LIFE PROCESSES CLASS 10 QUESTIONS AND ANSWERS Download

Transcript
Cynesure Institute
TEST PAPER
Class 10
LIFE PROCESSES
Questions & Answers:
Q. What is NUTRITION:
Ans. In animals, the entire process of ingestion of food conversion into easily
absorbable components and transport to the different cells is known as
nutrition.
Q. What is life processes?
Ans. The main fundamental functions, performed by living organisms to
maintain their life are called life processes.
1. Why is diffusion insufficient to meet the oxygen requirements of
multicellular organisms like humans?
Answer: The size of the multicellular organisms is very large compare to
unicellular organisms. Diffusion is a passive mode of transport of substances
and can transfer gases up to a very small distance only. This will not be
sufficient for multicellular organisms’ needs.
2. What criteria do we use to decide whether something is alive?
Answer: The main criteria to check for life, is the sign of breathing and
respiration. If there is no sign of breathing or respirations then the given
organism is not alive.
3. What are outside raw materials used for by an organism?
Answer: Minerals and water and gases are outside raw materials used by an
organism.
4. What processes would you consider essential for maintaining life?
Answer: Processes essential for maintaining life are as follows:
1. Nutrition 2. Respiration 3. Reproduction 4. Excretion 5. Locomotion or
movement
5. What are the differences between autotrophic nutrition and
heterotrophic nutrition?
Answer: Autotrophic nutrition means that the organism is preparing its own
food and is not dependent on any other organism for food. Green plants are
autotrophs.
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Heterotrophic nutrition means that the organism does not prepare its own food
and is dependent on other organisms for food. All organisms which are not
among green plants are heterotrophic.
7. What is the role of the acid in our stomach?
Answer: The hydrochloric acid is found in our stomach. It helps in killing
harmful germs which may have come along with food.
8. What is the function of digestive enzymes?
Answer: The function of digestive enzyme is to hasten the process of breaking
up of complex molecules into simpler and absorbable molecules. This makes it
easy for the body to absorb food.
9. How is the small intestine designed to absorb digested food?
Answer: In the small intestine the innermost layer is in the shape of finger like
structures. These are known as villi. Several folds because of villi increase the
absorbing surface of small intestine. The blood capillaries in villi absorb
simpler molecules from food.
10. What advantage over an aquatic organism does a terrestrial organism
have with regard to obtaining oxygen for respiration?
Answer: In the aquatic habitat the concentration of oxygen is good up to a
certain depth only. Moreover, as oxygen is available as dissolved in water, so
taking oxygen from there is not a very efficient method to that.
In terrestrial habitat oxygen is available in free form so it is easier to absorb by
organisms. This is more efficient so terrestrial organisms can facilitate better
utilization of food by way of respiration.
11. What are the different ways in which glucose is oxidised to provide
energy in various organisms?
Answer: There are two types of respiration for oxidization of glucose.
(a) Aerobic respiration: This involves complete oxidation of glucose hence
optimum output of energy is achieved. This happens in presence of oxygen.
(b) Anaerobic respiration: As the name suggests this happens in the absence of
oxygen hence complete oxidation of glucose does not take place. Usually
bacteria show anaerobic respiration. Even sometimes in our calf muscles
anaerobic respiration takes place.
12. How is oxygen and carbon dioxide transported in human beings?
Answer: Oxygen and carbon dioxide are transported in human beings with a
dedicated gas transportation system. This system is mainly composed of
following parts:
Lungs: Lungs help in breathing in oxygen rich air and breathing out carbon
dioxide rich air.
Heart: Heart pumps deoxygenated blood to lungs for oxygenation and pumps
oxygenated blood to different organs of body.
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Veins: Veins usually carry deoxygenated blood from different body parts to the
heart. One exception is the pulmonary vein which carries oxygenated blood
from lungs to heart.
Arteries: Arteries usually carry oxygenated blood from heart to different parts of
the body. One exception is pulmonary artery which carries deoxygenated blood
from heart to lungs.
13. How are the lungs designed in human beings to maximise the area for
exchange of gases?
Answer: The bronchioles in lungs are finely branched and end up in air sacs.
The structure of air sac increases the surface area inside lungs. This helps in
making a larger area for exchange of gases.
14. What are the components of the transport system in human beings?
What are the functions of these components?
Answer: The transport system is mainly comprised of following organs:
Heart: Heart is a pumping organ and pumps blood. As blood carries gases and
food and waste product along with it so heart plays a major role in
transportation.
Lungs: The main job of lungs is in facilitating transport of oxygen and carbon
dioxide to and from the body respectively.
Liver: Food goes to liver after it is absorbed by small intestine. From liver the
food is distributed to different parts of body. This system is also called as
hepatic portal system.
15. Why is it necessary to separate oxygenated and deoxygenated blood in
mammals and birds?
Answer: Mammals and birds are warm blooded animals. This means they can
control their body temperature and don’t have to depend on environment for
their body temperature regulation. Because of this birds and mammals require
optimum oxidization of glucose which would be possible with good supply of
oxygen. By developing four chambered heart they have made it possible to
completely segregate the oxygenated and deoxygenated blood in their bodies
which is their need because of their habit and habitat.
16. What are the components of the transport system in highly organized
plants?
Answer: The plant transport system in highly organized plants contains
following:
(a) Xylem: To transport water and minerals from roots to other parts.
(b) Phloem: To transport food from leaves to other parts.
17. How are water and minerals transported in plants?
Answer: Water and minerals are transported from roots. At the level of roots
the root pressure helps in rise of water and minerals up to some height. After
that there is complex mechanism at work. The transpiration taking place in
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leaves creates a suction effect which pulls up water in minerals to great
heights.
18. How is food transported in plants?
Answer: Food is transported in plants through phloem. The transport in
phloem is an active process and involves use of energy. The energy in the form
of ATP created osmotic gradient which results in transportation of food through
phloem.
19. Describe the structure and functioning of nephrons.
Answer: The nephron is the functioning unit of kidneys. Nephron consists of a
capsule shaped structure called Bowman’s capsule. The filtration of blood
takes place in Bowman’s capsule under very high pressure. After that waste
product goes to a network of collecting tubules which finally meet in a common
collecting duct. The collecting duct meets in ureters which carries urine to the
urinary bladder.
20. What are the methods used by plants to get rid of excretory products?
Answer: Plants get rid of carbon dioxide and oxygen through diffusion. Old
branches and leaves are shed off when they become useless. Plants release
some waste products through roots also. Some waste products are deposited
near bark as raisins or gums.
21. How is the amount of urine produced regulated?
Answer: The kidney has a mechanism to reabsorb water from the filtrate. This
depends on how much water is left in the body and in the filtrate. The
comparative concentration of water gives a signal to the brain which then takes
the required corrective action of either reabsorbing water or releasing more
water. Thus the amount of urine formation is regulated by kidneys.
22. The kidneys in human beings are a part of the system for
(a) nutrition. (b) respiration. (c) excretion. (d) transportation.
Answer: (c)
23. The xylem in plants is responsible for
(a) transport of water. (b) transport of food. (c) transport of amino acids. (d)
transport of oxygen.
Answer: (a)
24. The autotrophic mode of nutrition requires
(a) carbon dioxide and water. (b) chlorophyll. (c) sunlight. (d) all of the above.
Answer: (d)
25. The breakdown of pyruvate to give carbon dioxide, water and energy
takes place in
(a) cytoplasm. (b) mitochondria. (c) chloroplast. (d) nucleus.
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Answer: (b)
26. How are fats digested in our bodies? Where does this process take
place?
Answer: Fats are present in the intestine in the form of large globules which
makes it difficult for enzymes to act on them. Bile salts break them down into
smaller globules increasing the efficiency of enzyme action. The pancreas
secretes pancreatic juice which contains enzyme called lipase for breaking
down emulsified fats. The walls of the small intestine contain glands which
secrete intestinal juice. The enzymes present in it finally convert fats into fatty
acids and glycerol.
27. What is the role of saliva in the digestion of food?
Answer: Saliva contains the enzyme amylase which breaks complex molecules
into sugar.
28. What are the necessary conditions for autotrophic nutrition and what
are its byproducts?
Answer: Conditions necessary for photosynthesis:
Sunlight, carbon dioxide and chlorophyll.
Byproduct of photosynthesis: Oxygen
29. What are the differences between aerobic and anaerobic respiration?
Name some organisms that use the anaerobic mode of respiration.
Answer: In aerobic respiration there is complete oxidation of glucose and the
end product is water and carbon dioxide.
In anaerobic respiration there is incomplete oxidation of glucose and the end
product is either lactic acid or alcohol.
Yeast and bacteria use anaerobic mode of respiration.
30. How are the alveoli designed to maximise the exchange of gases?
Answer: The wall of alveoli contains a fine network of blood capillaries. This
ensures maximum exchange of gases.
31. What would be the consequences of a deficiency of haemoglobin in our
bodies?
Answer: Haemoglobin is the carrier of oxygen in blood. Deficiency of
haemoglobin will lead to less supply of oxygen to different cells. This will, in
turn lead inefficient utilization of food by the body. Finally person’s health will
deteriorate.
32. Describe double circulation in human beings. Why is it necessary?
Answer: In double circulation there is complete segregation of oxygenated and
deoxygenated blood. Because of this the blood passes twice through the heart
in one cycle of circulation hence the name double circulation.
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This is necessary for optimum oxygen utilization as humans are warm blooded
animals and need extra energy to maintain their body temperature.
33. What are the differences between the transport of materials in xylem
and phloem?
Answer: Transport in xylem: The transport in xylem is from roots to upwards
and takes place in only one direction. This is a kind of passive transport as no
energy is required. Through xylem only water and minerals are transported.
Transport in phloem: The transport in phloem is bidirectional and food and
some other products are transported. The transport in phloem is an active
transport as it requires energy.
34. Compare the functioning of alveoli in the lungs and nephrons in the
kidneys with respect to their structure and functioning.
Important Terms:
Autotrophic nutrition - Nutrition characterized by the ability to use simple
inorganic substances for the synthesis of more complex organic compounds, as
in green plants and some bacteria
Autotrophs - An organism capable of synthesizing its own food from simple
inorganic substances, using light or chemical energy.
Heterotrophic nutrition – A type of nutrition in which energy is derived from
the intake and digestion of organic substances, normally plant or animal
tissues
Heterotrophs – An organism that cannot synthesize its own food and is
dependent on complex organic substances for nutrition
Photosynthesis – The process by which plants and other organisms generate
carbohydrates and oxygen from carbon dioxide and water using light energy,
with the help of chlorophyll.
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Stomata – The minute pores present in the epidermis of a leaf or stem through
which gaseous exchange and transpiration occur.
Alimentary canal – A long tube extending from the mouth to the anus that has
regions specialized for ingestion, digestion, absorption, and egestion.
Enzymes – The biological catalysts which speed up the rate of biochemical
reactions in the body.
Peristalsis – The process of wave-like contractions and relaxations of the
alimentary tract that propels the food forward through the tract.
Gastric glands – The glands present in the wall of the stomach that release
HCl, pepsin and mucus.
Pepsin – A digestive enzyme found in gastric juice that catalyzes the
breakdown of proteins to peptides.
Emulsification of fat – A process in which bile salts emulsifies fat globules.
Bile – A digestive juice secreted by the liver, stored in the gallbladder and aids
in the digestion of fats.
Pancreatic juice - A clear alkaline secretion of the pancreas containing
enzymes that aid in the digestion of proteins, carbohydrates, and fats.
Trypsin – A pancreatic enzyme that catalyzes the breakdown of proteins into
smaller units.
Lipase – An enzyme that catalyze the breakdown of fats into fatty acids and
glycerol.
Intestinal juice – The digestive fluid secreted by the glands lining the walls of
the small intestine.
Villi – The numerous projections arising from the inner lining of the small
intestine, which increase the surface area for absorption.
Egestion – The elimination of the waste and undigested matter from the
digestive tract through the anus.
Respiration – The process by which food is burned by living cells to release
energy in the form of ATP, for various body purposes.
Aerobic respiration – The metabolic process that uses oxygen to break down
food and produce carbon dioxide and water, along with the release of energy.
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Anaerobic respiration – The metabolic process by which nutrients are broken
down in the absence of oxygen to release energy.
Alveoli – The tiny air sacs of the lungs where gas exchange occurs with the
circulatory system.
Trachea – A thin walled tube of the respiratory system with cartilaginous rings
that conveys inhaled air from the larynx to the bronchi.
Bronchus – Either of the two main branches of the trachea, which delivers air
to the lungs from trachea.
Haemoglobin – The respiratory pigment present in the red blood cells of
vertebrates, which transports oxygen from lungs to the tissues.
Blood plasma – The fluid portion of the blood in which the blood cells are
normally suspended.
Atria – The two upper chambers in the heart, which receive blood from the
veins and push it into the ventricles.
Ventricles – The two lower chambers of the heart, which receive blood from the
atria and pump it into the arteries.
Double circulation – A type of circulation in which the blood flows through the
heart twice, during each cycle of passage through the body.
Arteries – The blood vessels which carry blood away from the heart to various
organs of the body.
Veins – The blood vessels which collect blood from different organs of the body
and bring it back to the heart.
Blood clotting – The process by which the blood coagulates to form solid
masses, or clots so as to prevent blood loss during injury.
Blood clot - A semisolid gelatinous mass of coagulated blood that consists of
red blood cells, white blood cells, and platelets entrapped in a fibrin network.
Root pressure – Pressure exerted in the roots of plants as the result of osmosis
that causes sap to rise through a plant stem to the leaves.
Transpiration – The loss of water vapour from the aerial parts of the plant.
Translocation – The transport of soluble products of photosynthesis from
leaves or storage organs to other parts of the plant through phloem.
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Excretion – The biological process by which the harmful metabolic wastes are
removed from the body.
Kidney – Either of the two bean-shaped excretory organs that filter wastes
(especially urea) from the blood and excrete them and water in urine.
Nephron – The basic filtration unit in the kidneys, which removes waste
products from the blood and forms urine.
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