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Chapter 6
Life process
1. Why visible movement is not enough for defining the characteristic of life?
A. Plants are not visibly growing and some animals can breath without, visible
movement. So using visible movement is not suitable for defining the characteristic
of life is not enough.
2. Why molecular movement needed for life?
A. Living organisms have organs, tissues, cells, and so on. Because of the effects of
the environment this organized, ordered nature of living structures is likely to keep
breaking down over time. If order breaks down, the organism will no longer be alive.
So living creatures must keep repairing and maintaining their structures. Since all
these structures are made up of molecules, they must move molecules around all the
time.
3. What are life processes?
A. The processes, which together perform maintenance job, are life processes.
4. Do maintenance functions of living organism go on even when they are not doing
anything particular?
A. Yes.
5. Why maintenance processes need energy?
A. Maintenance processes are needed to prevent damage and break down. So energy
is needed for them.
6. What is nutrition?
A. The process of transfer of food from outside to inside is called nutrition.
7. Why most of the food sources are carbon based?
A. Most of the food sources are carbon based because life on the earth depends on
carbon based molecules.
8. Which reactions are the most common chemical means to break down molecules?
A. Oxidising-reducing reactions are the most common chemical means to break
down molecules.
9. Which substance is used for the break down of molecules by most organisms?
A. Oxygen.
10. What is respiration?
A. The process of acquiring oxygen from outside the body, and to use it in the
process of breakdown of food sources for cellular needs, is called respiration.
11. Why is diffusion insufficient to meet the oxygen requirements of multi-cellular
organisms?
A. In multi-cellular organisms, all the cells may not be in direct contact with the
surroundings environment. Thus, simple diffusion will not meet the requirements of
all the cells.
12. What is the need of transportation in multi-cellular organisms?
A. Food and oxygen are taken up at one place in the body of the organisms, while all
parts of body need them. This situation creates a need for a transportation system for
carrying food and oxygen from one place to another in the body.
13. What is excretion?
A. The process by which waste products are removed and discarded outside is called
excretion.
14. Why energy is required even when we are not doing any work?
A. Energy is required even when we are not doing any work because to maintain a
state of order in our body.
15. What are autotrophs?
A. The organisms, which use simple inorganic substances for the preparation of
food, are called autotrophs.
16. What are heterotrophs?
A. The organisms, which utilize complex substances, which are broken down into
simpler ones before they can be used for the upkeep and growth of the body, are
called heterotrophs.
17. What is the need of enzymes in heterotrophs?
A. Heterotrophs need enzymes to break complex substances to simpler substances.
18. Quote another name of enzymes.
A. Bio-catalysts.
19. What is the internal energy reserve of plants?
A. Starch
20. What is the internal energy reserve of animals?
A. Glycogen.
21. What are various step occurring in photosynthesis?
A. Various step occurring in photosynthesis are
a. Absorption of light energy by chlorophyll.
b. Conversion of light energy to chemical energy and splitting of water
molecules into hydrogen and oxygen.
c. Reduction of carbon dioxide to carbohydrates.
22. Do gases exchange takes place across the surface of stems, roots and leaves?
A. Yes.
23. Give any one function of guard cells?
A. The opening and closing of the pore is a function of guard cells.
24. When do guard cells swell?
A. Guard cells swell when water flows into them.
25. When do guard cells shrink?
A. Guard cells shrink when water flows out of them.
26. Why do guard cells swell or shrink?
A. Guard cells swell or shrink to open or close the pore.
27. Name a compound, which absorbs carbon dioxide.
A. Potassium hydroxide [KOH].
28. Name the element used in protein synthesis by plants.
A. Nitrogen [N].
29. How does the form of nutrition differ in between different animals?
A. The form of nutrition differs depending on the type, availability of food and how
it is obtained.
30. Give some examples of parasites.
A. Cuscuta, orchids, ticks, lice, leeches and tape worms.
31. Why digestive system is different in various organisms?
A. Digestive system is different in various organisms because the food and the way
it is obtained differ.
32. Describe the nutrition in amoeba and paramecium.
A. Amoeba takes in food using pseudopodia, which fuse over food particle forming
a food vacuole. Inside the food vacuole, complex substances are broken down into
simpler ones, which then diffuse into the cytoplasm. The remaining undigested food
is moved to the surface of the cell and thrown out.
In paramecium food is taken in at a specific spot. Food is moved to this spot by
the movement of cilia, which cover the entire surface of the cell.
33. How food is generated to particles of same texture and small size?
A. Food is generated to particles of same texture and small size by crushing the food
with teeth.
34. Which substance wets the food in the mouth to make its passage smooth in
lining?
A. Saliva.
35. Which enzyme breaks starch to give sugar and which gland releases it?
A. Salivary amylase released by salivary glands.
36. What mixes food thoroughly with saliva and moved around the mouth?
A. Muscular tongue.
37. Why food should be moved in a regulated manner along the digestive tube?
A. Food should be moved in a regulated manner along the digestive tube so that it
can be processed properly in each part.
38. What is peristaltic movement?
A. The rhythmic contraction and relaxation of muscles to send food forward is called
peristaltic movement.
39. Name a protein-digesting enzyme.
A. Pepsin.
40. What are released by gastric glands digestion?
A. Hydrochloric acid [HCl], pepsin and mucus.
41. What is the function of HCl?
A. HCl provides acidic medium to facilitate the action of enzyme pepsin.
42. What is the function of mucus?
A. The mucus protects the inner lining of the stomach from the action of acid under
normal conditions.
43. What regulates the exit of food from stomach?
A. Sphincter muscle.
44. What is the longest part of alimentary canal?
A. Small intestine.
45. Why herbivores have longer small intestine?
A. Meat is easier to digest. So they have shorter small intestine.
46. What is the site of complete digestion of carbohydrates, fats and proteins?
A. Small intestine.
47. Which medium is required for the action of pancreatic enzymes?
A. Alkaline medium.
48. What are digested by the action of trypsin?
A. Proteins and lipase.
49. What is the action of intestinal juice in proteins, carbohydrates and fats?
A. Proteins are converted to amino acids, carbohydrates are converted to glucose and
fats are converted to fatty acids and glycerol.
50. How absorbed food is sent to every part of the body?
A. Villi absorbs the food, which is richly supplied with blood vessels and takes the
absorbed food to each and every part of the body.
51. What regulates the exit of waste material?
A. Anal sphincter regulates the exit of waste material.
52. What is the advantage of having of villi in small intestine?
A. Villi increase the surface area for absorption.
53. What is the first step in the break down of glucose in all organisms?
A. Glucose is converted into pyruvate [which takes in cytoplasm].
54. What happens to pyruvate in yeast during fermentation?
A. Pyruvate is converted to ethanol and carbon dioxide.
55. What happens to pyruvate in mitochondria?
A. Pyruvate breaks up into 3 molecules of carbon dioxide [CO2], water [H2O] and
energy.
56. In which case energy is more- aerobic or anaerobic respiration?
A. Aerobic respiration.
57. What happens to pyruvate in muscle cells in the absence of oxygen?
A. Pyruvate is converted to lactic acid, which creates cramps.
58. In which process energy released during cellular respiration is used?
A. Synthesis of ATP [Adenine Dinucleotide Phosphate].
59. On factors does the direction of diffusion depends?
A. Direction of diffusion depends upon environmental conditions and the
requirements of plant.
60. Is the rate of respiration slow or fast in aquatic animals as compared to terrestrial
animals? Why?
A. Fast because the amount of oxygen dissolved in water is fairly lower than the
amount of oxygen in air.
61. Describe the breathing of fish.
A. Fish take in water through their mouths and force it past the gills where the
dissolved oxygen is taken up by the blood.
62. Describe the respiration in humans.
A. Air is taken into the body through the nostrils. Fine hairs that line the passage,
then it through the throat into the lungs filter the air passing through the nostrils. The
throat has rings of cartilage, which ensure that air passage does not collapse. Within
the lungs the passage divides into smaller and smaller tubes, which finally terminate
into balloon-like structures, which are called alveoli. Alveoli provide a surface for the
exchange of gases. The walls contain an extensive network of blood vessels. The
blood brings carbon dioxide from the rest of the body for release into the alveoli and
the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be
transported to all the cells in the body.
63. What is the surface area of alveolar surface?
A. 80 m2.
64. What is the estimated time to move oxygen from lungs to toes by diffusion?
A. 3 years.
65. What are the functions of blood?
A. Blood transports food, carbon dioxide, nitrogenous wastes, oxygen and salts.
66. Describe the process of circulation of blood in heart.
A. Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the
heart on the left, the left atrium. The left atrium relaxes when it is collecting blood. It
then contracts and left ventricle expands, so that blood is transferred to it. The left
ventricle contracts, the blood is pumped out to the body. De-oxygenated blood comes
from parts of the body to the right atrium as it expands. As the right atrium contracts
the right ventricle dilates. This transfers blood to the right ventricle, which in turn
pumps it to the lungs for oxygenation.
67. What is the function of valves present in heart?
A. Valves ensure that the blood does not flow backwards when the atria or ventricles
contract.
68. What is the advantage of separating oxygenated and de-oxygenated blood?
A. The advantage of separating oxygenated and de-oxygenated blood is it allows a
high efficient supply of oxygen to the body.
69. Does double circulation take place in fish?
A. No.
70. What is double circulation?
A. The blood goes through the heart twice during each cycle. This is known as
double circulation.
71. Name the group of organisms, which has four-chambered heart.
A. Mammals and Aves [Birds].
72. What is blood pressure?
A. The force that blood exerts against the wall of a vessel is called blood pressure.
73. What is systolic pressure?
A. The blood pressure inside artery during contraction is called systolic pressure
[120mm of Hg].
74. What is disystolic pressure?
A. The blood pressure inside artery during relaxation is called disystolic pressure
[80mm of Hg].
75. Name the instrument used to measure blood pressure.
A. Sphygmomanometer.
76. What is hypertension?
A. High blood pressure caused by the construction of arterioles, which results in
increased resistance to blood flow is called hypertension.
77. Why artery walls are thick while vein walls are thin?
A. Blood emerges from heart under high pressure so the arteries have thick, elastic
walls. Blood in veins is no longer under pressure instead. So they have thin walls.
78. Why do veins have valves?
A. Veins have valves to ensure that blood flows only in one direction.
79. What are capillaries?
A. The smallest vessels have walls which are one-cell thick are called capillaries.
80. What is tissue fluid?
A. Lymph is tissue fluid.
81. How lymph is formed?
A. Through the pores present in the walls of the capillaries some amount of plasma,
proteins and blood cells escape into intercellular spaces in the tissues to form lymph.
82. What is lymph?
A. Lymph is similar to the plasma of blood but colourless and contains less protein.
83. What are the functions of lymph?
A. The functions of lymph
a. Carries digested and absorbed fat from intestine.
b. Drains excess fluid from extra cellular space back into the blood.
84. Do plants need high energy?
A. No, plants do not need high energy.
85. Compare the transportation systems of plants and animals.
A. Plants have relatively slower transportation system than animals.
86. What is the function of transportation system in plants?
A. The function of transportation system in plants is to move energy stores from
leaves and raw materials from roots.
87. Describe the transport of water in plants (from roots).
A. At the roots, cells in contact with the soil actively take up ions. This creates a
difference in the concentration of these ions between the root and the soil. Water
therefore moves into the root from the soil to eliminate this difference. The
transpiration of water from leaves creates a suction, which pulls water from the xylem
cells of roots to leaves or other parts where there is need.
88. What are advantages of transpiration to plant?
A. Advantages of transpiration to plant
a. Transpiration helps in the absorption and upward movement of water and
minerals dissolved in it from roots to the leaves.
b. It helps in temperature regulation.
89. What is translocation?
A. The transport of soluble products of photosynthesis is called translocation.
90. Which tissue helps in translocation?
A. Phloem.
91. Where does translocation takes place in phloem?
A. The translocation takes place in sieve tubes with the help of companion cells both
in upward and downward direction.
92. Explain translocation in phloem.
A. Translocation in phloem is achieved by utilizing energy. Materials like sucrose
are transferred into phloem tissue using energy from ATP. This increases the osmotic
pressure of the tissue causing water to move into it. This pressure moves the material
in the phloem to tissues, which have less pressure. This allows the phloem to move
material according to the plant needs.
93. Why sugar stored in stem or root tissue transported to bud during spring season?
A. Sugar stored in stem or root tissue transported to bud during spring season to
provide energy to bud to grow.
94. What are the components of excretory system?
A. The components of excretory system are a pair of kidneys, a pair of ureters, a
urinary bladder and urethra.
95. How urine is produced? How it is excreted?
A. Like lungs kidneys also have capillary clusters. Each capillary cluster in the
kidney is associated with the cup-shaped end of a tube that collects the filtered urine.
Some substances in the initial filtrate, such as glucose, amino acids, salts and a major
amount of water are selectively reabsorbed as urine flows along the tube. The urine
forming in each kidney eventually enters a long tube, the ureter, which connects the
kidneys with the urinary bladder. Urine is stored in the urinary bladder until the
pressure of the expanded bladder leads to the urge to pass it out through the urethra.
The bladder is muscular so it is under nervous control.
96. How artificial kidneys are different from natural kidneys?
A. In artificial kidney only purification of blood takes place but absorption does not
take place.
97. How artificial kidney works?
A. Artificial kidneys contain a number of tubes with a semi-permeable lining,
suspended in a tank filled with dialyzing fluid. This fluid has the same osmotic
pressure as blood, except that it is devoid of nitrogenous wastes. The patient’s blood
is passed through the tubes. During this passage, the waste products from the blood
pass into dialyzing fluid by diffusion. The purified blood is pumped back into the
patient.
98. How much volume of urine is excreted by a healthy adult every day?
A. A litre or two a day.
99. What is the initial filtrate of a healthy adult daily?
A. 180 litres.
100. How plants excrete different waste from them?
A. Oxygen and excess water are excreted by transpiration. Since plants have many
dead cells, they lose that which has more waste. May plant waste products are stored
in the cellular vacuoles. Plants excrete some wastes into the soil around them. Other
wastes produced are stored as resins and gums.
101. What are the components of circulatory system?
A. Heart, blood and blood vessels are the components of circulatory system.
102. Give a function of circulatory system.
A. The transport of materials such as oxygen, carbon dioxide, food and excretory
products is a function of the circulatory system.
103. How do we tell the difference between what is alive and what is not alive?
A. We tend to think of some sort of movement, either growth-related or not a
common evidence for being alive.
104. On which organisms there is a controversy about whether they are truly alive or
not?
A. Viruses.
105. Why different organisms use different kinds of nutritional process?
A. Depending on the complexity of carbon compounds or sources, different
organisms then use different kinds of nutritional process.
106. Why single-celled organisms have no specific organs for taking in food and
excretion?
A. Single-celled organisms have no specific organs for taking in food and excretion
because the entire organism is in contact with the environment.
107. Why do we need materials from outside?
OR
Why should we eat food?
A. We need materials from outside in order to grow, develop synthesise protein, to
get energy and other substances needed in the body.
108. How are carbohydrates stored which are not used immediately?
A. Carbohydrates stored in the form of starch not used immediately.
109. How energy requirement of autotrophs fulfilled?
A. Energy requirement of autotrophs is fulfilled by photosynthesis.
110. How does photosynthesis takes place in desert plants?
A. Desert plants take up carbon dioxide at night and prepare an intermediate, which
is acted upon by the energy absorbed by the chlorophyll.
111. What are the green dots present on the cross section of the leaf?
A. The green dots are cell organelles called chloroplast.
112. How is nitrogen taken in plants?
A. Nitrogen in plants is taken in the form of inorganic nitrates or nitrites or as
organic compounds, which have been prepared by bacteria from atmosphere.
113. Name the organisms, which break down food material outside and absorb it.
A. Bread mould, yeast and mushrooms.
114. Which glands secrete saliva?
A. Salivary glands secrete saliva.
115. What breaks carbohydrates (starch) to sugar?
A. Salivary amylase breaks carbohydrates (starch) to sugar.
116. How do muscular walls help in digestion?
A. The muscular walls of stomach help in mixing the food thoroughly with more
digestive juices.
117. How does the length of the small intestine differ in various animals?
A. The length of the small intestine differs in various animals depending on the food
they eat.
118. How is alkaline medium facilitated in small intestine?
A. Bile juice facilitates alkaline medium in small intestine.
119. How are fats digested?
A. Bile salts broke down large globules of fats to smaller globules.
120. Which part of gut receives undigested food from small intestine?
A. Large intestine.
121. From were does waste material is removed?
A. Anus.
122. How can plaque be removed?
A. Brushing the teeth a eating removes plaque.
123. Describe how can we remove chlorophyll from a leaf?
A. ACTIVITY
 Pluck a leaf from a plant.
 Dip the leaf in boiling water for a few minutes.
 After this, immerse it in a beaker containing alcohol. The chlorophyll
dissolves.
124. In which part of cell glucose is converted to pyruvate (in any organism)?
A. In cytoplasm glucose is converted to pyruvate (in any organism).
125. What is aerobic respiration?
A. Respiration that takes place in the presence of air (oxygen) is called aerobic
respiration.
126. What is anaerobic respiration?
A. Respiration that takes place in the absence of air is called anaerobic respiration.
127. What is known is energy currency of cell?
A. ATP.
128. How is ATP formed?
A. ATP is formed from ADP and inorganic phosphate.
129. How much energy is released when ATP is broken using water?
A. 30.5KJ/mol.
130. For what purposes ATP is used?
A. ATP is used for contraction of muscles protein synthesis, conduction of nerve
impulses and many other activities.
131. What ensures that all the cells in the plant are in contact with air?
A. Intercellular spaces.
132. What are the major activities taking place in plant at day and night in the
stomata?
A. Carbon dioxide release at night and Oxygen release at daytime.
133. What covers the gill-slits of fish?
A. Operculum.
134. Why is the surface where gaseous exchange takes place is very fine and
delicate?
A. The exchange of oxygen and carbon dioxide has to takes place across this
surface, so this surface is very fine and delicate.
135. Why a residual volume of air always present in lungs?
A. The lungs always contain a residual amount or volume of air so that there is
sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
136. Why diffusion pressure cannot alone transport oxygen to different parts in
higher animals?
A. Since body size of animals is large, so diffusion pressure cannot alone transport
oxygen to different parts in higher animals.
137. How is oxygen transported in human beings?
A. In human beings, the respiratory pigment is haemoglobin, which has a very high
affinity for oxygen, take up oxygen from air in lungs and carry it to tissues, which are
deficient in oxygen before releasing it.
138. Where is haemoglobin present in blood?
A. In red corpuscles.
139. Why is most carbon dioxide transported in the dissolved from in our blood?
A. Carbon dioxide is more soluble in water so it is mostly transported in dissolved
from in our blood.
140. Which is more soluble in water-oxygen or carbon dioxide?
A. Carbon dioxide.
141. In blood which component carries oxygen?
A. Red blood cells.
142. What is the function of plasma present in the blood?
A. Plasma transports food, carbon dioxide and nitrogenous wastes in dissolved
form.
143. What is the need of pumping organ, network of tubes and a system?
A. Pumping system or organ is needed to push blood around the body, a network of
tubes to reach all the tissues and a system in place to ensure that this network can be
repaired if damaged.
144. What is the importance of chambers in the heart?
A. Heart has different chambers to prevent the oxygen rich blood from mixing with
the blood containing carbon dioxide.
145. Why ventricles have thicker muscular walls than atria?
A. Ventricles have to pump blood into various organs; they have thicker muscular
walls than atria.
146. Name the organisms, which constantly use energy to maintain their body
temperature?
A. Mammals and birds.
147. Name the organisms whose body temperature depends on the temperature in the
environment?
A. Amphibians and some reptiles.
148. What are the differences between arteries and veins?
A.
Differences between arteries and veins.
1.
2.
3.
4.
5.
Artery
Thick and elastic walls.
Pressure of blood is more.
Does not have valves.
Carries pure blood.
Ends with capillaries.
1.
2.
3.
4.
5.
Vein
May have thin walls.
Pressure of blood is less.
Valves are present.
Carries impure blood.
Starts with capillaries.
149. What are the disadvantages of leaking blood?
A. Disadvantages of leaking blood.
a. Loss of pressure.
b. Reduces the efficiency of pumping system.
150. Name the fluids involved in transportation.
A. Blood and lymph.
151. What is the nearest and richest source of raw material to plants?
A. Soil is the nearest and richest source of raw material to plants.
152. Why a proper system of transportation is needed in some plants?
A. If the distance between soil-contacting organs and chlorophyll containing organs
are large, because of changes in the body design, a proper system of transportation is
necessary, since diffusion pressure alone cannot transport.
153. What are the two pathways of plant transportation system?
A. Xylem and Phloem are the two pathways of plant transportation system.
154. What is the function of xylem?
A. Xylem moves water and minerals from the soil.
155. What is the function of phloem?
A. Phloem transports products of photosynthesis from leaves to other parts of the
plant.
156. What are the components of xylem, which are interconnected to form a
continuous system of water-conducting channels?
A. Vessels and trachieds of roots, stem and leaves are interconnected to form a
continuous system of water-conducting channels.
157. Where are kidneys located?
A. Kidneys are located in the abdomen, one on either side of the backbone.
158. What is the purpose of making urine?
A. The purpose of making urine is to filter out waste products from the blood.
159. What reduces the activities of kidney?
A. Infections, injury or restricted blood flow to kidneys reduce the activity of
kidneys.
160. What is an artificial kidney?
A. An artificial kidney is a device to remove nitrogenous waste products from the
blood through dialysis.