Chapter 3-Protein Structure And Function

Front 1

Nonpolar R group

Back 1

Hydrophobic, do not form hydrogen bonds, coelesce in water.

Front 2

Polar R group

Back 2

Hydrophillic. Dissolve in water easily, form hydrogen bonds.

Front 3

monomers

Back 3

a molecular subunit with only one part, amino acid, nucleotide, or a sugar. When they bind (polymerize) together, they are called polymers (more than one part)

Front 4

Polymerization

Back 4

the process of linking monomers together. requires energy and is nonspontaneous. Done through condensation reactions, which release a water molecule. AKA dehydration reactions.

Front 5

Hydrolysis

Back 5

Reverse of Condensation. breaks polymers apart by adding water

Front 6

Oligopeptides

Back 6

A polypeptide consisting of less than 50 amino acids.

Front 7

Proteins

Back 7

A polypeptide consisting of more than 50 amino acids.

Front 8

polypeptide backbone characteristics

Back 8

-R group orientation
-Directionality
free amino group on the left is the N terminus and the free carboxyl group on the right is the c terminus
-Flexibility
single bonds on either side can rotate.

Front 9

Protein function

Back 9

-Catalysis-enzymes, speed up chemical reactions
-defense-antibodies
-movement-motor and contractile proteins
-signaling-cell to cell communication
-structure-define cell shape and comprise body structures
-transport-transport proteins

Front 10

Proteins Primary Structure

Back 10

Unique sequence of amino acids. the R group makes it unique, just one amino acid alteration can change the structure and function of the protein

Front 11

Secondary structure

Back 11

hydrogen bonds between the carbonyl group of one amino acid and the amine group of another makes this.

Front 12

tertiary structure

Back 12

interactions between r groups or between r groups and the polypeptide backbone.

Front 13

vane der waals reactions

Back 13

weak electrical interactions between hydrophobic side chains.

Front 14

covalent disulfide bonds

Back 14

form between sulfur containing r groups

Front 15

quaternary structure

Back 15

the bonding of two or more polypeptide subunits

Front 16

molecular chaperones

Back 16

specific proteins that help proteins fold. Many belong to a family of molecules called heat shock proteins. produced in high quantities after cells experience high temperatures, that make the proteins lose their tertiary structures, they help aid proteins in speeding up their folding into their normal shape after denaturation has occurred

Front 17

prions

Back 17

improperly folded normal proteins that are present in normal individuals. The only thing that is different in the protein is the folding, they can also induce normal proteins to go into an abnormal shape.

Front 18

catalysis

Back 18

acceleration of the rate of a chemical reaction due to a decrease in the free energy of the transition state, called the activation level.

Front 19

Activation energy

Back 19

the amount of energy required to initiate a chemical reaction; specifically, the energy required to reach the transition state.

Front 20

Enzyme functions

Back 20

1. bring reactants together in precise orientations
2. stabilize transition states.

Front 21

Active site

Back 21

on the enzyme, the substrates bind and react here.

Front 22

induced fit

Back 22

when many enzymes go under a conformational change when the substrates are bound to the active site.

Front 23

Enzyme catalysis has 3 steps:

Back 23

1. Initiation-substrates are precisely orientated as they bind to the active site.
2. Transition state faciliation-interactions between the substrate and active site r groups lower the activation energy
3. termination-reaction products are released from the enzyme

Front 24

cofactors

Back 24

Some enzymes require these to function normally. they are either metal ions or organic molecules called coenzymes

Front 25

competitive inhibition

Back 25

inhibition of an enzymes ability to catalyze a chemical reaction via a nonreactant molecule that competes with the substrates for access to the active site.

Front 26

allosteric regulation

Back 26

when a molecule causes a change in enzyme shape by binding to the enzyme at a location other than the active site. can activate or deactivate the enzyme.

Front 27

The rate of enzyme catalyzed reaction depends on

Back 27

1. substrate concentration
2. the enzymes intrinsic affinity for the substrate
3. temp
4. pH