Proteins

Question 1

How many amino acids are there?

Answer 1

20

Question 2

What dictates a proteins function

Answer 2

Order of amino acids the way they fold

Question 3

What examples are there of proteins?

Answer 3

All enzymes
All antibodies
Haemoglobin

Question 4

What makes up an amino acid?

Answer 4

An anime group (NH2)
A CH in the middle
A variable group
A carboxyl group (COOH)

Question 5

How can you denote the variable group in amino acids?

Answer 5

With the letter R

Question 6

What bond is formed between 2 amino acids?

Answer 6

Peptide bond

Question 7

Describe how a dipeptide is formed

Answer 7

The amine group from 1 amino acid lines up with the carboxyl group from the other amino acid
The OH in the carboxyl group joins with a H in the amine group to form water
The N and C now can form another bond with each other (peptide bond)
This is a condensation reaction.

Question 8

What is primary structure?

Answer 8

It is the order the amino acids join up forming a polypeptide
1000s of amino acids can join up

Question 9

Where are polypeptides made?

Answer 9

Ribosomes and rough ER

Question 10

What is secondary structure?

Answer 10

How the chain folds up on itself

Question 11

What are the 2 secondary structures?

Answer 11

Alpha helix

Beta pleated sheet

Question 12

Describe the bonding in secondary structure

Answer 12

Hydrogen bonds hold them in position

Individually they are weak but there are lots of them it is strong

Question 13

What is tertiary structure?

Answer 13

How the polypeptide chain fold up on itself again

More complex shapes are made

Question 14

What are the 4 bonds in tertiary structure (strongest to weakest)

Answer 14

Disulfide bond/bridge
Ionic bonds
Hydrogen bonds
Hydrophobic/hydrophilic interaction

Question 15

Describe disulfide bonds (tertiary structure)

Answer 15

Adjacent cysteine amino acids form strong covalent bonds between sulfur

Question 16

How do you break a disulfide bond?

Answer 16

Using a reducing agent

Question 17

Describe ionic bonding (tertiary structure)

Answer 17

Forms between ionised amine and carboxyl groups

Question 18

How do you break the ionic bonds in tertiary structure?

Answer 18

Extreme pH

Question 19

Describe hydrogen bonding in tertiary structure

Answer 19

Forms between delta- oxygen and delta+ hydrogen

Question 20

Describe hydrophilic/hydrophobic interaction (tertiary structure)

Answer 20

Between non polar R groups
Hydrophilic go towards water (outside)
Hydrophobic go away from water (inside)

Question 21

Describe quaternary structure

Answer 21

More than 1 polypeptide joined together

Any bonds used in tertiary structure can be used

Question 22

What is a conjugated protein?

Answer 22

A protein that has a non-protein prosthetic group

Question 23

Which 3 proteins are globular?

Answer 23

Haemoglobin
Insulin
Enzymes eg catalase

Question 24

Which 3 proteins are fibrous?

Answer 24

Collagen
Keratin
Elastin

Question 25

What is the structure of haemoglobin?

Answer 25

4 chains | Contains a prosthetic haem group that contain Fe2+ ions

Question 26

What are the properties of haemoglobin?

Answer 26

Soluble | Haem group works reversibly with oxygen

Question 27

What is the function of haemoglobin?

Answer 27

Combines with oxygen/carbon dioxide and transports it in red blood cells

Question 28

Structure, properties and function of collagen

Answer 28

3 chains Tensile strength/insoluble Part of tendons, skin and cartilage

Question 29

Structure, properties and function of keratin

Answer 29

2 chains, disulfide bonds Insoluble, inflexible/strong Waterproofs cells

Question 30

Structure of insulin

Answer 30

81 amino acids | 2 chains held together by disulfide bonds

Question 31

Properties of insulin

Answer 31

Soluble | Has polar groups

Question 32

Function of insulin

Answer 32

Regulates blood glucose concentration

Question 33

Structure of enzymes eg catalase

Answer 33

2000 amino acids 4 chains Has prosthetic haem group containing Fe2+ ions

Question 34

Properties of enzymes eg catalase

Answer 34

Soluble

Question 35

Function of enzymes eg catalase

Answer 35

Breaks down hydrogen peroxide quickly

Question 36

Structure, properties and function of elastin

Answer 36

Fibrous Stretches and recoils, insoluble Blood vessels and alveoli contain elastin

Question 37

What makes proteins soluble?

Answer 37

Having hydrophilic/hydrophobic parts

Question 38

What are the properties of fibrous proteins?

Answer 38

Insoluble Strong Unreactive Have structural roles

Question 39

What is the difference between tertiary and quaternary

Answer 39

Quaternary includes other polypeptide chains and prosthetic groups

Question 40

What are the properties of globular proteins?

Answer 40

Compact Soluble Have metabolic roles