Fundamentals of Genetics and Mutations

Question 1

What is the unit of inheritance?

Answer 1

A gene.

Question 2

Define a locus.

Answer 2

The position of a gene on a chromosome.

Question 3

Define gametogenesis.

Answer 3

The process in which cells undergo meiosis to form gametes.

Question 4

How many copies of each gene are carried per gamete?

Answer 4

One copy.

Question 5

How many copies of each gene are carried per zygote?

Answer 5

Two copies.

Question 6

What are the phenotypic ratios for independent assortment?

Answer 6

9:3:3:1

Question 7

Why do plants have so many genes?

Answer 7

They are unable to move so must be able to tolerate a wider range of environmental conditions.

Question 8

Are males or females hemizygous?

Answer 8

Males - they only have one copy of the X chromosome.

Question 9

What is crossing-over?

Answer 9

The exchange of genetic information between homologous chromosomes.

Question 10

What is produced from crossing-over?

Answer 10

A hybrid chromosome and genetic variation.

Question 11

How do you calculate recombination frequency?

Answer 11

(Number of Recombinant Progeny/Total Number of Progeny) X 100

Question 12

Define a mutation.

Answer 12

Any heritable change in the DNA sequence.

Question 13

Define a transition mutation.

Answer 13

Substituting a purine for a purine or a pyrimidine for a pyrimidine.

Question 14

Define a transversion mutation.

Answer 14

Substituting a purine for a pyrimidine or vice versa.

Question 15

Define a silent mutation.

Answer 15

A change to the codon that has no effect on the amino acid.

Question 16

Define a missense mutation.

Answer 16

A change to the codon for a specific amino acid to a different amino acid.

Question 17

Define a nonsense mutation.

Answer 17

A change to the codon for a specific amino acid to a STOP codon.

Question 18

Define an INDEL.

Answer 18

Small insertions or deletions of bases.

Question 19

How can replicating DNA gain or lose single bases?

Answer 19

Via replication slippage.

Question 20

How can large insertion mutations occur?

Answer 20

Either by transposon mobilisation, virus insertion or retroposition.

Question 21

Define transposon mobilisation.

Answer 21

PLACEHOLDER

Question 22

Define virus insertion.

Answer 22

PLACEHOLDER

Question 23

Define retroposition.

Answer 23

PLACEHOLDER

Question 24

What mutations have the biggest effects?

Answer 24

Translocation, inversion, duplication and chromosome fusion.