Chapter 8 Review Questions answer key PDF

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Chapter 8 Review Questions with Answer Key
Professor Rongsun Pu...

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CHAPTER 8 REVIEW QUESTIONS Questions 1-6. Refer to the following karyotype of a human.

1. B) C) D) E)

This karyotype is that of a __________ who has ________ number of chromosomes. Male; abnormal Female; normal Female; abnormal It cannot be determined from the given information.

Use the following choices for questions 2-6: A) Metacentric B) Submetacentric C) Acrocentric D) Telocentric 2. 3. 4. 5. 6.

Chromosomes 21, 22 and Y are ____ _____. Chromosomes 1, 3, 16, 19 and 20 are ___ _______. Chromosomes 2, 4 and X are _____ ____. Which type of chromosomes is the most common in the karyotype? Which type of chromosomes is absent in the karyotype?

7. A chromosome that is metacentric has its centromere A) at the very top. B) near one end, but not at the very top. . D) at two distinct locations. 8. Staining eukaryotic chromosomes is useful because it makes it possible to A) Distinguish chromosomes that are similar in size and centromere locations. 1

B) C)

Identify changes in chromosome structure. Explore evolutionary relationships among different species.

9. A change in chromosome structure that does not involve a change in the total amount of genetic material is A) A deletion. . C) A duplication. 10. Which of the following statements is correct? B) C) D)

If a deletion and a duplication are the same size, the duplication is likely to be more harmful. If a deletion and a duplication are the same size, they are likely to be equally harmful. A deletion is always harmful, whereas a duplication is always beneficial.

11. A paracentric inversion A) Includes the centromere within the inverted region. C) D)

Has two adjacent inverted regions. Has an inverted region at the very end of a chromosome.

12.

Which of the following causes a translocation?

B) C)

Crossing over between homologous chromosomes. Crossing over between two sister chromatids.

13. Humans have 23 chromosomes per set. A person with 45 chromosomes could be described as being A) Euploid. . C) Monoploid. D) Trisomic. 14. In a trisomic individual such as a person with trisomy 21 (Down syndrome), a genetic imbalance occurs because ) B) Genes on chromosome 21 are underexpressed. C) Genes on the other chromosomes are overexpressed. D) Genes on the other chromosomes are underexpressed. 15. Humans with extra X or Y chromosomes can survive. A possible explanation why these abnormalities permit survival is because A) The chromosomes have clusters of genes that aid in embryonic growth. 2

B)

The sex chromosomes are small and carry relatively few genes.

16. In agriculture, an advantage of triploid plants is that they are A) More fertile. C) D)

Always disease-resistant. All of the above.

17. A diploid fruit fly has 8 chromosomes (2n=8). Which of the following terms should not be used to describe a fruit fly with 4 sets of chromosomes? A) Polyploid C) D) E)

Euploid Tetraploid 4n

Short Answers. 18.

Explain why human trisomies 13, 18 and 21 can survive, but other trisomies are lethal.

19.

What is a gene family? How are gene families produced over time? With regard to gene function, what is the biological significance of a gene family?

Reference Key to Short Answers.

18. f

because the . The

and probably because they

relative to the chromosomes that are trisomic.

19. Ag y is a . They have similar sequences, but the sequences have some differences due to the accumulation of mutations over many generations. . The specialization may occur in different cells or at different stages of development.

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