IMPORTANT VIVA
QUESTIONS
Q. What are
enzymes? Give two most important characteristics of enzymes.
A: Enzymes are
biocatalysts that are involved in various metabolic reactions in a living
system. All enzymes are proteins chemically, and they remain unchanged at the
end of a reaction.
Q. Name the
glands from which saliva is produced.
A. 3 pairs of
salivary glands: parotid, submaxillary and sublingual.
Q. What is
achromic point?
A: It is the
time required to digest starch completely by salivary amylase.
Q: What happens
to enzyme activity at very high or very low temperature?
A: Enzymes get
denatured at high temperature and deactivated at low temperature, as they are
proteins in nature.
Q: How are
enzymes different from hormones?
A: (i) All
enzymes exceptionally are proteins in nature while hormones can either be
proteins or amies or lipids.
(ii) Hormones
always have a target organ to act while the enzymes don’t.
Q: What are
conjugated enzymes?
A: When along
with the protein, some other non-protein moiety is also attached to the enzyme,
it is known as conjugated enzyme.
Q: Can a haploid cell divide meiotically?
A: No, since
meiosis reduces the chromosome number to half.
Q: What is the
significance of crossing over in meiosis?
A: During
crossing over in meiosis, exchange of genetic material between non-sister
chromatids occurs; as a result, the genotype of the cells is altered. So it
results in genetic recombination and finally helps in introducing variations in
populations.
Q: What do you
mean by the term karyokinesis?
A: Karyokinesis
means the division of the nucleus.
Q: What is a
meiocyte cell?
A: A cell that
is to divide by meiosis is called a meiocyte.
Q: How do you
differentiate the chromosomes of mitosis and meiosis?
A: Meiotic
chromosomes are comparatively longer and thiner. They show a characteristic
beaded appearance by the presence of chromomeres.
Q: From one
parent cell, how many daughter cells will be produced after meiosis and mitosis
respectively?
A: two cells
after mitosis and four cells after meiosis.
Q: At what
stage of cell division does nuclear membrane reappear?
A: Telophase
Q: In which
stage of cell division chromosomes are seen best?
A: metaphase
stage
Q: Name the
chemical that can arrest the process of cell division at metaphase stage.
A: Colchicine
Q: What do you
mean by cytokinesis?
A: division of
the cytoplasm
Q: Why is mitosis
termed as equational division and meiosis as reductional division?
A: Mitosis is
equational division because the daughter cells formed are identical to the
parent cell in all respects. Meiosis is termed as reduction division because
the daughter cells formed have half the number of chromosomes as the parent
cell.
