1.3 Gene Expression

Question 1

Processes involved in Gene Expression

Answer 1

Transcription & Translation

Question 2

Components of RNA (ribonucleic acid)

Answer 2

• a ribose sugar
• a base
• a phosphate

Question 3

What base replaces Thymine in RNA

Answer 3

Uracil

Question 4

Types of RNA

Answer 4

• Messenger RNA (mRNA)
• Transfer RNA (tRNA)
• Ribosomal RNA (rRNA)

Question 5

mRNA

Answer 5

Carries a copy of the required gene from the nucleus to the ribosome

Question 6

tRNA

Answer 6

• has a cloverleaf shape
• has an anti codon site and an attachment site for specific amino acids
• each tRNA molecule carriers its specific amino acid to the ribosome

Question 7

rRNA

Answer 7

Forms the ribosome with the addition of proteins

Question 8

Protein Synthesis

Answer 8

A process in which instructions are carried from DNA sequences to ribosomes where proteins are synthesised.

Question 9

Codon

Answer 9

A group of 3 bases that codes for an amino acid

Question 10

Exons

Answer 10

coding regions of DNA

Question 11

Introns

Answer 11

non-coding regions of DNA

Question 12

Splicing

Answer 12

When non-coding introns are edited out so that the coding exons can be turned into protein.

Question 13

Splicing process

Answer 13

• The gene is copied in full to produce a primary transcript
• introns are removed and exons are joined together to produce a mature transcript

Question 14

Alternative RNA splicing

Answer 14

• allows one gene to code for a variety of proteins
• different mature mRNA
  transcripts are produced from the same
  primary transcript depending on which
  exons are retained

Question 15

Transcription

Answer 15

• synthesis of mRNA from a section of DNA
• occurs in the nucleus

Question 16

Translation

Answer 16

• synthesis of a protein under the direction of mRNA
• occurs in the ribosome

Question 17

What bonds are amino acids held together by?

Answer 17

Peptide bonds

Question 18

what are chains of amino acids linked by peptide bonds called?

Answer 18

polypeptide chains

Question 19

How is the shape of a protein produced?

Answer 19

by the folding of a polypeptide chain

Question 20

what does the shape of a protein determine?

Answer 20

its function

Question 21

what are proteins held together by?

Answer 21

• hydrogen bonds
• interactions between amino acids

Question 22

what is the phenotype of an individual determined by?

Answer 22

proteins that are a result of gene expression