This set of Cytogenetics Multiple Choice Questions & Answers (MCQs) focuses on “Effects of Environment”.
1. The age of onset for gene of baldness is _________________
Explanation: All the genes of an individual are not expressed at the same time. The age of onset of baldness gene in men is 20 years and above.
2. Duchenne muscular dystrophy is an X linked gene. What has expected if an individual has this gene?
a) Neonatal death
b) 2-5 months life expectancy
c) 2-5 years life expectancy
d) 30 years life expectancy
Explanation: In case of Duchenne muscular dystrophy the age of onset of the disease is about 2-5 years of age. This is a lethal gene which is X linked recessive.
3. Which of the following is not an environmental factor for gene expression?
Explanation: Genotype is not directly an environmental factor but it is rather influenced by the different environmental factors. The other options given are determined by environment.
4. Which one of the following is wrong for temperature sensitive mutant?
a) The mutants die beyond the range of certain temperature
b) The enzymes they produce are always very unstable
c) The enzymes breakdown making the individual temperature sensitive
d) These are grown in special temperature controlled incubator
Explanation: The enzymes produced are stable and functional at a particular temperature but non- functional and unstable beyond the range of another temperature.
5. In which of the cats the pattern observed in coat colour is due to environmental effect?
Explanation: In the case of Siamese cats the temperature of the extremes of the body are different from the main body. There some temperature sensitive enzymes are active, which are otherwise inactive in main body, giving it a different colour.
6. When certain drugs can mimics the condition produced during some disease, it is known as ______________
a) Duplicate epistasis
c) Pseudo dominant
Explanation: In phenocopy a drug or a condition mimics the effect of some disease. It is an environmental effect and non-heritable condition.
7. Deafness can only be hereditary.
Explanation: Deafness can be caused by the presence of duel copy of homozygous recessive allele. Or it can be caused if the expectant mother is affected by Rubella virus in the 1st 12 weeks of pregnancy.
8. Phecomelia is _________________
a) Sex linked
b) Temperature sensitive
Explanation: Phecomelia is a phenocopy produced when the mother takes sedative like thalidomide during child birth. It is non-hereditary.
9. A person with phenyl ketone urea can behave as normal.
Explanation: If the diet of the person is properly controlled such that only specific amino acids are taken, then the individual can behave as normal.
10. In an experiment you attach an ice pack on the chest of the Himalayan rabbit for several days. What will you expect to see?
a) The heart will beat slower
b) The rabbit will die
c) Sweat glands from that area will degenerate
d) The coat colour of that area will be darker
Explanation: In Himalayan rabbits, like Seamese cats the body temperature affects the coat colour. Parts that are cooler have a darker colour than the warmer parts. Here the cooler part will gradually accumulate the dark colour enzyme which otherwise is unstable at the main body parts and give the pattern.
Sanfoundry Global Education & Learning Series – Cytogenetics.
To practice all areas of Cytogenetics, here is complete set of 1000+ Multiple Choice Questions and Answers.