Proteins pt2

Question 1

Amino acid sequence determines

Answer 1

protein structure

Question 2

Proteins are polymers of

Answer 2

amino acid monomers

Question 3

Amino acids link by __________ _____ to form polypeptides

Answer 3

peptide bonds

Question 4

How are amino acids classified?

Answer 4

according to their R groups

Question 5

basic amino acids are

Answer 5

positively charged

Question 6

acidic amino acids are

Answer 6

negatively charged

Question 7

All types of amino acid R groups

Answer 7

basic, acidic, polar, hydrophobic

Question 8

The diversity of R groups result in

Answer 8

the wide range of functions carried out by proteins

Question 9

What is the primary structure?

Answer 9

The sequence in which the amino acids are synthesised into the polypeptide

Question 10

What results in regions of secondary structure?

Answer 10

Hydrogen bonding along the backbone of the protein strand

Question 11

Examples of secondary structures

Answer 11

alpha helices, parallel or anti parallel beta sheets, or turns

Question 12

When the polypeptide folds into a tertiary structure this conformation is stabilised by

Answer 12

interactions between R groups: hydrophobic interactions; ionic bond; LDFs; hydrogen bonds; disulfide bridges.

Question 13

Quaternary structure exists in proteins with

Answer 13

2 or more connected polypeptide subunits.

Question 14

What is a prosthetic group?

Answer 14

A non-protein unit tightly bound to a protein necessary for its function

Question 15

Interactions of the R groups can be influenced by

Answer 15

temperature and pH

Question 16

The ability of haemoglobin to bind to oxygen is dependent upon the

Answer 16

non-protein haem group

Question 17

The charges on acidic and basic R groups are affected by

Answer 17

pH

Question 18

Key component of basic R group

Answer 18

NH2

Question 19

Key component of acidic R group

Answer 19

COOH

Question 20

Key component of polar R group

Answer 20

OH,NH3,SH

Question 21

Key component of hydrophobic (non-polar) R group

Answer 21

Hydrocarbon

Question 22

What is a ligand?

Answer 22

A substance that can bind to a protein

Question 23

R groups not involved in protein folding can

Answer 23

allow binding to ligands

Question 24

What happens as a ligand binds to a protein binding site?

Answer 24

The conformation of the protein changes. This change in conformation causes a functional change in the protein

Question 25

Where do allosteric interactions occur?

Answer 25

between spacially distinct sites

Question 26

Many allosteric proteins consist of

Answer 26

multiple units (have quaternary structure)

Question 27

Allosteric proteins with multiple subunits show cooperativity in binding in which

Answer 27

changes in binding at one sub-unit alter the affinity of the remaining subunits

Question 28

Allosteric enzymes contain a second type of site called

Answer 28

an allosteric site

Question 29

What do modulators regulate?

Answer 29

The activity of the enzyme when they bind to the allosteric site

Question 30

Following the binding of the modulator, what happens?

Answer 30

The conformation of the protein changes and this alters the affinity of the active site for the substrate

Question 31

The binding and release of oxygen in haemoglobin shows

Answer 31

cooperativity

Question 32

The binding of a substrate molecule to one active site of an allosteric enzyme…

Answer 32

increases the affinity of the other active sites for binding of subsequent substrate molecules.

Question 33

The activity of allosteric enzymes can vary greatly with small changes in

Answer 33

substrate concentration.

Question 34

What do positive modulators do?

Answer 34

increase the enzyme’s affinity for the substrate

Question 35

What do negative modulators do?

Answer 35

reduces the enzymes affinity for the substrate

Question 36

Changes in binding of oxygen at one subunit

Answer 36

alter the affinity of the remaining subunits of oxygen

Question 37

What lowers the affinity of haemoglobin for oxygen so that the binding of oxygen is reduced

Answer 37

An increase in temperature or a decrease in pH

Question 38

What will reduced pH and increased temperature do to actively respiring tissue?

Answer 38

it will reduce the binding of oxygen to haemoglobin promoting increased oxygen delivery to tissue

Question 39

Adding a phosphate group adds

Answer 39

negative charges

Question 40

Ionic interactions in the unphosphorylated protein can be

Answer 40

disrupted and new ones added

Question 41

What do protein kinases do?

Answer 41

catalyse the transfer of a phosphate group to other proteins

Question 42

What do protein phosphatases do?

Answer 42

catalyse the reverse reaction (removes a phosphate group from a protein)