1.2 The Proteome

Question 1

What is the Proteome

Answer 1

Entire set of proteins that is or can be, expressed by a genome, cell, tissue or organism at a certain time.

Question 2

Why is the Proteome larger than the genome

Answer 2

More than 1 protein can be produced from a single gene as a result of alternative RNA splicing.
Especially in the eukaryotes

Question 3

Factors affecting protein expression by a cell

Answer 3

• Metabolic activity of cell
• Cellular stress
• The response to signalling molecules
• Diseased vs healthy cells

Question 4

Introns and exons

Answer 4

Intron of RNA usually removed during splicing.
Exon RNA section usually retained during splicing.

Question 5

Why are not all genes expressed in the cell

Answer 5

Some genes are switched off due to cellular differentiation.
e.g. haemoglobin is only expressed in red blood cells.

Question 6

Examples of non-coding RNA genes

Answer 6

Transcribed to produce tRNA and rRNA.
Transcribed to produce RNA that controls the expression of other genes

Question 7

Alternative RNA splicing

Answer 7

Removal of a non coding introns from a primary mRNA transcript to leave only the coding exons.
Several mature transcripts can be produced from a single primary transcript.

Question 8

Amino acids

Answer 8

Amino acids sequence determines Protein structure

Question 9

Polymers

Answer 9

Proteins are polymers of amino acid monomers.