10 - Nucleic Acids, Mitosis and Cancer

Question 1

What is a nucleotide made up of?

Answer 1

Phosphate group
Pentose sugar
Nitrogenous base

Question 2

How are nucleotides joined together?

Answer 2

Phosphate groups bond to sugar in the next nucleotide by phospohodiester bonds, strong covalent

Question 3

What is the sugar found in DNA nucleotides called?

Answer 3

Deoxyribose is the pentose sugar

Question 4

Describe the structure of DNA

Answer 4

Two polynucleotide chains, running anti-parallel, twisting to form a double helix.
Bases held together by H-bonds

Question 5

How is the structure of DNA related to it’s function?

Answer 5

It is stable - many H-bonds
Complementary base pairing
Compact
Has a precise genetic code

Question 6

Describe the structure of RNA

Answer 6

Ribose sugar

Single strand of polynucleotides

Question 7

What is the mechanism of DNA replication called?

Answer 7

Semi-conservative replication

Question 8

Describe semi-conservative replication

Answer 8

DNA helicase unwinds double helix
Each strand acts as a template
DNA nucleotides bind to templates via complementary base pairing
DNA polymerase joins new nucleotides together - phosphodiester bonds between nucleotides

Question 9

Describe the structure of ATP

Answer 9

Organic base adenine
Ribose sugar
Three phosphate groups

Question 10

Describe the synthesis of ATP

Answer 10

ADP + inorganic phosphate - condensation catalysed by ATP synthase

Question 11

Describe the breakdown of ATP

Answer 11

ATP hydrolase hydrolyses covalent bond between 2nd and third phosphate group, releasing energy.
ATP becomes ADP

Question 12

What is ATP used for?

Answer 12

Active transport - against conc. gradient
Exocytosis
Synthesis of substances
Movement (muscle cells only)
Activation of other substances