Chapter 9

Question 1

Mutation definition

Answer 1

Any change in the quantity or the base sequence in the DNA of an organism

Question 2

What are the two types of gene mutation

Answer 2

Base deletion and base substitution

Question 3

What are the 3 effects of gene substitution

Answer 3

Nothing happens as it codes for the same amino acid, codes for a different amino acid, codes for a stop codon which stops translation early

Question 4

Hybridisation definition

Answer 4

Combing genes of different varieties or species of organisms to produce a hybrid

Question 5

Hybrid definition

Answer 5

The offspring resulting from combining the genetic material of two organisms of different breeds through sexual reproduction

Question 6

What is the process of meiosis I

Answer 6

Homologous chromosomes pair up along the equator during metaphase I, chromatids from different chromosomes of the homologous pair wrap around each other and exchange genetic material between chromosomes, homologous pairs separate with both sister chromatids attached to each other by the centromere, this produces two haploid daughter cells produced with one copy of each chromosome

Question 7

What is the process of meiosis II

Answer 7

Chromosomes line up along the equator in a single line with spindle fibres attached to both sides of the centromere, sister chromatids separate when the centromere splits, 4 haploid daughter cells are produced from the two daughter cells

Question 8

Gene defintion

Answer 8

A region of DNA that codes for a polypeptide or functional RNA

Question 9

Locus defintion

Answer 9

Specific location on a specific chromosome where a gene is found

Question 10

Homologous chromosomes defintion

Answer 10

Have the same genes at the same loci

Question 11

Genetic diversity definition

Answer 11

A measure of the different alleles within a population

Question 12

Population definition

Answer 12

A group of individuals of the same species within a community that can inter breed

Question 13

How do you calculate the possible combinations for a daughter cell

Answer 13

2 to the power of n, where n =the number of pairs of homologous chromosomes.

Question 14

What is stabilising selection

Answer 14

Stabilising selection steepens the distribution curve by selecting against the extremes

Question 15

What is directional selection

Answer 15

Selecting towards one of the extremes

Question 16

Founder effect

Answer 16

Reduction in genetic variation that results when a small subset of a large population is used to establish a new colony

Question 17

Genetic bottleneck

Answer 17

Extreme example of genetic drift where the size of a population is severely reduced

Question 18

Genetic drift

Answer 18

Variation in relative frequency of different genotypes in a small population in the disappearance of particular genes

Question 19

3 types of adaptations

Answer 19

Anatomical, physiological, behavioural

Question 20

4 mutagenic agents

Answer 20

Ionising radiation, some viruses, unhealthy diet, mutagenic chemicals like tar

Question 21

Non disjunction definition

Answer 21

Nondisjunction means that a pair of homologous chromosomes has failed to separate at anaphase so that both chromosomes of the pair pass to the same daughter cell

Question 22

Comparing mitosis and meiosis type of cells formed

Answer 22

Mitosis forms somatic cells, meiosis forms gametes

Question 23

Comparing mitosis and meiosis - if both start with a diploid cell what is the outcome

Answer 23

Mitosis - diploid remains diploid
Meiosis - diploid to haploid

Question 24

Comparing mitosis and meiosis genetic variation in daughter cells

Answer 24

Mitosis - daughter cells genetically identical
Meiosis - daughter cells genetically different

Question 25

Comparing mitosis and meiosis number of cells produced

Answer 25

Mitosis - 2 cells produced
Meiosis - 4 cells produced

Question 26

Comparing mitosis and meiosis - do they allow crossing over

Answer 26

Mitosis - no crossing over
Meiosis - yes

Question 27

Independent segregation definition

Answer 27

The random separation of homologous chromosomes in meiosis 1 that produces genetic variation