Genetics II Ch 12 - Take Home Quiz

1. Which refers to turning a chromosome segment around 180º and rejoining it to the original chromosome?
A. translocation
B. monosomy
C. duplication
D. deletion
E. inversion

2. Which statement is NOT true about X-linked characteristics?
A. More males than females are affected.
B. Females can be carriers of the gene without showing it.
C. If a female has the characteristic, all her sons will show it.
D. The characteristic often skips a generation, from a woman's father to her son.
E. Males can have two copies of the alleles for the trait, but females can have only one.

3. A human male has ____ chromosomes with ____ sex chromosomes.
A. 46, XY
B. 48, XY
C. 48, XX
D. 48, YY
E. 46, XX

4. Which refers to the loss of a complete chromosome?
A. translocation
B. inversion
C. monosomy
D. deletion
E. duplication

5. Generally, it is not possible to determine whether nondisjunction failed to occur in oogenesis or spermatogenesis. However, it is possible to assert that _________resulted in nondisjunction in __________.
A. XYY; spermatogenesis
B. XO; oogenesis
C. XXX; oogenesis
D. XXY; oogenesis
E. XXY; spermatogenesis

6. Which of these terms would be equivalent to 3n chromosomes?
A. trisomy
B. diploidy
C. triploidy
D. tetraploidy
E. tetrasomy

7. Which of the following is NOT true about a karyotype?
A. Banding patterns are used in pairing chromosomes.
B. Chromosome pairs are assorted by both size and shape.
C. Homologous chromosomes are paired.
D. Sex chromosomes are identified separately from autosomes.
E. Chromosome pairs are numbered from smallest to largest.

8. "Polyploid" is a term that refers to
A. having 2 sets (2N) of chromosomes.
B. None of these
C. having many expressions of the same gene.
D. having 3 or more sets of chromosomes (3N, 4N, etc)
E. having multiple sex cell available for fertilization.

9. Women with X-linked disorders always pass the genes for the disorder to ______, while men with X-linked disorders always pass the genes for the disorder to _______.
A. both their daughters and sons; only their daughters
B. both their daughters and sons; only their sons
C. their sons, their daughters
D. only their daughters; only their daughters
E. both their daughters and sons; their daughters and sons

10. Which statement is NOT true about Down syndrome?
A. It is associated with chromosomal nondisjunction in meiosis.
B. Greatly increased incidence occurs with fathers over age 35.
C. It is caused by a third copy of chromosome 21.
D. Characteristics include mental retardation and extra eyelid folds.
E. Affected individuals have a considerably shortened life expectancy.

11. Which refers to the addition of an extra segment of a chromosome?
A. monosomy
B. duplication
C. deletion
D. inversion
E. translocation

12. What kind of mutation causes trisomy 21 or Down syndrome?
A. change in the base sequence of DNA in a single gene
B. change in the number of chromosomes
C. duplication of an allele with change in the base sequence of one of the copies
D. recombination of genetic information between unpaired chromosomes
E. change in the arrangement of alleles on a chromosome

13. Which refers to the movement of a piece of one chromosome to another nonhomologous chromosome?
A. inversion
B. monosomy
C. deletion
D. translocation
E. duplication

14. If a woman is a carrier for the color-blind recessive allele and her husband is normal, what are their chances that a son will be color-blind?
A. None since he will also be just a carrier.
B. 50% since the mother is the only carrier.
C. None since the father is normal.
D. 100% because the mother has the gene.
E. 25% because the mother is a hybrid.

15. Consider the case of a lethal recessive gene located on the nonhomologous part of the human X-chromosome; it is therefore sex-linked. Its effect is to prevent the full development of the embryo, which is therefore reabsorbed at an early stage. Beginning with a female who carries this gene in a heterozygous state, what proportion of the offspring will be female?
A. one-half
B. all, because the lethal recessive gene will express itself in the absence of any genes on the short Y-arm for the XY male embryos
C. two-thirds
D. No offspring will be produced at all.
E. three-fourths

16. Which refers to the loss of a portion of a chromosome?
A. duplication
B. inversion
C. translocation
D. monosomy
E. deletion

17. When homologous chromosomes fail to separate during meiosis, this is termed
A. RFLP.
B. disjunction.
C. nondisjunction.
D. cross-over.
E. linked genes.

18. A genetic disorder (not counting disjunctions) is more likely to be common in the population if it
A. All of the choices would increase the survival of a deleterious gene.
B. is not sex-linked if recessive.
C. is recessive.
D. bestows some benefit in a heterozygous state.
E. does not manifest itself until after reproductive age has passed.