DNA, RNA and Protein Synthesis

Question 1

As well as DNA what else do chromosomes contain? [1]

Answer 1

Histones

Question 2

How is DNA arranged is Prokaryotes [2]

Answer 2

Can be a circular chromosome which has been super coiled to fit in the cell or as plasmids

Question 3

What is a gene? [2]

Answer 3

A section of DNA that codes for either a polypeptide or functional RNA

Question 4

What is a cells genome [1]

Answer 4

The complete set of genes in a cell

Question 5

What is a cells proteome [1]

Answer 5

The full range of proteins that the cell is able to produce

Question 6

How many bases are needed to code for an amino acid? [1]

Answer 6

3, a triplet

Question 7

The DNA code is said to be degenerate, explain what is meant by this [2]

Answer 7

That there are different orders of DNA bases that still code for the same amino acid

Question 8

Base triplets that don’t code for a polypeptide are said to be … [1]

Answer 8

Introns

Question 9

An alternative version of the same gene is called an … [1]

Answer 9

Allele

Question 10

At what stage of protein synthesis is m-RNA made? [1]

Answer 10

Transcription

Question 11

What enzyme breaks open the DNA helix [1]

Answer 11

Helicase

Question 12

Describe the process of transcription [5]

Answer 12

• RNA polymerase attaches to the DNA helix at the start of a gene, hydrogen bonds broken bases are left exposed one of the strands is then used as a template for m-RNA
• RNA polymerase lines up free nucleotides along side exposed bases on the template strand, once whole section has RNA nucleotides they are joined together by RNA polymerase
• Once a stop triplet is reached the RNA molecule detaches from the DNA and leaves the cell by the nuclear pores

Question 13

If ATA CTG AGC are the DNA triplets what is the codon in the m-RNA?

Answer 13

UAU GAC UCG