Unit 14:

Conservation Biology

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