Nucleotides

Question 1

Does a nucleotide have a phosphate group?

Answer 1

Yes

Question 2

Does a nucleoside have a phosphate group?

Answer 2

No, it is inert

Question 3

What components make up a nucleotide structure?

Answer 3

Pentose sugar
- either aldehyde or beta-furanose ring

Nitrogenous base
- either pyrimidine (C, T, U) or purine (A, G)

Phosphate group
- attached to 5’ end of the pentose sugar

Question 4

What is the role of nucleic acids as energy sources?

Answer 4

ATP
- ester bonds between 5’ on pentose sugar and 1st phosphate
- anhydride bonds between phosphate groups
When the bonds are broken, energy is produced.
Energy efficient process that occurs in the mitochondria

Question 5

What is the role of nucleic acids as metabolic intermediates?

Answer 5

To buffer the build up of toxic metabolites (as these may lead to abnormalities)

Question 6

What is the role of nucleic acids as a source of genetic information?

Answer 6

A-T pairing has 2 hydrogen bonds
G-C pairing has 3 hydrogen bonds

Hydrogen bonds hold base pairs together

Question 7

What is the role of nucleic acids?

Answer 7

• to store genetic information and enable protein production

RNA

• U replaces T and binds to A
• singles stranded

DNA

• T binds to A
• double stranded

Question 8

What are the 5 functions of nucleic acids?

Answer 8

• energy currency
• chemical signalling
• structural integrity
• metabolic intermediates
• transmission of genetic information

Question 9

What type of reactions are cofactors used in?

Answer 9

Enzymatic

Question 10

What are coenzymes also known as?

Answer 10

Organic carrier molecules

Question 11

Name two sources of cofactors/ coenzymes

Answer 11

Vitamin B3 and B5

Minerals, such as magnesium and calcium

Question 12

What aspect of the structure of a nucleic acids make them suitable cofactors?

Answer 12

Side chain

Question 13

What do nucleic acids initiate when they are acting as signalling molecules?

Answer 13

Signalling cascades

Question 14

Define autocrine

Answer 14

A cell-produced signalling molecules that has an effect on the cell in which it was produced
Provides feedback to the cell it acts upon
Useful for self-regulation
Initiates intracellular signalling

Question 15

Define paracrine

Answer 15

The secretion (usually a hormone) binds to a receptor on another cell
Allows cell to cell communication
Occurs locally in tissues

Question 16

Define endocrine

Answer 16

The signalling molecule is transported out of the cell and into the circulatory system, where it is transported around the body until it binds to an appropriate receptor

Question 17

Name a type of signalling that is an example of autocrine, paracrine and endocrine

Answer 17

Nerve signalling

Question 18

How many rings does a pyrimidine base have?

Answer 18

1

Question 19

How many rings does a purine base have?

Answer 19

2

Question 20

What is the structure of ATP?

Answer 20

ATP is a nucleotide that consists of three main structures: the nitrogenous base, adenine; the sugar, ribose; and a chain of three phosphate groups bound to ribose.