Life processes

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GOALPARA PUBLIC SCHOOL
CLASS-X SUB- G.SC
CHAPTER-6 LIFE PROCESSES
PREPARED BY MOZIBOR RAHMAN
INTRODUCTION
Something which is living is said to be alive. The most important criterion to decide whether something is
alive or not is the molecular movement. However, we can decide something is alive or not by using the
folioing characteristics of living things:-
1) Living things can move by themselves
2) Living things need food ,air and water
3) Living things can grow
4) Living things can respond to changes around them
5) Living things respire
6) Living things excrete
7) Living things can reproduce
What are life processes?
The basic functions performed by living organisms to maintain their life on earth are called life
processes. These includes: -
a) Nutrition
b) Respiration
c) Transportation
d) Excretion
e) Control and coordination
f) Growth
g) Movement
h) Reproduction
NUTRITION
Nutrition is a process of intake of nutrients like carbohydrates, proteins, fats, vitamins, minerals and water
by an organism as well as the utilizations of these nutrients by an organism.
MODES OF NUTRITION:
A) AUTOTROPHIC MODE NUTRITION
B) HETEROTROPHIC MODE OF NUTRITION
AUTOTROPHIC MODE NUTRITION:
Autotrophic mode of nutrition is that mode of nutrition in which an organism make their own
food from the simple inorganic materials like carbon dioxide and water present in the
surroundings with the help of sunlight energy.
PHOTOSYNTHESIS:
Q. What is photosynthesis? What are the steps involve in photosynthesis? HSLC 2017
Ans: The process, by which green plants make their own food (glucose) from CO2 and H2O buy using
sunlight energy in presence of chlorophyll, is called Photosynthesis.

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STEPS OF PHOTOSYNTHESIS:
A) Absorption of light energy by chlorophyll.
B) Conversion of light energy into chemical energy and splitting of H2O molecule into H2 (g) and O2(g).
H2O H2(g) + O2(g).
C) Reduction of CO2(g) to Carbohydrate i.e. glucose
CO2(g) + H2(g) C6H12O6 (s) + H2O(g)
(Carbon Dioxide) (hydrogen) (Glucose) (Water)
Q. What are the conditions and raw materials necessary for photosynthesis?
Ans :
Conditions necessary for photosynthesis Raw materials for photosynthesis
1) Sunlight
2) Chlorophyll
3) CO2
4) H2O
1) CO2
2) H2O
3) Other raw materials like nitrogen,
phosphorus, iron and magnesium for
body building.
Q. Where is the photosynthesis takes place?
Ans: Photosynthesis takes place in Chloroplasts.
Q. What are stomata? What are the functions of stomata? Describe the opening and closing
action of stomata. CBSC 2010
Ans :
Stomata: The tiny pores present on the lower epidermis of leaves are called stomata.
Functions of stomata:
1) Massive amount of gaseous (gases like CO2 and O2) exchange takes place in leaves through
the stomata.
2) Transpiration takes place through stomata.
NOTE
Chloroplasts are the organelles in the cells of
green plants which contain green pigment called
Chlorophyll. These chloroplasts are the site of
photosynthesis.

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Opening and closing of stomata:
The opening and the closing of the pores of stomata is a function of guard cells. The guard cell swells
when water flows into them, become curved and cause the pore to open. On the other hand, when the
guard cells lose water, they shrink, become straight and close the stomata pore.
Q. How the plants obtain CO2 for photosynthesis? HSLC 2017
Ans: The CO2 gases enter the leaves of plant through stomata present on their surface.
Q. How the plants obtain H2O for photosynthesis?
Ans: The H2O required for photosynthesis is absorbed by the roots of the plants from the soil through
the process of osmosis. The H2O absorbed by the roots of the plants is transported upward through the
xylem vessels to the leaves where it reaches the photosynthetic cells and utilized in photosynthesis.
HETEROTROPHIC MODE OF NUTRITION
Heterotrophic mode of nutrition is that mode of nutrition in which an organism cannot make their own
food from simple inorganic materials like CO2 and H2O, and depends on other organisms for its food.
E.g.… All the animals.
TYPES OF HETEROTROPHIC NUTRITION:
A) Saprotrophic nutrition/Saprophytic nutrition.
B) Parasitic nutrition.
C) Holozoic nutrition.
Saprotrophic nutrition/Saprophytic nutrition.
Saprotrophic nutrition/Saprophytic nutrition is that nutrition in which an organism obtains its food from
decaying organic matter of dead plants, dead animals and rotten bread etc. e.g. – fungi.
Parasitic nutrition.
Parasitic nutrition is that nutrition in which an organism derives its food from the body of another living
organism. The organism which obtains the foods is called parasite and the organism from whose body
food is obtained is called a host. E.g. Cucuta, roundworms, plasmodium etc.
Holozoic nutrition:
Holozoic nutrition is that nutrition in which an organism takes the complex organic food materials into its
body by the process of ingestion; the ingested food is digested and then absorbed into the body cells of
the organism. E.g. – Humans, Amoeba.

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Q. With the help of a labelled diagram describe the nutritional process in amoeba.
CBSC2014,NCERT EXEMPLER
Ans: The process of obtaining food by amoeba is called ‘phagocytosis. The various process involve in
the nutrition of amoeba are- ingestion, digestion, assimilation and egestion.
A) Ingestion: When food particles comes near the amoeba, then the amoeba ingests this food
particles by forming temporary finger like projections called pseudopodia around it.
B) Digestion: The enzymes from the surrounding cytoplasm enter into food vacuole and
breakdown the food into small by chemical reactions.
C) Absorption: The digested food present in the food vacuole of amoeba is absorbed directly into
the cytoplasm by diffusion.
D) Assimilation: A part of the food is used to obtain energy and the remaining part is used for
growth.
E) Egestion: When a considerable amount of undigested food collects inside the body of amoeba,
then its cell membrane suddenly raptures at any place and the undigested food is thrown out of
the body of amoeba.
Question ans of page no 95.
Q1. Why diffusion is insufficient to meet the oxygen requirements of multicellular organisms
like humans?
Ans: Diffusion is insufficient to meet the oxygen requirements of multicellular organisms like humans
because in multicellular organisms all the cells may in be direct contact with the environment.
Q2. What criteria do we use to decide whether something is alive?
Ans: The most important criterion to decide whether something is alive or not is the molecular
movement. However, we can decide something is alive or not by using the following characteristics of
living things:-
1) Living things can move by themselves
2) Living things need food ,air and water
3) Living things can grow
4) Living things can respond to changes around them
5) Living things respire
6) Living things excrete
7) Living things can reproduce

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Q3. What are the outside raw materials used by an organism?
Ans: The outside raw materials used by an organism are- food, oxygen and water.
Q4. What process would you consider essential for maintaining life?
Ans: The various processes essential for maintaining life are-
a) Nutrition
b) Respiration
c) Transportation
d) Excretion
e) Control and coordination
f) Growth
g) Movement
h) Reproduction
PAGE NO 101.
Q1. What are the differences between autotrophic and heterotrophic nutrition? CBSC 2013
Autotrophic nutrition Heterotrophic nutrition
1) Food is synthesized from simple
inorganic raw materials like CO2 and
H2O.
2) Chlorophyll is necessary.
3) Digestion of food does not occur.
4) All green plants and bacteria have this
type of nutrition.
1) Food is obtained from autotrophs directly
or indirectly.
2) Chlorophyll is not present.
3) Digestion is requiring to breakdown
complex food into simple and soluble
forms.
4) All animals and fungi have this type of
nutrition.
Q2. Where do plants get each of the raw materials required for photosynthesis?
Ans: Plants get each of the raw materials required for photosynthesis by the following ways-
a) CO2(g) from the atmosphere.
b) H2O from the soil.
NUTRITION IN HUMAN BEINGS:
Fig: human alimentary canal
NOTE
**The organs of human alimentary canal are- Mouth,
oesophagus, stomach,
Small intestine and large intestine.
**The various glands of digestive system are- Salivary
gland, Liver and Pancreas

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Q. What is peristaltic movement?
Ans: The contraction and expansion movement of the walls of food pipe is called peristaltic movement.
Q. what is enzyme? Name the enzyme secreted by the salivary gland and state its function.
Ans- Enzyme are the bio-catalyst which breakdown complex molecules into simple molecule.
The enzyme secreted by the salivary gland is Salivary amylase.
The function of the Salivary amylase is that it breakdown starch which is complex molecule into simple
sugar.
Q. What are the chemicals secreted by the gastric glands? State their functions.
Ans- The chemicals secreted by the gastric glands are- Hydrochloric acids, Pepsin (an enzyme) and
mucus.
The functions of HCl are-
i) HCl makes the food substances acidic in nature.
ii) HCl kills the microorganisms present in food.
The functions of Pepsin (an enzyme) is that it digests protein part the food in the stomach.
The function of mucus is that it protects the inner lining of stomach from the action of acids.
Q. Write short note on the following.
a) Bile juice b) Intestinal juice c) Pancreatic juice
Ans:
a) Bile juice: Bile juice is secreted by the liver which is greenish yellow liquid stored in gall
bladder. Bile juice contains salts which are alkaline and perform two functions-
i) it makes acidic food coming from the stomach alkaline.
ii) It breakdown the large globules of fats into smaller globules known as emulsification of fats.
b) Pancreatic juice: Pancreas secretes pancreatic juice which contains digestive enzymes like
pancreatic amylase, trypsin and lipase. The pancreatic amylase breakdown the starch, trypsin
digests the proteins and lipase breaks down the emulsified fats.
c) Intestinal juice: The secretion of intestinal glands known as intestinal juice which contain
enzymes namely Amylolytic, Proteolytic and Lipolytic. The enzymes present in intestinal
juice finally convert the proteins into amino acids, complex carbohydrates into glucose and fats
into fatty acids and glycerol.
Q. What do you mean by emulsification of fats? HSLC 2015
Ans: The breaking down of large globules of fats into small globules by the bile salt is known as
emulsification of fats.

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Q. State the functions of the following enzymes- a) Salivary amylase b) Pancreatic amylase
c) Trypsin d) Lipase
Q. What is sphincter muscle? State their function.
An: A sphincter muscle is a circular muscle that normally maintains constriction of a natural body
passage or orifice and which relaxes as required by normal physiological functioning.
Sphincters control the passage of liquids and solids. Many sphincters are used every day in the
normal course of digestion. For example, the lower esophageal sphincter (or cardiac sphincter), which
resides at the top of the stomach, keeps stomach acids and other stomach contents from pushing up
and into the esophagus.
Q. What is villa? State their function?
An: The inner lining of the small intestine has numerous finger-like projections called villa. Villa
increases the surface area for the absorption digested food. The villi are richly supplied with blood
vessels which take absorbed food to each and every cell of the body.
FACTS ABOUT SMALL INTESTINE
Small intestine is the longest part of the alimentary canal.
The length of small intestine in an adult man is about 6.5 m
Herbivores have long small intestine to facilitate cellulose digestion.
Carnivores have shorter length of small intestine as meat is easily digested.
It is the site of complete digestion.
PAGE NO 101 Q. ANS:
Q3. What is the role of acids in our stomach?
Ans: The functions of acids (HCl) in our stomach are-
a) HCl makes the food substances acidic in nature.
b) HCl kills the microorganisms present in food.
Q4. What is the factions of digestive enzymes?
a) Ans: The digestive enzymes help to breakdown large m insoluble food molecules into small
molecules. E.g. - Amylase breakdown the starch, trypsin digests the proteins and lipase
breaks down the emulsified fats.
Q5. How is small intestine designed to absorb digested food? CBSC 2016
Ans: The inner lining of the small intestine has numerous finger-like projections called villi. Villi increase
the surface area for the absorption digested food. The villi are richly supplied with blood vessels which
take absorbed food to each and every cell of the body.
NCERT EXAEMPLER:
Q. What is dental caries (tooth decay) and dental plaque?
Ans: The formation of small cavities in the teeth due to the action of acid formation by bacteria and
improper dental care is called dental caries.
If the teeth are not cleaned regularly, they become covered with a sticky, yellowish layer of food
particles and bacteria cells called dental plaque

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Q. Why is small intestine in herbivores longer than in carnivores?
Ans: Cellulose forms the 8ruminant part of the herbivore’s food. Digestion of the cellulose takes a
longer time, because the enzymes are produced by 8ruminant bacteria present in the gut of the
herbivore. Longer small intestine ensures that the food stays for a longer duration and proper digestion
is possible. In the case of carnivores, cellulose is not present in the diet, thus the length of the small
intestine is less.
Q. Name the correct substrate for the following-
A) Trypsin B) Amylase C) Pepsin D) Lipase
Ans:
Enzyme Substrate
Trypsin Proteins
Amylase Starch
Pepsin Proteins
Lipase Emulsified fats
Q. Describe the process of digestion in different parts of the alimentary canal in man.
HSLC2017
Ans: The digestion in different parts of the alimentary canal in man can be describe as follows-
A) Mouth: The mouth contains teeth which crush the food into small particles. Saliva moistens the
food and the enzyme salivary amylase present in saliva convert the starch into simple…..
…..sugar like Maltose.
B) Stomach: Gastric glands present on the walls of stomach which release HCl, Pepsin (enzyme)
and mucus.
The functions of HCl are-
j) HCl makes the food substances acidic in nature.
ii) HCl kills the micro-organisms present in food.
The functions of Pepsin (an enzyme) is that it digest protein part the food in the stomach
The function of mucus is that it protects the inner lining of stomach from the action of acids.
C) Small intestine: It is the side of complete digestion. It receives the secretions from liver and
pancreas.
1) Bile juice: It is secreted by the liver. It convert the acidic food into alkaline and breakdowns
the large globules of fats into small globules.
2) Pancreatic juice: Pancreas secretes pancreatic juice which contains digestive enzymes like
pancreatic amylase, trypsin and lipase. The pancreatic amylase breakdown the starch,
trypsin digests the proteins and lipase breaks down the emulsified fats.
3) Intestinal juice: The secretion of intestinal glands known as intestinal juice which contain

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enzymes namely Amylolytic, Proteolytic and Lipolytic. The enzymes present in intestinal
juice finally convert the proteins into amino acids, complex carbohydrates into glucose and
fats into fatty acids and glycerol.
4) The inner lining of the small intestine has numerous finger-like projections called villi. Villi
increase the surface area for the absorption digested food. The villi are richly supplied with
blood vessels which take absorbed food to each and every cell of the body.
D) Large intestine: The undigested food from the small intestine enters into the small intestine
where H2O part of the food is absorbed.
E) Anus: The remaining undigested solid part of the food is given out through the anus time by
time.
RESPIRATION
The breaking down of six carbon molecule glucose into tree carbon molecule pyruvate in the cytoplasm
ad releasing of energy from tree carbon molecule pyruvate is known as respiration.
C6H12O6 in cytoplasm C3H4O3 In presence of O2 CO2(g) + H2O(l) + Energy(ATP)
(glucose) (Pyruvate) In Mitochondria (Carbon dioxide) (water)
HOW ENERGY RELEASED DURIG RESPIRATIO IS STORED?
The energy produce during respiration is stored in the form of ATP.
ATP= Adenosine Tri-Phosphate. ADP= Adenosine Di- Phosphate.
The energy released during respiration is used to make ATP molecules from the ADP and
inorganic phosphate.
AD E E AD AT .
ATP is the energy currency for most cellular processes.
TYPES OF RESPIRATION
a) Aerobic respiration: The respiration which takes place in presence of oxygen in the
mitochondria is known as aerobic respiration.
C6H12O6 in cytoplasm CH3COCOOH In presence of O2 6CO2(g) + 6H2O(l) +Energy(38ATP)
b) Anaerobic respiration; The respiration which takes place in absence of oxygen in the yeast
cell is known as aerobic respiration.
C6H12O6 in cytoplasm CH3COCOOH In absence of O2 2CH3CH2OH +2 CO2(g) +Energy(2ATP)
(glucose) (Pyruvate) In yeast (ethanol) (Carbon dioxide)
c) In muscle cells: In the muscle cells of human, anaerobic respiration takes place. When
anaerobic respiration takes place in the human muscle cells, then glucose is converted into
lactic acids with the releasing of a small amount of energy.
C6H12O6 in cytoplasm CH3COCOOH insufficient O2 2CH3CHOHCOOH + Energy(2ATP)
(glucose) (Pyruvate) In muscle cell ( lactic acid)

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SUMMERY OF RESPIRATION
Explain the tree pathways of breakdown of glucose in living organisms. NCERT EXEMPLER
OR
What are the different ways in which glucose is oxidized to provide in energy in various
organisms? NCERT PAGE NO 105, HSLC2015
Ans: The different ways in which glucose is oxidized to provide in energy in various organisms
are-
a) Aerobic respiration: The respiration which takes place in presence of oxygen in the
mitochondria is known as aerobic respiration.
C6H12O6 in cytoplasm CH3COCOOH In presence of O2 6CO2(g) + 6H2O(l) +Energy(38ATP)
b) Anaerobic respiration; The respiration which takes place in absence of oxygen in the yeast
cell is known as aerobic respiration.
C6H12O6 in cytoplasm CH3COCOOH In absence of O2 2CH3CH2OH +2 CO2(g) +Energy(2ATP)
(glucose) (Pyruvate) In yeast (ethanol) (Carbon dioxide)
Q. What is the storage food in plants and animals?
Ans: The storage food in plants is starch and that of animals is glycogen.
Q. Why do muscle cell cramps when we do heavy physical exercise?
Ans In the muscle cells of human, anaerobic respiration takes place. When anaerobic respiration takes
place in the human muscle cells, then glucose is converted into lactic acids with the releasing of a small
amount of energy. This lactic acid accumulates in the muscle cells. The accumulation of lactic acids in
the muscle causes muscular cramps.
C6H12O6 in cytoplasm CH3COCOOH insufficient O2 2CH3CHOHCOOH + Energy(2ATP)
(glucose) (Pyruvate) In muscle cell ( lactic acid)

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BREATHING
Describe the process of breathing in human beings. NCERT EXEMPLER,HSLC2017
Ans: Breathing in humans involve three steps-
A) Inspiration/Inhalation: When we breathe in, ribs move up ad flatten the diaphragm due to
which the chest cavity becomes larger. As a result air is suck into the lungs and fills the
expanded alveoli.
B) Gaseous exchange: Hemoglobin binds with the oxygen and carries it along the blood in the
body whereas CO2 which is produced during respiration diffuses into the blood and is carried to
the lungs for expiration.
C) Expiration: Ribs move down and diaphragm becomes dome-shaped decreasing the chest
cavity. Thus, pushing the air out from the lungs.
Fig: Human respiratory system
Do You Know?
Smoking is injurious to health.
Lung cancer is one of common causes of deaths in the world.
The upper part of respiratory tract is provided with small hair-
like structures called cilia. These cilia help to remove germs,
dust and other harmful particles from inhaled air. Smoking
destroys these hair due to which germs, dust, smoke and other
harmful chemicals enter lungs and cause infection, cough and
even lung cancer.
If the alveolar surface were spread out, it would cover about 80 m2. How much do you
think the surface area of your body is? Consider how efficient exchange of gases
becomes because of the large surface available for the exchange to take place.
If diffusion were to move oxygen in our body, it is estimated that it would take 3 years
for a molecule of oxygen to get to our toes from our lungs. Aren’t you glad that we have
haemoglobin?
Q. What are alveoli? State their functions.
Ans: Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in
The main organs of human
respiratory system are-Nose,
Nasal cavity, Tracheae,
bronchi, Lungs and
Diaphragm.

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balloon-like structures which are called alveoli (singular–alveolus).
The walls of the alveoli contain an extensive network of blood-vessels. The alveoli provide a
surface where the exchange of gases can take place.
The average breathing rate in adult at rest is about 15 to 18 times per minute.
Q. How the fish breathes?
Ans: The fish breathes by taking I water through its mouth and sending it over the gills. When water
passes over the gills, the gills extract dissolved oxygen from this water.
NCERT PAGE O 105 Q & A:
Q1. What advantage over an aquatic organism does a terrestrial organism have with regard
to obtaining oxygen for respiration?
Or
Why the rate of breathing is much rapid in aquatic organisms than the terrestrial
organisms? HSLC 2017
OR
Why do aquatic animals breathe faster than the terrestrial animals? NCERT EXAMPLER
Ans: A terrestrial organism can obtain oxygen directly from the air and has low breathing rate,
whereas an aquatic organism has to obtain oxygen, which is dissolved in water and so, it is has
high breathing rate. This is, the amount of oxygen dissolved in water is fairly low as compared to
the amount of oxygen in air. Therefore, terrestrial organisms have much easier access to the
oxygen and have an advantage over aquatic organisms
2. What are the different ways in which glucose is oxidized to provide energy in various
organisms?
Ans: See under the heading” ES I ATIO ”
3. How is oxygen and carbon dioxide transported in human beings?
Ans: In human beings, oxygen is carried from the lungs by the respiratory pigment called
haemoglobin which is present in RBC. Haemoglobin has a very high affinity of oxygen.CO2 is more
soluble I water than the oxygen. So, most of the CO2 produced during respiration in the human body
is transported in the dissolved form in our body
4. How are the lungs designed in human beings to maximize the area for exchange of
gases?
Ans: Within the lungs, the passage divides into smaller and smaller tubes which finally terminate in
balloon-like structures which are called alveoli (singular–alveolus). The numerous number alveoli
provide a very large surface area where the exchange of gases can take place. For e.g. - If the
alveolar surface were spread out, it would cover about 80 m2
.

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TRANSPORTATION
TRANSPORTATION IN HUMAN BEINGS:
Q. What are the components of blood? Write the functions of each component.
Ans: Thus, the main components of blood are: 1. Plasma, 2. Red Blood Corpuscles (or Red Blood
Cells), 3. White Blood Corpuscles (or White Blood cell) 4. Platelets.
The functions of each components are-
1) Plasma: The liquid part (or fluid part) of blood is called plasma. Plasma carries proteins, digested
food, common salt, waste products (like carbon dioxide and urea), and hormones.
2) Red Blood Cells: Red blood cells carry oxygen from the lungs to all the cells of the body.
3) White Blood Cells: White blood cells fight infection and protect us from diseases.
4) Platelets: Platelets help in the coagulation of blood (or clotting of blood) in a cut or wound.
Q. What are the three types blood vessels?
Ans: Three types of blood vessels: (i) arteries, (ii) veins, and (iii) capillaries.
Q. What is lymph? State their functions. What are the components of lymphatic system
Ans: Through the pores present in the wall of blood capillaries some amount of plasma and
protein escape into the intercellular space in the tissue to form a fluid connective tissue called
lymph.
The functions of lymph are-
1) 1. Lymph (or lymphatic system) takes part in the nutritive process of the body.
2) 2. Lymph (or lymphatic system) protects the body by killing the germs drained out of the
body tissues with the help of lymphocytes contained in the lymph nodes, and by making
antibodies.
3) 3. Lymph (or lymphatic system) helps in removing the waste products like fragments of
dead cells, etc.
The lymphatic system consists of the following parts: (i) Lymph capillaries, (ii) Larger lymph
vessels, (iii) Lymph nodes (or Lymph glands), and (iv) Lymph. Lymph capillaries are tiny
tubes
Q. Write the differences between Artery, veins and capillaries.
Ans:
Artery veins Capillaries
1) Arteries are the blood
vessels which carry
blood from the heart to
all the parts of the body.
2) Arteries have thick and
elastic walls.
1) Veins are the blood
vessels which carry
blood from all the parts
of the body back to the
heart.
2) Veins have a thin wall.
1) The capillaries are thin
walled and extremely
narrow tubes or blood
vessels which connect
arteries to veins.
2) Capillaries are one
cell thick

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Q. Why do veins have thin walls as compared to arteries? NCERT EXEMPLER
ANS: Arteries have thick walls because blood emerges from the heart under high pressure. On the
other hand, Veins do not need thick walls because the blood flowing through them is no longer under
high pressure.
NOTE:
The exchange of various materials like oxygen, food, carbon dioxide, etc., between the blood and the
body cells takes place through capillaries.
Q. What is the advantage of having four chambered heart? NCERT EXEMPLER
Ans: The advantages of having four chambered heart are-
1) Ensures complete separation of oxygenated blood and de oxygenated blood.
2) Allows a highly efficient supply of oxygenated blood to the parts of body.
Q. What are the components of human circulatory system?
Ans: The human circulatory system consists of the heart, arteries, veins, capillaries, and blood.
Q. What is blood pressure? What is systolic and diastolic pressure? What is hypertension?
Ans: The pressure at which blood is pumped around the body by the heart is called blood pressure.
The maximum pressure, at which the blood leaves the heart through the main artery (aorta)
during contraction phase, is called the systolic pressure. The minimum pressure in the arteries during
the relaxation phase of heart is called the diastolic pressure.
The normal blood pressure values are : Systolic pressure : 120 mm Hg
Diastolic pressure : 80 mm Hg
This is usually written as 120/ 80
High blood pressure is called hypertension.
Q. What is the cause of hypertension? What is its effect?
Ans: High blood pressure is caused by the constriction (narrowing) of very small arteries (called
arterioles) which results in increased resistance to blood flow.
Very high blood pressure can lead to rupture of an artery and internal bleeding.
NOTE: Blood pressure is measured by using an instrument called sphygmomanometer.
PAGE NO 110 Q & A
Q1. What are the components of the transport system in human beings? What are the functions
of these components?
Ans: The components of transport system in human beings are blood and lymph.
The functions of blood are-

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1) Plasma: The liquid part (or fluid part) of blood is called plasma. Plasma carries proteins, digested
food, common salt, waste products (like carbon dioxide and urea), and hormones.
2) Red Blood Cells: Red blood cells carry oxygen from the lungs to all the cells of the body.
3) White Blood Cells: White blood cells fight infection and protect us from diseases.
4) Platelets: Platelets help in the coagulation of blood (or clotting of blood) in a cut or wound.
The functions of lymph are-
1) 1. Lymph (or lymphatic system) takes part in the nutritive process of the body.
2) 2. Lymph (or lymphatic system) protects the body by killing the germs drained out of the body
tissues with the help of lymphocytes contained in the lymph nodes, and by making antibodies.
3) 3. Lymph (or lymphatic system) helps in removing the waste products like fragments of dead
cells, etc.
Q2. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and
birds?
Ans: The mammals and birds are warm-blooded animals which have high energy needs because they
constantly require energy to maintain their body temperature. It is necessary to separate oxygenated
blood and deoxygenated blood in mammals and birds because such a separation allows a highly
efficient supply of oxygen to the body cells which is required for producing a lot of energy needed by
them.
TRANSPORTATION IN PLANTS:
Q. What is meant by translocation of organic foods?
Ans: The transport of food from the leaves to other parts of the plant is called translocation.
PAGE NO 110 Q & A
3. What are the components of the transport system in highly organised plants?
Ans: The two components of transport in highly organised plants are xylem and phloem.
(i) Xylem tissue is made of dead cells in the form of xylem vessels and tracheids. It transports water
and dissolved minerals from roots to all the parts of the plant.
(ii) Phloem tissue is made of living cells in the form of sieve tubes and companion cells. It transports
food made in leaves by photosynthesis to all the parts of a plant.
NOTE: Xylem tissue is made of dead cells in the form of xylem vessels and tracheids, xylem
fibre and xylem parenchyma.
Phloem tissue is made of living cells in the form of sieve tubes and companion cells, phloem
fiber and phloem parenchyma.
4. How are water and minerals transported in plants?
Ans: Water and the minerals dissolved in it are transported in plants by xylem tissue. The leaves of
plants have tiny pores called stomata. The water brought in by xylem to the leaves is constantly being
lost by evaporation through stomata. The continuous evaporation of water (or transpiration) from the
cells of leaves creates a kind of suction which pulls up water from the roots through the xylem. Thus,
transpiration helps in the upward movement of water and dissolved minerals from the roots to the
leaves.

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5. How is food transported in plants?
Ans: The transport of food (made by photosynthesis) in the plant leaves takes place through ‘phloem
tissue’. The sugar (food) made in leaves is loaded into the sieve tubes of phloem tissue by using
energy from ATP. Water now enters into sieve tubes containing sugar by the process of osmosis due to
which the pressure in the phloem tissue rises. This high pressure produced in the phloem tissue moves
the food to all the parts of the plant having less pressure in their tissues.. The movement of food in
phloem can be upwards or downwards depending on the requirements of the plant.
EXCRETION:
Excretion in Human Beings:
Q. What is excretion? What are the organs of human excretory system?
Ans: The process of removal of toxic wastes from the body of an organism is called excretion.
The excretory system of human beings consists of the following main organs: Two kidneys,
Two ureters, Bladder and Urethra.
Q. What is the structural and functional unit of kidneys? What is the function of
kidneys? Draw a labelled diagram of human excretory system.
Ans: Nephrons are the structural and functional unit of kidney.
The function of kidneys is to remove the poisonous substance urea, other waste salts and
excess water from the blood and excrete them in the form of yellowish liquid called urine.
Fig: Human excretory system. Fig: LS of kidney
Q. What is dialysis?
Ans: The procedure used for cleaning the blood of a person by separating the waste substance (urea)
from it is called dialysis.
Q1. Describe the structure and functioning of nephrons.
Ans: STRUCTURE:
The nephron has a cup-shaped bag at its upper end which is called Bowman’s capsule. The lower end
of Bowman’s capsule is tube-shaped and it is called a tubule. The Bowman’s capsule and the tubule
taken together make a nephron). One end of the tubule is connected to Bowman’s capsule and its

17
other end is connected to a urine-collecting duct of the kidney. One end of glomerulus is attached to
renal artery which brings the dirty blood containing the urea waste in it. The other end of glomerulus
comes out of Bowman’s capsule as a blood capillary, surrounds the tubule of nephron and finally joins
a renal vein.
FUNCTION:
The function of glomerulus is to filter the blood passing through it. During filtration, the substances like
glucose, amino acids, salts, water and urea, etc., present in the blood pass into Bowman’s capsule and
then enter the tubule of nephron. When the filtrate containing useful substances as well as the waste
substances passes through the tubule, then the useful substances like all glucose, all amino acids,
most salts, and most water, etc., are reabsorbed into the blood through blood capillaries surrounding
the tubule. Only the waste substances urea, some unwanted salts and excess water remain behind in
the tubule. The liquid left behind in the tubule of nephron is urine.
Q3. How the amount of urine is produced regulated?
Ans.The amount of urine produced is regulated by reabsorption
of water and some of the dissolved substances into the blood
through blood capillaries surrounding the tubules of nephrons.
The amount of urine produced depends on how much excess
water is present in the body and how much of dissolved
wastes are to be excreted.
Q. How urine is produced? Or Describe the process of urine formation in kidneys. NCERT
EXMPLER
ANS: Kidneys filter the blood. During filtration, the substances like glucose, amino acids, salts, water
and urea, etc., present in the blood pass into Bowman’s capsule and then enter the tubule of nephron.
When the filtrate containing useful substances as well as the waste substances passes through the
tubule, then the useful substances like all glucose, all amino acids, most salts, and most water, etc., are
reabsorbed into the blood through blood capillaries surrounding the tubule. Only the waste substances
urea, some unwanted salts and excess water remain behind in the tubule. The liquid left behind in the
tubule of nephron is urine.
EXCRETION IN PLANTS
Q2. What are the methods used by plants to get rid of excretory products?
The plants get rid of gaseous waste products through stomata in their leaves and lenticels in stems. (ii)
The plants store some of the solid and liquid wastes in their body parts such as leaves, bark and fruits.
The plants get rid of stored solid and liquid wastes by the shedding of leaves, peeling of bark and
felling of fruits.
(iii) The plants get rid of their wastes by secreting them in the form of gums and resins. The plants also
secrete some waste substances into the soil around them.
Fig: Structure of Nephron

18
EXERCISE
5. How are fats digested in our bodies? Where does this process take place?
Ans. Fats are digested in the small intestine in our body.
The liver secretes alkaline liquid called bile into small intestine. The salts present in bile emulsify (or
break) large globules of fat present in our food into smaller globules. Pancreas secretes pancreatic
juice into small intestine which also contains an enzyme called ‘lipase’. The enzyme lipase breaks
down the emulsified fat further. And finally, the enzymes present in intestinal juice bring about the
complete digestion of fats by converting them into fatty acids and glycerol.
6. What is the role of saliva in the digestion of food?
Ans: The enzyme secreted by the salivary gland is Salivary amylase.
The function of the Salivary amylase is that it breakdown starch which is complex molecule into simple
sugar.
7. What are the necessary conditions for autotrophic nutrition and what are its by-products?
ANS: The conditions necessary for autotrophic nutrition are the presence of: Carbon dioxide, Water,
Chlorophyll and Sunlight.
The major by-product of autotrophic nutrition are C6H12O6 ,H2O(g) and O2(g)
8. What are the differences between aerobic and anaerobic respiration? Name some organisms
that use the anaerobic mode of respiration.
Aerobic respiration Anaerobic respiration
1. Aerobic respiration takes place in the
presence of oxygen.
2. Complete breakdown of food occurs in
aerobic respiration.
3. The end products in aerobic respiration are
carbon dioxide and water..
4. Aerobic respiration produces a considerable
amount of energy.
5.
1. Anaerobic respiration takes place in the
absence of oxygen.
2. 2. Partial breakdown of food occurs in
anaerobic respiration.
3. 3. The end products in anaerobic
respiration may be ethanol and carbon
dioxide (as in yeast plants), or lactic
acid (as in animal muscles).
4. Much less energy is produced in
5. Anaerobic respiration. Let us answer
one question
Anaerobic mode of respiration is used by certain micro-organisms such as yeast and
some bacteria known as anaerobic bacteria.
9. How are the alveoli designed to maximise the exchange of gases?
Ans.There are millions of alveoli (thin-walled air-sacs) in the lungs. The presence of millions of alveoli in
the lungs provides a very large area for the exchange of gases. And the availability of large surface
area maximises the exchange of gases. For example, if all alveoli from the two human lungs are
unfolded, they would give an area of about 80 square meters.

19
10. What would be the consequences of a deficiency of haemoglobin in our bodies?
Ans. The oxygen required for breathing and respiration (release of energy) is carried by haemoglobin
present in our blood. The deficiency of haemoglobin in the blood of a person reduces the oxygen-
carrying capacity of blood resulting in breathing problems, tiredness and lack of energy. The person
looks pale and loses weight.
11. Describe double circulation of blood in human beings. Why is it necessary?
OR
Why is blood circulation in human heart called double circulation? NCERT EXEMPLER
Ans. A circulatory system in which the blood travels twice through the heart in one complete cycle of
the body is called double circulation. In the human circulatory system, the pathway of blood from the
heart to the rest of the body and back to the heart is called systemic circulation; and the pathway of
blood from the heart to the lungs and back to the heart is called pulmonary circulation. These two
types of circulation taken together make double circulation.
The double circulation is necessary to supply oxygenated blood to the whole body (except lungs), and
then to get deoxygenated blood deoxygenated in the lungs.
12. What are the differences between the transport of materials in xylem and phloem?
ANS:
xylem Phloem
1) Xylem tissue transports water and
dissolved minerals in plants.
2) Xylem tissue carries the water and
dissolved minerals only upwards from
the roots of the plant
3) The upward movement of water and
dissolved minerals in xylem tissue is
caused by a suction force produced by
the continuous evaporation of water (or
transpiration) from the cells of leaves of
the plant which pulls up water from the
roots.
1) Phloem tissue transports the food to all
the parts of the plant.
2) The movement of food from the leaves
through phloem can be upwards as well
as downwards depending on the
requirements of the plant.
3) On the other hand, the food made in
leaves is transported through phloem
tissue by utilizing energy from ATP
13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to
their structure and functioning.
Structure. Alveoli in the lungs and nephrons in the kidneys, both possess an elaborate network of
blood capillaries.
Functioning. Alveoli purify the deoxygenated blood by removing carbon dioxide from it and making it
oxygenated by introducing oxygen in it (during the gaseous exchange). Similarly, nephrons purify the
dirty blood by filtering out waste products like urea from it in the form of urine.

20
Q. Name the respiratory pigment present in our body. State its function. HSLC2019
ANS- The name of the respiratory pigment present in the blood in our body is Haemoglobin.
Haemoglobin has a very high affinity towards oxygen. So, it binds oxygen and carries to different parts
of the body.
Q. Draw a neat labelled diagram of the longitudinal section of the human heart and show the
direction of flow blood through the different chambers with arrow marks, and give a brief
description of the blood circulation through it. HSLC2019
Ans:
1) Oxygen-rich blood from the lungs comes to the
thin-walled upper chamber of the heart on the left,
the left atrium.
2) The left atrium relaxes when it is
collecting this blood. It then contracts,
while the next chamber, the left ventricle, relaxes,
so that the blood is transferred to it.
3) When the muscular left ventricle contracts
in its turn, the blood is pumped out to the body.
4) De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it
relaxes. As the right atrium contracts, the corresponding lower chamber, the right ventricle, dilates. This
transfers blood to the right ventricle, which in turn pumps it to the lungs for oxygenation.
.
.
.

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