Scientific reasons of biology

1. Chapter 6
DNA and Chromosome
(Don’t just pass life, just pass in life…!)
Biological Reasons: 1 Dr. Sajid Ali Talpur

2. Q 1: Why DNA is considered as King, RNA as
minister and protein as labour?
Ans. Because DNA by being lodged in nucleus
sends commands which are carried by RNA and
protein (or enzymes) finally function in the
metabolic reactions.
Q 2: Why the term chromosome is misnomer?
Ans. Because they are not colored bodies.
Q 3: If the term chromosome is misnomer then why
it is named so?
Ans. it is because when Germen Embryologist
Fleming discovered then they stained much darker
than the rest of the organelles.
Q 4: Can chromosomes be seen in normal, non-
dividing cells?
Ans. No, because in a resting cell they are present in
the form of a network and appear only during the
cell division.
Q 5: The sex of baby is determined by father or
mother?
Ans. It is determined by Father’s chromosome.
Because mother’s both the chromosomes are XX
are similar but the father’s XY chromosomes are
dissimilar and if the X is contributed the baby will
be girl and if Y is contributed the baby will be boy.
Biological Reasons: 2 Dr. Sajid Ali Talpur

3. Q 6: Can males have like and females unlike
chromosomes?
Ans. Yes, but in few animal species like moths,
birds and some fishes where males have ZZ and
females have ZW chromosomes.
Q 7: How the histones and DNA remain tightly
bound together?
Ans. DNA are negatively charged and histones are
positively charged so they remain tightly bound
together.
Q 8: Which of the sperm and egg contributes more
to the formation of zygote?
Ans. Both of the gametes contribute equally
because each of them contains equal no. of 23
chromosomes in humans.
Q 9: Why R-type bacteria are non virulent whereas
the S-type virulent?
Ans. S-type bacteria are virulent because they are
covered by capsule which prevents them from being
digested by WBC.
Q10: Why replication is considered as semi
conservative?
Ans. Since each DNA molecule is consist of two
strands and after replication new DNA molecule
contains one old and one new strand. Hence the
duplex is not conserved rather, each strand becomes
the part of the other duplex.
Biological Reasons: 3 Dr. Sajid Ali Talpur

4. Q11: Why the urine of Alkaptonuria patient turns
black on exposure to the air?
Ans. because such a urine contains homogentisic
acid which is oxidized when exposed to air and
turns black.
Q12: Why proteins are synthesized in cytoplasm but
not in the nucleus?
Ans. because the protein factories called ribosomes
are present in cytoplasm also the amino acids
required for protein synthesis are available in
cytoplasm but not in the nucleus.
Q13: There are only 20 basic different amino acids
and millions of the proteins. Explain it.
Ans. However, there are only 20 basic proteins but
their sequence is different in each protein. It is as
there are 26 basic alphabetic letters but millions of
the words.
Biological Reasons: 4 Dr. Sajid Ali Talpur

5. By the same Author:
 Success tips by Dr. Sajid Ali
Talpur
 Chemistry definitions by Dr.
Sajid Ali Talpur
 Definitions and MCQs on
branches of Biology
 Ninth Class Chemistry MCQs
 Ninth Class Chemistry MCQs
 Scientific Biological Reasons
 Definitions, Scientific Reasons
and MCQs on Chemistry
 Skeletal muscles Physiology
BCQs
Biological Reasons: 5 Dr. Sajid Ali Talpur

6.  Biology MCQs test for entry
test
 Chemistry MCQs test for entry
test
 Cardiovascular system anatomy
quiz
 Lower limb anatomy quiz
 Lower limb Anatomy MCQs
 Spiritual successful life
quotations
 Islamic poetry and quotations
 Love the Prophet Muhammad
(s.a.w)
 Quotations on the Prophet
Muhammad (s.a.w)
Biological Reasons: 6 Dr. Sajid Ali Talpur

7. Biological Reasons: 7 Dr. Sajid Ali Talpur