Lesson 10.2 - DNA replication

Question 1

By what method does DNA replicate?

Answer 1

Semi-conservative method

Question 2

What enzyme breaks down the hydrogen bonds between complementary bases in nucleotides, allowing DNA to unzip?

Answer 2

DNA helicase

Question 3

How do enzymes carry out a function?

Answer 3

Recognising and attaching to specific molecules or particular parts of molecules.

Question 4

How does DNA helicase work?

Answer 4

Unwinds and separates the two strands of DNA double helix. Travels along DNA backbone, catalysing reactions that break the hydrogen bonds between complementary base pairs as it reaches them.

Question 5

Role of DNA polymerase?

Answer 5

Catalyses the formation of phosphodiester bonds between nucleotides. Free nucleotides pair with newly exposed bases on template strands during ‘unzipping’.

Question 6

How do replication errors occur?

Answer 6

• Sequence of bases not always matched exactly, and incorrect sequence of bases may occur in the newly-copied strand.

Question 7

When do replication errors occur?

Answer 7

Spontaneously and randomly.

Question 8

What are replication errors?

Answer 8

Mutations

Question 9

What is the genetic code?

Answer 9

Proteins are the foundation for the different physical and biochemical characteristics of living things. They are made up of a sequence of amino acids, folded into complex structures. DNA must code for a sequence of amino acids.

Question 10

What is the code for base sequences?

Answer 10

Triplet code

Question 11

Three bases?

Answer 11

Codon

Question 12

What codes for an entire amino acid?

Answer 12

A gene

Question 13

How is genetic code universal?

Answer 13

All organisms use the same code.