CMA 1

Question 1

In a testcross between a female Drosophila that is heterozygous for two unlinked autosomal genes and a male that is homozygous recessive for both, what is the probability of finding a female fly amongst the offspring with the same genotype as her mother? (Enter your answer in decimal format eg 0.35)
NB Autosomal genes are inherited independent of sex

Answer 1

0.125

Question 2

Corn has a colour gene ‘C’ and a height gene ‘T’ with the following phenotypes: CC and Cc = purple; cc = white; TT = tall; Tt = medium; tt = dwarf. What phenotypic ratio would you expect in the progeny of the dihybrid cross CcTt x CcTt?

Answer 2

3:6:3:1:2:1

Question 3

Andy is blood group O, his mother and father are blood group A and B respectively. What is the probability that Andy’s new-born sister will be blood group A?

Answer 3

1/4

Question 4

Drosophila, homozygous for a null allele of the ebony gene have black bodies and the ebony allele is recessive to its wild type partner. Drosophila heterozygous for a mutant allele of the Curly gene have curly wings and Curly homozygotes die. Which of the following phenotypic ratios would you expect to see in the living progeny of flies which were heterozygous (mutant/wild type) for both genes?

Answer 4

6:3:2:1

Question 5

The phenotypic ratio expected in the F2 generation of a standard dihybrid cross is 9:3:3:1. If there are 24,000 F2 progeny, how many individuals would you expect to have the least frequent phenotype?

Answer 5

1500

Question 6

Full pod shape (F) is dominant to constricted pod shape (f) and yellow pod colour (Y) is dominant to green pod colour (y) in pea plants. A pure-breeding green plant with full pods is crossed with a pure-breeding yellow plant with constricted pods. What will be the phenotype(s) of the offspring?

Answer 6

All yellow with full pods

Question 7

Full pod shape (F) is dominant to constricted pod shape (f) and yellow pod colour (Y) is dominant to green pod colour (y) in pea plants. A pure-breeding green plant with full pods is crossed with a pure-breeding yellow plant with constricted pods. What will be the phenotype(s) of the offspring?

Answer 7

All yellow with full pods

Question 8

Let W = purple flowers, w = white flowers, D = tall plants and d = dwarf plants. What combination of gametes could be produced by an individual that is heterozygous for both traits?

Answer 8

WD, Wd, wD, wd

Question 9

Let W = purple flowers, w = white flowers, D = tall plants and d = dwarf plants. What combination of gametes could be produced by an individual that is heterozygous for both traits?

Answer 9

WD, Wd, wD, wd

Question 10

Which of the following scientists provided the explanation for the stability of the 50:50 sex ratio in disexual species

Answer 10

Fisher

Question 11

The cross AaBb x AaBb is called a

Answer 11

dihybrid cross

Question 12

The cross AaBb x AaBb is called a

Answer 12

dihybrid cross

Question 13

If a pure-breeding ebony-bodied female Drosophila is crossed with a pure-breeding wild type male and their offspring are allowed to interbreed, how many ebony-bodied flies would you expect to find amongst 8400 F2 progeny?

Answer 13

2100

Question 14

If a pure-breeding ebony-bodied female Drosophila is crossed with a pure-breeding wild type male and their offspring are allowed to interbreed, how many ebony-bodied flies would you expect to find amongst 8400 F2 progeny?

Answer 14

2100

Question 15

A set of genes located on the same chromosome is known as a linkage group. Members of a linkage group can assort independently if…

Answer 15

crossing over occurs between their locations

Question 16

A set of genes located on the same chromosome is known as a linkage group. Members of a linkage group can assort independently if…

Answer 16

crossing over occurs between their locations

Question 17

A pure-breeding wild type female Drosophila was crossed to a pure breeding male with ebony body, brown eyes and vestigial wings. All of the F1 progeny were wild type. If these F1 flies are allowed to interbreed, how many different phenotypes would you expect to see amongst their offspring?

Answer 17

8

Question 18

Which of the following statements about coelacanths is false?

Answer 18

they have lungs but no gills

Question 19

Which of the following statements about coelacanths is false?

Answer 19

they have lungs but no gills

Question 20

In the human ABO blood groups, IA and IB are dominant over IO, but not over one another. IA and IB are said to be ………..

Answer 20

codominant

Question 21

In the human ABO blood groups, IA and IB are dominant over IO, but not over one another. IA and IB are said to be ………..

Answer 21

codominant

Question 22

When a pure-breeding wildtype female fly (genotype bw+bw+, e+e+) is crossed to a pure-breeding brown-eyed, ebony-bodied male (genotype bw bw, e e), the F1 progeny are all wildtype. If the F1 flies interbreed, what is the probability of finding a brown-eyed fly with wildtype body colour amongst their offspring?

Answer 22

3/16

Question 23

When a pure-breeding wildtype female fly (genotype bw+bw+, e+e+) is crossed to a pure-breeding brown-eyed, ebony-bodied male (genotype bw bw, e e), the F1 progeny are all wildtype. If the F1 flies interbreed, what is the probability of finding a brown-eyed fly with wildtype body colour amongst their offspring?

Answer 23

3/16

Question 24

Full Pod shape (F) is dominant to constricted pod shape (f) and yellow pod colour (Y) is dominant to green pod colour (y) in pea plants. Which TWO of the following genotypes could apply to a yellow plant with constricted pods? (Note that choosing more than two options will result in a score of 0)

Answer 24

YYff, Yyff

Question 25

Alternative versions of a gene are called...

Answer 25

alleles

Question 26

Alternative versions of a gene are called...

Answer 26

alleles

Question 27

If a dihybrid individual BbCc is testcrossed, what is the probability of finding an individual that is homozygous for one gene and heterozygous for the other in the resulting generation?

Answer 27

1/2

Question 28

If a dihybrid individual BbCc is testcrossed, what is the probability of finding an individual that is homozygous for one gene and heterozygous for the other in the resulting generation?

Answer 28

1/2

Question 29

If a dihybrid individual BbCc is testcrossed, what is the probability of finding a double homozygous recessive in the resulting generation?

Answer 29

1/4

Question 30

If a dihybrid individual BbCc is testcrossed, what is the probability of finding a double homozygous recessive in the resulting generation?

Answer 30

1/4

Question 31

A diploid individual whose two copies of a given gene are the same is said to be __________ for the gene

Answer 31

homozygous

Question 32

A diploid individual whose two copies of a given gene are the same is said to be __________ for the gene

Answer 32

homozygous

Question 33

The extant species Latimeria chalumnae belongs to a group that is an important link in evolution because it was the first group of?

Answer 33

jointed fins

Question 34

The extant species Latimeria chalumnae belongs to a group that is an important link in evolution because it was the first group of?

Answer 34

jointed fins

Question 35

Which one of the following terms best describes an organism with two homologous sets of chromosomes?

Answer 35

diploid

Question 36

Which one of the following terms best describes an organism with two homologous sets of chromosomes?

Answer 36

diploid

Question 37

Full pod shape (F) is dominant to constricted pod shape (f) and yellow pod colour (Y) is dominant to green pod colour (y) in pea plants. A pure-breeding green plant with full pods is crossed with a pure-breeding yellow plant with constricted pods. The offspring are then testcrossed. Presuming independent assortment, what is the expected phenotypic ratio of resulting progeny?

Answer 37

9:3:3:1

Question 38

Full pod shape (F) is dominant to constricted pod shape (f) and yellow pod colour (Y) is dominant to green pod colour (y) in pea plants. A pure-breeding green plant with full pods is crossed with a pure-breeding yellow plant with constricted pods. The offspring are then testcrossed. Presuming independent assortment, what is the expected phenotypic ratio of resulting progeny?

Answer 38

9:3:3:1

Question 39

Which of the following geological periods is the most recent (closest to the present)?

Answer 39

Cretaceous

Question 40

How may different genotypes would you expect to find amongst the wild type offspring of a cross between Drosophila that are heterozygous for both ebony and vestigial wing (ie they are both e+e, vg+vg)?

Answer 40

9

Question 41

The diagram below illustrates a human pedigree for an inherited disease. Females and males are represented by circles and squares respectively. Red symbols indicate persons affected by the disease. What form of inheritance does the disease show? The disease is present in each generation, both men and women are affected, each affected individual has an affected parent.

Answer 41

autosomal dominant

Question 42

The diagram below illustrates a human pedigree for an inherited disease. Females and males are represented by circles and squares respectively. Red symbols indicate persons affected by the disease. What form of inheritance does the disease show? The disease is present in each generation, both men and women are affected, each affected individual has an affected parent.

Answer 42

autosomal dominant

Question 43

Which one of the following explains why men tend to suffer from sex-linked genetic disorders more frequently than women?

Answer 43

Men have only one X chromosome therefore have only a single allele of most X-linked genes.

Question 44

Genes A, B and C are unlinked and encode enzymes which act sequentially in a metabolic pathway that normally synthesises black pigment via colourless intermediates. If two individuals that are heterozygous (wild type and null alleles) at all 3 gene loci are mated, what proportion of their progeny will be colourless?

Answer 44

37/64

Question 45

Genes A, B and C are unlinked and encode enzymes which act sequentially in a metabolic pathway that normally synthesises black pigment via colourless intermediates. If two individuals that are heterozygous (wild type and null alleles) at all 3 gene loci are mated, what proportion of their progeny will be colourless?

Answer 45

37/64

Question 46

A diploid individual who only has one copy of a given gene is said to be __________ for that gene.

Answer 46

hemizygous

Question 47

A diploid individual who only has one copy of a given gene is said to be __________ for that gene.

Answer 47

hemizygous

Question 48

If genes A, B and C each control a different visible characteristic, and each gene has two alternative alleles that exhibit contrasting phenotypes with one showing complete dominance over the other, how many different phenotypic combinations will be found amongst the progeny of an Aa,Bb,Cc x Aa,Bb,Cc cross?

Answer 48

8

Question 49

If genes A, B and C each control a different visible characteristic, and each gene has two alternative alleles that exhibit contrasting phenotypes with one showing complete dominance over the other, how many different phenotypic combinations will be found amongst the progeny of an Aa,Bb,Cc x Aa,Bb,Cc cross?

Answer 49

8

Question 50

If the alleles of both of the genes involved in a dihybrid cross exhibit incomplete dominance and independent assortment, what proportion of the F2 progeny would you expect to show the most frequent phenotype?

Answer 50

1/4

Question 51

If the alleles of both of the genes involved in a dihybrid cross exhibit incomplete dominance and independent assortment, what proportion of the F2 progeny would you expect to show the most frequent phenotype?

Answer 51

1/4

Question 52

Under normal circumstances, what phenotypic ratio would you expect to see in the offspring of a cross between Drosophila that are both heterozygous for a single gene that controls a visible phenoype such as eye colour? (presume wild type is dominant to mutant)

Answer 52

3 wild type to 1 mutant

Question 53

Under normal circumstances, what phenotypic ratio would you expect to see in the offspring of a cross between Drosophila that are both heterozygous for a single gene that controls a visible phenoype such as eye colour? (presume wild type is dominant to mutant)

Answer 53

3 wild type to 1 mutant

Question 54

A diploid individual whose two copies of a given gene are different is said to be __________ for the gene

Answer 54

heterozygous

Question 55

Presuming that none of the following phenomena cause lethality, which of them is most likely to affect the genotypic ratios observed in the progeny of a dihybrid cross?

Answer 55

close linkage of the two genes

Question 56

Presuming that none of the following phenomena cause lethality, which of them is most likely to affect the genotypic ratios observed in the progeny of a dihybrid cross?

Answer 56

close linkage of the two genes

Question 57

The cross AaBb x aabb is called a

Answer 57

testcross

Question 58

The cross AaBb x aabb is called a

Answer 58

testcross

Question 59

Sometimes an allele of one gene will interact so as to modify the expression of the alleles of a second gene in an interaction called...

Answer 59

epistasis

Question 60

Environmental temperature influences the body tem­perature of many animals, especially those that live in _______ environments.

Answer 60

aquatic

Question 61

Environmental temperature influences the body tem­perature of many animals, especially those that live in _______ environments.

Answer 61

aquatic

Question 62

If two individuals, both heterozygous for a particular gene, are crossed and the phenotypic ratio amongst their numerous progeny is 2 : 1 (dominant : recessive). The simplest explanation is that…

Answer 62

the dominant allele is also lethal in homozygotes

Question 63

If two individuals, both heterozygous for a particular gene, are crossed and the phenotypic ratio amongst their numerous progeny is 2 : 1 (dominant : recessive). The simplest explanation is that…

Answer 63

the dominant allele is also lethal in homozygotes

Question 64

Corn has a colour gene 'C' and a height gene 'T' with the following phenotypes: CC and Cc = purple; cc = white; TT = tall; Tt = medium; tt = dwarf. What phenotypic ratio would you expect in the progeny of the dihybrid cross CcTt x CcTt?

Answer 64

3:6:3:1:2:1

Question 65

Corn has a colour gene 'C' and a height gene 'T' with the following phenotypes: CC and Cc = purple; cc = white; TT = tall; Tt = medium; tt = dwarf. What phenotypic ratio would you expect in the progeny of the dihybrid cross CcTt x CcTt?

Answer 65

3:6:3:1:2:1

Question 66

If two genes are at opposite ends of a large chromosome, they will usually behave as if...

Answer 66

they are on different chromosomes

Question 67

Abnormally high concentrations of ______ have been found in rocks dating from the end of the Cretaceous.

Answer 67

iridium

Question 68

Abnormally high concentrations of ______ have been found in rocks dating from the end of the Cretaceous.

Answer 68

iridium

Question 69

In the fungus Aspergillus nidulans, wild type (+) conidial colour is green and is controlled by two genes: y which gives yellow conidia when mutant (-), and w which gives white conidia when mutant. The w gene is epistatic to y. An auxotrophic strain of the fungus has yellow conidia and requires biotin and proline for growth. Which one of the following genotypes could it have?

Answer 69

?

Question 70

Most physiological processes...

Answer 70

occur more rapidly as temperature increases

Question 71

Gene A and gene B both lie on the same chromosome approximately 12 centimorgans appart. If one of the F1 progeny of the cross AABB x aabb were mated to an individual with the genotype aabb, how many individuals with the genotype AaBb would you expect amongst 1000 progeny?

Answer 71

?

Question 72

In the haploid fungus Neurospora the amino acid arginine is synthesised from its precursor in a sequential 4 step reaction via the intermediates of ornithine, citrulline and arginosuccinine. If an auxotrophic mutation in one strain blocks the pathway at step 3, and an unlinked auxotrophic mutation in a second strain blocks the pathway at step 2, what would be the result of crossing these two mutant strains?

Answer 72

all progeny will be able to synthesize arginine

Question 73

Full pod shape (F) is dominant to constricted pod shape (f) and yellow pod colour (Y) is dominant to green pod colour (y) in pea plants. A pure-breeding green plant with full pods is crossed with a pure-breeding yellow plant with constricted pods. The offspring are then testcrossed. How many different phenotypes do you expect in the offspring?

Answer 73

4

Question 74

Full pod shape (F) is dominant to constricted pod shape (f) and yellow pod colour (Y) is dominant to green pod colour (y) in pea plants. A pure-breeding green plant with full pods is crossed with a pure-breeding yellow plant with constricted pods. The offspring are then testcrossed. How many different phenotypes do you expect in the offspring?

Answer 74

4

Question 75

Suppose the sporophyte generation of a moss is heterozygous for a gene (Ll) which affects leaf shape in the haploid gametophyte. The allele L causes elongate leaves and the allele l causes short leaves. What will be the expected proportions of elongate-leaves and short-leaved gametophytes produced from the sporophyte?

Answer 75

half short-leaved and half-long leaved

Question 76

In the fungus Aspergillus nidulans, wild type (+) conidial colour is green and is controlled by two genes: y which gives yellow conidia when mutant (-), and w which gives white conidia when mutant. The w gene is epistatic to y. An auxotrophic strain of the fungus has yellow conidia and requires biotin and proline for growth. Which one of the following genotypes could it have?

Answer 76

w+y-bi-pro-

Question 77

Gene A and gene B both lie on the same chromosome approximately 12 centimorgans appart. If one of the F1 progeny of the cross AABB x aabb were mated to an individual with the genotype aabb, how many individuals with the genotype AaBb would you expect amongst 1000 progeny?

Answer 77

440

Question 78

Full pod shape (F) is dominant to constricted pod shape (f) and yellow pod colour (Y) is dominant to green pod colour (y) in pea plants. A pure-breeding green plant with full pods is crossed with a pure-breeding yellow plant with constricted pods. The offspring are then testcrossed. Presuming independent assortment, what is the expected phenotypic ratio of resulting progeny?

Answer 78

1:1:1:1

Question 79

How may different genotypes would you expect to find amongst the wild type offspring of a cross between Drosophila that are heterozygous for both ebony and vestigial wing (ie they are both e+e, vg+vg)?

Answer 79

4

Question 80

Gene A and gene B both lie on the same chromosome approximately 12 centimorgans appart. If one of the F1 progeny of the cross AABB x aabb were mated to an individual with the genotype aabb, how many individuals with the genotype AaBb would you expect amongst 1000 progeny?

Answer 80

440

Question 81

In the haploid fungus Neurospora the amino acid arginine is synthesised from its precursor in a sequential 4 step reaction via the intermediates of ornithine, citrulline and arginosuccinine. If an auxotrophic mutation in one strain blocks the pathway at step 3, and an unlinked auxotrophic mutation in a second strain blocks the pathway at step 2, what would be the result of crossing these two mutant strains?

Answer 81

some progeny will be able to synthesize arginine and some will not