Unit 1.2 (2) - amino acid structures + protein conformations

Question 1

Acidic (negatively charged) structure of amino acid?

Answer 1

are POLAR
have extra carboxylic acid group (COOH-)

Question 2

Basic (positively charged)

Answer 2

Have extra amine group (NH2)

Question 3

Polar amino acids

Answer 3

hydrophic groups such as
C=O (CARBONYL)
OH (HYDROXYL)
NH ( AMINE )

Question 4

Hydrophobic (Non-polar)

Answer 4

contains long hydrocarbon chains (pure hydrocarbon alkyl groups)
benzene rings

Question 5

What is the secondary structure of a protein, and what does it result in

Answer 5

hydrogen bonds along the backbone (gives 3d shape)
- results in:
alpha helices
beta sheets
turns

Question 6

What is the tertiary structure of protein?

Answer 6

hydrogen bonds
disulphide bridges
LDF
ionic bonds

Question 7

Quaternary structure?

Answer 7

Two or more polypeptide chains aggregated into one functional macromolecule:
e.g. haemoglobin

Question 8

Prosthetic group?

Answer 8

Non protein structure (that strongly bound to a polypeptide unit)

Question 9

Ligand?

Answer 9

substance that can bind to a protein

Question 10

Allosteric enzymes

Answer 10

certain substances called modulators that bind to allosteric site and bring about conformational change

Question 11

positive modulation

Answer 11

modulator that enhances affinity of active site for substrate ( so activates the enzyme)

Question 12

negative modulation

Answer 12

modulator that reduces affinity of active site for substrate ( so inhibits the enzyme)

Question 13

co-operativity in haemoglobin

Answer 13

after first oxygen binds to first haem group from one subunit , the conformation changes which forces adjacent subunits to also change conformation

Question 14

what do ATPases do

Answer 14

hydrolyse ATP

Question 15

ATP synthase?

Answer 15

enzymes found in mitochondria and chloroplasts and usually
harnesses a proton (H+ ion) gradient to regenerate ATP