Biology STAAR Review

Mechanisms of Genetics

REPORTING CATEGORY

1

Cell Structure and Function

Biomolecules

Proteins

Lipids

Carbohydrates

Nucleic Acid

Biomolecules are organic molecules that are made up of

carbon, hydrogen, nitrogen, oxygen and sometimes phosphorus.

Proteins are made of chain of amino acids

that can be used to make the proteins that

the body needs to maintain muscles, bones

& other body organs. Proteins control the

structure and metabolism of cells.

Carbohydrates are made up of carbon, hydrogen and

oxygen in a 1:2:1 ratio. Carbohydrates store energy,

starch in plants and glycogen in animals, add

structure to organism, cellulose in cell wall of plant

and chitin in cell wall of fungi. Carbohydrates also

play a role in nucleic acids by providing the sugar

deoxyribose for DNA and ribose for RNA.

Nucleic Acids include DNA and RNA.

DNA , an organism’s hereditary code,

controls the synthesis of RNA molecules

which work to form proteins. Nucleic

acids are made up of nucleotides

which are composed of a nitrogen base,

phosphate and sugar.

Lipids are fats, oils used for energy storage,

cell membrane composition and composition

of vitamins and steroids.

Cellular Processes

Just like the human body, cells must carry

out specific functions for an organism to

maintain homeostasis.

These functions include: reproduction, transport of nutrients & waste products, production & use of energy and communication.

Cellular Reproduction uses the

nucleus and centrioles.

Production & Use of Energy organelles

includes the

chloroplast & mitochondrion.

Transportation of nutrients

occurs through the cell membrane,

endoplasmic reticulum,golgi body

& vacuoles

Communication Organelles include the

nucleus, ribosome, vesicles and

intra-cellular junctions.

Homeostasis is the maintenance of

an internal balance in the cell or organism.

Positive and negative feedback loops signal

cell organelles to cause changes to maintain

a stable internal environment.

Examples of feedback loops include:

osmotic pressure

calcium ion regulation

blood sugar regulation

Cell Cycle

The cell cycle is divided into three parts:

Interphase, Mitosis, and Cytokinesis.

Interphase is divided into G1, organelles replicate

and cell size increase, S phase, synthesis or

replication of DNA, and G2, re-check DNA

and prepare to divide.

Mitosis is the division of the nucleus and includes:

Prophase,

Metaphase,

Anaphase

& Telophase.

Cytokinesis, division of cytoplasm,

follows mitosis. Mitosis creates two

diploid (2N) daughter cells

identical to original cell.

Viruses

The basic virus structure includes a capsid, protein coat, envelope with DNA or RNA.

Viruses reproduce by taking over normal healthy cells and injecting their nucleic acids into the cells.

The shape of a virus allows the virus to match the shape of certain receptors sites found in the cell membrane allowing attachment followed by injection of viral nucleic acid.

REPORTING CATEGORY

2

DNA

Deoxyribonucleic acid, DNA, is a double helix structure made of a phosphate-sugar backbone held together by phosphodiester bonds.

The genetic code is found between the phosphodiester bonds in the order or sequence of the nitrogen bases.

Nitrogen bases are adenine(A), thymine(T), cytosine(C) and guanine(G). Adenine base pairs with thymine while

cytosine base pairs with guanine by hydrogen bonds.

DNA is composed of many repeating nucleotides. A nucleotide is made of a phosphate group, deoxyribose sugar, and a nitrogen base. All living organisms (animals, plants, fungi, protists and bacteria) have DNA made of the same four nitrogen bases A,T,C and G. Sections of a chromosome, called a gene, codes for the making of a protein (aka polypeptide).

DNA is “unzipped” between nitrogen bases by the breaking of hydrogen bonds. The reading of DNA nitrogen bases occurs during DNA replication

(during S phase of cell cycle before mitosis) and transcription ( the making of messenger RNA)

Mutations of DNA

Changes in the nitrogen base sequence of DNA are called genetic mutations. Genetic disorders are caused by:

point mutations (single change of nitrogen bases),

insertion mutations (additions of nitrogen bases),

deletion mutations (removal of nitrogen bases),

inversion mutations ( backward sequence of nitrogen bases)

translocation mutations ( nitrogen bases moved to another location on the chromosome).

Genetic disorders caused by failure of chromosomal pairs to separate during meiosis are called nondisjunction. Nondisjunction mutations can be detected by creating a karyotype, or picture of an organism’s chromosomes.

Predicting Genetic Crosses

Punnett squares are graphic organizers used to predict the outcome of monohybrid and dihybrid crosses. Letters are used to represent alleles or versions of a trait and are called the genotype. Phenotypes are the physical appearance the alleles.

Mendelian inheritance represents patterns in which a dominant allele masks or hides the phenotype of a recessive allele. Gregor Mendel, father of heredity, developed the Law of Segregation, principle states that the alleles for a trait separate when gametes are formed during meiosis, and the Law of Independent Assortment, alleles for different traits are distributed to sex cells (& offspring) independently of one another.

Non-mendelian inheritance patterns include: co-dominance or the expression of two dominant alleles (ex: human blood type ABO) , incomplete dominance or the phenotype is a blend of two alleles (ex: red flower crossed with white flower creates a pink flower) and sex-linked inheritance or gene expression shown more frequently in males while females are carriers ( ex: color blindness or hemophilia).

REPORTING CATEGORY

3

Biological Evolution & Classification

Evidence of Common Ancestry

Embryological

Development

Vestigial

Structures

DNA Evidence

Homologous Structures or

Analagous Structures

Common ancestry is determined by looking at similarities organism’s share among the fossil record, biogeography and the anatomical, molecular and developmental homologies of the organisms.

Fossil records are the preserved remains or impressions found in rock of organisms which lived in the past. The number of fossils and the layering of sediment where fossils are discovered give researcher information about the organisms. Older fossils are located at the bottom while newer fossil are located near the surface.

Biogeography explains the patterns of species distribution in a given location and studies the type and amount of organisms in a location.

Homologies are similar structures between parts of different species and looks at similarities in their anatomical structure or skeletal components, molecular or differences in DNA and amino acid sequence and the developmental stages such as embryology.

Adaptive Radiation

Divergent Evolution

Convergent Evolution

Coevolution

Natural Selection

Natural selection is a process where changes in a population occur from one generation to the next. These changes cause the organism with adaptations best suited for the environment to survive and pass on their genetic material to their offspring.

Adaptation is a process by which an organism’s structure, coloration or behavior offers an advantage to better survive in a given habitat. Examples of adaptations can be mimicry, symbiotic relationships or behaviors such as migration.

Biodiversity related to the variations among all living organisms. Diversity leads to survival for an organism if environmental changes are extreme. For example, plants tolerant to high salinity levels will survive if estuary forms at the end of a river near the Gulf of Mexico.

Classification Systems

Taxonomy is the science of classifying organisms into related groups. The Linnaean system names organism by their Genus and species. Organisms with the same genus name are related & have high number of similarities. Ex: Bull Frog Rana catesbeiana and Wood Frog Rana sylvatica.

The six kingdom system divides organisms two prokaryotic kingdoms:

Archaebacteria (ancient bacteria in harsh environments) and

Eubacteria (true bacteria) and

four eukaryotic kingdoms:

Animal (heterotrophic &moving)

Plant (autotrophic & stationary)

Fungi (heterotrophic decomposers) and

Protists (mostly unicellular aquatic organisms with either animal-like, plant-like or fungus-like characteristics).

Levels of Taxonomy: Domain, Kingdom, Phylum, Class, Order, Family, Genus & Species. Domains have the greatest diversity while species level is most specific.

Cladistics is the study of the classification of organisms based on the branchings of descendant lineages from a common ancestor. Phylogeny is the evolutionary development and history of a species or higher taxonomic grouping of organ or the evolutionary development of an organ or other part of an organism.

REPORTING CATEGORY

4

Biological Processes & Systems

Systems Interactions in Animals

Function: Regulation

Function:Nutrient Absorption

Function: Reproduction

Function: Defense

Human Body Systems can be divided into four functions groups: Regulation, Nutrient Absorption, Reproduction, and Defense.

The functions of regulation include interactions between the endocrine (hormones), excretory (liquid wastes) and Integumentary systems (skin, hair & nails).

The function of nutrient absorption includes interactions between the digestive (breakdown of food), respiratory (exchanges of oxygen & carbon dioxide), cardiovascular systems (aka circulatory system for transport).

Reproduction is directed by the reproductive system (production of gametes), however many other systems and functions in the body need to interact for reproduction to occur successfully such as the nervous (detect & respond to stimuli) and endocrine.

Defenses require interactions by any number of systems, depending on the type of defense that is taking place. Integumentary provide barrier while skeletal system (protection, support, blood formation & mineral storage) produces white blood cells. The thymus gland of the Immune (aka Lymphatic – fight infection) also produces white blood cells. The muscular system (provides movement) offers some protection from injury.

Systems Interactions in Plants

Function: Transport

Function: Reproduction

Function: Response

Transport in plants can include the movement of water and nutrients within individual cells, from cell to cell, and the transport of the sap within the xylem and phloem

Transport can include the:

plant roots (absorb water & nutrients), xylem (conduct water up),

phloem (move food up & down), stems (conduct water & nutrients ; support leaves),

leaves (make food with chloroplast by photosynthesis),

stoma or stomata (opening for gas exchange), guard cells (control opening & closing of stoma)

Reproduction in plants includes the flower with:

Petals (attract pollinators such as bees, birds, wasps)

Pistil aka carpel (female part of flower divided into stigma, style & ovary)

Stamen (male part of flower divided into anther & filament)

Seeds (created after pollination & fertilization)

Pollen (male gamete produced in the anther of the stamen)

Methods of transport of pollen include animals, wind and water.

Plants respond to the amount of light available (length of day), gravity and temperature.

REPORTING CATEGORY

5

Interdependence within Environmental Systems

Organism Interactions

Parasitism

Mutualism

Commensalism

Predation

Competition

Flow of Matter & Energy

Primary ecological succession is the changing sequence of communities from the first biological occupation of a place where previously there were no living beings. For example, the colonization and the following succession of communities on a bare rock.

Secondary ecological succession is the changing sequence of communities from the substitution of a community by a new one in a given place. For example, the ecological succession of the invasion of plants and animals in an abandoned crop or land.

Ecological succession is the gradual change in the ecosystems over time.

Primary Succession includes beginning with abiotic factors such as rock only. Lichens (algae-fungi symbiotic relationship) chemically weather rock into soils with added physical weathering from climate precipitation. Soils then gradually allow vegetation growth, animal movement into area followed by growth of shrubs and tree until stable ecosystem is attained (climax community).

Secondary succession begins with soil and some biotic conditions until climax community is attained. Disturbances such as: flood, drought, tornado, hurricane or wildfire can disrupt an ecosystem and create an ecological succession.

A population is a single species in an ecosystem while a community is a group of different species interacting within a small environment.

Symbolic Relationships- relationship between living organisms with at least one organism receiving benefits.

Parasitism (good- bad) Commensalism (good-nothing) Mutualism (good-good)

Community Interactions- relationships between species

Predator-Prey relationships (good-dead)

Competition (Two organism fighting for the same habitat requirements of: food, water, shelter or space)

Trophic levels - nutrition levels

Autotrophs (producers) - create own energy by photosynthesis (light energy to chemical energy) or chemosynthesis (chemical energy conversion)

Heterotrophs (consumers) - Primary, Secondary, Tertiary

Carnivores consume meat

Decomposers or Saprotrophs break down dead or decaying organisms by secreting enzymes

Detrivores consume dead and decaying matter

The Principles of Ecosystem Stability are:

1. Ecosystems dispose of waste and replenish nutrients by recycling all elements.

2. Ecosystems use sunlight as their source of energy.

3.Ecosystems maintain the size of a consumer population from overgrazing and other forms of overuse do not occur

4. Ecosystems maintain biodiversity.

Factors influencing ecosystem stability are biotic potential and environmental resistance (positive and negative factors of population growth -either abiotic or biotic, species diversity that is highly correlated with stability, as well as climate)

Stability of an ecosystem also needs to have a resistance to change such as:

Inertia - the resistance to change,

Resilience - the ability to recover from change,

Succession - the replacement of species by another.

Ecological Succession:

Change Population & Species Diversity

Environmental Change Impact

on Environmental Stability

Biology

STAAR Test

Review

Donna Sue Perkins

April 2012

Aquatic Biomes

Savannahs

Terrestrial Biomes

Coniferous Forest

Desert

Omnivores consume plants & meat

Herbivores consume plants

Punnett squares are graphic organizers used to predict the outcome of monohybrid and dihybrid crosses. Letters are used to represent alleles or versions of a trait and are called the genotype. Phenotypes are the physical appearance the alleles.