3.9 Dna Replication And Genetic Code

Question 1

What first happened in semi-conservative replication

Answer 1

Double helix unwinds by the hydrogen bonds breaking done by dna helicase and now there are 2 separate strands

Question 2

What happens with free nucleotides in semi-conservative replication

Answer 2

They will pair up with the complementary bases on the exposed strands and new hydrogen bonds are formed

Question 3

What enzyme joins th new adjacent nucleotides together and through what bonds do they join in the final stage of semi-conservative replication

Answer 3

DNA polymerase joins the nucleotides through phosphodiester bonds

Question 4

Why is it called semi-conservative replication

Answer 4

The new dna molecule has 1 old strand and 1 new strand

Question 5

Where does the enzyme dna helicase stay

Answer 5

Travels along the dna back bone catalysing reactions that break the hydrogen bonds between the base pairs

Question 6

What is the genetic code

Answer 6

DNA must code for a sequence of amino acids which make up proteins

Question 7

What is the triplet code

Answer 7

A sequence of 3bases known as a codon and this codes for an amino acid
A complete sequence of these different codon will eventually code for an entire protein

Question 8

What is a gene

Answer 8

Section of dna that contains the complete sequence of bases that code for an entire protein

Question 9

What is the degenerate code

Answer 9

There are a lot more codons than amino acids so, many amino acids can be coded for by more than 1 codon

Question 10

How many different base triplets are possible

Answer 10

64

Question 11

What’s a start codon

Answer 11

Signals start of a sequence that codes for a protein

Question 12

What are stop codons

Answer 12

They signal the end of the sequence