Ka 3

Question 1

Two processes involved in gene expression

Answer 1

Transcription
Translation

Question 2

What is transcription

Answer 2

Production of a complimentary copy of the DNA code

Question 3

What is translation

Answer 3

The interpretation of mRNA to assemble a chain of amino acids to produce a protein

Question 4

What does gene expression mean

Answer 4

Transcription and translation of DNA sequences to produce proteins

Question 5

Name three types of RNA involved in transcription and translation

Answer 5

mRNA
tRNA
rRNA

Question 6

Describe the structure of an RNA nucleotide

Answer 6

Ribose sugar
Phosphate
Base

Question 7

State the location of transcription and translation

Answer 7

Transcription- nucleus
Translation- ribosome

Question 8

State the function of a codon on mRNA

Answer 8

A codon is a triplet of bases that codes for a specific amino acid

Question 9

State function of mRNA

Answer 9

Carries a complementary copy of the DNA sequence from the nucleus to the ribosome

Question 10

Explain why tRNAs single strand is folded into its recognisable shape

Answer 10

Due to complementary base pairing

Question 11

State the function of a tRNA molecule

Answer 11

Transports amino acids into the correct order by matching their anti codons on the mRNA

Question 12

Describe the structure of a tRNA molecule

Answer 12

A tRNA molecule has an anticodon (exposed triplet of bases) at one end and an attachment site for a specific amino acid at the other end

Question 13

Name 2 components that make up a ribosome

Answer 13

rRNA
protein

Question 14

⭐️describe the process of transcription⭐️

Answer 14

*RNA polymerase moves along DNA unwinding the double helix and breaking the hydrogen bonds between the bases.
*RNA polymerase synthesises a primary transcript of mRNA from RNA nucleotides by complementary base pairing. Uracil in RNA is complementary to adenine. RNA splicing forms a mature mRNA transcript.
*Introns of the primary transcript are removed.
*The exons are joined together to form the mature transcript. The order of the exons is unchanged during splicing

Question 15

⭐️Describe the process of translation⭐️

Answer 15

*tRNA is involved in the translation of mRNA into a polypeptide at a ribosome.
*Translation begins at a start codon and ends at a stop codon.
*Anticodons bond to codons by complementary base pairing, translating the genetic code into a sequence of amino acids.
*Peptide bonds join the amino acids together.
*Each tRNA then leaves the ribosome as the polypeptide is formed.

Question 16

State how amino acids are linked to form a polypeptide

Answer 16

By peptide bonds

Question 17

Describe how a polypeptide becomes a protein

Answer 17

Peptide chains fold to form the three-dimensional shape of a protein held together by hydrogen bonds and other interactions between individual amino acids

Question 18

State what determines a proteins function

Answer 18

Its shape

Question 19

Describe the functions of rRNA

Answer 19

Makes up part of a ribosomes structure alongside proteins

Question 20

⭐️describe the process of alternative RNA splicing⭐️

Answer 20

Different proteins can be expressed from one gene
Different mature mRNA transcripts are produced from the same primary transcript depending pn which exons are retained
Exons will remain in the same order but some may not be retained

Question 21

Name 4 bases in RNA

Answer 21

Adenine
Cytosine
Guanine
Uracil

Question 22

State a factor the other than gene expression that can influence an organism phenotype

Answer 22

Environmental factors

Question 23

State what determines an organism’s phenotype

Answer 23

Phenotype is determined by the proteins produced as the result of gene expression