Genetics/Meiosis Review Questions

1
Genetics/Meiosis Review Questions
2
Question

• A cross between two pea plants hybird for a
  single trait produces 60 offspring. Approximately
  how many of the offspring would be expected to
  exhibit the recessive trait?

3
Answer

• Pp x Pp
• ¼ pp recessive trait
• Answer 60 offspring x ¼ 15 offspring would
  express the recessive trait

4
Question

• Compare the final products of mitosis to the
  final products of meiosis.

5
Answer

• Mitosis
• 2 diploid (2n) daughter cells that are identical
  to the original cell
• Meiosis
• 4 haploid (n) gametes (sperm or eggs)

6
Question

• Determine the possible genotypes phenotypes of
  the children for a couple who's blood types  are
  homozygous A heterozygous B.

7
Answer

• 50 (2 of 4 squares) are IAIB those kids would
  have AB blood. The other 50 (2 of 4 squares) are
  IAi, those kids will have Type A blood.

8
Question

• Explain the difference between diploid and
  haploid.

9
Answer

• Diploid The state of having each chromosome in
  two copies per nucleus or cell.
• Haploid The state of having one copy of each
  chromosome per nucleus or cell.

10
Question

• In hamsters, black coat is dominant to white coat
  and rough coat is dominant to smooth coat. If two
  heterozygous black-rough coated hamsters where
  mated. What would be the phenotype ratio of the
  F1 generation?

11
Answer

• 9 Black-rough 3 Black-smooth
• 3 White-rough 1 White-smooth

12
Question

• Explain the difference between homologous
  chromosomes and sister chromatids.

13
Answer

• Homologous Chromosomes A pair of chromosomes
  made up of two homologs. Homologous chromosomes
  have corresponding DNA sequences and come from
  separate parents one homolog comes from the
  mother and the other comes from the father.
  Homologous chromosomes line up and synapse during
  meiosis.
• Sister Chromatids 2 duplicates of a chromosome
  created by replication.

14
Question

• In cats, the allele for black fur is dominant to
  the allele for brown fur, and the allele for
  short hair is dominant to the allele for long
  hair.
• Homozygous black fur heterozygous short hair
  male, heterozygous black fur long hair female
• Give Genotype and Phenotype Ratio

15
Answer

• BBSs x Bbss
• Genotype ratio 4 BBSs 4 BBss 4 BbSs 4
  Bbss
• Phenotype ratio 8 Black-short 8 Black-long

16
Question

• In human cells, 2N46. How many chromosomes
  would you expect to find in a sperm cell? In an
  egg cell? In a cell in your brain? Explain your
  answers.

17
Answer

• Sperm cells (haploid n) 23
• Egg cells (haploid n) 23
• Brain cells (diploid 2n) 46

18
Question

• If a man with hemophilia (difficulties with blood
  clotting) marries a homozygous normal woman, what
  is the probability of them having a hemophiliac
  child?

19
Answer

• Since the mom is not a carrier there is a 0
  chance of having a hemophiliac child

20
Question- 2 part

• What is crossing over and when does it occur?
• Which part of meiosis is most like mitosis?

21
Answer

• Crossing Over The exchange of DNA sequences
  between chromatids of homologous chromosomes
  during meiosis, occurs in prophase 1.
• Meiosis 2

22
Question

• A test was done to determine the biological
  father of a child.  The child's blood Type is A
  and the mother's is B.  Dude 1 has a blood type
  of O, dude 2 has blood type AB.  Which dude is
  the biological father?

23
Answer

• It is possible with the mom and Dude 2 to
  produce the child

24
Question

• In tomato plants, the allele for purple stems is
  dominant to allele for green stems and the allele
  for red fruit is dominant to the allele for
  yellow fruit. If two tomato plants heterozygous
  for both traits are crossed. state what
  proportion of the offspring would be expected to
  have purple stems and yellow fruit.

25
Answer

• 3/16

26
Question

• When a mouse with black fur is crossed with a
  mouse with white fur, all F1 generation offspring
  have gray fur. What genotypic and phenotypic
  ratios be expected in the F2?

27
Answer

• Genotype ratio 1 BB 2 Bb 1 bb
• Phenotype ratio 1 Black 2 Gray 1 White

28
Question

• Give the gametes for the following
• AaBb

29
Answer

• AB, Ab, aB, ab

30
Question

• In garden peas, tall vine (T) is dominant and
  short vine (t) is recessive. If a heterozygous
  tall pea plant is crossed with a short pea plant,
  what genotypes and phenotypes are possible in the
  F1 generation?

31
Answer

• Heterozygous tall pea plant Tt
• Short pea plant tt
• Answer
• Genotypes for F1 Tt and tt
• Phenotype for F1 Tall and short

32
Question

• Give the genotypic and phenotypic ratio of the
  potential children of a couple, if the man is
  heterozygous A-type blood and his wife is
  heterozygous B-type blood.

33
Answer

• Genotype ratio 1 IAIB 1 IBi 1 IAi 1 ii
• Phenotype ratio 1 AB 1 B 1 A 1 O

34
Question

• What are the possible blood types of a child
  who's parents are both heterozygous for "B" blood
  type?

35
Answer

• There is a 75 (3 of 4) chance that the child
  will be Type B, and a 25 (1 of 4) chance that
  the child will inherit Type O (ii).

36
Question

• In dogs, wirehair is a dominant trait, smooth
  hair is recessive. Two wire-haired dogs produce a
  male puppy that is wire-haired. To find out most
  quickly whether he carries the allele for smooth
  hair, he should be mated to a specific type of
  female. What is the name of this senario? (be
  specific for the term)

37
Answer

• He should be mated with a smooth haired
  (homozygous recessive), this would be a test
  cross

38
Question

• In garden peas, axial flower position is dominant
  and terminal flower position is recessive tall
  vine is dominant and short vine recessive. A
  plant known to be purebred for tall vine and
  axial flowers is crossed with a plant having
  short vines and bearing terminal flowers. What is
  the genotype of the offspring?

39
Answer

• AaTt

40
Question

• In cocker spaniels, black is a dominant trait
  (B), red is recessive (b). Solid color is
  dominant (S) and white spotting is recessive (s).
  A red male was mated to a black-and-white female.
  They had five puppies as follows 1 black, 1 red,
  1 black-and-white, and 2 red-and-white. What are
  the genotypes of the parents?

41
Answer

• Male bbS?
• Female B?ss
• need to look at puppies to determine genotypes
• Since all phenotypes appeared, then the parents
  must have been heterozygous for the traits
• Answer Male bbSs
• Female Bbss

42
Question

• What are the chances of a woman with Type AB and
  a man with Type A having a child with Type O?

43
Answer

• 0, because the woman has blood type AB

44
Question

• Optic atrophy (blindness due to degeneration of
  the optic nerve) occurs as a result of the action
  of an X-linked recessive gene. A woman with the
  optic atrophy marries a normal man. What is the
  expected genotypic and phenotypic ratio of their
  children?

45
Answer

• WomanXaXa woman with optic atrophy
• Man XAY normal man
• Genotypic Ratio 2XAXa2XaY
• Phenotypic Ratio 2 female carriers 2 males with
  optic atrophy

46
Question

• In cattle, hair color shows codominance. Red is
  dominant, and white is recessive. In the
  heterozygous condition codominance is shown as
  roan (something of a light red) coat color. If a
  roan bull and a roan cow are mated over several
  years and produce 12 offspring. How many of the
  offspring would be expected to be white? Roan?

47
Answer

• RWxRW
• 3 red6 roan3 white

48
Question

• In flies, white eyes are an X-linked recessive
  trait. Cross a carrier female with a red-eyed
  male fly. What of the children would have
  white eyes? What of the girls would be
  carriers? What percent of all the kids would be
  carriers?

49
Answer

• FemaleXRXr
• MaleXRY
• 25 white eyed offspring
• 50 of girls would be carriers
• 25 of all kids would be carriers

50
Question

• Polyploid organisms results from
• (a) crossing over
• (b) non disjunction
• (c) mitosis
• (d) random assortment