DAILY 5 QUESTIONS (DATE: 31/01/2010)
What are outside raw materials used for by an organism?
·
Carbon based molecules were the
basis for the outside raw materials used by organisms because life on earth
depends upon carbon based molecules.
·
The raw materials required by an
organism can be quite varied depending on the complexity of the organism and
its environment.
·
Autotropes uses inorganic energy
like CO2, water and minerals as outside raw materials.
·
Heterotropes used carbohydrates
and oxygen as outside raw materials.
What is the role of the acid in our stomach?
HCl secreted from the parietal (oxyntic) cells of stomach has
4 important function:
1.
HCl converts inactive
propepsin(pepsinogen) into active
pepsin.
2.
HCl makes the stomach environment
acidic (pH=2.0-2.3) which is essential for the proper function of propepsin.
3.
HCl softens the food the kill the
microorganisms in food.
4.
HCl also stops the function of
salivary amylase.
What is the function of digestive enzymes?
·
Enzymes are proteins which
catalyze the biological reactions and act as molecular scissors.
·
Enzyme causes hydrolytic
splitting of complex macro-molecules into simple soluble and diffusible
micro-molecules.
·
These simple particles can be
easily absorbed by the blood and thus transported to all the cells of the body.
Proteins ----àpeptones------àpeptides-----àamino
acid
How is the small intestine designed to absorb digested food?
·
The inner epithelial lining of
small intestine possesses numerous finger like projections called as villi,
which increases the surface area for efficient absorption of digested food.
·
Villi possess blood capillaries
and lymph vessels (lacteals) for quick transport of absorbed food.
·
From the blood stream, the absorbed
food is delivered to each and every cell of the body.
What advantage over an aquatic organism does a terrestrial
organism have with regard to obtaining oxygen for respiration?
·
Aquatic organisms obtain oxygen
for respiration from water, which is very low in amount. It is less than 1%
oxygen in dissolved state in water.
·
Terrestrial organisms take oxygen
directly from the environment, which has a very high concentration of oxygen
(up to 21%).
·
Since the amount of oxygen in
water is fairly low as compared to the amount of oxygen in the air, thus the rate
of breathing in aquatic organisms is much faster than in terrestrial organisms.
DIFFERENCE BETWEEN ARTERIES , VEINS AND CAPILLARIES
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ARTERIES
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VEINS
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CAPILLARIES
|
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Arteries are the distributing blood vessels which carry the
blood away from the heart to various organs.
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Veins are the collecting blood vessels, which carry the blood
towards the heart from various organs.
|
Capillaries are exchanging blood vessels that is helpful in exchanging
glucose and respiratory gases.
|
|
Arteries have oxygenated blood except pulmonary artery.
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Veins have de-oxygenated blood except pulmonary vein.
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Capillaries contain both oxygenated and de-oxygenated blood.
|
|
Blood flow rapidly and under pressure in arteries.
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Blood flow slowly and with little pressure in veins.
|
Blood flows with moderate pressure.
|
|
Arteries have thick elastic walls because arteries have the
bear the high blood pressure.
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Veins are thin walled because blood pressure is low in veins
|
Capillaries are thin walled and one cell thick because they
hae to exchange nutrition and gases.
|
|
Arteries do not have valves because blood flows with jerks in
them.
|
Veins have internal valves to prevent back flwo of blood
|
|
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Lumen of arteries is narrow
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Lumen of vein is wide
|
|
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Arteries are deep seated
|
Veins are superficial.
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How
is the movement of leaves of the sensitive plant different from the movement of
a shoot towards light?
|
|
Movement
of a shoot towards light
|
Movement
of leaves of sensitive plant
|
|
|
It
is a tropic movement which depends on the direction of stimulus applied.
|
It
is a nastic movement that does not depend upon the direction of stimulus
applied.
|
|
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The
stimulus is light.
|
The
stimulus is touch(or contact stimuli)
|
|
|
It
is caused by the unequal growth on the 2 sides of the shoot.
|
It
is caused by the sudden losss of water from the swellings at eh base of
leaves.
|
|
|
This
type of movement is directional and is growth dependent
|
This
movement is independent of growth
|
How
do auxins promote the growth of a tendril around a support?
·
Tendrils are the thin, thread-like growths on the stems or
leaves of climbing plants. Tendrils are sensitive to the touch (or contact) of
other objects.
·
When the tip of the tendril touches a support, then the auxins
(plant hormone) present in its tip move to that side of tendril which is away
from the support.
·
Because Auxin promotes growth so the side of the tendril which
is away from the support grows faster (and becomes longer) than the side which
is in contact with the support. This makes the tendril to curve (or bend)
towards the support.
·
This curving tendril can then encircle the support & appear
as a watch spring.
What is the difference between the manner in which movement
takes place in a sensitive plant and the movement in our legs?
|
Movement
in sensitive plants
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Movement
in our legs
|
|
The
movement that takes place in a sensitive plant such asMimosa pudica occurs
in response to touch (stimulus).
|
Movement
in our legs is an example of voluntary actions
|
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For
this movement to occur, the plant cells change shape by changing the amount
of water in them.
|
In
animal muscle cells, some proteins are found which allow the movement to
occur
|
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The movement in the leaves of a
sensitive plant takes place due to the sudden loss of water in the pad-like
swellings (called pulvini) at the base of all the leaves.
The loss of water makes the
pulvini limp leading to drooping and folding of leaves.
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