Unit 1: Topic Three

Question 1

What are some of the structures that make up an amino acid?

Answer 1

Amino group: attached to the central carbon(NH3)
Central (a) carbon: has a R group, hyrdogen atom, carbon and amino group attched.
Carboxyl group: CO2
R group: functional group that varies between the 20 amino acids

Question 2

How are amino acids linked to make peptides?

Answer 2

Through peptide bonds between amino acids(Carboxyl group attched to the amino group), that form through dehydration.

Question 3

N- terminus:

Answer 3

Peptide chain always starts with a N-terminus (amino group).

Question 4

C-terminus:

Answer 4

Peptide chain always ends with a C-terminus(carboxyl group).

Question 5

Central carbons:

Answer 5

Always have a functional group attched.

Question 6

Functional groups can either be ______________ or ________________.

Answer 6

Hydrophilic(water loving).
Hydrophobic(water hating).

Question 7

Hydrophilic:

Answer 7

Contians hydrogen bonds(weak, polar, non covalent). Has a O-O or O-H and possibily a charge

Question 8

Hydrophobic:

Answer 8

Does not contain hydrogen bonds(non-polar). Has C-C or C-H.

Question 9

What is a peptide?

Answer 9

Polymer of an amino acid.

Question 10

What is a polypeptide?

Answer 10

More then 10 amino acids joined together.

Question 11

What is a protien?

Answer 11

Polypeptides folded over itself to mold a 3D shape, created by 3 structures( a fourth for some protiens).

Question 12

1st degree (Primary Structure):

Answer 12

Polypeptide sequence of amino acids that are connected by peptides.

Question 13

2nd degree (Secondary Structure):

Answer 13

1) Helices- primary structure folded into a helix, and stabilized by hydrogen bonds between the main chain( C=O…..H-N- ).
2) Sheets: primary structure folded into sheets, and stabilized by hydrogen bonds between the main chain.

Question 14

3rd degree ( Tertariary structure ):

Answer 14

Secondary structure folded into a 3D shape, due to multiple levels of interaction between R groups-Hydrogen bonds, ionic interactions, van deer wals interactions, covalent bonds (disulfide) between 2 cysteines.

Question 15

4th degree ( Quatranery Structure):

Answer 15

When a protien is made up of multiple polypeptide chains each folded into a 3D structure.

Question 16

Naming a 4th degree protien:
Subunits-
1=
2=
3=
4=
5=
6=

Answer 16

Homo
Dimer
Trimer
Tetramer
Pentamer
Hexamer.

Question 17

When a quatranary structure has the same subunits ______________, when it has different subunits.

Answer 17

Homo
Hetero

Question 18

Activation energy(Ea)

Answer 18

Energy that destabilizes bonds in the reactants and forms bonds in the products. The enrgy barrier that must be overcome for a reactant to take place.

Question 19

Transition state:

Answer 19

Top of the curve- Point where bonds are breaking and forming.

Question 20

Name 3 ways to speed up a chemical reaction:

Answer 20

1. Increase the temp(increases reactant energy during collision)
2. Increase the concentration of reactants( collide with eachother more often).
3. Add a catalyst (Enzyme -protien catalyst. ribozyme-RNA catalyst)

Question 21

Enzymes decrease the_________ and do not change the ___________ .

Answer 21

Ea
deltaG(free energy change)

Question 22

Name 2 ways enzymes reduce Ea:

Answer 22

1) Enzyme structure: large molecule made up of folded polypeptide chains to create a very specific 3D structure.
2) Active site: Region that reacts with a specific substrate.

Question 23

Induced fit model:

Answer 23

The ES complex forces reactants into the transition state.

Question 24

ES:

Answer 24

Enzyme-substrate complex, created when a subsrate binds to the active site of a enzyme.

Question 25

What happens to an enzyme after a reaction is complete?

Answer 25

The enzyme changes back into its originak form and is used in another reaction.

Question 26

Name 3 ways enzymes help form the transition state:

Answer 26

1) Brings reacting molecules closer together in the correct orientation. 2) Charge interactions, stabilize the transition state through ionic interactions with charger R groups. 3) Distort or strain molecules.

Question 27

Enzyme Kenetics:

Answer 27

The rate of an enxyme reaction.

Question 28

Rate depends on:

Answer 28

1) Temp 2) pH 3) Concentration of Enzyme 4) Concentration of the reactants.

Question 29

Concentration of the enzyme:

Answer 29

Increase the enzyme= the rate of reaction to a certian point wher it reaches a saturation point. can also be regulated by adding inhibitors/activaters.

Question 30

pH effect on rate of reaction:

Answer 30

Every enzyme has a different optimal pH, the point at which the pH has not made the protien denature(change shape through h-bonds and ionic interactions)

Question 31

Temperatures effect on rate of reaction:

Answer 31

The higher the temp the better until the temp is too high and denatures the protien.

Question 32

What is a reversible competitive inhibitor?

Answer 32

Competes with the substrate for the active site, when it wins blocks the substrate from binding. Whichever molecule has a higher concentration wins.

Question 33

What is a reversible non-competitive inhibitor?

Answer 33

Not chemically like a substrate , binds away from the active site to change the overall shape of the enzyme which decreases the affinity for the substrate.

Question 34

V max with a ___________ inhibitor reaches the same level without the inhibitor and a ___________ inhibitor does not.

Answer 34

Competitive Non competitive

Question 35

What is a regulatory allosteric enzyme?

Answer 35

Control the rate of the entire pathway, and have a quatranary structure.

Question 36

Allosteric activators:

Answer 36

Bind to enzyme, change shape to a move active form.

Question 37

Allosteric inhibitors:

Answer 37

Bind to enzyme, change shape to a less active form. Final product pathway inhibits enzyme early in the pathway(Feedback inhibition).