NABTEB 2015 REAL BIOLOGY AND LITERATURE ANSWERS.

1a.
i.Each chromosome shortens and
thickness,and
is seen to consist of two chromatids,the
centroles begin to separate
ii.the nuclear membrane dissapears; a
spindle
forms, the chromosomes lines up across
the
middle of the cell and become attached to
the
spindle fibres at their centromeres
iii.the sister chromatids are pulled apart to
opposite ends (poles) of the cell as the
spindle
fibres contract
iv.A nuclear membrane forms around
each set of
chromatids, and the cell divides into two
daughter cell
b.
i.Growth
ii.Genetic stability
iii.Regeneration and cell replacement
iv.Asexual reproduction
v.Response to external stimuli
4a.
i.has a neural canal for the passage of the
spinal cord
ii. has a neural spine which projects
upward
dorsally
ii. has a two process known as transverse
process,which project from the side of
each
vetebra
4aii.
i.hydrostatic skeleton-earthworm
exoskeleton-Anthropods
endoskeleton-mammal
4bi.
i.Protection – the cranium and ribs protect
the
brain and vital organs in the chest.
ii.Shape – gives shape to the body and
makes
you tall or short.
iii.Support – holds your vital organs in
place
when playing sport. The vertebral column
holds
the body upright.
iv.Movement – muscle are attached to
bones,
which are jointed. When the muscles
contract
the bones move.
v.Blood production – red blood cells (to
carry
oxygen) and white blood cells (to protect
against
infection) are produced in the bone
marrow of
some
4bii.
i.Ball and socket joints
ii.Ellipsoidal joints
iii.Gliding joints
iv.Hinge joints
v.The pivot joint
5a.Carbohydrates such as bread are made
up of
hydrogen, oxygen and carbon, and are
processed
in the body as glucose. Glucose, derived
primarily from carbohydrates, is necessary
for
endurance athletes, and those who
workout or
train for extended periods of time. Thus
giving
glucose directly helps athletes more fast
than
giving a bread which will pass the break
down
process before it turns into glucose.
b.
i.Gather a number of food samples. Try to
use a
wide variety: fruits, vegetables, breads,
cereals,
dairy products and “junk” foods such as
candy or
chips.
ii.Put a sample of each food on a
washable plate
or tray.
iii.Fill the eyedropper with iodine and
drop a few
drops onto each food sample.
iv.Observe what happens to the drops of
iodine
on the food. If the food contains starch,
the
iodine drops will turn black. If the food
does not
contain starch, the drops will stay the
same
color (reddish-orange).
v.Discard the samples when you are done
with
them. Do not let anyone eat them, as
iodine is
toxic.
c,
i.Water as a Solvent
ii.Water as a Solvent
iii.Protection
iv.Chemical Reactant
v.pH regulation
6a
i.sex linked characters determined by a
gene
located on only the X-chromosome are
said to
be sex-linked.such traits show a different
pattern
of inheritance in males and females.
ii.in Co-dominance,both the alleles in the
heterozygous individual are fully
expressed i.e
the effect of each allele is not modified by
the
presence of the other.
iii. is the improved or increased function
of any
biological quality in a hybrid offspring.
6b.
i.any difference between cells, individual
organisms, or groups of organisms of any
species caused either by genetic
differences
(genotypic variation) or by the effect of
environmental factors on the expression
of the
genetic potentials (phenotypic variation).
bii.
i.It makes a species better adapted to the
environment and makes it a suitable
organism to
thrive in those conditions.
ii.It makes a species better able.
iii.The predator-prey relationship between
two
species is affected in a positive as well as
negative aspect.
iv.It might not effect the ecosystem
balance but
it surely affects the offsprings so
produced
v.Sex can introduce new gene
combinations into
a population
c.
TABULATE
Continuous Variations:
i.The variations fluctuate around an
average or
mean of species.
ii.Direction of continuous variations is
predictable.
iii.They are already present in the
population.
Discontinuous Variations:
i.A mean or average is absent in
discontinuous
variations.
ii.The direction of discontinuous
variations is
unpredictable.
iii.Discontinuous variations are new
variations
though similar variations might have
occurred
previously.
LITERATURE ANSWERS LOADING

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