Genes

Question 1

Heterochromatin

Answer 1

DNA tightly packaged & genes not expressed

Question 2

Euchromatin

Answer 2

DNA loosely packaged & genes expressed

Question 3

Gene

Answer 3

Sequence of nucleotides which determines the order of monomers in a polypeptide or nucleic acid molecule which a cell (or virus) may synthesise

Question 4

Genome

Answer 4

The entire DNA sequence (human genome is 24 chromosomes)

Question 5

Promoter

Answer 5

region of DNA that initiates transcription of a particular gene

Question 6

Transcription reading & synthesis

Answer 6

• DNA read 3’ to 5’

- mRNA synthesis 5’ to 3’

Question 7

Translation reading & synthesis

Answer 7

• mRNA read 5’ to 3’

- Polypeptide synthesis N to C

Question 8

Mutation

Answer 8

A heritable alteration in a gene or chromosome and the process that produces the alteration

Question 9

Small scale DNA changes

Answer 9

• Base substitutions

- Base additions & deletions

Question 10

Large scale DNA changes

Answer 10

• Chromosome rearrangements

- Transposable element insertions

Question 11

Transition base substitution

Answer 11

Change to same type of base

Question 12

Transversion base substitution

Answer 12

Change to different type of base

Question 13

Phenotype

Answer 13

The form (trait) that you will see

Question 14

Genotype

Answer 14

The genetic make up

Question 15

Mutation causing sickle cell anaemia

Answer 15

Base substitution mutation (missense)

Glu6 -> Val

Question 16

How mutations change the amount of gene product

Answer 16

• Alter promoter activity
• Alter translation initiation at AUG
• Prevent mRNA splicing
• Reduce mRNA stability

Question 17

How mutations change the polypeptide length

Answer 17

Deletion & additions

• Change ‘sense’ codon into stopcodon (nonsense mutation)
• Deletion of stopcodon

Question 18

Mutations that cause large scale changes (chromosome rearrangement)

Answer 18

• Insertion
• Deletion
• Inversion
• Translocation

Question 19

Mutations that cause large scale changes (transposable element insertions)

Answer 19

• Movement of discrete DNA elements

- Gene inactivity by insertion

Question 20

Transposable elements

Answer 20

Sequences of DNA that move from one location in the genome to another