Structured Essay 2.
01. A (i) What is meant by the
primary structure of a polynucleotide?
(ii) Name the
components of the building block of a polynucleotide?
(iii) Why is the 2
poly nucleotide strands of a DNA molecule are said
to be
(a) Complementary
to each other?
(b) Antiparallel to
each other?
(iv) (a)
Name two examples for modified parenchyma tissues.
1
2
(c) Name the
main function of each of the tissue you mentioned in (a) above.
1
Function of 1
2 Function of 2
B (i) Name two
differences between Domains Archaea and bacteria
Archea
bacteria
1.
1.
2
2.
(ii) Name two characteristic features
of Echinoderms which are only found in them.
(a)
(b)
(iii)
Name two phyla which possess following ciliated larvae in
their life cycle.
(a)
Bipinnaria
(b)
Planula
-
(iv) Name two adaptations shown by Reptiles,
to live in terrestrial habitats.
(a) '
(b)
(C) (i) When categorizing
organisms according to their mode of nutrition, carbon
source and energy source had been considered. Accordingly, explain the following nutritional
modes of organisms.
Carbon
source Energy
source
(a)
Photoautotrophs-
(b) Chemoautotrophs
(ii) Given below are three different
modes of nutrition found among
organisms. Write examples for
each.
Mode of
nutrition
Example
(a)
saprophytic
(b)
holozoic
(c ) Commensalism
(iii) What is the composition of pancreatic juice
of humans?
(iv) Name three unhealthy habits
causing constipation. '
2. A (i) Name
the respiratory organs of following classes?
Amphibia-
.
Arachnida-
.
Reptilia
(ii) Name
three adaptations of human alveoli for gaseous exchange.
(a)
(b)
(c)
(iii) (a) What is the compound which
comes from the glycolysis and enter to the Kreb cycle in aerobic
respiration?
(b) Which part of the above compound is
given to the Kreb cycle?
B (i) Hepatic portal vein is one of the
vein found in human blood vascular system. Write two differences
between the hepatic portal vein and a normal vein.
(a) (b)
(ii) Explain the absorption of end products
of fat digestion to the lacteal.
C (i) What is the reason to have a less solute
potential (ψs) of the 0.1M sugar
solution (-0.23 M Pa) than
water potential of pure water (0 MPa).
(ii) What
are the main tissues which obtain the mineral salts which is transported in
xylem by mass flow?
03 (A) (i) Human brain is responsible for both of
the functions, nervous coordination and hormonal coordination. Name the two
structures of the brain help in hormonal coordination?
(a)
(b)
(ii)
Write the function done in hormonal coordination by each of the structure
you written above in ((A) (i) )
Structure Function
(a)
(b)
'
(iii) Name the growth substances that are important in
performing following functions.
Function
growth hormone
(a) senescence
(b) Cell
division
(c) Cell enlargement and differentiation
(B)
(i) What are the membranes which make the
pre synaptic membrane and post synaptic membrane in a synapsis of a
neuromuscular junction
Pre synaptic membrane-
Post synaptic membrane-
(ii) What are the features shown in a synapsis to ensure
the unidirectional path of nerve impulses through it?
(iii) State the presence or absence of rods and cones in
following places of the retina of human eye
(a) Blind spot-
(b) Fovea
(C)
(i) Name the sensitive structures or organs
of following taxon in animal kingdom
(a) Insecta
(b) Platyhelminthes
(c) Cephalopoda
4. (i) Name
three uses of exoskeleton of Arthropoda
(a)
(b) (c)
(ii) Write one function done by human hand using the
movements supination
and pronation
(iii) Explain the reason to have wide range movements of the upper limb and
comparatively limited movements of the lower limb.
B (i) (a) Name
the things which can be found in the glomerular filtrate of a nephron
in humans.
(b) Among the things you mentioned above, what
are the things which
are not eliminated
by a healthy person.
(ii) Explain the
hormonal involvement in the process of excreting hypertonic urine by a
person who drinks less water.
'
(C)
(i) What is asexual reproduction?
(ii) (a) Name
another importance of underground stems ( corm, rhizome and
bulb) other than the vegetative reproduction.
(b) What are the adaptations of rhizome to do
the function you mentioned
above?
(iii) What is alteration of generation found
in land plants?
(iv) What is the difference between parthenocarpy
and parthenogenesis?
(v) Write
two main functions of human placenta
(a) (b)
Structured
Essay 2.
Answers
01. A (i) Sequence of the
nucleotides
(ii) Phosphate group, Sugar of 5 Carbon atoms, Nitrogen
base
(iii) (a)
Complementary to each other?
The base sequence of one strand is determined by
the base sequence of other strand
(b) Antiparallel to each other?
Two strands are parallel to each other and oriented in opposite directions
(iv) (a) 1. Endoderm
of root ' 2. pericycle of stem
(v)
Function of 1: Does
not allow to enter the unwanted mineral ions
Function of 2: as a supportive
tissue
B (i)
|
Archea |
Bacteria |
|
Cell wall is made out of proteins and polysaccharides. |
Cell wall is with peptidoglycan |
|
Cell
membrane lipids have branched hydro carbons |
Not b |
(ii) (a) Tube feet (b) Water vascular system
(iii) (a) Bipinnaria -
Echinodermata (b) Planula- Coelenterata
(iv) (a) Eggs with
calcified shells (b)
dry, scaly skin without glands
(C) (i) .
Carbon source
Energy source
(a)
Photoautotrophs- Carbon dioxide.
Sun, light
(b) Chemoautotrophs Carbondioxide chemical compounds
(ii)
Mode of nutrition
Example
(a) saprophytic
Fungi
(b)
holozoic
Animals. example, cat
(c ) Commensalism
Barnacles living on whales
(iii) Water, mineral salts, Pancreatic amylase,
Pancreatic lipase,
Chymotrypsinogen, trypsinogen,
Chymotrypsinogen and trypsinogen
these two are enzyme precursor
(iv) Inadequate fiber in
the diet, inhibition of reflex action in defecation
2. A (i)
Amphibia- Lungs, wet
skin, mouth cavity, gills in tadpoles
Arachnida- Book
lungs.
Reptilia- lungs
(ii)
(a) The very thin wall of the alveoli is made of simple
squamous epithelium
(b) Alveoli wall is surrounded by a
blood capillary network.
(c) Large surface area
(iii) (a) Acetyl Co A (b)
Acetyl group
B (i)
Hepatic portal
vein
Normal vein
(a) It starts
from an organ and ends at an organ It starts from
an organ but ends at heart
(b) Have high
glucose percentage in its blood. Comparatively
low glucose percentage.
(ii) End products of
fat digestion are fatty acids and monoglycerides. First they enter to the cells
through microvilli. Within the cells chylomicrons are formed and they
transported to the lacteals and then to the blood through lymph.
C (i) When
solutes are added to pure water solute particles bind with water and it will cause the reduction of free water
molecules. This will reduce the capacity of movement of water and function
of it. So, solute potential is less than water potential and carries a
negative value.
(ii) Apical and lateral meristems, tender leaves,
developing fruits. Storage tissues.
03. (A)
(i) (a) Hypothalamus
(b) Pituitary
(ii) (a) Hypothalamus- Secretion of releasing of stimulating hormones. E g
Gonadotrophin releasing hormone
(GnRH), Thyrotropin releasing hormone
(b) Pituitary _Secretion of stimulating
hormones for many other endocrine organs or structures. E. g. Thyroid
stimulating hormone, Follicle stimulating hormone.
(iii)
. Function
growth hormone
(a) Senescence
Ethine
(b) Cell
division
Cytokinin
(c) Cell enlargement and differentiation Gibberalin , Auxin
(B)
(i)Presynapticmembran-
Axolemma of the motor neuron
Post synaptic membrane-
Sarcolemma of the muscle fibre
(ii)
Transmitters are secreted near the presynaptic membrane and transmitter
acceptors are present in the post synaptic membrane
(iii)
(a) Blind spot_ No light sensitive
cells that is cones or rods
(b) Fovea –
Only cones are present
(C) (i) (a) Insecta . Compound eyes, sensitive hair
(b)
Platyhelminthes- eye spots
(c)
Cephalopoda - Simple eyes
4. (i)
(a) protection
(b) prevention from desiccation
(c)Support
(d) insertion of
muscles
(ii) Opening a door using a key, When using a screw
driver to fix or remove a screw nail
(iii) Upper limb has an incomplete ball and socket joint
at the shoulder joint
Lower limb has
a complete ball and socket joint at the hip joint
B (i) (a) Glucose, amino acids, vitamins" hormones, water, mineral ions, creatin,
(b) Reabsorption
(ii) When
the amount of water in blood is less, the ability to dissolve substances in
blood is also less. This stimulates the osmoregulatory cells in hypothalamus
and secrete ADH. ADH increase the permeability to water in distal convoluted
tubules and collecting ducts and allow to absorb more water to the blood.
(C) (i) Sexual reproduction is the combination of (usually
haploid) reproductive cells (male and female gametes) from two individuals to
form an offspring (usually diploid)
(ii) (a) Perennation
(withstanding the adverse conditions by remaining underground and make new
plant when conditions are favourable.)
(b)
What are the adaptations of rhizome to do the function you mentioned above?
Having apical bud and axial buds
(iii) The life cycles of all land plants exhibit
alternation of generations, which means the presence of haploid generation and
diploid generation alternatively, with each producing the other.
(iv)In
some plants fruits are developed without fertilization. This condition is known
as parthenocarpy and fruits without seeds are known as
parthenocarpic fruits. In parthenogenesis seeds
are developed without fertilization by sperm nucleus but by fusing with polar
nucleus or by duplicating the genetic material.
(v) (a) Secretion of hormones, such as chorionic
gonadotropin, oestrogen and progesterone
(b) Exchange of materials between mother and child
