Nuecleosides and Nucleotides

Question 1

What biochemical processes are nucleotides involved in?

Answer 1

• Cellular energy exchanges (ATP, ADP)
• Coenzymes (NAD, FAD, CoA)
• Second messengers (cAMP)

Question 2

What are nucleotides?

Answer 2

Monomeric units from which nucleic acids are produced

• Base + sugar + phosphate
• DNA - Deoxyribonucleotide
• RNA - Ribonucleotide

Question 3

What types of nucleic acid are there and what are their functions?

Answer 3

1. Deoxyribonucleic acid
2. Ribonucleic acid

Functions:

• Direct synthesis of proteins
• Transmit genetic information

Question 4

What types of bases can be found in nucleic acids?

Answer 4

• Purine

- Pyrimidine

Question 5

Which bases are purine bases?

Answer 5

• Adenine

- Guanine

Question 6

Which bases are pyrimidine bases?

Answer 6

• Cytosine
• Thymine
• Uracil

Question 7

Which sugars are found in RNA and DNA?

Answer 7

RNA - Ribose sugar

DNA - Deoxyribose sugar

Question 8

What are nucleosides?

Answer 8

Same as nucleotides but no phosphate group present: base + sugar only

• Ribonucleoside - Ribose sugar
• Deoxyribonucleoside - Deoxyribose sugar

Question 9

What is ATP and where is it produced?

Answer 9

• It is the main biological energy store

- It is produced in the mitochondria

Question 10

What is cyclic AMP?

Answer 10

Second messenger in action of many hormones

Question 11

What is ATP catalysed by?

Answer 11

Adenyl cyclase in the presence of magnesium ions

Question 12

What is cAMP catalysed by?

Answer 12

Phosphodiesterase in the presence of magnesium ions

Question 13

How does cAMP act as a second messenger?

Answer 13

1. Hormone binds to receptor in plasma membrane of cell
2. Adenyl cyclase stimulated
3. Increase adenyl cyclase activity leads to increased cAMP inside cell
4. cAMP acts inside cell to alter rate of one or more processes