Nucleic Acids

Question 1

What are individual nucleotides made up of?

Answer 1

• A phosphate group,
• A pentose sugar,
• A nitrogen-containing organic base.

Question 2

What is the bond formed between the deoxyribose sugar of one mononucleotide and the phosphate group of another called?

Answer 2

A phosphodiester bond

Question 3

What is a chain of nucleotides called?

Answer 3

A polynucleotide

Question 4

What is the pentose sugar called in DNA?

Answer 4

Deoxyribonucleic acid

Question 5

What are the bonds that form between the organic bases?

Answer 5

Hydrogen bonds

Question 6

Name two reasons why DNA is a stable molecule.

Answer 6

• The phosphodiester backbone protects the more chemically reactive organic bases inside the double helix,
• 2 or 3 hydrogen bonds hold the strands together

Question 7

Name 5 ways the structure of DNA is adapted to its function

Answer 7

• Stable structure,
• The hydrogen bonds can separate during replication,
• Large, carries large amounts of genetic information,
• Base pairs are protected by the phosphodiester backbone from chemical and physical forces,
• Base pairing allows DNA to replicate and transfer information by mRNA.

Question 8

What are the 2 stages in DNA replication?

Answer 8

Nuclear division and cytokinesis.

Question 9

What are the four requirements for semi-conservative replication?

Answer 9

• Nucleotide bases must be present,
• Both strands of DNA act as a template for the attachment of these nucleotides,
• The enzyme DNA polymerase,
• A source of chemical energy.

Question 10

What is the function of DNA helicase?

Answer 10

Breaks the hydrogen bonds between the base pairs in DNA.

Question 11

What is the function of DNA polymerase?

Answer 11

The free-nucleotides are joined together by a condensation reaction by DNA polymerase.

Question 12

What is the structure of ATP?

Answer 12

• Adenine,
• Ribose,
• Phosphates.

Question 13

What catalyses the reaction for ADP to ATP?

Answer 13

ATP synthase.

Question 14

Why is ATP a better immediate energy source compared to glucose?

Answer 14

• Each ATP releases small manageable amounts of energy,

- Provides immediate energy.

Question 15

What is the charge on the oxygen molecule in water?

Answer 15

Slight negative

Question 16

Why can water act as a buffer against sudden temperature changes?

Answer 16

It has a high specific heat capacity, it takes a lot of energy to heat water due to its hydrogen bonding.

Question 17

Where are inorganic ions found in an organism?

Answer 17

In the solution in the cytoplasm of cells and in body fluids.