SMU-DDE-Assignments-Scheme of Evaluation
PROGRAM
SEMESTER
SUBJECT CODE &
NAME
BK ID
DRIVE
MARKS
Q.
No
1
2
MSC BIOINFORMATICS
1
BI0024
CELL BIOLOGY AND GENETICS
B0697
FALL 2016
60
Criteria
Marks
Explain the fundamental properties of cell.
Explaining any 10 fundamental properties of cells:
10
 Cells are the fundamental units of life
 Cells are alive and ‘life’ is the most basic property of
cells.
 Cells are highly complex units of life
 Cells are hereditary units
 Cells are generally self duplicating.
 Cells need energy for structural and functional
maintenance and growth,
 Cells have the property of acquiring and utilizing
energy.
 Cells function like miniaturized chemical factories.
 Cells have the capacity to respond to external stimuli.
Explain the basic features of fluid mosaic model of plasma membrane.
The basic features of plasma membrane:
10
 Singer and Nicolson proposed the ‘Fluid Mosaic’
model for the plasma membrane.
 Fluid mosaic model presented the membrane as
dynamic structures in which the components are
mobile, and are capable of coming together to engage
in various interactions.
 According to fluid mosaic membrane concept, the
core of the membrane is made of a continuous lipid
bilayer.
 The lipid molecules are in a fluid state capable of
turning around and moving laterally along the
membrane.
 Lipid bilayers form through the process of selfassembly.
 Proteins of the membrane either occur as “mosaic” of
discontinuous particles that penetrate deep into the
lipid layer or even completely passing through it.
Total Marks
(Unit 1, Page No. 4)
10
(Unit2 , Page No. 33)
10
SMU-DDE-Assignments-Scheme of Evaluation

3
A
4
A
Proteins may also occur on the surface of the lipid
sheet and these are peripheral or extrinsic proteins.
 Lipids and integral (intrinsic) proteins of the plasma
membrane are “amphipathic” in nature.
 Hydrophobic or non-polar groups are situated
internally in the lipid bilayer,
 Hydrophilic groups or the polar regions of lipids and
proteins are directed to the surfaces (the water
phase).
Define giant chromosome. Explain the properties of Polytene chromosome.
(Unit 4, Page No. 146)
Definition of giant chromosome:
2
10
Over-sized chromosomes specific to dipteran flies
Explanation for the properties of polytene chromosome:
8
 Polytene chromosomes of D. melanogaster salivary
gland are 1000 times greater in volume than that of
somatic chromosomes.
 Chromomeres (tightly coiled DNA region),
alternate with regions where fibres are arranged
loosely.
 Polytene chromosomes have alternate light and
dark bands along their length.
 The dark bands resemble the disc shaped
chromomeres of euchromatin,
 The
light
interbands
resembles
fibrillar
chromomeres of heterochromatin.
 In polytene chromosomes maternal and paternal
homologous pair remain associated side by side,
which is called as somatic pairing.
 Polytene chromosomes give rise to swellings or
local enlargement where the chromosomal fibres
open out to form many loops due to intense
transcription. Such swellings are called as puffs.
 The puffs are formed for the production of specific
proteins in large quantities.
State the law of independent assortment. Explain the forked line method for the calculation of
phenotypic ratios.
(Unit 6, Page No. 194)
The law of independent assortment:
2
10
It states that, if the inheritance of more than one pair of
character is studied simultaneously, “the factors (genes) for
each pair of characters assort out independently of the other
pairs”, it means each member of a pair of alleles may
combine in a random fashion with either allele of another
pair.
Explanation for forked line method for the calculation of
8
SMU-DDE-Assignments-Scheme of Evaluation
5
A
6
A
phenotypic ratios:
 To find out the types of gametes formed, and the
nature of individuals result in F2, forked- line
method is used.
 Explaining an example.
Define crossing over. Explain the factors controlling crossing over.
(Unit 7, Page No.214)
Definition of crossing over:
2
10
The phenomenon of breakage and interchange of alleles
between
non-sister
chromatids
of
homologous
chromosomes is termed as crossing over.
Factors controlling crossing over:
8
• High and low temperatures increase the frequency of
crossing over.
• X-rays and other irradiations increase the crossing
over.
• The age of the individual also affect the crossing over
frequency.
• Gene mutations affects the frequency.
• Crossing over at one point of the chromosome tends to
prevent other crossing overs in nearby places. This
phenomenon is called interference.
• Crossing over does not take place in male Drosophila
and female silk moth. Thus, sex also affects the crossing
over.
• Crossing over is less frequent near centromeres and
tips of chromosomes.
• Inversions of the chromosome segments suppress the
crossing over.
Explain any five functions of endoplasmic reticulum.
(Unit 2, Page No. 59)
Explanation for any five of the following functions of
5X2
10
Endoplasmic reticulum:
 Mechanical support
 Exchange and translocation
 Protein synthesis
 Glycogen storage and glucose metabolism
 Lipid synthesis and storage
 Synthesis of cholesterol and Steroid hormones
 Detoxification of drugs
 Sequestering calcium ions
 Formation of microbodies
 Formation of other cytomembranes
*A-Answer
SMU-DDE-Assignments-Scheme of Evaluation
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