Proteins and Enzymes

Question 1

Polar covalent bond

Answer 1

electrons are drawn to one nucleus more than the other because on atom has a greater electronegativity

Question 2

Ionic bond

Answer 2

when one atom is so electronegative that it removes an electron from another atom to form an ionic bond

Question 3

isomer

Answer 3

molecules with the same chemical formula but atoms are arranged differently

Question 4

Structural isomer

Answer 4

differ in how their atoms are joined together

Question 5

Optical isomer

Answer 5

occur when a carbon atom has four different atoms or groups of atoms attached to it
- result from asymmetrical carbons

Question 6

function of genetic regulatory proteins

Answer 6

regulate when, how, and to what extent a gene is expressed

Question 7

structure of amino acid

Answer 7

1. Carbon
2. Amino group (H3N+)
3. Hydrogen
4. Carboxyl group (COO-)

Question 8

What two isometric forms exist in amino acids

Answer 8

D- amino acids (dextrose, right)
L- amino acids (levy, left) - found in organisms

Question 9

Three amino acids with special functions

Answer 9

Methionine
Proline
Cysteine

Question 10

Methionine amino acid

Answer 10

initiates chains of amino acids

Question 11

Proline amino acid

Answer 11

causes kinks in chains of amino acids

Question 12

Cysteine

Answer 12

links amino acid chains together

Question 13

Disulphide bridges

Answer 13

-SH group of cysteine react with another to form disulphides bridges
- common in extracellular proteins
= they will receive more stresses outside of the cells

Question 14

How do amino acids bond together

Answer 14

condensation reaction

Question 15

What link is produced by condensation reaction

Answer 15

peptide linkages

Question 16

Primary structure

Answer 16

sequence of amino acids

Question 17

Secondary structure

Answer 17

a helix
b pleated sheet

Question 18

Tertiary structure

Answer 18

folding results in macromolecule with specific three dimensional shape
- outer surface present functional groups that can interact with other molecules

Question 19

How is tertiary structure determined

Answer 19

Interactions of R groups
- Disulphide bridges
- Hydrogen bonds
- Aggregation of hydrophobic side chains
- van der Waals forces
- ionic bonds

Question 20

Quaternary structure

Answer 20

interactions of subunits by hydrophobic interactions, van Der Waals, ionic and hydrogen bonds

Question 21

How is specificity determined

Answer 21

shape and chemistry

Question 22

Conditions that affect secondary and tertiary structure

Answer 22

• High temp
• pH changes
• High conc of polar molecules
• Nonpolar substances

Question 23

Two forms of energy

Answer 23

Potential - stored
Kinetic - movement

Question 24

Anabolic reactions

Answer 24

molecules made from simple molecules
- energy required

Question 25

Catabolic reactions

Answer 25

molecules are broken down and energy is released

Question 26

First law of thermodynamics

Answer 26

energy is neither created or destroyed

Question 27

Second law of thermodynamics

Answer 27

energy is converted from one form to another, some of that energy becomes unavailable

Question 28

What is entropy

Answer 28

a measure of the disorder in a system

Question 29

ΔG = ΔH – TΔS

Answer 29

if ΔG is neg = energy released
if ΔG is pos = energy consumed

Question 30

What is an exergonic reaction

Answer 30

releases free energy (catabolic)
- complexity decreases

Question 31

What is an Endergonic reaction

Answer 31

Consume free energy (anabolic)
- complexity increases

Question 32

At chemical equilibrium

Answer 32

ΔG = 0

Question 33

how is ΔG related to equilibrium

Answer 33

the further towards completion the point of equilibrium is, the more free energy is released

Question 34

What mechanisms would an enzyme use to catalyse a reaction

Answer 34

• orientation
• physical strain
• chemical strain

Question 35

Induced fit

Answer 35

enzymes change shape when they bind to the substrate