3.4.2-DNA And Protein Synthesis

Question 1

What is the genome of a cell?

Answer 1

The complete set of genes in a cell

Question 2

What is the proteome of a cell?

Answer 2

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

Question 3

What is mRNA and its function?

Answer 3

A copy of a gene from DNA created in the nucleus and carries the copy of the genetic code of one gene from the nucleus to a ribosome in the cytoplasm

Question 4

The structure of mRNA

Answer 4

Single-stranded
short
every three bases in the sequence (codons) code for a specific amino acid

Question 5

Where is tRNA found and what is its job?

Answer 5

Found in the cytoplasm
Transfer amino acid to the ribosome to create the polypeptide chain

Question 6

Structure of tRNA

Answer 6

Single-stranded
Create a cloverleaf like shape held by hydrogen bonds
Contains an anticodon

Question 7

What is transcription?

Answer 7

Where one gene on the DNA is copied into mRNA

Question 8

The process of transcription

Answer 8

1.The DNA helix unwinds
2.One strand of the DNA acts as a template
3.Free RNA nucleotides form complementary base pairs
4.Phosphodiester bonds form
5.By RNA polymerase
6.This results directly n the production of mRNA in prokaryotes
7.This results in pre-mRNA in eukaryotes
8.pre-mRNA is then spliced removing introns and leaving exons to exit the nucleus as mRNA

Question 9

Describe how the production of mRNA in a eukaryotic cell is different to the production of mRNA a prokaryotic cell

Answer 9

Pre-mRNA is only produced in eukaryotic cells and splicing only occurs in eukaryotic cells

Question 10

Describe the process of translation

Answer 10

mRNA attaches to a ribosome
The ribosome attaches at the start codon
The tRNA molecule with the complementary anticodon aligns opposite the mRNA start codon
The ribosome will move along the mRNA molecule to enable another complementary tRNA to attach to the next codon
The two amino acids delivered by the tRNA molecule join by a peptide bond catalysed by an enzyme and energy from ATP
The process repeats until the ribosome reaches the stock code on where the ribosome and translation ends
The polypeptide chain is released

Question 11

Describe the role of ATP in the process of translation in protein synthesis

Answer 11

Provide energy so peptide bonds form between amino acids

Question 12

Describe the role of a ribosome in the production of a polypeptide

Answer 12

mRNA binds to ribosome
allows tRNA with anticodons to bind
Moves along mRNA to the next codon