Proteins

Question 1

What is a protein?

Answer 1

A protein is a macromolecule consisting of monomers called amino acids. They arranged in particular structures and arrangements to allow specific functionality.

Question 2

Describe the broad structure of an amino acid.

Answer 2

Amino group (NH2), side chain/residue, carboxyl group (COOH)

Question 3

How many amino acids are there?

Answer 3

20

Question 4

What gives amino acids their specificity?

Answer 4

The residue side chain.

Question 5

Are amino acids chiral?

Answer 5

Yes- they have a carbon attached to four non-carbon other groups giving an asymmetric approach.

Question 6

What are the 7 types of amino acid?

Answer 6

Aliphatic 
Aromatic 
Sulfur
Basic 
Acidic 
Polar 
Miscellaneous

Question 7

What does the R-group of aliphatic amino acids contain?

Answer 7

Hydrocarbons

Question 8

What does the R-group of aromatic amino acids contain?

Answer 8

Benzene ring

Question 9

What does the R-group of sulphur amino acids contain?

Answer 9

Sulfur

Question 10

What does the R-group of basic amino acids contain?

Answer 10

NH group

Question 11

What does the R-group of acidic amino acids contain?

Answer 11

COOH group

Question 12

What does the R-group of polar amino acids contain?

Answer 12

Electronegativity

Question 13

What does the R-group of miscellaneous amino acids contain?

Answer 13

Does not fit with any other.

Question 14

What is the primary structure?

Answer 14

The initial sequence of amino acids in the polypeptide chain.

Question 15

What is the secondary structure?

Answer 15

The initial chain of AA folds to form structures called alpha-helices and beta-pleated sheets, held by hydrogen bonding.

Question 16

How is secondary structure stabilised?

Answer 16

Hydrogen bonding.

Question 17

How is tertiary structure established?

Answer 17

Tertiary structure results through the reactions of functional groups in the residue chains of amino acids, These include ionic bonds, further hydrogen bonds, hydrophobic interactions, VDW forces, hydrophilic reactions and disulfide bridges.

Question 18

How does tertiary structure occur?

Answer 18

Quarternary structure occurs when there are multiple chains interacting with each other.

Question 19

What is denaturation?

Answer 19

Denaturation occurs when the bonds in the protein are broken and the functionality is lost.

Question 20

Why are the bonds in the primary structure usually not broken in denaturation?

Answer 20

Strong peptide bonds.

Question 21

What is protein conjugation?

Answer 21

Reversible combination of proteins and factors.

Question 22

What are glycoproteins?

Answer 22

Proteins that are covalently attached to a carbohydrate factor.

Question 23

How are glycoproteins formed?

Answer 23

The carbohydrate attaches through a post-translational modification called glycosylation whereby a sugar molecule binds via an amino acid to the protein.

Question 24

What are lipoproteins?

Answer 24

Proteins that are covalently or non-covalently attached to fats.

Question 25

What are metalloproteins?

Answer 25

Proteins that are ionically attached to metals. One third of body proteins require a metal cofactor for function.

Question 26

What is co-operativity?

Answer 26

Co-operativity occurs when the shape of one protein sub-unit is altered by the substrate or some other molecule so as to alter the affinity of a neighbouring subunit and change its shape. (Eg. haemoglobin).

Question 27

What are globular proteins?

Answer 27

Storage / enzymes / hormones / transporters / structural

Question 28

What is the pathology of globular proteins?

Answer 28

Myeloma

Question 29

What are fibrous proteins?

Answer 29

Muscle fibres / connective tissue

Question 30

What is the pathology of fibrous proteins?

Answer 30

Scurvy.

Question 31

What are membranous proteins?

Answer 31

Membrane transporters / membrane enzymes / cell adhesion molecules

Question 32

What is the pathology of membranous proteins?

Answer 32

Familial hypercholesterolaemia