Year 10 Advanced Science – Genetics Revision Name: ______

Part A : Multiple Choice

Use the following information to answer Questions 1 and 2.

In animals, being unable to produce pigment is called albinism. This condition occurs in humans as well as in other animals. Albinism is inherited as an autosomal recessive trait.

  1. A cross between two individuals, both heterozygous for albinism, could be represented by
    (VCE question)
  1. AA x AA.
  2. aa x aa.
  3. Aa x Aa.
  4. Aa x aa.
  1. A cross that could confirm that a prize-winning dog was a carrier for albinism is
    (VCE question)
  1. AA x AA.
  2. aa x aa.
  3. AA x Aa.
  4. Aa x aa.
  1. Which of the following is NOT an example of continuous variation?
  2. Intelligence
  3. Free or attached ear lobes
  4. Height
  5. Blood pressure
  6. Which of the following cannot be inherited?
  7. Pneumonia
  8. Sickle-cell Anaemia
  9. Down’s Syndrome
  10. Colourblindness
  11. Which is the term used to describe the genotype with two contrasting alleles?
  12. Homologous
  13. Heterozygous
  14. Homozygous
  15. Hemizygous
  16. Which type of following human cells have the most number of chromosomes?
  17. Nerve cell
  18. Red blood cell
  19. Sperm cell
  20. Egg cell
  1. A fruit fly has four pairs of chromosomes in its cells. At meiosis, how many different combinations of maternal and paternal chromosomes are possible in the gametes?
  2. 4
  3. 6
  4. 8
  5. 16
  6. A plant with red flowers is crossed with a white-flowered plant of the same species. All the seeds, when grown, produce plants with red flowers. Assuming that the flower colour is controlled by a single pair of alleles, which allele is dominant and which is recessive?
  7. White is dominant and red is recessive
  8. Red is dominant and white is recessive
  9. Both white and red are dominant
  10. Both white and red are recessive
  11. What is not true for sex-chromosomes in human?
  12. A male has an X chromosome and a Y chromosome.
  13. A female has 2 X chromosomes
  14. There is no gene in Y chromosome
  15. X chromosome is larger than Y chromosome.
  16. Eye colour in humans can range from dark brown to light blue and is controlled by multiple genes. Eye colour is an example of (VCE question)
  17. multiple alleles.
  18. codominance.
  19. polygenic inheritance.
  20. discontinuous variation.
  21. A goldfish has 94 chromosomes in its somatic cells. The diploid number for a goldfish is
    (VCE question)
  22. 47
  23. 94
  24. 188
  25. 376
  26. Compared with the amount of nuclear DNA in a nerve cell, the amount of nuclear DNA in an unfertilised egg cell will be (VCE question)
  27. double.
  28. the same.
  29. half.
  30. a quarter.
  31. Red-green colour blindness is X-linked in humans. If a male is red-green colour blind, and both parents have normal colour vision, which of the male's grandparents is most likely to be red-green colour blind? (VCE question)
  32. Maternal grandmother
  33. Maternal grandfather
  34. Paternal grandmother
  35. Paternal grandfather
  36. Which is found in RNA but not in DNA? (VCE question)
  37. adenine
  38. cytosine
  39. guanine
  40. uracil
  41. A segment of DNA has one strand with the following sequence of bases.

A G C G C A T A G C A A (VCE question)

The complementary strand of DNA is

  1. U C G C G U A U C G U U
  2. T C G C C G A T C G T T
  3. T C G C G T A T C G T T
  4. T C G C A T T A C A U U
    Questions 16 and 17 refer to the following

In rabbits, spotted coat (D) is dominant to solid colour (d).

  1. A cross that would show whether a spotted individual is heterozygous for coat colour would be (VCE question)
  1. DD  DD
  2. Dddd
  3. dddd
  4. DD Dd
  1. When two rabbits with spotted coats were mated, they produced some offspring with spotted coats and some with solid colour. It is reasonable to conclude that (VCE question)
  1. all the offspring with spotted coats have the same genotype
  2. neither the parents are heterozygous
  3. no offspring could be homozygous for spotted coat
  4. all the offspring with solid colour are homozygous

Information for Questions 18 and 19

The following photograph shows the karyotype of a human.

  1. This karyotype is for a (VCE question)

Sex / Normal or Abnormal / Diploid number
A. / female / abnormal / 2n = 45
B. / female / normal / 2n = 48
C. / male / abnormal / 2n = 47
D. / male / normal / 2n = 46
  1. Red-green colourblindness is inherited as a sex-linked recessive gene. A colourblind person with the karyotype in Figure 2 would have the genotype (VCE question)
  1. XHXh
  2. XhY
  3. XhO
  4. XhXh
  1. Structure II in the diagram shows (VCE question)
  2. two chromatids
  3. two centromeres
  4. two chromosomes
  5. four chromatids

Part B: Short answer questions

Question I - Cell Division and Chromosomes [ 32 marks ]

  1. A cell in the basal layer of the skin contains 46 chromosomes and divides by mitosis to produce new skin cells. After ten successive divisions, how many chromosomes will the basal cell have? Explain your answer [2]

______

  1. The drawings below depict stages in the mitotic division of a cell

(a) Write the letters in the order in which these stages occur. [2]
______

(b) How many pairs of chromosomes are there in the cell? [1]
______

(c) What is the diploid number of chromosomes in these cells? [1]

______

3. Choose the most appropriate word to complete the sentence.

When chromosomes replicate, they produce ______[1].

tissues, nuclei, chromatids, somatic cells

4. In which three of the following cells is mitosis unlikely to occur?

a sperm cell, an epithelial cell of a villus, a hair cell, a cell in the red bone marrow, a red blood cell, a lymphocyte, a cell in the basal layer of the skin [3]

______

5. An animal has 36 chromosomes in each of its body cells. How many of these chromosomes came from its male parent? [1]

______

6. Which pairs of chromosomes in the cell shown hereare homologous? [3]

______

7. Fill in the missing words. [3]

The ______of a cell contains a fixed number of
chromosomes. Before mitosis, each chromosome
______to produce two ______.

8. The following drawings-show the sequence of events early in cell division.

(a) Is the division meiotic or mitotic? [1]
______

(b) How do you know? Give 2 reasons. [2]

______
______

9. Give two examples in each case of organs or tissues in which you would expect

(a) meiosis [2] ______
(b) mitosis to be taking place. [2] ______

10. From the list below, choose the most suitable words to complete the sentence. [8]

cells, gene, gamete, radiation, chromosome, nucleus, ovum, organism

Mutations are changes which occur in a ______or a ______If a mutation

occurs in a cell which is going to form a ______the mutation may affect the whole

______which develops. Down's syndrome results from a ______mutationin
the ______. Sickle cell anaemia results from a ______mutation which affects
______of the blood system. Exposure to ______may increase the rate of
mutation.

Question II - Heredity

11. In cats, the allele (S) for short fur is dominant to the allele (s) for long fur. [ 6 marks ]

(a) What is the genotype of a true-breeding, long-furred cat? [1] ______

(b) What is the phenotype of a cat with the genotype Ss? [1] ______

(c) In an Ss genotype, which allele is expressed in the phenotype? [1]
______

(d) Which of the fo1lowing genotypes is (i) heterozygous (ii) homozygous dominant?

SS, Ss, ss (i) ______(ii) ______[3]

12. In rabbits, assume that the dominant allele (B) produces black fur. The allele (b) for white fur is recessive to B. [ 15 marks ]

(a) What colour fur will each of the following rabbits have? [4]

Rabbit 1 Rabbit 2 Rabbit 3 Rabbit 4

genotype BB Bb bB bb
phenotype ______

(b) Which of them will breed true? [2] ______

(c) Which rabbits are homozygous for coat colour? [2] ______

(d) If rabbits 1 and 4 were mated together and had 12 babies, how many of these would you

expect to be black? Explain your answer. [3]
______
______

(e) If rabbits 2 and 3 are interbred and produce several litters, totalling 48 babies, how

many white babies would be predicted by the laws of genetics? [2]
______
______

(f) If rabbits 3 and 4 are mated together on several occasions and have 50 babies altogether,

how many of their babies would you 'expect' to be black? Explain your answer [2]

______
______

13. In fruit flies, the allele (n) for ebony (black) body is recessive to the allele (N) for normal

(grey) body. [ 6 marks ]

(a) Complete the Punnett square, for a

cross between normal (grey-bodied)

flies which are heterozygous for this

allele (i.e. Nn genotypes). [3]

(b) State the expected proportion of normal

and ebony-bodied flies in a large sample of

the offspring. [2] ______

(c) State the proportion of the normal phenotypes which would be true breeding. [1]
______.

14.Haemophilia (recessive sex-linked disorder)[ 19 marks ]
a) Use appropriate symbols to represent chromosomes and genes and complete the following table [4]

Normal female = ______/
Carrier female = ______
Normal male = ______/ Male with haemophilia = ______

b) Because the male only has sex-linked genes on the ______chromosome, there is nothing on the ______chromosome to mask the disorder on the ______chromosome. So if a male has even 1 copy of the disordered gene, he suffers from the disorder. A female can carry 1 disordered gene on one ______chromosome but still have a normal gene to mask it on the other ______chromosome. A "carrier female" usually doesn't suffer from the disorder, she just carries it and can pass it on ....usually to her SONS. [5]

,
c) Cross a carrier female (for haemophilia) with a normal male. Of all their offspring, what is the probability they will produce a haemophiliac son? [1+3]

______

d) Cross a haemophiliac female with a normal male. Of all their offspring, what is the probability they will produce a haemophiliac daughter? [1+3]

______

e) A "carrier female" usually doesn't suffer from the disorder, she just carries it and can pass it on ....usually to her SONS. Why? [2]
______
______

15. The genetic disorder phenylketonuria (PKU) is caused by a recessive allele (n). The family tree below shows the incidence of the disease over three generations. [ 13 marks ]

(a) What can you deduce about the genotypes of the grandparents? [2]
______

(b) Explain your reasoning. [2]
______
______

(c) What is the genotype of Jane's husband? [1] ______

(d) Explain your reasoning. [2]
______
______

(e) What are the chances that Peter is the carrier of the PKU allele that resulted in

having an affected son? Explain it [2]
______
______

(f) If Jane had been normal, what are the possible genotypes of the grandparents? [2]
______

(g) Is it possible that the allele for PKU is sex-linked? Why? [2] ______
______