Ch9 Genetic diversity and adaptation

Question 1

Causes of mutations

Answer 1

1. high energy ionising radiation
2. mutagenic

Question 2

Mutation affect on enzyme

Answer 2

1. change in base sequence
2. change in sequence of triplet codes
3. change in primary structure
4. change in tertiary structure
5. change in active site
6. substrate no longer complementary
7. can no longer from ES complex

Question 3

Mutation affect on protein

Answer 3

1. change in base sequence
2. change in sequence of triplet codes
3. change in primary structure
4. change in tertiary structure
5. no longer functional

Question 4

Why mutation doesn’t affect protein

Answer 4

1. degenerate code
2. affects introns which are spliced

Question 5

Meiosis

Answer 5

1. produces 4 gametes
2. genetically different cells
3. haploid chromosomes

Question 6

How does meiosis produce variation

Answer 6

1. crossing over
2. independent assortment

Question 7

Crossing over

Answer 7

1. prophase 1
2. homologous pairs of chromosome twist around each other
3. sections of DNA break off
4. exchange in sister chromosomes (recombination)
5. produces different combo of alleles

Question 8

Independent assortment

Answer 8

1. anaphase I- homologous pairs of chromosomes separate
2. anaphase II- chromatids separate
3. independent assortment produces mixes of alleles

Question 9

Meiosis I vs Meiosis II

Answer 9

1. metaphase I- homologous chromosome pairs line up on equator
2. metaphase II - single chromosome randomly arranged on equator
3. independent segregation produces different combinations of alleles

Question 10

Homologous chromosomes

Answer 10

1. pair of chromosomes with same loci
2. one maternal and one paternal

Question 11

Calculation of chromosomal combinations

Answer 11

2^(number of homologous chromosomes)

Question 12

Genetic diversity

Answer 12

total number of different alleles in a population

Question 13

Founder effect

Answer 13

1. small number of individuals
2. low variety of alleles
3. low genetic diversity
4. group interbreeds
5. individuals more likely to inherit mutated allele

Question 14

Genetic bottleneck

Answer 14

1. event causes reduction in population size
2. low number of individuals
3. low variety of alleles
4. low genetic diversity

Question 15

Directional selection

Answer 15

1. occurs in changing environment
2. selection against one extreme
3. mean is shifted towards favoured extreme

Question 16

Stabilising selection

Answer 16

1. occurs in unchanging environment
2. selection against extreme phenotypes
3. standard deviation reduced
4. mean unaltered(best adapted)
5. repeated over many generations
6. increased proportion of mean phenotype

Question 17

Disruptive selection

Answer 17

1. occurs in changing environment
2. selection against mean phenotype
3. mean shifts towards both extreme phenotypes