Nucleic Acids

Question 1

What are the differences between nucleotides and nucleosides?

Answer 1

Nucleotides HAVE a phosphate group

Nucleosides do NOT have a phosphate group. They are targets for kinase enzymes (which add phosphate groups)!

Question 2

Examples of nucleic acids?

Answer 2

DNA + RNA
ATP
Coenzyme A
NAD + FAD + NADP (cofactors)

Question 3

Differences between RNA and DNA?

Answer 3

DNA - deoxyribose (OH / H)
has had an oxygen taken away!

RNA - ribose (OH /OH)
has a hydroxyl group on 2 prime carbon, so an additional oxygen! This makes it MORE reactive + therefore less stable.

Question 4

Why is ATP energy rich?

Answer 4

Due to the presence of phosphate groups that are REALLY reactive!

Question 5

If nucleic acids can be energy sources, what kind of foods do we need to eat to INCREASE our energy intake?

Answer 5

Carbohydrate - to make ribose / sugars

Foods that contain phosphorous eg. spinach / leguminous plants which are a source of nitrogen (as well as proteins)

Question 6

During a 2 step reaction (where ATP is hydrolysed to ADP + Pi), what is the role of a phosphate containing group?

Answer 6

To donate a phosphoryl group

Question 7

Co-enzyme A is a primary source for which of the following processes?

Answer 7

Fatty Acid Synthesis

Question 8

Co-enzyme A is generated in the mitochondria by which of the following processes?

Answer 8

B-oxidation of fatty acids

Question 9

The primary job of NAD+ and FAD+ is to…

Answer 9

Accept hydrogens and transport them to the inner membrane of the mitochondria

Question 10

What are properties of cAMP?

Answer 10

Intracellular signalling molecule
Co-factor for Protein Kinase A
Generated by Adenylyl Cyclase
Acts as a neurotransmitter

Question 11

Purines are metabolised to Allantoin and excreted in the urine and faeces, however dysfunction of Adenosine Deaminase (1st step in metabolism) can result in which of the following?

Answer 11

Accumulation of Adenosine and appearance of Adenosine Deaminase Deficiency!

Question 12

Methylmalonyl- semi aldehyde is an intermediate of Pyrimidine metabolism.
Which amino acids can also be metabolised to this intermediate?

Answer 12

Isoleucine + Valine

Question 13

What kind of bond links deoxy-nucleotides together to form DNA?

Answer 13

Phosphodiester Bond

Question 14

Why is a nucleotide pairing in DNA of G and C MORE thermodynamically stable than an A and T pairing?

Answer 14

A and T only form 2 hydrogen bonds whereas G and C form 3 hydrogen bonds!

Question 15

Which reactive group is ESSENTIAL to the functioning of Co-enzyme A?

Answer 15

Thiol (SH)

Question 16

Nucleic acids are composed of a …, a … ring and a … group.

Answer 16

Nitrogenous base
Furanose
Phosphoryl

Question 17

ATP can be used to generate energy, what is the best way of doing this?

Answer 17

Donation of a pyrophosphoryl, phosphoryl or adenylyl group

Question 18

Acetyl Co A is important for which of the following processes?

Answer 18

Fatty acid biosynthesis
B-oxidation of fatty acids
Krebs cycle
Transport of fatty acids into the mitochondria