Human Genetics Quiz II (2022/2023) PDF

# UNIVERSITY OF CAPE COAST ## COLLEGE OF HEALTH AND ALLIED SCIENCES ### SCHOOL OF ALLIED HEALTH SCIENCES #### DEPARTMENT OF BIOMEDICAL SCIENCES ##### BMD 404: HUMAN GENETICS (2 CREDITS) **QUIZ II (2022/2023)** Time: 30 min Answer ALL Questions on this sheet. 1. Explain Klinefelter syndrome, and...

# UNIVERSITY OF CAPE COAST ## COLLEGE OF HEALTH AND ALLIED SCIENCES ### SCHOOL OF ALLIED HEALTH SCIENCES #### DEPARTMENT OF BIOMEDICAL SCIENCES ##### BMD 404: HUMAN GENETICS (2 CREDITS) **QUIZ II (2022/2023)** Time: 30 min Answer ALL Questions on this sheet. 1. Explain Klinefelter syndrome, and list four common features associated with this syndrome. 2. Define karyotyping, and list one application of karyotyping. (2 marks) 3. Explain the designation t(9,22)(q34;q11). (2 marks) 4. What is the meaning of the designation 46,XX, add(19)(p13) as chromosome structural alterations. (2 marks) 5. Mention the three types of colour blindness, indicating the specific chromosome that is mutated in each type of colour blindness. (2 marks) 6. Inactivated X chromosome absorbs stain much faster than the active X chromosome because... (3 marks) 7. List four structural features of the chromosome that contribute to the formation of bands when stained. (1 marks) 8. Describe the role of the gene SRY in sex determination. (2 marks) 9. Distinguish between terminal deletion and interstitial deletion in chromosome. (2 marks) 10. What is the function of Leydig cells and Sertoli cells in genital development? (2 marks) ## UNIVERSITY OF CAPE COAST ### COLLEGE OF HEALTH AND ALLIED SCIENCES #### SCHOOL OF ALLIED HEALTH SCIENCES ##### DEPARTMENT OF BIOMEDICAL SCIENCES **BMD 404: HUMAN GENETICS (2 CREDITS)** **QUIZ 2** Choose from the letters A-E the most appropriate option for each question. 1. A karyotypically normal couple has a child with trisomy 21 Down syndrome. DNA analysis of 21 polymorphic markers reveals the following results (letters refer to polymorphic loci; numbers refer to alleles at that locus). In which meiotic division did nondisjunction occur? Marker Locus | Father | Mother | Child ------- | -------- | -------- | -------- a | 1,2 | 2,2 | 1,2,2 b | 1,1 | 2,2 | 1,2,2 c | 1,1 | 1,1 | 1,1,1 d | 1,1 | 1,2 | 1,2,2 A. Maternal meiosis I B. Maternal meiosis II C. Paternal meiosis I D. Paternal meiosis II E. Paternal meiosis I or II 2. The genotypic ratio of a monohybrid cross A. 1:2:1 B. 3:1 C. 2:1:1 D. 9:3:3:1 3. The crossing of F1 to either of the parents A. Testcross B. Backcross C. F1 crosses D. True cross 4. An alpha-thal silent carrier man (aa/a−) mates with an alpha-thal trait woman (aa/--). Assuming no genetic recombination, which of the following is not a possible genotype of their offspring? A. aa/-- B. aa/aa C. a−/a− D. a−/-- E. aa/a− 5. Homozygosity and heterozygosity of an individual can be determined by A. Back cross B. Self-fertilization C. Test cross D. Forward cross 6. Pea plants were used in Mendel’s experiments because A. They were cheap B. They had contrasting characters. C. They were available easily D. All of the above 7. Which of the following statements is true regarding the "law of segregation"? A. Law of segregation is the law of purity of genes B. Alleles separate from each other during gametogenesis C. Segregation of factors is due to the segregation of chromosomes during meiosis D. Segregation of factors is due to the attachment of spindle fibres during meiosis 8. A gene showing codominance A. Has one allele dominant to the other B. Has both alleles independently expressed in the heterozygote C. Has alleles tightly linked on the same chromosome D. Has alleles expressed at the same time in development E. Has alleles that are recessive to each other 9. The phenomenon of "independent assortment" refers to A. Expression at the same stage of development B. Unlinked transmission of genes in crosses resulting from being located on different chromosomes, or far apart on the same chromosome. C. Association of an RNA and a protein implying related function D. Independent location of genes from each other in an interphase cell E. Association of a protein and a DNA sequence implying related function 10. A geometrical device that helps to find out all possible combinations of male and female gametes A. Bateson Square B. Mendel Square C. Punnett Square D. Mendel’s Cube 11. Which term represents a pair of contrasting characters? A. Heterozygous B. Homozygous C. Codominant genes D. Allelomorphs 12. Which of the following below is correct with respect to autosomal dominant inheritance? A. One of the parents of an affected person will be affected. B. Both parents of an affected person may be unaffected, but one of them at least will carry the mutant allele in all of their nucleated cells. C. A child born to an affected parent and a normal parent has a 50% chance of inheriting the mutant allele. D. The term dominant applies equally to the phenotype of affected individuals with one mutant allele (heterozygotes) and individuals with two mutant alleles because in practice the phenotypes are essentially identical. 13. An exception to Mendel’s law is A. Independent assortment B. Linkage C. Dominance D. Purity of gametes 14. Pea plants were used in Mendel’s experiments because A. They were cheap B. They had contrasting characters. C. They were available easily D. All of the above 15. When the activity of one gene is suppressed by the activity of a non-allelic gene A. Pseudo-dominance B. Hypostasis C. Epistasis D. Incomplete dominance 16. Cystic fibrosis A. Sex-linked recessive disorder B. Autosomal dominant disorder C. Autosomal recessive disorder D. Sex-linked dominant disorder 17. What does a ratio of 9:7 in the F2 generation represent? A. Incomplete dominance B. Co-dominance C. Epistasis D. Complementary interaction 18. A small amount of lethal mutation is always present in the population due to ... A. Positive selection B. Negative selection C. Frequency-dependent selection D. Mutation-selection balance 19. Find the probability of getting an AABB genotype (A and B are not linked) if a plant with genotype AaBb is self-fertilized A. 1/2 B. ¼ C. ⅛ D. 1/16 20. A represents the dominant allele and a represents the recessive allele of a pair. If, in 1000 offspring, 500 are aa and 500 are of some other genotype, which of the following are most probably the genotypes of the parents? A. Aa and Aa B. Aa and aa C. AA and Aa D. AA and aa E. aa and aa 21. With respect to autosomal dominant inheritance in human genetics, which, if any, of the following statements is correct? A. One of the parents of an affected person will be affected. B. Both parents of an affected person may be unaffected, but one of them at least will carry the mutant allele in all of their nucleated cells. C. A child born to an affected parent and a normal parent has a 50% chance of inheriting the mutant allele. D. The term dominant applies equally to the phenotype of affected individuals with one mutant allele (heterozygotes) and individuals with two mutant alleles because in practice the phenotypes are essentially identical. 22. A form of vitamin D-resistant rickets, known as hypophosphatemia, is inherited as an X-linked dominant trait. If a male with hypophosphatemia marries a normal female, which of the following predictions concerning their potential progeny would be true? A. All of their sons would inherit the disease B. All of their daughters would inherit the disease C. About 50% of their sons would inherit the disease D. About 50% of their daughters would inherit the disease E. None of their daughters would inherit the disease 23. Which of the following best describes the parents in a testcross? A. One individual has the dominant phenotype and the other has the recessive phenotype. B. Both individuals are heterozygous. C. Both individuals have the dominant phenotype. D. Both individuals have the recessive phenotype. E. Both individuals have an unknown phenotype. 24. Which of the following statements is incorrect with respect to autosomal recessive inheritance? A. Affected individuals normally have unaffected parents. B. For unaffected parents who have a previously affected child, there is a 1 in 4 risk of having an affected child on each occasion that they produce a new child. C. Heterozygotes are always asymptomatic carriers. D. Some affected individuals have alleles with identical pathogenic mutations but many have two different mutant alleles and are described as compound heterozygotes. 25. Which of the following statements concerning X-linked dominant inheritance is false? A. There are significantly more affected females than males. B. Each child born to an affected mother has a risk of 1 in 2 of being affected. C. Each daughter born to an affected father has a risk of 1 in 2 of being affected. D. Each boy born to an affected father has a negligible risk of being affected. 26. The pedigree below shows a family with cystic fibrosis (autosomal recessive). What is the chance that I-3 is a carrier of cystic fibrosis? 1 2 3 4 5 6 7 A. ¼ B. 1/3 C. ½ D. ¾ 27. A karyotypically normal couple has a child with trisomy 21 Down syndrome. DNA analysis of 21 polymorphic markers reveals the following results (letters refer to polymorphic loci; numbers refer to alleles at that locus). Locus | Father | Mother | Child ------- | -------- | -------- | -------- a | 1,2 | 2,2 | 1,2,2 b | 1,1 | 2,2 | 1,2,2 c | 1,1 | 1,1 | 1,1,1 d | 1,1 | 1,2 | 1,2,2 In which meiotic division did nondisjunction occur? A. Maternal meiosis I B. Maternal meiosis II C. Paternal meiosis I D. Paternal meiosis II 28. Which of the following patterns of inheritance best explains the transmission of the trait in the pedigree below? 1 2 3 4 5 6 7 A. Sex-linked dominant B. Sex-linked recessive C. Autosomal recessive D. Autosomal dominant E. Incompletely dominant 29. The pedigree below shows a family with cystic fibrosis (autosomal recessive). What is the chance that I-3 is a carrier of cystic fibrosis? 1 2 3 4 5 6 7 A. ¼ B. 1/3 C. ½ D. ¾ 30. A karyotypically normal couple has a child with trisomy 21 Down syndrome. DNA analysis of 21 polymorphic markers reveals the following results (letters refer to polymorphic loci; numbers refer to alleles at that locus). Locus | Father | Mother | Child ------- | -------- | -------- | -------- a | 1,2 | 2,2 | 1,2,2 b | 1,1 | 2,2 | 1,2,2 c | 1,1 | 1,1 | 1,1,1 d | 1,1 | 1,2 | 1,2,2 In which meiotic division did nondisjunction occur? A. Maternal meiosis I B. Maternal meiosis II C. Paternal meiosis I D. Paternal meiosis II ## UNIVERSITY OF CAPE COAST ### SCHOOL OF ALLIED HEALTH SCIENCES #### DEPARTMENT OF BIOMEDICAL SCIENCES **BMD 404: HUMAN GENETICS (2 CREDIT)** **QUIZ I, FIRST SEMESTER-2019/2020 ACADEMIC YEAR** (TIME ALLOWED: 40 Minutes) Q1. What is Klinefelter syndrome? List four common features associated with this syndrome. Klinefelter syndrome is a chromosomal disorder in which there is the addition of one X chromosome (sex chromosomes) and it is designated as 47,XXY. The features include: tall males with long legs and a stout build; infertility, mental retardation (reduced or low intellectual capability, and small testes). Q2. What is Turner syndrome? List four features associated with this aneuploidy. Turner Syndrome is a chromosomal disorder where there is the loss of one X chromosome of the female sex chromosome designated as 45,X. The features include: webbed neck, shortening of stature, heart defects, and mental retardation (reduced capabilities & infertility). Q3. List four chromosome types which have secondary constriction The chromosomes 13, 14, 15, and 21 have secondary constriction. Q4. What is Karyotyping? Karyotyping is the process of cutting out and arranging metaphase spread chromosomes of a particular chromosome. The same chromosome length is arranged into aligned pairs of the same chromosome length. The process is termed karyotyping, and the result is called karyotype. Q5. Explain the designation t(9,22)(q34;q11), and name disease associated with it. This designation implies reciprocal translocation between chromosome 9 on the long arm of band q34 and chromosome 22 on the long arm of band q11. The result is a translocated type of chromosome. It is associated with Chronic myelogenous leukemia. Q6. A band is that part of the chromosome which is clearly distinguishable from its adjacent segments. These bands may denote. - the base sequence of DNA lining that chromosome - It is related to structural properties, such as DNA loop formation within that segment. - The presence of specific proteins. - The relative proportion of amino acids within different segments of the chromosome. Q7. What is the meaning of the designation 46,XX, add(19)(p13) as chromosome structural alterations. The designation implies a female (XX) with an additional chromosome to the terminal end of the short arm of band p13 on chromosome 19. Q8. What is chromosome? A chromosome is a complex structure located inside a nucleus of a cell. It is composed of DNA and proteins. Q9. Explain Edwards syndrome, and list two (2) symptoms associated with this aneuploidy. Edwards Syndrome is the addition of an extra chromosome in the female, specifically chromosome 18, which is designated as 47,XX, 18. The features include: clenched hand with overlapping fingers; a cleft palate and closed hand with overlapping fingers. Q10 Differentiate between acrocentric and metacentric chromosomes. List four examples of acrocentric chromosome. An acrocentric chromosome is a type of chromosome that has the centromere nearer to the end (tip) of the chromosome whereas, a metacentric chromosome is a type of chromosome that has the centromere at the center of the chromosome. Examples of acrocentric chromosomes include chromosome 13, 14, 15, and 21.