Life’s Internal Secrets
Q1. Fill in the blanks.
1.
________________ artery takes the blood to the
lungs for oxygenation. (Pulmonary)
2.
______________ is the largest gland in the body. (Liver)
3.
The digested food is absorbed by the __________ in
the small intestine. (Villi)
4.
Lymph flows in ____________ direction. (one)
Q2. Correct the following statements.
1.
Aquatic animals breathe at a slower rate than the
terrestrial animals.
Ans. Aquatic animals breathe faster than terrestrial animals.
2.
In human beings the blood goes to the heart in one
cycle once.
Ans. In human beings the blood goes to the heart twice during each
cycle of circulation.
3.
Plasma is called as tissue fluid.
Ans. Lymph is called as the tissue fluid.
4.
Carbohydrates are the body building nutrients.
Ans. Carbohydrates are the energy giving nutrients.
5.
Calcium oxalate crystals present in the cells of
some plants are called as resins.
Ans. Calcium oxalate crystals present in the cells of some plants are
called as raphides.
Q3. Give scientific reasons.
1.
Breathing rate increases during vigorous
exercising.
Ans.
i.
During vigorous exercise, the demand for oxygen
increases due to increased energy production.
ii.
Therefore, breathing rate increases to provide more
oxygen.
2.
Translocation is needed in all higher plants.
Ans.
i.
Transport of nutrients from leaves to other parts
of the plant is termed translocation.
ii.
It is needed in all higher plants because every
part of the plant needs food for harnessing energy and for building and
maintaining the organism.
3.
The plants are kept in dark before determining the
factors essential for photosynthesis.
Ans.
i.
When the plants are kept in dark all the starch
stored in them gets used up and no new starch is produced.
ii.
Such destarched plants help to determine the
factors essential for photosynthesis.
4.
It is necessary to separate oxygenated blood from
the deoxygenated blood in mammals.
Ans.
i.
Mammals have high energy needs since they
constantly use energy to maintain their body temperature.
ii.
It is necessary to separate oxygenated blood from
deoxygenated blood in mammals because such separation allows a high efficient
supply of oxygen to the body required for high energy production.
Q4. Draw a well labeled diagram of
the following.
1.
Human excretory system.
2.
Vertical section of the human heart.
3.
Digestive glands.
Q5. Answer the following.
1.
How are fats digested in the human body?
Ans.
i.
Whenever food enters the small intestine, the bile
and pancreatic juice enter there through a common duct.
ii.
Bile makes the food alkaline and breaks the large
fat globules into smaller ones.
iii.
The enzyme lipase in the pancreatic juice breaks
down the fats.
iv.
Various intestinal juices secreted by the walls of
the small intestine complete the digestion of fat converting it into fatty
acids.
2.
What would be the consequences of deficiency of
haemoglobin in the human body?
Ans.
i.
Haemoglobin in the blood performs a very important
function of absorbing and carrying oxygen from lungs to the body tissues and CO2 from body tissues to the lungs.
ii.
Therefore, due to the deficiency of haemoglobin,
the body tissues do not get sufficient oxygen which leads to a state called
anaemia.
iii.
Fatigue, palpitation, dizziness, headache, nausea,
lack of concentration etc., are some of the symptoms of anaemia.
3.
How do plants get rid of their excretory products?
Ans.
i.
Gaseous excretory materials are eliminated by diffusion.
ii.
Waste products stored in the vacuoles of the
leaves, flowers, fruits and bark are removed by the periodical shedding of
these parts.
iii.
Some waste products are stored as resins and gum in
old xylem. When the trunks of these trees are cut, these substances ooze out.
iv.
Plants also excrete some waste substances into the
soil around them.
Q6. Given below are the end products
of different reactions involving glucose.
Write the reaction number in
front of the following:
1.
Anaerobic reaction =
2.
Reaction in human muscles =
3.
Aerobic respiration =
4.
Reaction in plant cells =
5.
Reaction in liver =
Ans.
1.
Anaerobic reaction = 5
2.
Reaction in human muscles =4
3.
Aerobic respiration = 3
4.
Reaction in plant cells = 1
5.
Reaction in liver = 2
Q7. Answer briefly:
1.
Explain the process of translocation in plants.
Ans.
i.
Transport of nutrients from leaves to other parts
of the plant is called translocation.
ii.
It takes place through phloem in upward as well as
downward direction.
iii.
This process needs energy which is obtained from
ATP.
iv.
When food materials like sucrose are transferred to
phloem tissue, using ATP, the concentration of water molecules decreases in
that area.
v.
This results in the movement of water into the
cells due to osmosis.
vi.
The increased contents within the cells exert a
high amount of pressure on their wall.
vii.
This pressure moves the food materials to the
adjacent cells with low pressure.
viii.
This allows the phloem to move material according
to the plant’s needs.
2.
Explain the structure and function of a nephron.
Ans.
i.
The basic filtration unit in the kidney is a
cluster of thin walled blood capillaries called as nephron.
ii.
Each nephron has a cup shaped thin walled upper and
called Bowman’s capsule which contains a bundle of blood capillaries called
glomerulus.
iii.
When blood containing urea enters the glomerulus it
gets filtered through glomerular capillaries.
iv.
The selectively permeable wall of the Bowman’s
capsule allows the water molecules and small molecules of the other substances
to pass through them and forms glomerular filtrate.
v.
The blood, free from these materials is taken to
the heart through the renal vein.
vi.
The glomerular filtrate collected in the Bowman’s
capsule further passes through the nephron tubule where reabsorption of water
and useful molecules take place.
vii.
The remaining fluid containing the waste forms the
urine which eventually enters a long tube called the ureter.
viii.
It is further stored in the urinary bladder and
from there it is thrown out through the urethra.
