1. AP Biology Discussion Notes
Wednesday 9/14/2016

2. Goals for Today: Be able to describe how polymers are broken & built
Be able to describe Protein structure & Function
Be able to describe enzyme structure and function.

3. 9/14 Question of the Day:
IDENTIFY the four Biomolecules?

4. Organic Chemistry - the chemistry of _________
All organic compounds contain: ____
BIOTIC
ABIOTIC
is the reverse true? give an example

5. The Molecules of Life
All living things are made up of four classes of large biological molecules: carbohydrates, lipids, proteins, and nucleic acids
Macromolecules are large molecules composed of thousands of covalently connected atoms
Molecular structure and function are inseparable

6. Macromolecules are polymers, built from monomers
A polymer is a long molecule consisting of many similar building blocks
These small building-block molecules are called monomers
Three of the four classes of life’s organic molecules are polymers
Carbohydrates
Proteins
Nucleic acids

7. The Synthesis and Breakdown of Polymers
A dehydration synthesis occurs when two monomers bond together through the loss of a water molecule
Polymers are disassembled to monomers by hydrolysis, a reaction that is essentially the reverse of the dehydration reaction

8. (a) Dehydration reaction: synthesizing a polymer
Figure 5.2a
(a) Dehydration reaction: synthesizing a polymer 1 2 3
Short polymer
Unlinked monomer
Dehydration removes a water molecule, forming a new bond.
Figure 5.2 The synthesis and breakdown of polymers. 1 2 3 4
Longer polymer

9. (b) Hydrolysis: breaking down a polymer
Figure 5.2b
(b) Hydrolysis: breaking down a polymer 1 2 3 4
Hydrolysis adds a water molecule, breaking a bond.
Figure 5.2 The synthesis and breakdown of polymers. 1 2 3

10. The Diversity of Polymers
Each cell has thousands of different macromolecules
Macromolecules vary among cells of an organism, between individuals, vary more within a species, and vary even more between species
An immense variety of polymers can be built from a small set of monomers
*Think alphabet & words HO

11. Characteristics of Proteins
Comes from the greek proteios, meaning first or primary
50% of the dry weight of each cell is protein - instrumental in almost everything organsims do.

12. Proteins
Proteins account for more than 50% of the dry mass of most cells
Protein functions include structural support, storage, transport, cellular communications, movement, and defense against foreign substances

13. Amino Acids - building blocks of proteins
Amine Group
Carboxyl Group
“ACID”
End
“AMINO”
End

14. Where do we get proteins or the building blocks of proteins?
Foods!
What kind of foods?
Comes from the greek proteios, meaning first or primary
50% of the dry weight of each cell is protein - instrumental in almost everything organsims do.

15. High Protein Foods

16. Jobs of Proteins Defense Storage Transport
Cellular communication/Coordination
Movement
Structural support
Speeding up chemical reactions
Comes from the greek proteios, meaning first or primary
50% of the dry weight of each cell is protein - instrumental in almost everything organsims do.

17. Enzymatic proteins Enzyme
Figure 5.15a
Enzymatic proteins
Function: Selective acceleration of chemical reactions
Example: Digestive enzymes catalyze the hydrolysis of bonds in food molecules.
Enzyme
Figure 5.15 An overview of protein functions.

18. Storage proteins Ovalbumin Amino acids for embryo
Figure 5.15b
Storage proteins
Function: Storage of amino acids
Examples: Casein, the protein of milk, is the major source of amino acids for baby mammals. Plants have storage proteins in their seeds. Ovalbumin is the protein of egg white, used as an amino acid source for the developing embryo.
Figure 5.15 An overview of protein functions.
Ovalbumin
Amino acids for embryo

19. Hormonal proteins Insulin secreted High blood sugar Normal blood sugar
Figure 5.15c
Hormonal proteins
Function: Coordination of an organism’s activities
Example: Insulin, a hormone secreted by the pancreas, causes other tissues to take up glucose, thus regulating blood sugar concentration
Figure 5.15 An overview of protein functions.
Insulin secreted
High blood sugar
Normal blood sugar

20. Contractile and motor proteins
Figure 5.15d
Contractile and motor proteins
Function: Movement
Examples: Motor proteins are responsible for the undulations of cilia and flagella. Actin and myosin proteins are responsible for the contraction of muscles.
Actin
Myosin
Figure 5.15 An overview of protein functions.
Muscle tissue
100 m

21. Defensive proteins Antibodies Virus Bacterium
Figure 5.15e
Defensive proteins
Function: Protection against disease
Example: Antibodies inactivate and help destroy viruses and bacteria.
Antibodies
Virus
Bacterium
Figure 5.15 An overview of protein functions.

22. Transport proteins Transport protein Cell membrane
Figure 5.15f
Transport proteins
Function: Transport of substances
Examples: Hemoglobin, the iron-containing protein of vertebrate blood, transports oxygen from the lungs to other parts of the body. Other proteins transport molecules across cell membranes.
Transport protein
Figure 5.15 An overview of protein functions.
Cell membrane

23. Figure 5.15g
Receptor proteins
Function: Response of cell to chemical stimuli
Example: Receptors built into the membrane of a nerve cell detect signaling molecules released by other nerve cells.
Receptor protein
Signaling molecules
Figure 5.15 An overview of protein functions.

24. Structural proteins Collagen Connective tissue 60 m Function: Support
Figure 5.15h
Structural proteins
Function: Support
Examples: Keratin is the protein of hair, horns, feathers, and other skin appendages. Insects and spiders use silk fibers to make their cocoons and webs, respectively. Collagen and elastin proteins provide a fibrous framework in animal connective tissues.
Collagen
Figure 5.15 An overview of protein functions.
Connective tissue
60 m

25. Enzymes -- protein catalysts
Catalyst - chemical agent that speeds up chemical reactions without being consumed by the reaction.
Let’s Draw one! 

26. Enzymes -- Metabolic Proteins
Substrate - what the enzyme acts on.
Active Site

27. Enzymes -- Metabolic Proteins
Active Site - place on the enzyme where the reaction takes place.
Active Site
Where the substrate binds

28. Enzymes -- Metabolic Proteins
This shows the “induced-fit model” of enzyme activity.
Each enzyme is very specific and only works on one or a few chemical reactions.
Active Site
*Structure & function are correlated at all levels of organization
Each enzyme has a unique shape which means it has a unique function!

29. How a CATABOLIC Enzyme Works

30. How an ANABOLIC Enzyme Works
Produc

31. What Enzymes Actually Do
Enzymes lower the “activation energy” of a reaction.
Enzymes lower the “activation energy” of a reaction.
The ΔG of the reaction does not change, but the rate of the reaction does.
The ΔG of the reaction does not change, but the rate of the reaction does.

32. anOTHER type of enzyme….

33. Allosteric Enzymes “Allo-” = “Other” site Allosteric site “-ster” =
Site/space
Other than active site!!!

34. Allosteric Enzymes “Enzymes might be too helpful!?
Well, not really, but when a chemical reaction doesn’t need to be done the allosteric site can function like an on/off switch to turn the enzyme “off”
Other
Site/space

35. Allosteric Enzymes
Competitive inhibitor – another chemical that competes with the substrate for active site
Other
Site/space

36. Allosteric Enzymes
Non-Competitive inhibitor – does NOT compete for active site. Binds to the allosteric site changing the shape of active site so substrate can’t bind.
Other
Site/space

37. Characteristics of Enzymes
•Are PROTEINS
•Are made of the elements:
•Are built of ________ ________
•They are reusable
•They have an ACTIVE SITE
•Two kinds: CATABOLIC and ANABOLIC
•Some are also ALLOSTERIC
Could catabolic/anabolic enzymes be allosteric? YES YES YES
Ask what proteins are made of (amino acid, CHON(s))
Ask if an allosteric enzyme can also be catabolic/anabolic – absolutely
All enzymes are either Catabolic or Anabolic (They help build or they help break), having an allosteric site is just an additional feature of some enzymes that allows for a binding site for a non-competitive inhibitor.

38. Characteristics of Enzymes So much good….
•They speed up reactions—sometimes as much as a million times!
•They lower the Ea of a reaction
They are physically flexible, and change shape when contacted
Explain what E sub a means – activation energy

39. What is this graph showing?
Ask students to talk to a neighbor and describe what is happening in the graph.

40. Characteristics of Enzymes …..comes with a price.
They are VERY specific to a particular substrate
They are VERY picky about pH and temperature
They can become “denatured” at pH and temperature extremes
Discuss what it means to be “denatured” and explain the loss of shape with a loss of organization – tie to them theme of emergent properties – when we lose the organization we lose the emergent properties.

41. Questions on enzymes?