Role Of Phosphorus In Biology

Question 1

Phosphorus is highly ( stable / reactive )

Answer 1

Reactive 💥

Question 2

Roles of phosphorus in the body (4)

Answer 2

• Control of protein activity (phosphorylation)
• A critical component of high energy molecules
• Form the backbone of DNA/RNA
• Used in phospholipid membranes

Question 3

The pH at which dissociation is 50% is known as…

Answer 3

pK

Question 4

Fully dissociated phosphoric acid (phosphate) is never found in the body. Why?

Answer 4

The required pH doesn’t exist within the cells

Question 5

Henderson-Hasselback Equation

Answer 5

pH = pK + log [A-]/[HA]

Question 6

Carboxylic acid + alcohol =

Answer 6

Ester + water

Question 7

Ester functional group general structure

Answer 7

R–COO–R

Question 8

Hydrogens from the hydroxyl group of a phosphate can be substituted with…

Answer 8

The R group from an alcohol

Question 9

Hydrogens from the hydroxyl group of a phosphate can be lost, resulting in…

Answer 9

A negative charge (up to -3 if no OH hydrogens have been substituted for R groups)

Question 10

Nucleic acids (nucleotides) are made up of which 3 basic components?

Answer 10

1. Base
2. Ribose sugar
3. Phosphate(s)

Question 11

A & G are known as…

Answer 11

Purine bases

Question 12

Purine bases have a heterocyclic…

Answer 12

Double ring structure

Question 13

Pyrimidine bases have heterocyclic…

Answer 13

Ring structure

Question 14

A nucleoside is a base plus…

Answer 14

Ribose sugar

Question 15

C, T and U are known as…

Answer 15

Pyrimidine bases

Question 16

The bond between a ribose sugar and the first phosphate is an…

Answer 16

Ester bond

Question 17

The bonds between subsequent phosphates attached to the first phosphate of a nucleotide are…

Answer 17

Anhydride bonds

Question 18

DNA must be stable, whereas RNA is…

Answer 18

Labile

Question 19

Nucleotides polymerise by…

Answer 19

Forming ester bonds between 5’ phosphate and 3’ hydroxyl

More specifically this is a phosphodiester bond

Question 20

RNA is less stable than DNA because as a single strand it is…

Answer 20

Less resistant to nucleophilic attack

Question 21

The presence of a hydroxyl group proximal to the phosphate in RNA enables…

Answer 21

Base hydrolysis

Question 22

4 reasons why the hydrolysis of ATP is energetically favourable…

Answer 22

1) Resonance stabilisation - electrons on terminal oxygens are more delocalised
2) Charge repulsion between the O- on adjacent phosphates
3) Solvation by water increases entropy
4) Enzyme catalysis lowers Ea

Question 23

NAD exists in which 2 forms?

Answer 23

Oxidised (NAD+) and Reduced (NADH) forms

Question 24

NAD is derived from…

Answer 24

Nicotinate (niacin)

Question 25

RNA needs to be labile so that…

Answer 25

It can function more effectively as a messenger