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These are the major carbohydrates used for energy
Massive polymers of sugars are called "polysaccharides"
Glucose polymers have two main functions in organisms
Hexose sugars are the most "famous" monosaccharides
Three kinds: Glucose, Galactose, & Fructose
They are typically shown as carbon rings.
Combine 2 by dehydration synthesis, and you get a "disaccharide" (What are their molecular formulas?)
Glucose + Glucose = Maltose ("Malt sugar")
Glucose + Fructose = Sucrose ("Table sugar")
Glucose + Galactose = Lactose ("Milk sugar")
Cellulose is the major component of plant-like cell walls.
The difference between starch and cellulose is in the linkages between glucose units.
Starch = alpha linked. Cellulose = beta linked
Polysaccharides are great for short term storing of energy.
In plants, amylose ("starch") is the major energy storage polysaccharide.
Animals use glycogen for energy storage
Herbivores need to digest cellulose.
Animals lack the enzymes necessary to break beta linkages
Several strategies are employed.
Chitin = a modified polysaccharide.
Used in fungi cell walls, arthropod exoskeletons, and dissolving stitches!
Peptidoglycan = another modified polysaccharide. Used in bacterial cell walls
The most famous wood-eater of the animal kingdom has a symbiotic relationship with a protist.
In exchange for a place to live (the termite gut), the protist does the cellulose digestion
Caecophores like bunnies have an expanded lower GI tract. Food can not be regurgitated, but there is still a way to put partially digested cellulose back in to the animal...
Ruminants like cows have a vastly expanded upper GI tract. The action of bacteria, and continual regurgitation and chewing of "cud" leads to the digestion of cellulose
Because of the diversity of amino acids, proteins have very complex 3-D structures.
Generally, we can consider 4 levels of protein structure:
What it is:
Regular, repeating 3D structures found in all polypeptide chains.
What it is:
The sequence of amino acids in one polypeptide chain
How it happens:
Hydrogen bonding between atoms in the CN backbone of the polypeptide (no R-groups involved)
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids
How it happens:
Peptide bonds between amino acids.
How does the cell "know" the order of amino acids?
Why do all proteins have similar secondary structures?
Chains of amino acids have a directionality, with an amino end ("N-terminus") & a carboxyl end ("C-terminus")
What it is:
The specific 3D shape of any protein that is made of more than one polypeptide chain (many are).
The only "optional" level of structure.
What it is:
The specific 3D shape of a particular polypeptide chain (aka the "conformation")
How it happens:
Interactions between R-group atoms with other R-groups and the local environments of the cell
How it happens:
The overall structure when multiple chains form a functional protein.
Why do some proteins consist of more than 1 polypeptide chain?
What kinds of interactions can occur to determine tertiary structure?
Sickle cell anemia: One example of the relationship between protein structure and organismal physiology (not the only one, by any means!)
What do proteins do?
Generally speaking: Proteins are responsible for all life activities of the cell (and by extension, the organism, population, etc.)
Your text gives a pretty good overview:
...or how to make a hairless cat (and every other living thing)
This is Hemoglobin!
It carries oxygen in your red blood cells
This change in the structure of hemoglobin affects the function.
Sickle-cell hemoglobin gets clumpy, and the red blood cells change shape.
They don't carry as much oxygen, and get stuck in blood vessels.
Sickle-cell anemic people die at a young age from the disease.
Some unlucky folks have a mutation that results in valine (hydrophobic) replacing glutamic acid (hydrophilic) in the beta chains of hemoglobin
Builds more complex molecules from smaller ones by removing 2 H & 1 O, and replacing it with a bond.
Water is produced!
Builds complexity ("anabolic")
Requires energy ("endergonic") & enzymes (more later)
Except for lipids, macromolecules exist in two forms
The movement between monomers and polymers is facilitated by adding/removing water.
There is a direct relationship between a protein's conformation and its function.
If the conformation is altered, the function of the protein will also be altered.
Denaturation: Change in the structure of a protein.
Denatured proteins do not work well (if at all).
What sorts of conditions can denature proteins? Why?
Reverse of dehydration synthesis
-lysis = "breaking"
Water is needed!
Reduces complexity ("catabolic")
Releases energy ("exergonic")
Enzymes still required!
Because of their complexity, studying protein structure & function ("proteomics") can be overwhelming.
(FREE!) Computer modeling software is frequently used to help visualize important structural aspects.
(a) & (b): two different views of the lysozyme protein
By only focusing on the interacting elements of the flu virus and an antibody, scientists can better understand these interactions
Things to focus on:
1. Structure & Function 2. Atoms Needed
3. Monomer 4. Polymer
It's easy to get confused!
Don't hesitate to ask questions!!!
While similar in structure, there are a few key differences which lead to major differences in function.
Pentose:
Bases:
Strands
DNA serves 2 functions in all life on Earth:
1. Stores information about the primary structure of proteins, and the sequences of RNA molecules.
2. Is heritable.
The most important biological discovery of the 20th century (and arguably, the 2nd most important ever).
Watson & Crick - published the paper
Wilkins & Franklin - did the X-Ray diffraction work
Some controversy about ethics of Watson & Crick.
Nobel Prize (1962)- Watson, Crick, & Wilkins (Franklin was dead)
DNA Structure:
RNA serves many functions for life:
1. Transmits and translates DNA information into protein.
2. Many enzymatic and regulatory functions.
3. 1 kind of DNA, ~15 types of known RNA at current (3 main types)
Turns out it is MUCH more interesting than DNA is.
RNA Structure:
How are the molecules of biological systems constructed?
Why are particular groups of molecules needed in biological systems?
How do the interactions of biological molecules lead to the emergence of life functions?
Identify the structures of the monomers and polymers of the four major classes of macromolecules.
Diagram the synthesis and hydrolysis of carbohydrates and polypeptides.
Explain the biological functions of all of the molecules discussed in this presentation.
Explain the emergence of all four levels of protein structure.
Describe the role of general role of nucleic acids in living systems.