VII CLASS - BIOLOGY (NON IAS)

Class - VII BIOLOGY (NON IAS)

Chapter – 1
Basic Biology

I. Define the following:
i) Cell ii) Nucleus iii) Cytoplasm iv) Protoplasm
v) Cell membrane vi) Microscopic organisms
A. i) Cell : Cell is the basic unit of living things.
ii) Nucleus : Nucleus is a prominent spherical body present in the cells; It is the controlling centre of all the activities in the cell.
iii) Cytoplasm : The cytoplasm is a jelly-like substance occupying most of the inside of the cell. It occupies the space between the cell membrane and the nucleus.
iv) Protoplasm : The cytoplasm surrounded by the cell membrane and enclosing the nucleus together constitute the protoplasm (proto=first; plasm= form).
v) Cell membrane : Cell membrane is a very thin skin covering the cell. There are very tiny holes in the cell membrane.
vi) Micro organisms : The organisms that can not be seen with the naked eye and can be seen with a microscope are called microorganisms.

II. Answer the following questions.
1. Define a cell.
A. Cell is the basic unit of living things.
2. Give three examples of unicellular organisms
A. Amoeba, paramoecium, bacteria

3. Mention the functions of the following: 1) Cell membrane 2) Chromosomes

A. 1) Cell membrane: The plasma membrane performs the following functions :
i) It protects the cell.
ii) It provides shape to the cell.
iii) It allows materials to enter and leave the cell through the tiny openings.
2] Chromosomes: They help in the inheritance of characters from one generation to another ie., from the parents to the children.
3) Mitochondria : Performs the function of respiration and provide the cell with energy.
4) Nucleus : The nucleus controls all the activities in the cell.
4. Why are the following important to plant cell?
A. 1) Cell wall: It provides rigidity and protection to the cell
2) Chloroplast: Chloroplast contains a green pigment called chlorophyll which help in food manufacture.
3] Mitochondria: Performs the function of respiration and provide the cell with energy.
4] Nucleus: The nucleus controls all the activities in the cell
5. Which cell organelle is found only in animal cells?
A. Centrosome.
6. Mention at least four differences between plant cells and animal cells.
A. Animal Cell
Plant cell
1. Cell wall is lacking .
1. A rigid cell wall is present.
2. Chloroplasts are absent.
2. Chloroplasts are present.
3. Centrosome (a cell organelle that helps in cell division) is present near the nucleus.
3. Centrosome is absent.
4. Vacuoles are absent; if present, they are smaller in size and lesser in number.
4. Vacuoles are larger in size and more in number.

7. What features are possessed by both plant cells and animal cells?
A. 1. Plasma membrane is present in both.
2. Nucleus is present in both.
3. Mitochondria is present in both
4. Endoplasmic reticulum, golgi complex, lysosomes and ribosomes are present in both.

8. Name the cell organelles which are found only in the plant cell.
A. Chloroplasts, large vacuole

9. Name the different cell organelles and the functions these organelles perform in the cell.
A.
Organelles
Function (s)
1. Mitochondria (singular mitochondrion) power house of the cell.
1. Performs the function of respiration and provide the cell with energy.
2. Endoplasmic reticulum
2. Being a network of membranes, it provides a large surface area for life functions to take place.
3. Chloroplasts (present only in plant cells) ‘kitchen of the cell’
3. Chloroplasts contain a green pigment called chlorophyll, which help in the manufacture of food. (photosynthesis)
4. Golgi complex
Collects and distributes the substances made in the cell (for example, protein synthesis and secretion of many materials.)
5. Lysosomes (suicide bags)
Contain enzymes which help in breaking down or destroying the various materials.
6. Centrioles and centrosome (present in animal cells)
Concerned with cell division
7. Ribosomes
Site of protein synthesis

10. Mention the two types of cell division
A. The two types of cell division are mitosis and meiosis. Mitosis takes place in normal cells (vegetative or non-reproductive cells) of the body. It is responsible for the growth of organisms.
Meiosis is the type of cell division which occurs only in the reproductive parts of the body.

11. How do cells increase in number?
A. Cells arise only from other cells by a process called cell division. Most cells are capable of growing and splitting into two similar cells. The cells so produced are called the daughter cells. During the formation of daughter cells, the nucleus of the mother cell divides into two, so that each daughter cell gets one nucleus each. This is followed by division of the cytoplasm. Finally, two daughter cells are formed. In a multicellular organism, the growth is brought about by an increase in the number of cells by cell division. The cells so produced in due course of time undergo a change in size and shape. The whole organism, thus, shows overall growth.

Chapter – 2
Organisation in the living things – I


I. Differentiate between the following:
i) Organism and Population:-
A. The organ systems collectively form an organism. All the individuals of a single species existing in a given locality or area constitute a population.

ii) Population and Community:-
A. All the individuals of a single species existing in a given locality or area form a population.

A. The population of different species occurring in a locality constitute the next higher level of organisation called the community or biotic community.

iii) Ecosystem and Biosphere :-
A. The biotic community in an area interacts with the non – living physical environment, and the two (i.e., the biotic community and the abiotic environment) together constitute the ecosystem. All living organisms inhabiting soil, air and water constitute biosphere.

iv) Tissue and Organs:-
A. A group of similar cells that work together to do the same job is called a tissue. Tissues combine to form organs. An organ is made of different kinds of tissues.

II. Name the main organs of the following systems.
i) Digestive system:-
A. 1. Mouth, 2. Oesophagus (food pipe) 3. Stomach , 4) Liver and gall bladder, 5) Small intestine , 6) Pancreas, 7) Large intestine , 8) Anus.

ii) Respiratory system:-
A. 1. Nose, 2. Trachea (wind pipe), 3. Bronchi, 4. Lungs.

iii) Circulatory system:-
1. Heart, 2. Blood vessels (arteries, capillaries, veins)

iv) Nervous System:-
1. Brain, 2. Spinal Cord, 3. Nerves, 4. Sense organs (eye, ear, nose, tongue, skin)

v) Excretory System:-
1. Kidneys, 2. Ureters, 3. Urinary bladder, 4. Urethra

vi) Skeletal System:- Bones and cartilages

III. Classify the following as cells, tissues , organs, organ systems or organisms.
i) Chlamydomonas – Organism ii) Leaf - organ iii) Stomach – organ
iv) Stem – organ v) Shoot system – organ system vi) Skin- organ
vii) Amoeba – organism viii) Blood – Tissue ix) Flower – organ x) Bone – Tissue


IV. Answer the following:

1. What is meant by i) higher levels of organisation and ii) lower levels of organisation?
A. There are two broad levels of organisation- one below the level of the organism (the individual plant or animal) and the other above the level of the organism. These two levels constitute the “lower” levels and “higher” levels of organisation respectively.

Levels of organisation in the Living World

Biosphere

­

Ecosystem

­

Community

­

Population

­

Organism (Individual)

­

Organ system

­

Organs

­

Tissues

­

Living cells

­

Organelles
­
Molecules and Compounds

­
Atom
2. Arrange the following in an increasing order of their organisation. Also, complete the missing links in the hierarchy. Cell, Organ, Community, Population,
biosphere
A. Cell ® Tissue ® Organ ® Organ systems ® Organism ® Population
® Community ® Ecosystem ® Biosphere.

3. Mention the different levels of organisation in a multicellular organism.
A. Molecular and cellular levels of organisation of a multicellular organism is represented as follows.
Levels of organisation in the Living World

Biosphere
­

Ecosystem

­

Community

­

Population

­

Organism (Individual)

­

Organ system

­

Organs

­

Tissues

­

Living cells
­

Organelles
­
Molecules and Compounds

­
Atom



4. Explain the relationship between cells, tissues and organs.
A. Cell is the basic unit of life A group of similar cells that work together to do the same job form a tissue. Tissues combine to form an organ. An organ is made of different kinds of tissues.

5. Give the functions of each of the following systems.
A. i) Digestive system:- To convert complex food into simple soluble form so that it can be easily absorbed by the blood.

ii) Respiratory system:- To exchange oxygen and carbondioxide and produce
energy.

iii) Circulatory system:- to transport gases and materials throughout the body.

iv) Nervous System:- To control the working of body and coordinating the body
parts.

v) Excretory System:- To remove waste products from the body.

vi) Skeletal System:-1) To give shape and support to the body.
2) To protect the internal organs.
3) To help in movement.

Test yourself:-

1. Define the following terms:
i Organisation :- Organisation denotes the manner in which smaller units or components of any structure are aggregated into higher or bigger units.
ii. Organ system :- A group of organs working together is called an organ system.

2. What is meant by molecular level of organisation? Discuss.
A. All organisms are made up of cells . The cells are made up of smaller parts called organelles. The organelles inturn are made up of various molecules. The molecules are made up of atoms of various elements.
Six of these elements (Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur and Phosphorus) make up 95% of living matter. Atoms of these elements are organised to form important molecules like those of water, carbondioxide, methane, and so on. These molecules have further given rise to large molecules and compounds like carbohydrates, proteins, fats, nucleic acids (DNA and RNA) The living substance called protoplasm is made up of these compounds. DNA is responsible for the transfer of characters from parents to children. It is known as the molecule of life. Thus at the molecular level the following organisation is found.
Atoms ® Molecules ® Compounds ® organelles ® Cells.

3. What is basic living unit of organisms?
A. Cell

4. What are the different categories in the higher levels of organisation?
A. Population, Community, Ecosystem, biosphere
5. Name the highest level of organisation in the living world.
A. Biosphere

Chapter – 3
Organisation in the living things - II

I. Answer the following questions.
1. Name the different types of animal tissues.
A. The different types of animal tissues are 1. Epithelial tissue, 2. Muscular tissue 3. Nervous tissue 4. Connective tissue.

2. How is connective tissue different from other tissues?
A. Unlike the epithelial, muscular and nervous tissues where cells are closely packed together, the cells in the connective tissues are separated from one another. The space between the cells is filled with solid or liquid materials forming matrix.

3. Mention the main characteristics of meristematic tissues.
A. The main characteristics of meristematic tissues are i) The cells are small ii) the cells are thin walled iii) The cells are rich in cytoplasm with large prominent nuclei. iv) The cells lack spaces between them. v) They divide actively adding to the growth. Meristematic tissues give rise to permanent tissues.

4. Where do we find the meristematic tissue in plants?
A. Meristematic tissues are found in the growing regions – the tip of the root and the tip of the stem.

5. What is the function of meristematic tissues?
A. Meristematic tissues are found in growing regions the tip of the root and the tip of the stem. The growth in thickness is due to meristematic tissue which is present laterally in the plant body. The growth in height is due to meristematic
tissue present at the tip of the stem.

6. Name the different types of plant tissues.
A.
Plant Tissues




Meristematic Tissues Permanent tissues



Simple Complex




Parenchyma Collenchyma Sclerenchyma Xylem Phloem








7. Where are stomata present in a plant cell?
A. On the leaves.

8. What is the function of stomata?
A. i) Exchange of oxygen and carbon dioxide takes place through stomata.
ii) The process of transpiration (removal of excess amount of water from the plant body in the form of water vapour) takes place through stomata.

9. Name the tissue which takes part in the movement of water and minerals in the body.
A. Xylem.

10. Describe the structure and functions of different types of animal tissues.
A. The different types of animal tissues are (i) Epithelial tissue ii) Muscular tissue iii) Nervous tissue iv) Connective tissue.

I) Epithelial tissue: Epithelial is a protective tissue. It forms a continuous outer layer all over the body and also forms a lining of all organs such as the stomach, oesophagus, mouth, intestine, and trachea. Epithelial cells, lie close to each other. The cells may be flattened (squamous epithelium) cubical (cuboidal epithelium) or tall forming a column; (columnar epithelium)

Functions: (a) It is a protective tissue. It protects the underlying pars of the body from injury, entry of germs, and desiccation.

b) Epithelial cells lining the stomach wall secrete juices. These juices help in digestion.

c) Epithelial cells of the skin help in the removal of waste as sweat.

d) Epithelial cells of small intestine help in absorption of digested food.

II) Muscular Tissue: The movement of body or its parts in most animals is brought about by a group of cells called muscle cells.

These are long and cylindrical in shape. There are three types of muscle tissues.

Voluntary or skeletal or striated muscles.
Involuntary or smooth or unstriated muscles.
Cardiac or heart muscles.

Skeletal (or striated)
Cardiac muscles
Smooth (or unstriated)
Muscles are elongated, cylindrical with blunt ends, possess transverse bands (striations)
Muscles are elongated, cylindrical, branched, fused with one another
Muscles are elongated, spindle – shaped with pointed ends, no striations


Voluntary muscles, work at our will. These muscles help in working, writing, running or doing other jobs.

Involuntary muscles work on their own. These muscles take part in breathing movements, digestion and other activities.

Cardiac muscles, found in the heart, help in pumping the blood to different parts of the body.




III) Nervous Tissue: Nervous tissue consists of nerve cells or neurons.

Each nerve cell consists of three parts.

a) The cell body or cyton.
b) The dendrites which are short branching structures arising from the cell body, and
c) The tail or axon which is a long tube- like part with fine terminal nerve endings.


Functions : Nerve cells are joined end to end forming long nerve fibres. The nerve fibres conduct messages from one part of the body to the other.

IV) Connective Tissue : Connective tissue is composed of cells which are embedded in a non- living medium or fluid. a) Connective tissue proper: consisting of tendons and ligaments connects parts of the body, muscles to bones, bones to other bones.

b) Skeletal tissue: consisting of cartilage and bones, provides support to the body.
c) Fluid connective tissue: consists of blood and lymph. Cartilage, is less harder than the bone.

II. Differentiate between
1. Parenchyma and Collenchyma :-
A.

Parenchyma
Collenchyma
Parenchyma is composed of thin walled cells.
It is present in the softer parts of the plants.
It stores food, as in potato. In leaves, these cells contain chloroplasts, and thus help in photosynthesis.

1. Collenchyma has cells which possess thickenings at the corners
2. It is present in growing stems and leaves.
3. It provides mechanical support

2. Collenchyma and Sclerenchyma

Collenchyma
Sclerenchyma

Collenchyma has cells which possess thickenings at the corners.
It is present in growing stems and leaves providing mechanical support.

It is composed of thick walled dead cells.
It is present in hard parts of the plant body and provides strength to the plant parts.

3. Skeletal muscle tissue and Cardiac muscle tissue.
A.
Feature
Skeletal muscle tissue
Cardiac muscle tissue
Shape
Elongated, cylindrical with blunt ends, possess transverse bands (Striations)
Elongated, Cylindrical, branched, fused with one another
Location
Attached to skeleton
Wall of heart



4. Squamous epithelium and Columnar epithelium.
A. i) Squamous Epithelium:- If the epithetial cells are flattened it is called squamous epithelium.
ii) Columnar Epithelium:- If the epithelial cells are tall forming a column, it is called columnar epithelium.

5. Meristematic tissue and Permanent tissue.
A. Meristematic tissue :- A tissue capable of cell division and contribute towards growth in length and width of the plant is called meristematic tissues.
Permanent tissue:- In this tissue, cells donot divide. These form the bulk of the body.

6. Simple and Complex tissue.
A. Simple tissues consist of only one type of cells while more than one type of cells are present in a complex tissue.

III. Name the tissue found in the following:
1. At the tips of root and stem
A. Meristematic tissue

2. On the surface of roots
A. Dermal tissue

3. Lining of stomach
A. Smooth (unstriated)

4. Wall of heart
A. Cardiac

5. Blood
A. Fluid connective

6. Brain
A. Nervous tissue

7. Mango peel
A. Dermal


Chapter – 4
Life Under a Microscope

I. Name the following:-
1. A bacterium that helps in the curdling of milk.
A. Lactobacillus

2. A fungus used in the preparation of antibiotics.
A. Penicillium

3. A fungus used in bread industry.
A. Yeast

4. The specialized cell found in blue- green algae.
A. Heterocyst

5. A micro-organism used in the production of alcohol.
A. Yeast

6. Two diseases caused by bacteria, fungi, protozoa and viruses.
A.
Micro-organism
Disease
Virus
Common cold, chickenpox, smallpox, measles, polio, rabies
Bacteria
Cholera, typhoid, tuberculosis, diphtheria, plague.
Protozoa
Malaria, dysentery, sleeping sickness.
Fungi
Ringworm (skin disease)

7. Two diseases each caused by mycoplasma.
A. Atypical pneumonia – caused by Mycoplasma pneumoniae
Pneumocystes carinii pneumonia - caused by pneumocystes carinii

8. The scientist who discovered penicillin.
A. Alexander Fleming

9. Two food items prepared using yeast.
A. 1. Bread, 2. Idli

10. A Nitrogen fixing bacterium .
A. Rhizobium

11. Malaria causing microorganism
A. Plasmodium

12. Five protozoans
A. Amoeba, Euglena, Paramecium, Plasmodium, Entamoeba.

13. Two bacteria causing food poisoning.
A. i) Botulism by Clostridium botulinum
ii) Contamination of food by Salmonella enteritidis

14. Two fungi causing food poisoning
A. Poisonous fungi of Amanita species, poisoning by mushroom.

I. Answer the following questions.
1. What are the micro-organisms? Mention the different kinds of micro-organisms.
A. Very small organisms which can not be seen with our naked eyes and can be seen by magnifying lens or microscope are called microorganisms.
Major kinds of micro-organisms include: i) bacteria, ii) fungi, iii) algae, iv) Protozoans, and v) viruses.

2. How do microbes survive adverse environmental conditions?
A. Microorganisms are very hardy. Under unfavourable environmental conditions, they form a hard outer covering called the cyst. Thus they can survive under extreme temperature conditions and dryness.

3. Mention the different habitats in which micro-organisms are found.
A. Micro-organisms are found all around us in all types of places- in air, in water, in soil, on plants, inside our bodies and bodies of all other animals. They can survive in extremely harsh environmental conditions like hot springs, desert soil, saline water, ice-cold water and marsh lands. They are also found at the bottom of sea.

4. How are bacteria classified on the basis of their shapes?
A. Bacteria have three basic shapes i) Rod-shaped called bacilli (singular bacillus) meaning “little rod” examples- Bacillus, Lactobacillus and Pseudomonas.
ii) Ball – shaped called cocci (singular coccus) meaning “berry”; examples – Micrococcus, Streptococcus and Sarcina.
iii) Spiral or corkscrew-shaped called spirilla (singular spirillum) meaning “spiral”; examples – Vibrio, Triponema and Camphilovector.

5. Describe nutrition in bacteria.
A. On the basis of nutrition, bacteria are of two types -
i) Autotrophs-which can synthesize their own food, and ii) Heterotrophs-which depend on food synthesized by other organisms.
Autrotrophic bacteria may be i) Phototrophs which utilize energy from sunlight, and (ii) chemotrophs which utilize energy of inorganic compounds of hydrogen, ammonia and iron.
Heterotrophic bacteria may be saprophytic or parasitic.

6. Mention some beneficial effects of bacteria
A. Bacteria cause the decay of dead plants and animals. By enabling cows to digest grasses, bacteria play a part in the production of milk. Some bacteria, called nitrogen- fixing bacteria, are the only organisms that can take nitrogen from the air. They change nitrogen into substances that plants can use. They live in root nodules of leguminous plants. The flavour of tea, and cheese is brought about by different species of bacteria. Ethyl alcohol is converted to vinegar by acetobacter. Milk is converted to curd by Lactobacillus.

7. Describe reproduction in bacteria.
A. Bacteria generally reproduce by binary fission, that is a bacterium divides into two, and so on. Rate of reproduction is very high under favourable conditions of nutrition, temperature and moisture.


Parent cell
¯
Cell elongation
¯

Invagination of cell wall and distribution of nuclear material

¯

Formation of transverse cell wall and organized distribution of cellular material into two cells
¯
Separation into two new cells. Each cell repeats process

8. What are the three groups of organisms in fungi?
A. Yeasts, Moulds, Mushrooms

9. Mention two important uses of fungi.
A. i) Some fungi produce antibiotics that are used to treat infections and diseases. Penicillin is obtained from a fungus, Penicillium.
ii) Another fungus Aspergillus is used for producing large quantities of citric acid used in soft drink industry.

10. Why does the milk spoil quickly during summer?
A. Temperature of the summer season, favours the growth of bacteria. So the milk gets spoiled quickly.

11. What beneficial role do micro-organisms play in the life of human beings?
A. Bacteria:-
1. Nitrogen fixing bacteria of Leguminous plants can take nitrogen from air and change it into nitrates and increase the fertility of the soil.
2. Scientists have developed a way to produce methane (an inflammable gas and a fuel) from manure of cattle with the help of anaerobic bacteria.
3. Secondary treatment of yeast involves the use of bacteria.
4. Gene splicing is used to change bacteria so that they produce insulin.
Fungi:
1. Mushrooms are edible.
2. Some fungi produce antibiotics
3. Yeast is used in bread- making industry.
4. Saprophytic fungi help in recycling of nutrients
Algae:
1. Blue- green algae can fix atmospheric nitrogen. These algae are used to increase the soil- fertility and thus function as biofertilizers.
2. Sea weeds are also used as fertilizers..
3. Agar obtained from red algae is used in laboratory experiments.
4. See weeds are used as food in China and Japan.
5. Kelp – a brown alga is a rich source of iodine.

12. State two ways in which the following microorganisms are harmful to mankind: Bacteria Protozoa, Viruses
A. Bacteria:- Diseases like cholera, diphtheria, pneumonia, tetanus, tuberculosis etc are caused by bacteria.
2. Food poisoning is caused by bacteria.
Protozoa
1. Amoebic dysentery in man is caused by a protozoa called Entamoeba hystolityca.
2. Measles, mumps, flu, small pox, common cold etc are caused by viruses.

13. How are viruses different from other microbes?
A. Viruses are peculiar – their structure is unlike all the other microbes. These are not considered to be organisms at all since they do not possess a cellular organisation. They have no life until they enter another living cell. They are unable to carry out any of the typical life functions until they are inside a host cell. Outside a host cell, viruses are like any non-living substance.

14. Why do farmers cultivate plants of pea family?
A. Plants of pea family (leguminous plants) contain nitrogen fixing bacteria in their root nodules. These Bacteria can take nitrogen from the air . They change the free nitrogen of air into substances that plants can use. Thus they increase the fertility of the soil. So farmers cultivate plants of pea family.


15. Mention the role of nitrogen fixing bacteria in soil .
A. Nitrogen fixing bacteria found in the root nodules of Leguminous plants can take nitrogen from the air. They change the nitrogen into substances that plants can use. Thus they increase the fertility of the soil.


16 Name the causal organisms of the following diseases: a) Amoebic dysentery
b) Sleeping sickness c) Measles d) Common cold.
A. a) Protozoa
b) Protozoa
c) Virus
d) Virus

17. Mention the contributions of the following.
a) Louis Pasteur b) Leeuwenhoek

A. a) Pasteurization . It is a method to preserve milk.
b) Discovery of cell in the year 1665

18. Describe the role of blue- green algae in the fertility of soil.
A. The blue- green algae can fix atmospheric nitrogen. These algae are used to increase the soil-fertility and thus function as biofertilisers.

19. Mention some advantages of food preservation.
A. 1. Reduces food wastage by avoiding spoilage.
2. Increases the storage period of foodstuff.
3. Nutritive value is retained for a longer period.
4. Ensures food availability in distant places and during off-season.

20. Define Pasteurization.
A. Pasteurization is the method to preserve milk by first heating it and then suddenly cooling it and storing at low temperature.


21. Describe the different methods used to prevent the spoilage of food.
A. 1. By Sun Drying – Drying in the sun reduces the moisture content Micro-organisms cannot grow in dry condition. Sun drying is generally used for spinach, cauliflowers and methi leaves.

2. By Heating – Heating kills germs.

3. By smoking – Smoking is used for dehydrating food items like meat, fish and their products. In this method, small pieces of fish or meat are dried with heat and smoke of the fire lit below.

4. By Salting and Sugar – Fruits and vegetables are commonly preserved by using salt or sugar. The food items are made into jams, jellies and pickles. In jams, sugar is used. In pickles salt is used. Besides salt and sugar, oil and spices are also used as preservatives. They do not allow the growth of micro- organisms and thus help in preserving the food items.

5. By Refrigeration and Freezing - A refrigerator keeps food at about 50C. This keeps the food fresh for a few days.
A freezer preserves food at below- 180C. This stops all microbial activity and food can be preserved for many months.

6. By Pasteurization – Milk is preserved by this method. First the milk is heated to kill bacteria. Next it is cooled very fast to prevent bacteria from growing. It is finally stored at low temperature. This method of preservation is called pasteurization. Pasteurization kills the bacteria in milk and does not affect its flavour.

Chapter - 5
Life Processes - Nutrition in Animals and Plants
I. Answer the following questions:
1. List three functions of food.
Ans : Functions of food are :
(i) For growth : Without proper food, growth would not be possible.
(ii) For repair of damaged or injured body parts.
(iii) For protection from diseases and infection.
2. Name the various components of food.
Ans: The various components of food are: (i) Carbohydrates (ii) Fats (iii) Proteins (iv) Mineral salts (v) Vitamins (vi) Water (vii) Roughage (fibre)
3. What is roughage? How is it important for the body?
Ans: Roughage is fibrous part of the food which is not digested by the body. It helps the food to go down the food pipe and also helps the waste matter produced during digestion to pass through the body.
4. Why is water essential for our bodies?
Ans: Water is a means of transportation in the organism . It helps to maintain a constant body temperature. Water helps in the absorption of food and excretion of waste products from the body.
5. Why is a balanced diet?
Ans: A mixed diet containing all the essential nutrients in the right proportion is necessary for body’s proper growth. Such a diet is known as a balanced diet.
6. Give a brief account of three food fads.
Ans: (i) A wrong notion is that weight reduction is possible by eating bread or chapatti instead of rice. It is well known that both rice and wheat contain about the same number of calories, and so eating one and leaving the other one will not make any difference. It is the total caloric intake that needs to be reduced for effective weight reduction.
(ii) White eggs are better than brown ones. There is no truth in it. Both types of eggs have same amount of nutrients.
(iii) Eating bhindi (lady’s – finger) makes a student good in Mathematics. There is no truth in this belief.
7. What is obesity?
Ans: Obesity is a type of disease caused by over eating. It often leads to other problems like heart disease and high blood pressure.
8. Mention five good food habits.
Ans: (i) Eat balanced diet, keeping in mind your age, health and occupation.
(ii) Eat clean food, kept protected from dust, houseflies and mosquitoes.
(iii) Avoid fried foods as far as possible.
(iv) Take adequate amounts of green salad, green vegetables, and fruits in your diet.
(v) Drink large quantities of clean filtered water.
9. Mention the roles of different components of food.
Ans: Carbohydrates : provide us energy.
Fats : These are also energy giving foods, producing more energy than carbohydrates.
Proteins : These are body building foods. They help in the growth and repair of the body. They also help the body to fight against infections and regulate body functions.
Vitamins and minerals : are required for the proper functioning of the body.
10. What are the average daily requirements of proteins in case of children and adults? Why do children need more proteins than adults?
Ans: Adults require 1gm for every 1kg of body weight; children require 1.46gm for every 1kg of body weight. Children need more protein as they help in the growth of the body.
11. Why should we include vitamins in our diet? Mention the sources of different vitamins.
Ans: We should include vitamins in our body as they are very important for proper functioning of our bodies .
S.No
Vitamin
Sources
1
Vitamin A
Milk, butter, cheese, tomatoes, carrots, cod liver oil, yellow fruits.
2
Vitamin B complex
(mixture of several vitamins)
Milk, eggs, cheese, meat, liver, husk of cereals and pulses.
3
Vitamin C
(ascorbic acid)
Citrus fruits (orange, lemon, lime), green vegetables, tomatoes.
4
Vitamin D
(produced by sun in skin)
Milk,yellow of egg, liver, fish liver oil, sunlight, cod liver oil.
5
Vitamin E
(made by bacteria in large intestine)
Leafy green vegetables (spinach, cabbage)



12. Which one offers you more energy? (a) One large banana or hundred grams of grapes (b) one egg or one teaspoon of butter.
Ans: (a) One large banana (b) One egg.
13. Which substances eaten by man have little or no nutrient value?
Ans: Roughage (fiber)
14. Why do living organisms need food?
Ans: Food is required by living organisms :
(i) For growth : Without proper food, growth would not be possible.
(ii) For repair of damaged or injured body parts.
(iii) For protection from diseases and infection.
15. Describe the role of chlorophyll in photosynthesis.
Ans: Leaves contain the green coloured pigment called chlorophyll inside their cells. The chlorophyll is present inside certain structures called chloroplasts. Chloroplasts trap energy from sunlight and help in the process of photosynthesis.
16. Define nutrition. What are the various types of nutritions?
Ans: The process of taking in or consuming and utilizing food is called nutrition. The two types of nutrition are (a) Autotrophic (b) Heterotrophic
(a) Autotrophic : Nutrition in green plants which can prepare their own food from simple inorganic substances.
(b) Heterotrophic : Nutrition derived from other organisms (dead or living) as in animals, fungi and some bacteria.
Heterotrophic animals are of three types – Herbivores, carnivores and omnivores.
Heterotrophic nutrition in plants are of four types – Saprophytic, parasitic, symbiotic and insectivorous.
17. Which part of the plant body takes in water?
Ans: Roots.
18. Where from does carbondioxide enter a plant?
Ans: Air.
19. What is produced during photosynthesis?
Ans: During photosynthesis, food is synthesized. Oxygen is released in the process.
20. Mention the different factors affecting the rate of photosynthesis.
Ans: The following factors affect the rate of photosynthesis
1) Light intensity : Photosynthesis increases with increase in light intensity, upto a certain point.
2) Availability of carbondioxide : photosynthesis increase with increase in carbondioxide concentration.
3) Temperature : Upto a certain temperature value, rate increases with increase in temperature. This value ranges generally between 200 to 350C.
4) Availability of water : Less availability of water reduces photosynthesis through closure of stomata.
5) Inorganic mineral ions : A dehydrated green plant consists of four elements – carbon, hydrogen, oxygen and nitrogen. These elements consists of about 96% of total plant’s dry weight. Remaining 4% of the green plant dry weight consists of the following inorganic compounds – sulphur, phosphorus, calcium, iron, magnesium etc., Each of the inorganic ions have different functions in the process of photosynthesis.
21. Describe the role of stomata in photosynthesis.
Ans: Exchange of gases (carbon dioxide and oxygen) takes place through stomata. The opening and closing of stomata is related to the photosynthetic activity in the leaves. Stomata are wide open during the day as photosynthesis occurs during this period. In dark or at night when there in no photosynthesis, stomata are closed.
22. How is food material transported from the leaves to other plant parts?
Ans: The prepared food material in a soluble form is carried through phloem, from the leaves to all other parts of the body.
II. Define the following.
1) Food :- Food is the substance from which an organism derives energy and materials for growth and maintenance.
2) Nutrient :- The substances present in the food are called nutrients.
3) Carnivores :- The animals that eat other animals, like dog, tiger and lion.
4) Omnovores :- The animals who eat both plants and animals, like humans, crow and cockroach.
5) Herbivores ;- The animals that eat plants like cow, buffalo, goat and elephant.
6) Insectivorous plants ;- Plants which feed on small insects are called insectivorous plants.
7) Symbiotic nutrition:- A mode of nutrition in which two different organisms live together and both benefit from each other.
8) Saprophytic Nutrition :- A mode of nutrition in which organisms feed on dead and decaying organic matter.
9) Parasitic nutrition :- A mode of nutrition in which organisms derive its food from the living body of another organisms (called hosts)
III. How do you test for -
Proteins in food:
(1) Take egg white in water in a test tube.
(2) Add two – three drops of copper sulphate solution and 10 – 12 drops of caustic soda solution.
(3) Shake well.
(4) A purple or violet colour indicates the presence of proteins in the given sample.
2. Carbohydrates in food.
Ans: 1) Take crushed pieces of potato, apple and glucose solution in three separate test tubes.
2) Add a few drops of Benedict’s solution in each test tubes.
3) Gently heat.
4) The test tubes containing crushed apple and glucose solution turn into a red precipitate; no such change occurs in the test tube containing potato. Development of red precipitate indicates the presence of sugar.
3. Water in food.
Ans: 1) Take equal weights of the two samples (fresh potato slices and spinach leaves) in separate dishes.
2) Keep these dishes in an oven at 80 – 900C or in sunlight for a few days.
3) Weigh the food samples again.
4) There is a reduction in weight of the two samples. Loss of water has taken place.
4. Fats in food.
Ans: 1) Rub a small amount of butter on the paper or put a drop of oil on the paper.
2) Let the paper dry. Hold it in front of a source of light.
3) The paper becomes smooth, oily and less transparent.
5. Starch in food items.
Ans: 1) Place a drop of iodine solution on a slice of bread.
2) Blue – black colour, where iodine solution is applied, indicates the presence of starch.
6. The role of light in photosynthesis.
Ans; 1) Destarch the potted plant by placing in a dark room for 48 hours.
2) Cover part of the leaves with black paper.
3) Place the pot in sunlight for 5 or 6 hours.
4) Remove a leaf from the potted plant.
5) Test the leaf for starch as follows:
(i) Put the leaf in a test tube containing boiling alcohol.
(ii) Now remove the test tube. Take out the leaf and wash it with water.
(iii) Spread the leaf on a glazed tile or a watch glass.
(iv) Put a few drops of iodine solution on the leaf.
6. The part of the leaf exposed to light turns blue – black in colour. The part of the leaf covered with black paper is brown
7. Starch is formed only in those parts of the leaf where light can reach. So light is necessary for photosynthesis.
7. The role of chlorophyll in photosynthesis.
Ans: 1) Detach a leaf from the potted plant and perform the starch test.
2) Green part of the leaf become blue – black.
3) Non green parts become brownish.



Chapter – 6
Life Processes – Ingestion, Digestion, Absorption and Assimilation
I. Define the following terms:
1) Ingestion 2) Absorption 3) Digestion 4) Assimilation
5) Alimentary canal
6) Digestive system 7) Plaque
A. 1) Ingestion: The process by which food is taken in by the organisms is called ingestion.
2) Absorption : It is the process by which digested food is taken up (or absorbed) by the body.
3) Digestion : It is the process of breaking down of complex food into simpler absorbable molecules.
4) Assimilation : The absorbed food is incorporated into living cells and is used by the body for its growth and other purposes.
5) Alimentary Canal : Alimentary canal is a long, muscular and coiled tube which starts from the mouth and ends at anus.
6) Digestive system : The alimentary canal along with the associated glands is called the digestive system.
7) Enzymes: Enzymes are biological catalysts.
8) Plaque : When food is eaten small amounts are left between the teeth Saliva and bacteria stick to the teeth and form a sticky film. This sticky film is called dental plaque.

II. Answer the following
1. How is digestive system different from an alimentary canal?
A. The alimentary canal along with the associated glands is called digestive system. Alimentary canal is a long, muscular and coiled tube which starts from the mouth and ends at anus.

2. Give the functions of different types of teeth in an adult human.
A. Incisors – for cutting and biting
Canines – for tearing the flesh. Premolars and molars- for grinding and chewing.

3. Describe the functions of the following: a) Saliva b) Oesophagus c) Tongue d) Liver

A. a) Saliva : Saliva helps in the digestion of food. Saliva contains an enzyme called amylase (also called ptyalin). Amylase acts on starch and changes into a sugar (called maltose).
b)Oesophagus : It only helps in pushing the food into stomach.
c) Tongue: Tongue helps in mixing the chewed food with saliva and swallowing the food. Further, the tongue tastes, as it has sense organs called the taste buds. These buds distinguish four basic tastes- salty, sour, sweet and bitter. In addition, tongue helps us to speak.
d) Liver : The liver secretes juices which help in digestion and are stored in a small bag called the gall bladder.

4. Describe the structure of a tooth.
A. Fixed to the gums, each tooth has the following three parts.
i) Root, the part embedded in the jaw.
ii) Crown, the top part projecting above the gums, and
iii) Neck, the part between the root and the crown.
Internally, there are three parts of a tooth – enamel, dentine and the pulp cavity. Enamel is the white part of the tooth, and is the hardest substance in our body. Below the enamel, dentine is present. Inner to dentine is the soft pulp cavity which contains blood vessels and nerves.

5. How are teeth different in herbivores and carnivores?
A. Dentition in herbivores : They have incisors which are sharp and used for cutting. Canines are absent and a gap occurs between the incisors and premolars. This gap is called diastema. The premolars and molars are used for chewing. Diastema allows the tongue to manipulate the food.
Dentition in carnivores : They have all four kinds of teeth. The incisors in the front of the mouth grip the food and strip off small pieces of flesh. The canines are long, sharp and pointed and adapted for flesh eating. The molars have somewhat flat surface for grinding and crushing the bones.
6. Write briefly about ‘care of the teeth’.
A. Plaque formation and other diseases can be avoided by
i) not eating foods like sweets, chocolates and ice-creams.
ii) consuming foods which contain sufficient calcium, phosphorus and vitamin D such as milk, fish, raw vegetables, carrots, spinach, radish, cabbage and fresh fruits .
iii) cleaning teeth after eating sweet, sticky food,
iv) brushing teeth thoroughly and regularly everyday in the morning and again before going to bed, and v) using fluoride toothpaste.
7. Define the following:- plaque
A. Plaque: When food is eaten small amounts are left between the teeth, saliva and bacteria stick to the teeth and form a sticky film. This sticky film is called dental plaque
8. Mention various steps in the process of digestion.
A. 1) Ingestion: The process by which food is taken in by the organisms is called ingestion.
2) Absorption : It is the process by which digested food is taken up
(or absorbed) by the body.
3) Digestion : It is the process of breaking down of complex food into simpler absorbable molecules.
4) Assimilation : The absorbed food is incorporated into living cells and is used by the body for its growth and other purposes.
5) Egestion : This is the process by which undigested food is removed from the body.
V. Name the following :
1. Different organs of the digestive system.
A. The different organs of the digestive system are as follows:
i) Mouth and mouth cavity.
ii) Oesophagus (gullet)
iii) Stomach
iv) Small Intestine
v) Large Intestine
vi) Anus
vii) Liver
viii) Pancreas
ix) Salivary glands
2. Different types of teeth in an adult human being.
A. There are four main kinds of teeth in man. They are incisors, canines, premolars and molars.
3. The digestive juices secreted by mouth, pancreas, stomach, small intestine.
A.
Part of the Digestive System
Enzymes/ Juices
Mouth
Saliva (amylase)
Stomach
Gastric juice (pepsin)
Pancreas
Pancreatic juice (several enzymes like trypsin, lipase and sucrase)
Small intestine
Intestinal juice (several enzymes)

CHAPTER – 7
Life Processes – Respiration and Excretion in Animals and Plants
1. Define the following terms:
1. Respiration : Process of releasing energy from the food eaten by organisms.
2. Breathing : It is a physical process in which exchange of gases (O2 and CO2) takes
place.
3. Internal respiration : A chemical process in which food molecules are broken down
into simpler molecules within cells and energy is produced.
4. Aerobic respiration : Respiration in the presence of oxygen.
5. Anaerobic respiration : Respiration in the absence of oxygen.
6. Transpiration : Process of loss of water in vapour form from the plant leaves.
II. Differentiate between the following:
1. Breathing and Respiration
Ans:
Breathing
Cellular Respiration
1. It is a physical process in which exchange of gases (O2 and CO2) takes place.
1. It is a chemical (or biochemical process as it occurs in living cells) process in which food molecules are oxidised to carbon dioxide and water.
2. It occurs outside the cells.
2. It occurs inside the cells
3.Enzymes are not involved
3. Enzymes take part in the process
4. No energy is released
4. Energy is released in a gradual and stepwise manner.

2. Combustion and Respiration
Ans:
Combustion
Respiration
1. It is a fast process
1. It is a slow stepwise process
2. It occurs at high temperature
2. It occurs at normal room temperature
3. Energy is produced in the form of heat and light
3. Energy is released in steps, and stored in a special chemical molecule. No heat or light is produced
4. Conversion to carbon dioxide and water is in one step . No enzyme is involved
4. Many steps are involved in the conversion of carbohydrates to carbon dioxide and water. These steps or reactions are catalysed by enzymes.

3. Aerobic respiration and Anaerobic respiration.
Ans:
Aerobic respiration
Anaerobic respiration
1. It takes place in the presence of Oxygen
1. It takes place in the absence of oxygen.
2. Food molecules are completely broken down into carbon dioxide and water, releasing energy.
2. Food molecules are partially broken down into ethyl alcohol , carbon dioxide and energy.
3. Energy released is more
3. Energy released is much less.


4. Transpiration and Excretion.
Ans: Transpiration : The process of loss of water in vapour form from the plant leaves is called transpiration.
Excretion : The process of removal of the waste products is called excretion.
III. Give one word for the following:
1. The process in which breaking down of food into small molecules occurs.
Ans: Digestion.
2. Coiled tubes acting as filters and present in kidneys.
Ans: Nephrons.
3. Large flat muscle found in the chest cavity.
Ans: Diaphragm.
IV. Answer the following questions:
1. Mention the end products of respiration.
Ans: End products of aerobic respiration are carbon dioxide, water and energy. End products of anaerobic respiration are ethyl alcohol, carbon dioxide and energy.
2. Mention the different organs / methods of breathing in animals.
Ans: (i) In Amoeba, breathing occurs by simple diffusion. Hydra also breathes through the
body surface.
(ii) In insects, movement of skeleton draws air in and out of the openings called
spiracles. These openings are present on the body surface.
(iii) Fishes and many other aquatic animals have special structures called gills. Through
these gills dissolved oxygen is used from the water entering these organs.
(iv) Earthworms absorb the atmospheric oxygen through their moist skin.
(v) Frogs when in water breathe through their moist skin. Frogs, on land, breathe
through their lungs.
(iv) We breathe through our lungs. Movements of the ribs and diaphragm help to draw
air in and out of our lungs through nose.
3. How does respiration occur in plants? Write a note on it.
Ans: In plants, specific organs for breathing are absent. The exchange of gases, however, occurs by the process of diffusion. Diffusion of gases (oxygen and carbon dioxide) occurs through three sources.
(i) Through stomata (singular stoma), the minute openings on the surface of leaves,
(ii) Through lenticels, openings present in old stems, and
(iii) Through general surface of the roots. In aquatic plants, gases diffuse though the body
surface. Cellular respiration in plants is similar to that found in animals. It occurs
inside mitochondria.

4. Write in short about the mechanism of respiration.
Ans: During inhalation (breathing in), two things happen. (i) the ribs move out (ii) the
diaphragm moves down. Thus, the chest cavity enlarge. Air then rushes into the lungs. The lungs inflate.
During exhalation (breathing out) the ribs move downwards and inwards . ii) the
diaphragm moves up. Thus, the chest cavity is reduced. Air rushes out of the lungs. The
lungs becomes smaller.

5. Name the organs of the respiratory system in human beings.
Ans: The organs of the respiratory system are : 1) Nose 2) Trachea 3) Bronchi 4) Lungs

6. Define transpiration.
Ans: Transpiration is the process of loss of water in vapour form from the leaves in plants.



7. Mention the factors affecting the rate of transpiration.
A. Factors Affecting Transpiration.
1) Day/Night : More transpiration takes place during the day than at night. This is because the stomata are open during the day and close at night.
2) Wind : Wind increases the rate of transpiration .
3) Humidity : Rate of transpiration is decreased if the air is humid. The air already contains a lot of water.
4) Temperature : Rate of transpiration is more on a hot day than a cold day.
5) Light : Light causes the stomata to open. This increases the rate of transpiration.

8. Write a brief note on excretion in flowering plants.
A. The various methods of excretion are given below.
1) Waste products of photosynthesis and respiration – oxygen, carbon dioxide, water and heat – are released into the atmosphere through stomata in the leaves and lenticels in stems. The waste products of one process are, however, usable as raw products in another process.
2) Ammonia is formed as a breakdown product of proteins. Plants use this ammonia to synthesize useful compounds.
3) Some of the waste products of photosynthesis collect in the leaves and bark of trees. Plants shed their leaves and bark to get rid of these wastes.
4) Some waste materials keep accumulating within cells. Calcium oxalate crystals, called raphides, are such wastes. Yam is rich in raphides.

Several of the plant wastes are useful to us. Latex, gums, resins, tannins, sandalwood oil and eucalyptus oil are such substances.

Latex, a white milky fluid, oozes out from any cut on the stem in case of some plants. Latex from rubber plant is used for making rubber. Resins are used for preparing varnish.

9. What waste products are removed by the following parts?
a) Skin b) Kidneys c) Lungs d) Large intestine

A. a) Sweat b) Urine c) Carbondioxide, water vapour d) undigested food.

10. Describe the importance of respiration in organisms.
A. Respiration is a process common to all plants and animals. It is a process whereby living organisms produce energy from the food they eat. This energy is necessary for various life activities.

11. Why did body cells require oxygen?
A. Body cells require oxygen to break down the digested food to release energy.

12. How does excretion occur in lower plants and animals?
A. In organisms like Amoeba, Paramecium, Hydra, etc., most of the metabolic wastes are removed through the general surface of the body by the simple process of diffusion. Specialized organs of excretion are lacking.

13. Name the various organs of excretion in humans.
A. Lungs, skin, large intestine, kidneys, liver.

CHAPTER – 8
Life Processes – Movement in Animals and Plants

I. Define the following:
1. Joints: The places where two or more bones meet are called joints.
2. Tendons : These are the fibres by which muscles are attached to bones.
3. Tropism : The movement of plant parts which take place towards or away from
the stimulus are tropisms.
4. Phototropism : The movement of plants towards light is called phototropism.
5. Thigmotropism : The movement of plants in response to the stimulus of touch is
called thigmotropism.

II. Differentiate between the following:
1. Tendons and ligaments: Tendons are the fibres by which muscles are attached to
bones. The bones are held together at a joint by tough
structures called ligaments.
Hydrotropism and thigmotropism : The movement of plant parts in response
to water is called hydrotropism. The
movement of plants in response to the
stimulus of touch is called thigmotropism.
3. Hinge joint and ball and socket joint :Hinge joints allow the movements only in
one direction like those of a door or the lid of a box. Ex. Elbow, knee.
In ball and socket joint, the rounded head of one bone fits into a cup shaped cavity formed by the other bone. This allows movement in all directions. Ex Hip and shoulder.

III. Answer the following :
1. Why do animals need locomotion?
Ans: 1) Animals have to move from place to place in search of food.
2) Locomotion helps animals to move from an unfavourable place to a favourable
place.
3) It helps them to escape from their enemies and predators.
4) Its helps animals to find their partners for reproduction, and to move to
favourable areas for egg laying.

2. How is locomotion brought about in humans?
Ans: Locomotion is result of coordinated action of muscles on the limb bones. The
contraction and relaxation of muscles move the bones.

3. Give a brief account of the various methods of locomotion in animals.
Ans: (i) Amoeba moves by extending its pseudopodia.
(ii) Paramecium uses cilia.
(iii) Euglena moves by the whip like action of the flagellum.
(iv) Hydra uses its tentacles for walking.
(v) Earthworms and leeches move by the contraction and relaxation of the
muscles.
(vi) Insects and birds uses wings.
(vii) Fishes have fins and tails for locomotion.
(viii) In frog hindlimbs with webbed feet help in locomotion.
(ix) Mammals use their hindlimbs as well as the forelimbs for locomotion.
Humans use only hind – limbs for locomotion.


4. How is locomotion different from movement?
Ans: The act of moving from place to place is known as locomotion. It involves the
movement of the whole body, as in walking, running, swimming or flying.
Movement is the change in position of only a part of the body, as movement of
stem towards light in plants.

5. In which animals do you find the following structures:
(a) Webbed feet – frog (b) Pseudopodia – Amoeba (c) Tentacles – hydra

6. How does locomotion take place in an earthworm?
Ans: Circular and longitudinal muscle fibres are present on the body wall of the
earthworm. When the circular muscles contract, the body gets longer and
narrower. When the longitudinal muscles contract, the body becomes thicker
and shorter. The movement of these muscles pushes the blood in the direction of
body movement. When it moves the front end becomes long and thin while its
hind end becomes short and thick. This is due to contraction and relaxation of the
body muscles.

7. What is meant by positive and negative responses?
Ans: When the movement is towards a stimulus, it is called a positive response. When
the movement is away from the stimulus, it is called a negative response.

8. How are tropic movements different from nastic movements?
Ans: The movements in which direction of movement is always related to the direction
of the stimulus are called tropic movements. Ex. Bending of stem towards light.
Nastic movements are non – directional as compared to tropic movements. Ex.
Opening and closing of flowers in response to light.

9. Writing in brief about the different types of tropic movements .
A. Tropic movements may be in response to light (Phototropism), gravity (geotropism), water (hydrotropism) and touch (thigmotropism).
Phototropism :- The movement of plants towards light is called phototropism. Shoots generally grow towards light. (positively phototropic). Roots grow away from light (negatively phototropic)
Geotropism : The movement in response to gravity is called Geotropism. Roots generally grow towards soil or gravity and are called positively geotropic. Shoots grow away from gravity (negatively geotropic)
Hydrotropism: The movement of plant parts in response to water is termed hydrotropism. Roots are usually hydrotropic.
Thigmotropism: The movement of plants in response to the stimulus of touch is called thigmotropism.
10. Name the stimulus which causes the following movements in plants:
A Geotropism- Gravity
Opening and closing of flowers – light Phototropism – light
Thigmotropism – touch Hydrotropism – water



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