DNA and protein synthesis

Question 1

Define genome

Answer 1

The complete set of genes in a cell

Question 2

define proteome

Answer 2

the full range of proteins that a cell can produce

Question 3

what is transcription

Answer 3

Production of mRNA from DNA, in the nucleus

Question 4

what is translation?

Answer 4

Production of polypeptide from the sequence of codons carried by mRNA, at ribosomes

Question 5

compare and contrast the structure of mRNA and tRNA

Answer 5

+Both a ginger polynucleotide strand
-tRNA is folded into a clover shape whereas mRNA is linear
-tRNA has hydrogen bonds between paired bases and mRNA doesn’t
-tRNA is shorter whereas mRNA is longer
-tRNA has an anticodon and mRNA has codons

Question 6

Describe how mRNA is formed by transcription in Eukaryotic cells

Answer 6

1-hydrogen bonds between DNA bases break
2-only one DNA strand acts as a temple
3-Free RNA nucleotides align next to their complimentary bases on the template strand
4-RNA polymerase joins adjacent RNA nucleotides
5-forms phosphodiester bonds via a condensation reaction
6-pre-mRNA is formed and is spliced to remove introns forming mRNA

Question 7

describe how production of mRNA in Eukaryotic cells in different from production of mRNA in prokaryotes

Answer 7

-pre-mRNA produced in Eukaryotes whereas mRNA is produced directly in Prokaryotic cells because genes in prokaryotic cells don’t contain introns so there s no splicing

Question 8

describe how translation leads to the production of a polypeptide

Answer 8

1-mRNA attaches to a ribosome and the ribosome moves to a start codon
2-tRNA brings specific amino acids
3-tRNA anticodons bind to complimentary mRNA codon
4-ribosomes move along to the next codon
5-tRNA released after amino acid joined polypeptide
6-ribosomes move along mRNA to form the polypeptide until a stop codon is reached

Question 9

what is the role of ATP in translation

Answer 9

hydrolysis of ATP to ADP +Pi releases energy so amino acids joined to tRNAs and peptide bonds form between amino acids

Question 10

describe the role of tRNA in translation

Answer 10

attaches and transports a specific amino acid and the tRNA anticodon complimentary base pairs to mRNA codon forming hydrogen bonds. 2 tRNAs bring amino acids together so peptide bonds can form

Question 11

describe the role of ribosomes in translation

Answer 11

mRNA binds to ribosome with space for 2 codons allowing tRNA with anticodons to bind. This catalyses the formation of peptide bond between amino acids