Gene Expression

Question 1

Chromosomes contain

Answer 1

a complete set with every gene needed to make every protein that the organism will ever need to make

however in a particular cell, only a small fraction of genes are ever expressed

Question 2

Gene expression

Answer 2

Process by which specific genes are activated to produce a required protein

Question 3

Gene expression process

Answer 3

Made up from transcription and translation

Involves RNA

Question 4

mRNA

Answer 4

Moves from nucleus to ribosome

linear molecule

every 3 bases is described as a codon (codes for amino acid)

Question 5

RIBOSOME

Answer 5

where proteins are synthesised in cytoplasm

Question 6

How many natural amino acids

Answer 6

20

Question 7

Protein Functions

Answer 7

Enzymes

Hormones

Other structures within body, such as collagen

Question 8

RNA

Answer 8

JOINED TO FORM SINGLE STRAND

nucleotides joined by strong covalent bond

has sugar ribose (not deoxy)
Thyamine is replaced by Uracil

Question 9

tRNA

Answer 9

cloverleaf-shaped molecule

made up from single stand RNA which folds due to base pairing to form unusual shape

Has triplet anti-codon site and an attachment for specific amino acid

Question 10

rRNA

Answer 10

rRNA and proteins form ribosome

ribosome is site of protein synthesis

Question 11

exons

Answer 11

Coding regions of gene

Question 12

Introns

Answer 12

Non-coding regions

Question 13

Process of removing introns

Answer 13

RNA splicing

Question 14

RNA splicing

Answer 14

Produce primary transcript

Then remove introns and join remaining exons

This forms MATURE transcript of mRNA

Question 15

Alternative RNA Splicing

Answer 15

Benefit of RNA splicing is that one gene can produce many different proteins as a result of segments are treated as introns and exons

Question 16

Transcription

Answer 16

RNA polymerase moves along DNA unwinding strand

Hydrogen bonds break between pairs, which allows unzipping of helix

RNA polymerase breaks bonds, synthesises a primary transcript of mRNA using RNA nucleotides - these form hydrogen bonds with exposed DNA strand by complementary base pairing

primary transcript of mRNA is processed to produce mature transcript of mRNA

mature mRNA now ready to leave nucleus to go to ribosome

Question 17

Translation

Answer 17

mRNA molecule leaves through cytoplasm and attaches to ribosome

tRNA molecule transport specific amino acid to ribosome

each mRNA codon codes for specific amino acid

First codon is start codon - beginning of translation

Anti-codons and codons match up and dorm complementary base pairs

peptide bond forms between adjacent amino acids to form polypeptide bond

using tRNA molecules exit ribosome and collect another specific amino acid

last codon is stop codon which signals end of translation

Question 18

What causes polypeptide chains to fold into repeating pattern

Answer 18

hydrogen bonds