SMART EDUCATIONS 1

LIFE PROCESS

Q. What are life processes?

Ans. The processes which are essential for a living being to keep themself alive on the

earth, are called the life processes. Life process includes the following:-

1. Nutrition

2. Respiration

3. Transportation

4. Excretion

5. Control and coordination

Q. What does nutrition mean?

Ans. The process of intake of food and utilising it, is called nutrition.

Q. What is the need for nutrition for a living organism?

Ans. Living organisms continuously need energy for their various life processes and

other activities which they perform and the energy comes from the food that the

organism intake during nutrition. So basically nutrition is necessary for obtaining energy.

Actually the term "nutrition" comes from the word "nutrient" which means 'source

of energy'.

Q. What are the modes of nutrition?

Ans. Modes of nutrition mean, the method by which an organism obtain its foods There

are mainly two modes of nutrition:-

1. Autotrophic

2. Heterotrophic

Q. What does autotrophic mean?

Ans. Autotrophic nutrition is that mode of nutrition in which an organism makes its own

food from the simple inorganic material like carbon dioxide and water present in the

surroundings.

There are two types of autotrophic nutrition:-

1. Photoautotrophic

2. Chemoautotrophic

The organisms having the autotrophic mode of nutrition are called autotrophs. All

green plants and some bacteria are examples of the autotrophs.

Q. What does heterotrophic mean?

Ans. Heterotrophic nutrition is that mode of nutrition in which an organism cannot make

its own food from the simple inorganic material like carbon dioxide and water present in

the surroundings and hence depends on other organisms for its food.

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The organisms which use the heterotrophic mode of nutrition are called

heterotrophs. All animals, fungi ,some bacteria and non green plants(Yeat) are

examples of the heterotrophs.

There are three types of heterotrophic nutrition:-

1. Saprotrophic nutrition

2. Parasitic nutrition

3. Holozoic nutrition

Q. What does saprotrophic nutrition mean?

Ans. Saprotrophic nutrition is that nutrition in which an organism obtains its food from

decaying organic matter of dead plants, dead animals and rotten bread etc. The

organisms having saprotrophic mode of nutrition are called saprophytes.

The saprophytes break down the complex organic molecules present in dead

and decaying matter and convert them into simpler substances outside their body.

Fungi(like bread molds, mushrooms, yeasts) and many bacteria are examples of

saprophytes.

Q. What does parasitic nutrition mean?

Ans. Parasitic nutrition is that nutrition in which an organism derives its food from the

body of another living organism(called its host) without killing it. The organisms having a

parasitic mode of nutrition are called parasites.

Some fungi, bacteria, few plants like Cuscuta and few animals like Plasmodium,

ticks, lice, leeches, tapeworm and roundworms are examples of parasites.

Q. What does holozoic nutrition mean?

Ans. 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.

Human beings, amoeba and most of the animals have a holozoic mode of

nutrition.

Q. Why is diffusion insufficient to meet the oxygen requirements of multicellular

organisms like humans?

Ans. Diffusion is the process in which exchange of gasses takes place between the cell

membrane and the environment and for this process all the cells of an organism must

be in contact with the environment but this is not in the case of multicellular organisms.

In addition to this diffusion is a slow process, so diffusion is insufficient to meet the

oxygen requirements of multicellular organisms like humans.

Q. What criteria do we use to decide whether something is alive?

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Ans. We decide whether something is alive or not just by looking at its movement and

responding to stimuli. But these are not the appropriate way to decide whether

something is alive. So the criterias must be use are:-

Respiration, Nutrition and Excretion.

Q. What are outside raw materials used for by an organism?

Ans. It depends on the type of organism for example:-

If it is an autotroph then the raw materials used are:- Sunlight, water, minerals and CO

But if it is a heterotroph then the raw materials used are:- Organic materials, water,

minerals and O

Q. What processes would you consider essential for maintaining life?

Ans. The processes which are essential for maintaining life are:-

Respiration, Nutrition, Excretion, Transportation and control and coordination.

Q. What is photosynthesis?

Ans. The process by which green plants make their own food from carbon dioxide and

water by using sunlight energy in the presence of chlorophyll, is called photosynthesis.

The process of photosynthesis takes place in the green leaves of a plant. The process

of photosynthesis can be represented as:-

6CO

+ 6H

O + Light energy C

+ 6O

The carbon dioxide gas required for photosynthesis is taken by the plant leaves

from the air. This carbon dioxide enters the leaves through tiny pores called stomata.

Water required for photosynthesis is taken from the soil. This water is transported

to the leaves from the soil through xylem.

The sunlight energy required for photosynthesis is absorbed by the green

pigment called chlorophyll present in green leaves.

The food prepared by the green leaves of a plant is in the form of a simple sugar

called glucose. This glucose is then sent to the different parts of the plant through

phloem. The extra glucose is changed into another food called starch. This starch is

stored in the leaves of the plants. Thus green plants convert sunlight energy into

chemical energy by making food.

The photosynthesis takes place in the following three steps:

1. Absorption of sunlight energy by chlorophyll.

2. Conversion of light energy into chemical energy and splitting of water into

hydrogen and oxygen by light energy.

3. Reduction of carbon dioxide by hydrogen to form glucose by utilizing the

chemical energy.

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These three steps need not take place one after the other immediately. For example,

desert plants take up carbon dioxide at night and reduction of the carbon dioxide by

hydrogen to form glucose takes place during the day when the sun shines.

So the conditions necessary for photosynthesis to take place are:

1. Sunlight

2. Chlorophyll

3. Carbon dioxide

4. Water

Among the above four, Carbon dioxide and water are the raw materials required for

photosynthesis. But in addition to these two, plants also need other raw materials such

as nitrogen, phosphorus, iron and magnesium etc for building their body.

Q. Explain the role of stomata in photosynthesis.

Ans. The tiny pores present on the surface of leaves are called stomata(singular

stoma). In most broad-leaved plants, the stomata occur only in the lower surface of the

leaf but in narrow-leaved plants, the stomata are equally distributed on both the sides of

the leaf. They help in the exchange of gasouses(breathing) and the loss of the excess

water(transpiration). Each stomatal pores is surrounded by the guard cells. When water

flows into the guard cells, they swell, 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 stomatal pores. In addition to leaves, the stomata are also present in the green

stems of a plant.

Q. How do the plants obtain water for photosynthesis?

Ans. The water required by the plants for photosynthesis is absorbed by the roots of the

plants from the soil through the process of osmosis. The water absorbed by the roots of

the plants is transported upward through the xylem vessels to the leaves .

Q. What are the sites of photosynthesis?

Ans. Chloroplasts are the sites of photosynthesis.

Q. How does nutrition take place in animals or heterotroph?

Ans. There are five steps in the process of nutrition in animals, which are as follows:-

1. Ingestion:- The process of taking food into the body is called ingestion.

2. Digestion:- The process in which the food containing large, insoluble molecules

is broken down into small, water soluble molecules is called digestion.

3. Absorption:- The process in which the digested food passes through the

intestinal wall into the bloodstream is called absorption.

4. Assimilation:- The process in which the absorbed food is taken in by body cells

and used for energy, growth and repair, is called assimilation.

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5. Egestion:- The process in which the undigested food is removed from the body

is called egestion.

Q. Explain the process of nutrition in Amoeba?

Ans. Amoeba is a unicellular animal. Amoeba eats microscopic plants and animals as

food which float in water in which it lives. The mode of nutrition in Amoeba is holozoic.

The process of obtaining food by Amoeba is called phagocytosis.

Steps of nutrition in Amoeba are the following:-

Ingestion:- Amoeba has no mouth or a fixed place for ingestion of food. Amoeba

ingests food by using its pseudopodia. When a food particle comes near Amoeba, then

Amoeba ingests this food particle by forming a temporary finger-like projection called

pseudopodia around it. The food is engulfed with a little surrounding water to form a

food vacuole inside the Amoeba. This food vacuole can be considered to be a

'temporary stomach' of Amoeba.

Digestion:- In Amoeba, food is digested in the food vacuole by digestive enzymes. The

enzymes from surrounding cytoplasm enter into the food vacuole and break down the

food into small and soluble molecules by chemical reaction.

Absorption:- The digested food present in the food vacuole of Amoeba is absorbed

directly into the cytoplasm of Amoeba cell by diffusion. The digested food just spreads

out from the food vacuole into the whole Amoeba cell. After absorption of food, the food

vacuole.

Assimilation:- A part of the food absorbed in the Amoeba cell is used to obtain energy

through respiration. The remaining part of absorbed food is used to make the parts of

Amoeba cell which lead to the growth of Amoeba and then Amoeba can reproduce by

dividing into two daughter cells.

Egestion:- Amoeba has no fixed place for removing the undigested part of food. When

a considerable amount of undigested food collects inside Amoeba, then its cell

membrane suddenly ruptures at any place and the undigested food is thrown out of the

body of Amoeba.

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Q. Explain the process of nutrition in humans?

Ans. The nutrition in human beings takes place through the human digestive system.

The human digestive system consists of the alimentary canal and its associated glands.

The various organs of the human digestive system in sequence are : Mouth,

Oesophagus(food pipe), Small intestine and large intestine. The glands which are

associated with the human digestive system and form a part of the human digestive

system are : Salivary glands, Liver and Pancreas.

Alimentary canal which runs from mouth to anus is about 9 meter long tube is the actual

site through which the food has to be passed.

Ingestion:- Human beings have a special organ for the ingestion of food. It is called

mouth. So, in human beings, food is ingested through the mouth.

Digestion:- In human beings, the digestion of food begins in the mouth itself.

1. Mouth:- The mouth cavity(buccal cavity) contains teeth, tongue, and

salivary glands.

The teeth cut the food into small pieces, chew and grind it. So, the

teeth help in physical digestion.

The salivary glands in our mouth produce saliva. Saliva is a watery

liquid so it wets the food in our mouth to be swallowed easily. The salivary

glands help in chemical digestion by secreting enzymes. The human

saliva contains an enzyme called salivary amylase which digests the

starch present in food into sugar.

The tongue helps in mixing the saliva with food and to swallow the

food.

Since the food remains in the mouth only for a short time, the digestion of

food remains incomplete in the mouth.

2. Food pipe:- From the mouth, the food is passed into the food

pipe(esophagus). The esophagus carries food to the stomach. This

happens as follows: The walls of the food pipe have muscles which can

contract and expand alternately. When the slightly digested food enters

the food pipe, the walls of the food pipe start contraction and expansion

movements. This movement is called peristaltic movement. This peristaltic

movement of the food pipe pushes the slightly digested food into the

stomach and this movement continues to the anus.

3. Stomach:- From the food pipe, the food enters the stomach. Stomach is a

J-shaped organ present on the left side of the abdomen. The food is

further digested in the stomach. The food is churned in the stomach for

about three hours. During this time , the food breaks down into smaller

pieces and forms a semi-solid paste. The stomach wall contains three

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tubular glands in its walls. The glands present in the walls of the stomach

secrete gastric juice. The gastric juice contains three substances:

Hydrochloric acid, the enzyme pepsin and mucus. Due to the presence of

hydrochloric acid, the gastric juice is acidic in nature. In the acidic

medium, the enzyme pepsin begins the digestion of proteins present in

food to form smaller molecules. Thus, the protein digestion begins in the

stomach. Pepsin is active only in the presence of an acid. So the function

of HCl acid in the mouth is to make the medium of gastric juice acidic so

that the enzyme pepsin can digest the proteins properly. Another function

of HCl is that it kills any bacteria which may enter the stomach with food.

The mucus helps to protect the stomach wall from its own secretion of

HCl. If mucus is not secreted, HCl will cause the erosion of the inner lining

of the stomach leading to the formation of ulcers in the stomach. The

partially digested food then goes from the stomach into the small intestine.

The exit of food from the stomach is regulated by a sphincter muscle

which releases it in small amounts into the small intestine.

4. Small intestine:- The small intestine is the longest part of the alimentary

canal. It is about 6.5 meters long for an adult man. Though the small

intestine is very long, it is called small intestine because it is very narrow.

The length of the small intestine differs in various animals depending on

the type of food they eat. For example, cellulose is a carbohydrate food

which is digested with difficulty, which is present in plants. So, the

herbivorous animals need a longer small intestine than carnivores.

The small intestine in human beings is the site of complete

digestion of food like carbohydrates, proteins and fats. This happens as

follows:-

The small intestine receives the secretions of two glands: liver and

pancreas.

Liver:- Liver secretes bile juice. Bile is a greenish yellow liquid made in the

liver which is normally stored in the gallbladder. Bile is alkaline, and

contains salts which help to emulsify or break down fat present in the food.

Thus bile perform two functions: (i) Makes the acidic food coming from the

stomach alkaline so that pancreatic enzymes can act on it, and (ii) bile

salts breaks the fats present in the food into small globules making it easy

for the enzyme to act and digest them.

Pancreas:- Pancreas is a large gland which lies parallel to and beneath

the stomach. Pancreas secretes pancreatic juice which contains digestive

enzymes like pancreatic amylase, trypsin and lipase. The enzyme

amylase breaks down the starch, the enzyme trypsin digest the proteins

and the enzyme lipase breaks down the emulsified fats. The walls of the

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small intestine contain glands which secrete intestinal juice. The intestinal

juice contains a number of enzymes which complete the digestion of

complex carbohydrates into glucose, proteins into amino acids and fats

into fatty acids and glycerol. Glucose, amino acids, fatty acids and glycerol

are small and water soluble molecules. In this way, the process of

digestion converts the large and insoluble food molecules into small and

water soluble molecules. The chemical digestion of food is brought about

by biological catalysts called enzymes.

Absorption:- After digestion, the molecules of food become so small that they can pass

through the walls of the small intestine and go into our blood. The small intestine is

especially adapted for absorbing the digested food. The inner surface of the small

intestine has millions of tiny, finger-like projections called villi. The presence of villi gives

the inner walls of the small intestine a very large surface area to absorb the digested

food. The digested food which is absorbed through the walls of the small intestine,

goes into our blood.

Assimilation:- The blood carries digested and dissolved food to all parts of the body

where it becomes assimilated as part of the cells. This assimilated food is used by the

body cells for obtaining energy as well as for growth and repair of the body. The energy

is released by the oxidation of assimilated food in the cells during respiration. The

digested food which is not used by our body immediately is stored in the liver in the form

of a carbohydrate called glycogen. This stored glycogen can be used as a source of

energy by the body as and when required.

Egestion:- A part of the body which we eat cannot be digested by our body. This

undigested food cannot be absorbed in the small intestine. So, the undigested food

passes from the small intestine into a wider tube called the large intestine. The walls of

the large intestine absorb most of the water from the undigested food. Due to this the

undigested part of the food becomes almost solid. The last part of the large intestine

called rectum stores this undigested food for some time. When we go to the toilet, then

this undigested food. is passed out from our body through anus as feces or stool. The

act of expelling the feces is called egestion. The exit of feces is controlled by the anal

sphincter.

Q. Explain dental caries?

Ans. The hard, outer covering of a tooth is called enamel. Tooth enamel is the hardest

material in our body. It is harder than even bones. The part of the tooth below enamel is

called dentine. Dentine is similar to bone. Inside the dentine is a pulp cavity. The pulp

cavity contains nerves and blood vessels. The formation of small cavities(holes) in the

teeth due to the action of acid-forming bacteria and improper dental care is called dental

caries.

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Q. What are the differences between autotrophic nutrition and heterotrophic nutrition?

Ans.

Autotrophic Nutrition

Heterotrophic Nutrition

Autotrophic nutrition is that mode of

nutrition in which an organism makes its

own food from the simple inorganic

material.

Heterotrophic nutrition is that mode of

nutrition in which an organism cannot

make its own food from the simple

inorganic material.

Chlorophylls are required for this nutrition

Chlorophylls are not required for this

nutrition

Plants kingdom and some bacteria use

this mode of nutrition.

Animal kingdoms and some non-green

plants use this mode of nutrition.

Q. Where do plants get each of the raw materials required for photosynthesis?

Ans. The raw materials required for photosynthesis by the plants are:-

1. Water and mineral:- obtained from soil by roots.

2. CO

:- Obtained from the atmosphere by stomata.

3. Solar energy:- Obtained from the sun by chlorophyll.

Q. What is the role of the acid in our stomach?

Ans. There are the three roles of acid in our stomach which are follows:-

1. Makes the food acidic for the proper function of pepsin.

2. Kills the bacteria and germs which enter with the food.

3. Prevent the fermentation of the food.

Q. What is the function of digestive enzymes?

Ans. The function of digestive enzymes is to break down of food and make it soluble so

that it can be absorbed easily. This process is known as chemical digestion.

Q. How is the small intestine designed to absorb digested food?

Ans. The complete digestion of food takes place in the small intestine and the digested

food is absorbed here only. To absorb the food, its inner surface has finger-like

projection which is known as villi which has blood capillaries inside. The villi increases

the surface area for absorption of food and then sends it into the blood.

Q. What is respiration?

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Ans. Intake of oxygen and utilizing it to oxidize the food to produce energy is known as

respiration.

The chemical reaction involves in respiration is as follows:-

+ 6O

→ 6CO

+ 6H

O + Energy(ATP)

There are two types of respiration:-

1. Aerobic Respiration:- Break down of glucose in presence of O

2. Anaerobic Respiration:- Break down of glucose in absence of O

Q. What are the paths of the breakdown of glucose?

Ans.

Q. What is glycolysis?

Ans. Breakdown of glucose(6 carbons molecules) into Pyruvate(3 carbons molecules)

in cytoplasm is called glycolysis.

Q. Describe the process of aerobic respiration.

Ans. As its name suggests, aerobic respiration means the breakdown of glucose to

produce energy occurs in the presence of air. It happens as follows:-

1. Conversion of glucose into pyruvate in cytoplasm.

2. Pyruvate is then in the presence of O

breaks down into CO

+ H

O + Energy. It

happens in mitochondria.

Q. Describe the process of anaerobic respiration.

Ans. As its name suggests, anaerobic respiration means the breakdown of glucose to

produce energy occurs in the absence of air. It happens as follows:-

1. Conversion of glucose into pyruvate in cytoplasm.

2. Pyruvate is then in the absence of O

breaks down into two ways :-

a. In the yeast :- It breaks to form Ethanol, CO

and energy.

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b. In the human muscle :- It breaks to form lactic acid and energy.

Q. In what condition does the human body undergo anaerobic respiration? OR

When do we get cramps in our muscles?

Ans. When we do heavy exercise then the involved muscle needs an extra amount of

energy for that. And for making high energy, the muscle needs a high supply of O

Which is sometimes not possible to provide such a large amount of O

, then to fulfill the

amount of the required energy the muscle undergoes anaerobic respiration and

produces the energy but in addition to this it also produces lactic acid which causes

cramp in the muscle. When the supply of oxygen is sufficient then the lactic acid is then

converted into CO

+ H

O and Energy and makes us relieve the cramp.

Q. What is the difference between aerobic respiration and anaerobic respiration?

Ans.

Aerobic Respiration

Anaerobic Respiration

It requires O

It does not require O

It happens in mitochondria.

It happens in yeast or human muscle.

It produces a higher amount of energy.

It produces a lower amount of energy.

Its final products are:- CO

+ H

O and

Energy

Its final products are:-

1. Ethanol + CO

and Energy (or)

2. Lactic acid and energy

Q. What is ATP?

Ans. ATP(Adenosine triphosphate) is the currency of energy. During the respiration

energy is formed and the unused energy is converted into ATP by combining

ADP(Adenosine diphosphate) and a Phosphate. When the body requires this ATP

releases energy.

Q. On what factors does the direction of diffusion depend in plants?

Ans. The direction of diffusion depends upon the environmental conditions and the

requirements of the plant. At night, when there is no photosynthesis occurring, CO

elimination is the major exchange activity going on. During the day, CO

generated

during respiration is used up for photosynthesis, hence there is no CO

release. Instead,

oxygen release is the major event at this time.

Q. How do animals fulfill the demand of O

to make energy?

Ans. It depends on the type of organism like aquatic animals or terrestrial animals.

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Aquatic animals:- Aquatic animals use the O

which is dissolved into the water. Because

the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the

air, the rate of breathing in aquatic organisms is much faster than that seen in terrestrial

organisms. Fishes take in water through their mouths and force it past the gills where

the dissolved oxygen is taken up by blood.

Terrestrial animals:- Terrestrial organisms use the oxygen in the atmosphere for

respiration. This oxygen is absorbed by different organs in different animals. For

example:-

Human :- By lungs

Frogs:- By lungs(in land) and skin(in water)

Earthworm:- By skin

Cockroach:- By trachea

Q. What is the respiratory system?

Ans. In human beings the respiration is done by a system called respiratory system,

which includes:- Nose, Mouth, Pharynx, Larynx, Trachea(WindPipe), Lungs and

Diaphragm.

Q. What are the paths through which O

travels in the respiratory system?

Ans. O

→ Nasal cavity→ Pharynx → Trachea → Bronchi → bronchioles → alveoli →

and CO

exchange → bronchioles → Bronchi → Trachea → Pharynx → Nasal cavity

→ CO

Q. What are the roles of hair which are present in our nose?

Ans. The hair filters the air which enters into our nose and the mucus ,which is also

present in our nose, helps in this process.

Q. What does ensure that the windpipe does not collapse?

Ans. Rings of cartilage are present in the windpipe and these ensure that the windpipe

does not collapse.

Q. Where does inside the lungs exchange of gases take place?

Ans. Through windpipe air enters into the bronchi and then bronchiole and then finally

into the alveolar sac and it is the place where the exchange of gases takes place.

Q. What is breathing?

Ans. Inhale of air and exhale of air is known as breathing. It is a mechanical process.

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Q. What are the mechanisms involved in breathing?

Ans. Basically breathing involves two steps:-

1. Inhale:- Intake of air into the lungs

2. Exhale:- let the air out from the lungs.

Mechanisms involved during inhalation:-

● The diaphragm is pulled downward.

● The muscles between the ribs contract and pull upward.

● Expandation of the lungs.

● Decreases the air pressure inside the lungs.

Mechanisms involved during exhalation:-

● The diaphragm is pulled upward.

● The muscles between the ribs relax and pull downward.

● Contraction of the lungs.

● Increases the air pressure inside the lungs.

Q. How are our lungs protected?

Ans. Our lungs are protected by the rib cages. Our lungs are inside the cage. The cage

protects the lungs from the external pressure and injuries.

Q. Describe the exchange of gases in the alveolar sac?

Ans. The alveolar sac is the site at where the exchange of gases take place, which

happens as follows:-

The air which we inhale has a higher concentration of O

as compared to in our blood.

So when the inhaled air reaches the alveolar sac which has blood capillaries, the O

from the sac is diffused into the blood. Hemoglobin, which is present in the blood, also

helps to attract the O

from the sac into the blood. So hemoglobin is also known as the

carrier of O

At the same time the blood which reaches the alveolar sac, has higher

concentration of CO

as compared to in the sac. So CO

is diffused out of blood into the

sac, which then expelled out through our nose.

Q. What advantage over an aquatic organism does a terrestrial organism have with

regard to obtaining oxygen for respiration?

Ans. The need of O

is same for aquatic organisms and for terrestrial organisms but

from where they obtain, the amount of O

is not the same.

Aquatic organisms obtain O

from the water which has a lesser amount of O

than air.

So to fulfill the demand of O

the aquatic organisms have to breathe at a higher rate

than terrestrial organisms. But it is not like that in the case of terrestrial organisms

because they obtain O

from air, where the concentration of O

is sufficient for them. So

they do not have to breathe fast.

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Q. What are the different ways in which glucose is oxidised to provide energy in various

organisms?

Ans. There are three ways in which glucose is oxidised to provide energy in various

organisms:-

Q. How are oxygen and carbon dioxide transported in human beings?

Ans. Both oxygen and carbon dioxide are transported in human beings by blood. Blood

carries O

from lungs to heart and then to the whole body. Blood carries CO

from the

whole body to the heart and then to the lungs.

Q. How are the lungs designed in human beings to maximise the area for exchange of

gases?

Ans. Inside the lungs the bronchioles end at alveolar sacs which are balloon like

structures and the site of the exchange of gases, which can expand itself on entering air

inside it and thus it gives the lungs the ability to maximise the area for exchange of

gases.

Q. What are the differences between Breathing and Respiration?

Ans.

Breathing

Respiration

It is a mechanical process.

It is a biochemical process.

It involves inhaling and exhaling air.

It involves oxidizing the glucose.

No energy is released

Energy is released

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Full process are done in respiratory

system

Full processes are done inside a cell. So

it is also known as cellular respiration.

Q. What is the need of transportation in multicellular organisms?

Ans. In multicellular organism, there is labour of division, means all different works are

done by different body parts, for example:- Food is digested by the small intestine in

human, food is prepared by the leaf in plants, but all the body parts, whether it is plant

or human, need the food. So it needs to be transported to the whole body.

Q. Describe the transportation in humans.

Ans. For transportation of materials human has a special system which is known as

circulatory system, which consist of :- Heart, Blood, Blood vessels, lymph and lymph

vessels

The materials which needs to be transported in humans are:-

Digested Food or Nutrients, O

, CO

and Hormones.

They all are transported by blood which flows inside the blood vessels and it is made to

flow by the heart.

Q. What is blood and describes its functions?

Ans. Blood is a connective tissue and is made up of :- RBC, WBC, Platelets and has a

fluid matrix called Plasma.

RBC(Red Blood Cell) or Hemoglobin:- Helps to carry oxygen.

WBC(White Blood Cell):- Helps to protect the body from diseases.

Platelets:- Helps to clotting the blood to prevent the excess flow of blood.

Plasma:- It makes blood a good solvent which helps in transportation of materials.

Q. Describe the heart and its functions?

Ans. The heart is a muscular organ which is as big as our fist. It is located at the left

side of our body. The human heart has four chambers which prevent the mixing of

oxygenated blood and deoxygenated blood. The main function of the heart is to pump

blood to the whole body.

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Oxygenated blood enters the heart via Pulmonary Veins into the Left atrium which

then goes into Left Ventricles.

Deoxygenated blood enters the heart via Vena Cava(veins) into the Right atrium and

then goes to Right ventricles.

When the heart contracts or pumps the Oxygenated blood and Deoxygenated blood

from the both ventricles are pushed out of the heart.

Because the blood is to be pumped out of the ventricles, so they have thicker walls as

compared to the atrium.

Oxygenated blood is pushed out through Aorta(Arteries) to the whole body.

Deoxygenated blood is pushed out through Pulmonary arteries to the lungs.

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Q. What is a double circulatory system?

Ans. In one cycle, blood has to enter the heart twice, first oxygenated blood and the

second deoxygenated blood, which is known as double circulatory system. It is a

system because of which oxygenated blood and deoxygenated blood does not mix and

ensures the proper supply of O

to the whole body. Proper supply of O

means a

sufficient amount of energy is released.

But it does not happen in all types of animals. It happens only in those animals

who have to maintain their body temperature by themselves and not by only the

environmental temperature. Such animals are:- Birds and all mammals.

But amphibians and fishes who maintain their body temperature by only the

environmental temperature, have only three chambers and two chambers respectively

in their heart and do not have the facility of a double circulatory system and they can

tolerate some mixing of the oxygenated and deoxygenated blood streams.

Q. What are systole and diastole?

Ans. Systole:- The contraction of heart is known as systole and the pressure exerted by

the blood on the blood vessels during this process is known as systolic pressure. For a

normal person it is 120 mm of Hg.

Diastole:- The relaxation of heart is known as diastole and the pressure exerted by the

blood on the blood vessels during this process is known as diastolic pressure. For a

normal person it is 80 mm of Hg.

Q. What are blood vessels and their types?

Ans. The blood vessels are tube-like structures through which blood flows. There are

three types of blood vessels:- Arteries, Veins and Capillaries.

Arteries:- The blood vessels which have the thickest walls are known as Arteries. Its

walls are thick because when the heart pumps the blood it flows through arteries in high

pressure.

There are two types of arteries:-

1. Aorta:- flows oxygenated blood from the heart to the whole body.

2. Pulmonary Artery:- flows deoxygenated blood from the heart to the lungs.

Veins:- The blood vessels which have thin walls are known as Veins. Its walls are thin

because it brings back the blood from the body or lungs to the heart in low pressure.

There are two types of Veins:-

1. Vena cava:- flows deoxygenated blood from the whole body to the heart.

2. Pulmonary Artery:- flows oxygenated blood from the lungs to the heart.

Capillaries:- These are the blood vessels which connect arteries and veins.

SMART EDUCATIONS

Q. What is lymph and describes its functions?

Ans. Through the pores present in the walls of capillaries some amount of plasma,

proteins and blood cells escape into intercellular spaces in the tissues to form the tissue

fluid or lymph. It is similar to the plasma of blood but colourless and contains less

protein. Lymph drains into lymphatic capillaries from the intercellular spaces, which join

to form large lymph vessels that finally open into larger veins. Lymph carries digested

and absorbed fat from the intestine and drains excess fluid from extracellular space

back into the blood.

Q. Describe the transportation in plants.

Ans. Transportation in plants is done by vascular tissue, which includes Xylem and

Phloem.

Xylem:- It helps to transport water and minerals from roots to the leaves. 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. This means that there is steady

movement of water into root xylem, creating a column of water that is steadily pushed

upwards.

However, this pressure by itself is unlikely to be enough to move water over the

heights that we commonly see in plants. Transpiration pull helps in the upward

movement of water and minerals through xylem.

Phloem:- It helps to transport food from leaves to the other part of the plants. Transport

of food from the leaves to the other part of the plants is known as translocation.

Translocation of food and other substances takes place in the sieve tubes with the help

of adjacent companion cells both in upward and downward directions. It requires energy

to transport the food.

Q. What are the differences between Xylem and Phloem?

Ans.

Xylem

Phloem

It is a vascular tissue, made up of three

dead cells and one living cell.

It is a vascular tissue, made up of three

living cells and one dead cell.

It transports water and minerals.

It transports food.

It is unidirectional

It is bidirectional

SMART EDUCATIONS

Q. What are the components of the transport system in human beings? What are the

functions of these components?

Ans. The components of the transport system in human beings are :-

Heart, Blood vessels, Blood, Lymph and Lymph vessels.

Functions:-

Heart:- Pumps blood to the whole body.

Blood vessels:- Gives a way for blood to flow through it.

Blood:- Transport the materials, Fight against diseases.

Lymph:- Transport fat.

Lymph vessels:- Gives a way for lymph to flow through it.

Q. Why is it necessary to separate oxygenated and deoxygenated blood in

mammals and birds?

Ans. Mixing of oxygenated and deoxygenated blood means poor supply of O

to cells

and it means less production of energy. Mammals and birds need high energy for the

activities they do and in addition to this they use most of the energy to maintain their

body temperature because their body temperature does not depend on the

environmental temperature. So it is necessary to separate oxygenated and

deoxygenated blood in mammals and birds.

Q. What are the components of the transport system in highly organised plants?

Ans. The components of the transport system in highly organised plants are :-

Xylem and Phloem.

Q. How are water and minerals transported in plants?

Ans. Water and minerals are transported in plants via Xylem vascular tissue. Minerals

dissolve into the water in the soil and the soil is in contact with roots of a plant. 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. This means that there is steady

movement of water into root xylem, creating a column of water that is steadily pushed

upwards.

However, this pressure by itself is unlikely to be enough to move water over the

heights that we commonly see in plants. Transpiration pull helps in the upward

movement of water and minerals through xylem.

Q. How is food transported in plants?

Ans. Food is transported in plants via phloem vascular tissue and the process is known

as translocation. Translocation of food and other substances takes place in the sieve

SMART EDUCATIONS

tubes with the help of adjacent companion cells both in upward and downward

directions. It requires energy to transport the food.

Q. What is excretion?

Ans. The removal of waste products from an organism is called excretion.

Q. What is the need of excretion?

Ans. If waste products are not removed from an organism the concentration of these

products would increase in the blood or body which leads to the death of the organism.

So they should be removed at regular intervals.

Q. How does unicellular excrete?

Ans. Excretion in unicellular organisms is a very simple process which is diffusion.

Q. How does multicellular excrete?

Ans. Excretion in multicellular organisms is a very complex process which is done by a

specalised system, known as excretory system.

Q. What are the components of the excretory system in humans and what are their

functions?

Ans. The components of the excretory system in humans are:-

A pair of Kidneys, A pair of Ureters, Urinary bladder and Urethra.

Functions:-

Kidney :- Filters blood and separates the waste products which are dissolved into the

blood. The waste product is called urine.

Ureter :- It is a pipe through which urine flows into the urinary bladder.

Urinary bladder :- It is a bag-like structure which stores the urine.

Urethra :- It controls the exit of urine.

Q. What is urine and how does it produce?

Ans. Urine is a nitrogen waste product such as urea or uric acid. What we intake has

many waste products into it. Some of them dissolve into the blood and when it is filtered

by the kidney then the separated part other than blood is called urine.

Q. How is the amount of urine produced regulated?

Ans. The amount of urine produced depends on the amount of excess water and

dissolved wastes present in the body.

Q. What is kidney and describe its function?

SMART EDUCATIONS

Ans. The kidneys are two bean-shaped organs, each about the size of a fist. They are

located just below the rib cage, one on each side of our spine. It is a blood filtering

organ.

The function of the kidney is to filter the blood.

Q. What is nephron and describe its function?

Ans. Nephron is a structural and functional unit of kidney. A kidney consists of millions

of such nephrons Nephron is made up of:- renal artery, glomerulus, bowman's capsule,

tubular part, collecting duct and renal vein.

Functions:-

Renal artery:- Blood enters a nephron through it.

Glomerulus:- It is the site where the blood is filtered. As the blood passes through the

glomerulus with high pressure, the small molecules are moved into the glomerular

capsules and travel through a winding series of tubules.

Bowman’s capsule :- It surrounds the glomerulus. It creates a urinary space through

which the filtrate can enter the tubular part.

Tubular part :- As its name indicates, it is a tube-like structure through which the filtrate

flows into the collecting duct. While the filtrate flows through it, the useful substances

such as glucose and water which were filtered at the glomerulus, are selectively

reabsorbed by the blood vessels which are in contact with the tubulus.

Collecting duct :- After the reabsorption of the useful substances, urine flows through it

and sends the urine to the ureter.

Renal veins :- At the glomerulus when nitrogenous blood is filtered to non nitrogenous

blood then it exits the nephrons through renal veins.

SMART EDUCATIONS

Q. What is hemodialysis?

Ans. Hemodialysis is an artificial kidney which is used when someone’s kidney does not

work properly.

Q. Describe the excretion in plants?

Ans. Plants also excretes but in different ways as compared to animals. The waste

products which should be removed by plants are:-

, CO

, Excess water, and other waste products.

and CO

are removed through the stomata by diffusion.

Excess water is removed by transpiration.

Other waste products are removed by many ways such as:- Loose of leaves, secretion

of resin, gums and some waste substances into the soil around them.

Exercise

Q. The kidneys in human beings are a part of the system for

Ans. (c) excretion.

Q. The xylem in plants are responsible for

Ans. (a) transport of water.

Q. The autotrophic mode of nutrition requires

Ans. (d) all of the above.

Q. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in

Ans. (b) mitochondria.

Q. How are fats digested in our bodies? Where does this process take place?

Ans. Bile juice first breaks down the big fat globules into small fat globules. This

process is known as emulsification of fat. The emulsified fats are converted into amino

acids and glycerol by intestinal juice and then it is absorbed by lymph vessels present in

villi.

These all processes take place in the small intestine.

Q. What is the role of saliva in the digestion of food?

Ans. Saliva is a watery liquid so it wets the food in our mouth to be swallowed easily.

The salivary glands help in chemical digestion by secreting enzymes. The human saliva

contains an enzyme called salivary amylase which digests the starch present in food

into sugar.

SMART EDUCATIONS

Q. What are the necessary conditions for autotrophic nutrition and what are its by-

Products?

Ans. The necessary conditions for autotrophic nutrition are :- CO

O, chlorophyll and

sunlight.

Its by - products are C

, O

Q. What are the differences between aerobic and anaerobic respiration? Name some

organisms that use the anaerobic mode of respiration.

Ans.

Aerobic Respiration

Anaerobic Respiration

It requires O

It does not require O

It happens in mitochondria.

It happens in yeast or human muscle.

It produces a higher amount of energy.

It produces a lower amount of energy.

Its final products are:- CO

+ H

O and

Energy

Its final products are:-

3. Ethanol + CO

and Energy (or)

4. Lactic acid and energy

Some organisms that use the anaerobic mode of respiration are :- Yeast, Algae and

Tapeworm.

Q. How are the alveoli designed to maximise the exchange of gases?

Ans. Alveoli are balloon-like structures which can expand themselves to maximize its

volume. Alveoli’s inner walls have a great supply of blood vessels. O

gas is diffused

into the blood and CO

from the blood is diffused into the alveoli.

Q. What would be the consequences of a deficiency of haemoglobin in our bodies?

Ans. Haemoglobin is the carrier of O

. So a deficiency of haemoglobin in our bodies

means poor supply of O

to our body and hence less amount of energy is released

which leads to weakness in the body.

Q. Describe double circulation in human beings. Why is it necessary?

Ans. In one cycle, blood has to enter the heart twice, first oxygenated blood and the

second deoxygenated blood, which is known as double circulatory system. It is a

system because of which oxygenated blood and deoxygenated blood do not mix. Mixing

of the two bloods means poor supply of O

to our body and hence less amount of

SMART EDUCATIONS

energy is released and human beings need additional energy to maintain their body

temperature. So double circulation is necessary in human beings.

Q. What are the differences between the transport of materials in xylem and phloem?

Ans.

Transport of materials in Xylem

Transport of materials in Phloem

Transported materials are :- Water and

soluble minerals.

Transported materials are :-

It transports the material in

unidirectional(only in upward direction)

It transports the material in bi

directional(upward as well as downward).

To transport the materials, it needs

physical force, such as transpiration full

and hence does not require any energy.

To transport the materials, it needs

energy in the form of ATP.

Q. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with

respect to their structure and functioning.

Ans.

Function of Alveoli

Function of Nephrons

It helps in the exchange of gas.

It filters the blood.

It removes CO

from blood.

It removes nitrogenous waste.