Exercise- Genetics. 1. Which of the following statements is true of mitosis but not of meiosis?

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1 Exercise- Genetics 1. Which of the following statements is true of mitosis but not of meiosis? A. The chromosome number is halved. B. Pairing of homologous chromosome occurs. C. Produces genetic variations. D. It increases the cell number for growth. 2. Three steps in meiosis are listed below: S: attachment of chromosomes to the spindles P: pairing of homologous chromosomes T: separation of chromatids The correct order of these steps is A. P T S B. P S T C. S P T D. T S P The following three questions(3 to 5) refer to the diagram which represents part of a DNA molecule. HS Wong (Rm116) helenwong@vtc.edu.hk 1

2 3. If N is adenine (A), which of the following is true of P? A. Cytosine (C) B. uracil(u) C. guanine(g) D. thymine(t) 4. L, M and N together make up a A. nucleolus. B. deoxyribosugar. C. nucleotide. D. organic base. 5. Which of the following correctly identifies the constituent parts of DNA> Sugar Phosphate Organic base A. M L N B. M N L C. L M N D. N L M 6. Which of the following comparisons between DNA and RNA is wrong? DNA RNA A. Double stranded Single-stranded helix B. Deoxyribose sugar Ribose sugar C. With phosphate Without phosphate D. Adenine paired up Adenine paired up with uracil with thymine HS Wong (Rm116) helenwong@vtc.edu.hk 2

3 7. The diagram below shows the base sequence of one strand of DNA C G T A C Which of the following diagrams correctly shows the base sequence of the other strand? A. C G T A C B. G C A T G C. C A T G C D. T G A T C The following three questions (8 to 10 ) refer to the photomicrographs below which show four stages of a cell division. HS Wong (Rm116) helenwong@vtc.edu.hk 3

4 8. The correct order of this type of cell division is A. (2) (3) (4) (1) B. (3) (1) (4) (2) C. (1) (4) (3) (2) D. (3) (4) (1) (2) 9. Which of the following statements about the type and function of this cell division is correct? A. meiosis for formation of gametes B. mitosis for formation of gametes C. meiosis for increasing the number of cells D. mitosis for increasing the number of cells 10. If the chromosome number of the parent cell is 46, what is the chromosome number of cell X? A. 34 B. 46 C. 58 D. 23 HS Wong (Rm116) 4

5 The following three questions (11 to 13) refer to the human pedigree below, which shows the inheritance of tongue rolling. Tongue rolling in human is controlled by a single pair of alleles in which tongue rolling is dominant over non-tongue-rolling. 11. Which of the following statements is true? A. Individual 4 is homozygous tongue roller. B. Individual 1 is heterozygous tongue roller. C. Individual 8 is homozygous tongue roller. D. Individual 10 or 11 is heterozygous non-tongue roller. HS Wong (Rm116) helenwong@vtc.edu.hk 5

6 12. What is the probability of the second child of individuals 7 and 8 to be non-tongue roller? A. 25% B. 50% C. 75% D. 100% 13. Let R be the dominant character for tongue roller and r be the recessive character for non-tongue roller. Which of the following crosses is true for individuals 1 and 2? 14. Which of the following statements about the chromosomes of human egg is correct? A. 22 autosomes and one Y chromosome B. 22 pairs autosomes and one X chromosome C. 22 autosomes and one X chromosome D. 21 autosomes and one X chromosome and one Y chromosome HS Wong (Rm116) helenwong@vtc.edu.hk 6

7 15. Which of the following cannot bring about variations? A. meiosis B. mutation C. environment D. mitosis 16. Which disease(s) below is/are hereditary diseases? 1. Night blindness 2. Colour blindness 3. Hemophilia A. 3 only B. 1 & 2 only C. 2 & 3 only D. 1, 2 & The inheritance of color blindness is sex-linked. A colour blinded man and a normal vision woman can give birth to 1. normal vision son. 2. colour blindness daughter. 3. carrier daughter. 4. carrier son. A. 1 & 3 only B. 2 & 4 only C. 1, 2 & 3 only D. 1, 2, 3 & 4 HS Wong (Rm116) helenwong@vtc.edu.hk 7

8 18. If half of the offspring of a parent are tongue roller (dominant) and half are non-tongue roller. The parent type must have been A. homozygous tongue roller x heterozygous tongue roller B. heterozygous tongue roller x heterozygous tongue roller C. heterozygous tongue roller x homozygous non-tongue roller D. homozygous tongue roller x heterozygous non-tongue roller 19. Albinism in human is controlled by a single pair of alleles. Albinism is a recessive character. The probability of father with normal skin pigment and mother with normal skin pigment in giving birth to an albino child is 5. 0% 6. 25% 7. 50% A. 2 only B. 3 only C. 1 & 2 only D. 2 & 3 only 20. A boy with recessive sex-linked character must have received his recessive gene from his A. mother B. father C. both mother and father D. grandmother HS Wong (Rm116) helenwong@vtc.edu.hk 8

9 21.The synthesis of protein is directed by A. endoplasmic reticulum B. DNA C. ribosomes D. RNA 22. The diagram below shows part of a strand of DNA C G A T A Which of the following is correct for a corresponding part of a RNA molecule? A. G C T U T B. C G U A T C. A T C G C D. G C U A U 23. The pathway of protein synthesis by DNA is called A. translation. B. replication C. transcription. D. mutation. HS Wong (Rm116) helenwong@vtc.edu.hk 9

10 24. Sex is determined at the time of A. formation of gametes. B. birth. C. union of gametes. D. ovulation. 25. The diagram below shows two homologous chromosomes of a cell. A pair of alleles T and t is also shown on the chromosomes Which of the following are types of gamete formed by this cell after meiosis? HS Wong (Rm116) helenwong@vtc.edu.hk 10

11 26. Hemophilia is a sex-linked hereditary disease. Hemophilia is due to a recessive gene (h). The followings are the genotypes of four persons 1. X H Y 2. X H Y h 3. X h X h 4. X h Y The phenotypic ration between normal male offspring to hemophilic female offspring from a cross between persons 2 and 4 is A. 1 : 1 B. 2 : 1 C. 1 : 2 D. 3 : Colour blindness is a sex-linked hereditary disease. Normal vision (C) is dominant over colour blindness (c). X C Y x P X C Y X C x c X c Y X C X C The genotype of P is A. X C X C B. X C X c C. X c X c D. X C Y HS Wong (Rm116) helenwong@vtc.edu.hk 11

12 28. Which of the following is a correct sequence in the control of protein synthesis in the cell? A. DNA ribosome mrna protein B. mrna DNA ribosome protein C. DNA mrna ribosome protein D. mrna trna ribosome protein Questions (28 to 30) refer to the diagrams below which show two dividing cells S and P at the same stage. 29. The original chromosome number in cells S and P are respectively S P A. 8 4 B. 4 8 C. 4 4 D. 8 8 HS Wong (Rm116) helenwong@vtc.edu.hk 12

13 30. The type of cell division undergoing by cells S and P are respectively S P A. Meiosis Mitosis B. Mitosis Meiosis C. Meiosis Meiosis D. Mitosis Mitosis 31. The chromosome number of each daughter cell formed from cell S is A. 2 B. 4 C. 8 D The diagrams below show an inheritance of eye colour in a family. Brown-eye Blue-eye Parents Blue gene x Blue gene Brown gene Blue gene Gametes Blue Brown Blue Blue gene gene gene gene Children (F)? HS Wong (Rm116) helenwong@vtc.edu.hk 13

14 Which of the following is true for the dominant eye colour and phenotypic ratio of the F 1 generation: A. blue; 1 blue : 1 brown B. blue; 1 blue: 3 brown C. brown; 3 blue: 1 brown D. brown; 1 blue: 1 brown 33. Which of the following comparisons about mitosis and meiosis is wrong? Mitosis Meiosis A. For growth For gametes formation B. Chromosome number Chromosome number is halved C. No genetic variation Brings about genetic variation D. Pairing of homologous chromosomes No pairing of homologous chromosomes 34. Which process(es) below is/are responsible for maintaining a constant chromosome number from generation to generation? 1. meiosis 2. division of the fertilized egg 3. fertilization A. 1 only B. 3 only C. 1 & 3 only D. 1, 2 & 3 HS Wong (Rm116) helenwong@vtc.edu.hk 14

15 35. The final appearance of a person depends on A. environment only. B. inheritance only. C. inheritance and intelligence. D. environment and inheritance. 36. Which of the following human characteristics is not inherited? A. fatty abdomen B. blood groups C. ability to roll tongue D. iris colour 37. A sex-linked gene is A. only passed on from father to son. B. Found on the X chromosome. C. Only passed on from mother to daughter. D. Found on the Y chromosome. 38. The following show some triplet codes of the mrna with their corresponding amino acids. Codes of mrna GCC AAG UAU Amino acid alanine lysine tyrosine HS Wong (Rm116) helenwong@vtc.edu.hk 15

16 Which DNA code below would result in part of a polypeptide chain having the amino acids sequence lysine-alanine- tyrosine? A. CCT CCC AAT B. TTC CGC TAT C. TTC CGC ATA D. CTT GGG TAT 39. Which of the following phenotypes is an effect of both inheritance and the environment? A. blood groups B. colour of skin C. re-green colour blindness D. eye colour 40. A red-haired man marries a brown-haired woman, and all the children are brown-haired. Which explanation below is true? A. Both parents are homozygous for red and brown-haired respectively; brown-haired is dominant. B. Both parents are heterozygous for red and brown-haired respectively; brown-haired is dominant. C. Both parents are homozygous for red and brown-haired respectively; red-haired is dominant. D. Both parents are heterozygous for red and brown-haired respectively; red-haired is dominant. HS Wong (Rm116) helenwong@vtc.edu.hk 16

17 Answer 1.D 2. B 3. D 4. C 5. A 6. C 7. B 8.B 9. D 10. B 11. B 12. B 13. D 14. C 15. D 16. C 17. C 18. C 19. C 20. A 21. B 22. D 23. A 24. C 25. C 26. A 27.B 28. C 29. C 30. A 31. A 32.D 33. D 34. C 35. D 36. A 37. B 38. C 39. B 40. A HS Wong (Rm116) helenwong@vtc.edu.hk 17