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1.
What are the raw materials for photosynthesis? (1 mark)
Answer:
The raw materials and other necessary items required for photosynthesis are Sunlight,
Water, CO2 and Chlorophyll.
2.
What is the role of bile juice in digestion? (1 mark)
Answer:
Bile is alkaline in nature and it is temporarily stored in gall bladder and
helps in digestion of fats,
it
also helps in absorption fats.
3. Write
the equation for respiration? (1 mark)
Answer:
Glycol sis
|
In presence of O2
|
|||||
C6H12O6
|
------->
|
C3H4O3
|
---------------->
|
6CO2
+
|
6H2O +
|
38ATP
|
Pyruvic acid
|
Kreb cycle in mitochondria
|
4.
Name three types of blood vessels used in the transport of blood. (1 mark)
Answer:
Arteries, vein and capillaries
Note:
There are three major types of blood vessels: the arteries, which carry the
blood away from the heart; the capillaries, which enable the actual exchange of
water and chemicals between the blood and the tissues; and the veins, which
carry blood from the capillaries back toward the heart.
5.
Name the artificial method for the removal of liquid nitrogenous waste from
body? (1 mark)
Answer:
Dialysis: Dialysis is a process by which waste materials and excess water are
removed from the blood. This is a normal function of our kidneys inside the
body.
6.
Write any two points of difference respiration in plants and respiration in
animals. (2 marks)
Answer:
Respiration in plants.
|
Respiration in animals
|
1.In plants separate respiratory organs are absent
|
1.In animals respiratory organs are generally present
|
2.The rate of respiration is slow.
|
2.The rate of respiration is fast.
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3.They lack respiratory surface
|
3. Respiratory surface is generally present.
|
7.
Draw the labelled diagram of the human respiratory system. (2 marks)
8.
How are the alveoli designed to maximize the exchange of gases? (2 marks)
Answer:
The alveoli are present at the terminal of bronchioles. They are balloon shaped
structures which increases the surface area for the exchange of gases and are
richly supplied with blood vessels to take the oxygen to different cells
9.
Amylase is secreted by two different glands. Name them. Write is the action of
amylase on food? (2 marks)
Answer:
Salivary glands are found in mouth cavity .They secrete enzyme called salivary
amylase or ptyalin. It helps in digestion of starch.
Pancreas
secrets pancreatic juice into small intestine. Pancreatic juice contains
tyrosine and pancreatic amylase.
Pancreatic
amylase is a major digestive enzyme, which can hydrolyze starch into simpler
sugars, like maltose and glucose, for absorption.
10.
Name the passage in sequence through which urine passes from kidneys to the
outside in humans. How is urine prevented from flowing back into the ureters?
(2 marks)
Answer:
kidney -> the urinary bladder -> the urethra ---->
outside [via vaginal opening
in women or via the penis in man]
There
are valves present in ureters called as ureterovesical valves which prevent the
backflow of urine.
11.
State the role of the following in the human respiratory system
(i) Nasal
cavity (ii) Diaphragm (iii) Alveoli (3 marks)
Answer:
(i) Nasal cavity: It contains hair and mucus which entrap the dust particles.
(ii) Diaphragm: Contract and relax to increase
and decrease the volume of chest cavity respectively
(iii)
Alveoli: it helps in exchange of air in blood. it transfer oxygen to the blood
and takes carbon di oxide from the blood.
12.
Give reasons for the following:
(i)The
glottis is guarded by epiglottis.
(ii)
The lung alveoli are covered with blood capillaries.
(iii)
The wall of trachea is supported by cartilage rings. (3 marks)
Answer
: (i) The epiglottis guards the entrance of the glottis and prevent flow of
food into wind pipe.
(ii)
Lungs alveoli are covered with blood capillaries for the exchange of gases to
take place and oxygen can easily diffuse into the blood stream and be
transported to various parts of the body through the heart.
(iii) The wall of trachea is supported by
cartilage rings which percent them to collapse when air is absent in them
13.
Leaves of a healthy potted plant were coated with Vaseline to block the
stomata. Will this plant remain healthy for long? State three reasons for your answer. (3 marks)
Answer:
By applying Vaseline on leaves stomata gets covered and transpiration stops.
This prevents loss of water vapour and the moisture of the leaf retain for
sometimes. But as the layer of vaselin stops all type of gaseous exchange, leaf
will end up dying.
(a) Respiration
will stop. (b) Transpiration will stop. (c) Photosynthesis will stop.
14.
What are the differences between aerobic and anaerobic respiration? Name some
organisms that use the anaerobic mode of respiration. (3 marks)
Answer :
Aerobic
|
Anaerobic
|
(i) It occurs in all living cells of higher plants.
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It occurs in bacteria, certain fungi, germinatin seeds and fleshy fruits muscles.
|
(ii) It requires oxygen.
|
Oxygen in not required
|
(iii) The end products are CO2 and H2O.
|
The end products are alcohol [fungi] or lactic acid [ muscles] and CO2.
|
(iv) The oxidation of one molecules of glucose produces 38 ATP molecules
|
The number of ATP molecules produced is only 2.
|
some organisms that use the anaerobic mode of respiration : bacteria, certain fungi, germinatin seeds and fleshy fruits muscles
|
15.
Describe double circulation in human beings. Why is it necessary? (3 marks)
Answer
:The blood passes to aorta from the left ventricle. The aorta gives rise to
many arteries that distribute the oxygenated blood to all the regions of the
body. Therefore, the blood goes
twice through the heart. This is known as double circulation.
Importance
of double circulation:: This separate oxygenated and deoxygenated blood that
ensure more efficient supply of oxygen to the body cells. This also help in maintaining
a constant internal temperature and allows mammals and birds to carry-out body
processes more efficiently.
16.
(i) Name the blood vessel that brings oxygenated blood to the human heart. (5
marks)
(ii)
Which chamber of human heart receives oxygenated blood?
(iii)
Explain how oxygenated blood from this chamber is sent to all parts of the
body.
Ans:
(i) The pulmonary vein (ii)
the left atrium