The genetic code

Question 1

What is DNA?

Answer 1

Genetic material within all cells, must be able to carry instructions to produce proteins

Question 2

How does DNA produce proteins?

Answer 2

DNA codes for sequence of amino acids, which are them assembled into proteins

Question 3

How many important features does the genetic code have?

Answer 3

4

Question 4

What are the 4 features of the genetic code?

Answer 4

Universal, triplet code, non-overlapping, degenerate

Question 5

Define universal:

Answer 5

Means its same in all organisms (e.g. ATG codes for methionine in all organisms)

Question 6

What does a simple triplet code mean in the base sequence?

Answer 6

Sequence of 3 bases is called a codon - codons code for 1 specific amino acid

Question 7

What does non-overlapping mean?

Answer 7

Each nucleotide base only contributes towards 1 codon - its only read once

Question 8

What does degenerate mean?

Answer 8

Theres more than 1 codon for some amino acids (e.g. both GGA and GGG code for glycine)

However, there is only 1 amino acid for each codon

Question 9

Why are a minimum of 20 code words needed?

Answer 9

Since theres 20 amino acids

Question 10

How many codons can be produced from a 1-base codon?

Answer 10

4 (A, T, G, C)

Question 11

How many codons can be produced from a 2-base codon?

Answer 11

16 (4x4) AA, AC, etc

Question 12

How many codons can be made from a triplet code?

Answer 12

64 (4x4x4) AAT, GGC, etc

Question 13

How many codons signal the end of a sequence?

Answer 13

3 stop codons

Question 14

How many codons are needed to mark start of sequence?

Answer 14

1 start codon