CSIR Genetics MCQ questions part -2

11. You cross a true-breeding red-flowered snapdragon with a true-breeding white-flowered one. All of the F1 are pink. What does this say about the parent traits?
(a) red and white are codominant
(b) red is dominant
(c) both red and white are recessive
(d) red and white show incomplete dominance

12. While on a field trip in the jungle you find a new species of mouse. You catch a pair and take them back to the lab. In mice, black coat color, B, is dominant to brown b,yet the female mouse gives rise to a large litter in which 9 of the offspring were black, 3 were brown and 4 were white. You conclude that
(a) a new mutation has occurred in the mice
(b) this is an example of polygenic inheritance
(c) there must be an epistatic interaction influencing coat color
(d) the coat color alleles are codominant

13. A new breed of domestic cat, the Indian Curl Cat, has unusual curled-back ears.When the owners of Shulamith, the foundation cat from which the breed arose, crossed her with a normal straight-eared domestic cat in each of her litters roughly half of the kittens had curled ears. When both parents are curl cats, all the kittens have curled ears. What does this tell you about the curled-ear trait?
(a) curled ears and straight ears are codominant traits

(b) curled ears and straight ears are show incomplete dominance
(c) curled ears are dominant
(d) curled ears are recessive

14. John and Jesica are planning a family, but since each has a brother who has sicklecell anemia, they are concerned that their children may develop sickle-cell disease.Neither John, Jane nor their respective parents have the disease. They consult agenetic counselor who tells them
(a) there is very little chance that any of their children will have sickle-cell disease
(b) that all of their children will have sickle-cell disease
(c) that one out of four of their children could be expected to have sickle cell-disease
(d) that its possible that none of their children will have the disease but blood tests on them both will be required to make sure

15. Why is sickle cell disease so called?
(a) because it makes people sick
(b) its named after a special type of white blood cell
(c) pH changes in the blood cells make them collapse into a sickle shape
(d) because its caused by an infectious microorganism that has sickle shaped cells

16. In people with sickle cell disease the red blood cells breakdown, clump, and clog the blood vessels. The broken cells accumulate in the spleen. Among other things this leads to physical weakness, heart failure, pain, brain damage and spleen damage. Affected individuals become paralyzed and can develop rheumatism, pneumonia and other diseases and kidney failure. This is an example of
(a) the polygenic nature of sickle cell disease
(b) the pleiotropic effects of the sickle cell allele
(c) an epistatic interaction between the sickle cell allele and a proteolytic enzyme gene
(d) infectious organisms acting on the sickle cell allele

17. Heart disease, diabetes, cancer, alcoholism and many mental illnesses can best be described as:
(a) symptoms of a bad life-style
(b) infectious diseases caused by microorganisms
(c) multifactorial disorders with a possible polygenic component
(d) all symptoms of Huntingdon’s disease

18. The genetic disease cystic fibrosis is caused by a defective allele that
(a) produces a dysfunctional enzyme that fails to break down brain lipids.
(b) causes hemoglobin molecules to collapse.
(c) produces a defective chlorine-channel membrane transport protein.
(d) produces a neurotoxin

19. Huntington’s disease is an example of a genetic disorder caused by
(a) a late-acting lethal dominant allele
(b) a non-lethal dominant allele
(c) a late acting recessive allele
(d) homozygous recessive alleles

20. Which of the following is a form of sexual reproduction?
(a) budding (b) fission
(c) hermaphroditism (d) regeneration

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