OUR NATURAL RESOURCES
I.
Choose the right answer
1. One of the following does not belong to the group.
a. Water
b. forests
c. petrol
d. soil
2. Government has banned hunting of wild animals. This helps to
a. Maintain biodiversity
b. promote tourism
c. provide food to animals
d. maintain soil fertility
Fill in the blanks
1.
2.
3.
4.
5.
II.
Resources that get replenished in nature are called Exhaustible resources.
Petrol and kerosene are Non-renewable forms of natural resources.
If there is rise in water table, soil becomes saline.
Soil provides Water and minerals to terrestrial plants.
An example of renewable resource is forests.
Answer the following:1. What are natural resources?
Ans: The things that occur in nature and that are useful to us are called
natural resource.
2. Differentiate between renewable and non renewable resource.
Ans: The natural resource can get replaced in nature easily. Such
resources are called renewable natural resource. Some are continuously
available and some can be replenished.Ex.; solar energy, forest etc.
Resource which cannot be replenished once depleted are called nonrenewable resources.Formed on earth over a long period of time. Ex.:
fossil fuels and minerals.
3. List the uses of Water?
Ans: 1. It is very much essential for the existence of life.
2. It is a factor for many aspects of life such as environmental stability,
biodiversity conservation, fuel security and health care.
3.Water is used for various human activities like drinking, agricultural,
purposes, washing and recreation.
4. The largest use of water occurs in the agricultural sector.
5. It is also used for last exchange process in industries and extinguishers.
1
6. It is used for producing hydro electricity.
What is mining ?
Ans: Mining is the process of extraction and processing of minerals.
4. What happens if too much of fossil fuel is used?
Ans: fossil fuels are non renewableresources, therefore they cannot be
replenished once depleted. Hence too much of the usage of fossil fuel
leads to energy crisis in the near future.
5. A student argues that a nation will be rich if its forests are conserved. Explain.
Ans: 1. Forests provide raw materials for various wood based industries
such as paper, board, rayon etc.
2. Forests provide timber which is an important material in constructing
building and furniture.
3. They provide many product like dyes, lac fibre, wax, honey, medicines
etc.
4. Forests have aesthetic value and provide opportunities in tourism.
5. Thus forest plays an important role in the country‟s economy.
III.
Match the following :1) high carbon content
2) Renewable
3) Low sulphur content
4) Formation of soil
anthracite
wind
L.P.G
Weathering of rocks
2
STUDY OF OUR ENVIRONMENT
I.
II.
Fill in the blanks
1. Fill in the box with appropriate organism
Grass-----= grass hopper------- frog------ snake------ eagle.
2. One of these is a decomposer fungi .
Fill in the blanks with suitable words:1. The crust of the earth is called lithosphere .
2. The basic unit of study in environment is Ecosystem.
3. Collection of individuals belonging to the same species ispopulation
.
4. Different kinds of ecosystem together constituteBiosphere.
5.In a parasitic food chain the pyramid of number will be inverted.
II.
Answer the following
1.
How was earth formed?
Ans: According to the scientists earth was formed from the mass of particles in the
space which came very close to each other. The condensed material formed the solid
earth, covered with fluid water and the gaseous atmosphere. Later, the chemical
restricting of molecules resulted in the origin of life which evolved to varieties in due
course.
2.
List the factors which have made life to exit on the earth.
Ans: Important factors that have made life possible on the earth are:a) Abundance of water.
b) Water has high capacity to absorb heat and sustain it.
c) Water release the heat energy back to the atmosphere.
d) Water expands when heated or cooled from 40C will remain at deeper layers.
e) The high surface tension of water and tendency to expand on freezing helps to
weathering of rocks leading to soil formation.
3.
What is an ecosystem?
Ans: A unit of nature where there is an interaction between living and non-living
components is known as ecosystem.
Or
An ecosystem consists of a community of different kinds of living organisms in an
area interacting among themselves and with the non living components in that area.
3
4. Why is the use of DDT not advisable?
Ans: DDT ( DichloroDiphenylTrichloro Ethane) is a toxic substance used as
insecticide especially to eradicate mosquitoes. But it goes transferred from the water
and soil to living beings, from one trophic level to another and appearws in higher
concentration at higher levels. Traces of DDT are found in the small fish, big fish,
predatory birds and even mother‟s milk. Hence the use of DDt is not advisable.
5. Construct a simple food chain?
Ans:
1.Grass – grass hopper – frog- snake- eagle.
2. Aquatic algae- protozoa- small fish- big fish.
6. What may happen if all herbivores are killed in a terrestrial ecosystem?
Ans: If all herbivores are killed in a terrestrial ecosystem, the immediate result will
be ,the predators or carnivores will starve to death. In the long run –there will be no
animals on land. This will lead to imbalance of oxygen-carbon dioxide in the
atmosphere. The scarcity of carbon dioxide will lead to decreasing growth of plants.
7. Define the following –
a) Lithosphere –The surface or crust of the earth is called lithosphere. It represents the
mountains, the ocean floors and the plain lands.
b) Population- A collection of individuals belonging to the same species occupying a
given area, at a given time is called population.
c) Biotic community- In an given area populations of different species of plants
animals and other organisms live. All these different populations together constitute a
biotic community.
d) Food web- Since most organisms feed on more than one kind of food item, every
organism at every trophic level becomes linked to several food chains at the same
time. Thus, in every ecosystem, we have a complex network of interconnected food
chains, forming a food web.
4
STUDY OF CELLS
I Fill in the blanks:1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
I.
A cell lacking in nucleus, also lacks in chromosome .
Cell wall is absent in the cell of mosquito
Organelle of the cell, which release energy through respiration is mitochondria
The part of the cell which is non-living is cell wall.
One of the following is the smallest organelle in a cell ribosome
The instrument that led to the understanding of cell iselectron microscope.
The organelle, which controls the various activities of the cell is nucleus.
The organelle, which is called the “kitchen of the plant cell” is chloroplast
The sites of photo synthesis in the cell are ribosome.
The main chemical component of the cell wall iscellulose
Match the following:-
1.
2.
3.
4.
Storage room of the cell
Gate way of the cell
Solar panels of the cell
Package of hereditary information
1.
Ans:
Answer the following:What are genes? Mention their importance.
Genes are the hereditary units. They are present inside the cell in the D.N.A.
They determine the particular characteristics of an organism.
II.
vacuole
cell membrane
chloroplast
chromosome
2.
Which organelle is responsible for the formation of spindle fibers during cell
division?
Ans: Centrioles are the organelles responsible for the formation of spindle fibres
during cell division.
3.
Ans:
Which is the most important types of chromoplast? Why?
Chloroplast is the most important type of chloroplast. It contains chlorophyll
and so it makes the green colour in many parts of the plant. Chromoplast help
in photosynthesis.
4.
Ans:
Which are the organells that are found more in number in following cells?
1.Muscle cells = Mitochondria
2.white blood cells= Lysosomes
3. Leaf cells=Chloroplasts
4. Pancreatic cells= Golgi complex.
5
5.
List any four differences between a plant cell and an animal cell.
Ans:Plant cell
Animals cell
1. Cell wall is present
Cell wall is absent.
2. Plastids present
Plastids are absent
3. Mitochondria are less in number.
More mitochondria present.
4. Lysosomes absent.
Lysosomes are usually present.
5. Large central vacuole present.
Vacuole – if present are small.
6. Diagrams of 2 different cells are given below. Which one of the two is a plant cell?
Support your answer.
Ans: The first diagram is of animal cell and the second is plant cell and the second is plant
cell.
The animal cell has mitochondria and centrioles.
It has no cell wall.
The plant cell has chloroplast, vacuole and cell wall. But no mitochondria.
Sub questions:1. Name the parts 1, 2,3 and 5.
Ans: 1Golgi complex.
2. Centrioles.
6
3. Cytoplasm
4. Chloroplast.
2. Write the functions of 1 and 3.
Ans: 1.Golgi complex- Helps in secreting chemicals required for cellular activities.
2. Cytoplasm-It is the seat for most of the cellular activities. It is also the medium for all
the chemical components present in the cell.
Classification of living organisms
I.
1.
2.
3.
4.
Match the following
Familiarise
Primate
Anacardiaceae
Magnoliophyta
Species
order
family
Phylum
II.
Fill in the blanks
1.
Plants with many woody stems are called trees
2.
Animals without a backbone are called invertebrates
3.
Most of the organism depend directly or indirectly upon plants for food
4.
Group of organism that breed among themselves and products fertile off
springs make a species.
5.
The main chemical component of the cell wall is cellulose.
III.
1.
Choose the right answer:A kingdom consisting of single celled, prokaryotic organism is
a. Mycota b.Plantae
c. Monera
d. protist
2. Which one of the following is the basic unit of classification of the living
organism?
a. Family
b. genus
c. species
d .kingdom
3. Most primitive organism among the following are
a. Monera
b. fungi
c. protists
d. algae
4. Which one of the following should be grouped with whales according to modern
classification
a. shark
III.
1.
b. snake
c.dolphin
d. tortoise
Answer the following
Why are animals included under eukaryotes?
7
Ans:
Animal body is made up of cells with definite nucleus. So, they are included
under eukaryotes.
2.
In which kingdom do you include multi cellular eukaryotes , primitive,
heterotrophic organism?
Ans: Multicellular, primitive eukaryotic, heterotrophic organisms are included in
kingdom „Mycota‟.
3.
Aristotle‟s classification include both fish and whale under one group how are
these related
Ans: Fish and whale are aquatic vertebrates. But they are different in many ways.
Fish have gill respiration but whales have lung respiration. Fish are cold blooded,
whale are warm blooded. Most important fact is whales give birth to young ones and
feed them with the milk. Fish do not birth to young ones,nor do they feed them with
milk.
4.
Ans:
Place the following organism in their respective kingdoms deer , paramecium,
mushroom.
Deer –animalia
Paramecium-protista
Mushroom-mycota
5.
How can you play an important role in conserving natural resources such as
plants and animals? Explain
Ans: Natural resources are very essential for the existence of life, including human
beings. They must be considered by us.
Resources like plants and animals can be conserved by many ways.
1.We should reduce cutting trees.
2.We should plant and grow more plants.
3.Celebrate „vanamahotsava‟.
4. Protect animals by establishing wild life sanctuary.
5. Preventing hunting of animals.
6.
Ans:
Which one of the following is a prokaryote cell? Why?
b. B is the diagram of Bacterium. It is prokaryotic because it has no
nucleus.
7.
What is difference between plants and animals with regard to nutrition
8
Ans:
plant are autotrophic, prepare their own food. Animals are
heterotrophic, they depend on the food produced by the plants directly or indirectly.
The world of microbes
I.
Choose the right answer:-
1.
One of the followingdoes not belong to the group
a. Aspergillusniger
c. staphylococcus aureus
b. clostridium tetani
d. Vibrio cholera
2.
The locomotary structure ofd amoeba is
a. Cilia
c. pseudopodia
b. Flagella
d. tentacle
3.
Chlorophyll ispresent in
a. Chlamydomonas
b. Yeast
c. Mushroom
d. Aspergillus
II. Fill in the blanks
1.
2.
3.
Biogenesis was established by Louis pasteur
Malaria is caused by plasmodium vivax
Vibrio are comma shaped bacteria
III Answer the following:1.
Ans:
What are microorganisms?
The organism which are so small that they cannot be seen by naked eyes are
called micro-organisms.
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2.
Ans:
Explain the structure of typical bacillus?
The „bacillus‟ bacterium is a rod shaped body. It has an outer most layer called
cell wall. Inside this there is cell membrane enclosing the cytoplasm
.cytoplasm does nor have mitochondria and nucleus. The genetic material is
freely present in the cytoplasm. It generally has flagella to help in movement.
There is an external layer called capsule which protects it from the outside
chemicals.
3.
Draw a diagram of typical bacillus and label its parts?
4.
How can the transmission of cholera be prevented?
Ans: Cholera germs get transmitted through contaminated water and food. This can
be prevented by avoiding eating and drinking contaminated food and water. Water
should be clean, boiled before drinking. Food substances should not be kept exposed.
Vaccination is another preventive measure.
5.
What are vaccines?
Ans: Vaccines are the serum containing agent that resembles a disease causing
microorganism. It is made from weakened or killed form of microbe or toxin. It
stimulates the body‟s immune system to recognize and destroy the micro-organism or
its toxins.
Food and Its Constituents
I. Choosethe right answer:1. The major compound present in the bones is the following metal
a. Sodium
b.Iron
c. calcium d. phosphorus
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2. Children are fond of eating too much of bakery products and chocolates. Elders
advise them to eat vegetables also and not to keep aside curry leaves while eating
food items. This shows the importance of
a. carbohydrate
c. protiens
b. dietary fibers
d. lipids
3. A green leaf that has fallen from a plant is takenand is kept in water for sometime
and then taken out It is then dipped in spirit and iodine solution the leaf turns to bluish
indicating the presence of
a. Starch
b. oil
c. protein
d. fiber
II.
Fill in the blanks :-
1.
2.
3.
nitrogen
4.
the
5.
Emlusion test is conducted to detect fat and oil.
Fat soluble vitamins are A,D,E and K
Amino acids contain the elements carbon hydrogen oxygen and
The micro nutrient that is responsible for transportation of oxygen to
different parts of the body the metal iron
Biuret solution contains sodium hydroxide and copper sulphate
III Match the following
1.
2.
Haemoglobin
Vitaminc
3.
4.
vitamin A
vitamink
oxygen carrier
improves immunity
System
night blindness
clotting of blood
IV Answer the following
1.
Why should we have variety in our diet?
Ans:
Wedo not get all the essential elements from just one type of food.
Hence, we need to eat different kinds of food to get all the nutrients required for the
body.
2.
Ans:
List four major sources of carbohydrates to the people in your region.
Major sources of carbohydrates for the people of Karnataka are- rice, wheat,
jawar, ragi and potato.
3.
What food items used in your region gives lipids to the people who
consume
them?
Ans: The food items which provide lipids to the people in Karnataka are:
a) Milk, butter, ghee and edible oils.
b) Coconut, ground nut and gingelly.
11
4. List the nutritional importance of proteins.
Ans:
Proteins are involved on many functions in our body. Most important among
them are
a) Building up cells and tissues.
b) As enzymes, they help in digestion.
c) As hormones they convey messages from one part of thebody to the other.
d) Transport oxygen by haemoglobin.
e) Help in defence by producing antibodies.
f) Help in clotting of blood in a wound.
5. Why do some people suffer from nutritional deficiencies despite having enough
food?
Ans:
Some people suffer from nutritional deficiencies despite having
enough food. This may be because of the digestive disorders. Enzymes secretion for
digestion may be inadequate. Then all the food substances will nto be digested and
nutrients are not absorbed into the blood.
6. Explain the importance of water in our diet?
Ans:
Water is very essential for different functions of the body. But our
body cannot store water. Instead water is getting lost from the body
through urine, perspiration and exhaling air. Hence water should be an
essential components of our diet to replace the lost water from tissue
and maintain normal functioning.
7. A beaker contains a thick liquid, how do you test whether it is a lipid?
Ans: Take few drops of the liquid and put them on a paper. Then allow it for an hour
to dry. Then if it continues to be semitransparent the liquid is an oil(lipid). If it
becomes opaque again on drying the liquid is not a lipid.
8. What is the function of calcium in our body?
Ans: Calcium helps to build bones and teeth. It also helps in proper functioning of
muscles, heart and nerves.
a) It is essential for the clotting of blood.
b) It relives pain and cramps.
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9. Why is water essential to our body?
Ans: Water helps to maintain the health of every cell in the body. Oit is the medium
for all the chemical reactions in the cell. It keeps the blood thin to flow through the
blood vessels. It helps to eliminate the wastes and excess materials. It regulates body
temperature through sweating. It keeps the lungs, mouth and mucous membrane moist.
It helps to carry nutrients and oxygen to the cells. It helps as medium for digestion.
10. List all the major classes of ingredients that should be present in balanced
diet.
Ans: A balanced diet is the food which contains all the essential nutrients in the
required proportion. Hence the balanced diet must include proper proportion of –
Carbohydrates, proteins, lipids, vitamins, minerals, roughage and water.
11. Make a list of food items that are rich in dietary fibres?
Ans: Some food items which are rich in dietary fibres are:
a) Fruits, greens and vegetables.
b) Grains which are consumed along with peels (like green gram, green peas, Bengal
gram etc.)
REPRODUCTION IN HIGHER PLANTS
I choose the right answer:
1. Seed develops from
a. ovary
b. ovule
c. embryo
embryo sac
2. colour of night blooming flowers is usually
a. violet
b.red c.yellow
d. whitish
3. The correct sequence of reproduction stages seen in flowering plants is
a. gametes ,zygote,embryo, seedling
b.zygote,gametes,embryo, seedling
13
c.seedling ,embryo,zygote,gametes
d.gametes,embryo,zygote, seedling
5.
a.
The anther contains
Ovules
b.female gamets
c.dioliod cells
d.pollen grains
Fill in the blanks
1. Flowers with blue petals nectar and strong scent are most likely pollinated
by insects
2. Variation in the off spring is the characteristic of sexual reproduction
3. There is much wastage of pollen grains in ( wind) cross pollination.
4. Fertilization leads to the formation of zygote
I. Answer the following
1. What is reproduction?
Ans: The process by which living organisms produce another organism of their own
kind is reproduction.
2. What is sexual reproduction?
Ans:
The reproduction resulting after fusion of special cells called gametes is known
as sexual reproduction.
3. What is pollination?
Ans:
The process of transfer of pollen grains from the anther to the stigma is called
pollination
4. Are insects friends of farmers? Explain
Ans:
Many insects are friends of farmers. The insects like butterflies, moths and
bees are involved in crops pollination in many flowers. This will help increase
the yield in crop plants. Some insects like ant and dung beetles also help in
enriching the soil fertility by involvement in cutting the plant mass into small
pieces.
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5. Draw a diagram of typical flower and label the parts.
Food production: soil and water management
I.Fill in the blanks
1. Father of green revolution in India is Dr Ms. Swamynathan
2. NPK Fertilizer has the elements nitrogen, phosphorus and potassium
3. Urea which is a chemical fertilizer is rich sources of nitrogen
4. By using animal dung and organic waste wecan make an organic manner
called compost
II .match the following
1. Deep rooted plants
occasional watering
2. Plants that are not
frequent watering
deep rooted
3.Plants roots containing
do not need
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rhizobium
4. Loss of water
nitrogenous fertilizer
furrow irrigation
III Choose the right answers
1. Rhizobium bacteria is associated with the fixation of
a. oxygen
b. carbon
c. nitrogen d. water vapor
2. Green plants normally do not suffer from the deficiency of
 a.phosphorus b.sulphur
c.iron
d.carbon
3.One of the argument against too much use of chemical fertilizers is that they
a. decrease the taste of the food
b. reduce the nutrients in food
c. affect soil bacteria
d. consume too much in water
4. One of the advantage of growing chilly plants between two rows of green
gram plants is that
a. Chilly plants are protected by the shade of dhal plants
b. Chilly plants get water from green gram plants
 Nitrogenous fertilizer prepared by green gram plants can be utilized by
chilly plants
d.Dhal plants are protected from pests in the presence of chilly plants
a.
b.
c.
d.
5. Pressurised irrigation system has the advantage of
Washing away pests from the plants
Conservation of water to maximum extent 
Conservation of fertilizer in the soil
Production of hydroelectricity
III.
Answer the following :1. List any two advantages and two disadvantage of using chemical fertilizer
Ans: The advantages of using chemical fertilizers are:
1.
Include all the vital nutrients essential for the plant growth.
2.
Contain the nutrients in specific ratios I a readily usable form.
3.
Can assess the requirement by soil testing and can adjust their usage to suit the
requirement.
16
4.
Can choose the fertilizers that provides single nutrient or mixed depending on
need.
5.
Cost effective and can supply plants with proper balance of N, P, k.
The disadvantages of using chemical fertilizers are:
1.
As chemical fertilizers add several salts to the soil, some have the tendency to
accumulate and alter the soil characteristics.
2.
May harm and destroy the soil fauna.
3.
Increased use of chemical causes pollution of land and water.
4.
Water pollution caused by chemical fertilizers affects the aquatic organisms
and their habitats.
5.
Chemicals may enter into food chain and cause biomagnifications.
2. Why should farmers enhance the amount of humus in their farmland?How
do they do that?
Ans:
Humus inthe soil improves the soil structure, resists soil erosion, retains water
and enriches the nutrients and ensures increased food production. Therefore
farmers enhance the amount of humus in their farmland.
Farmers enhance the amount of humus in their farm land by the following
methods:



Ans:









Ans:
Adding fresh organic matter such as dead plants, animal material and animal
droppings.
Adding organic manure such as compost.
Soil organisms transform the organic matter into humus.
3. Distinguish between organic manures and chemical fertilizers?
Organic manures:
Manures supply both nutrients and humus to the soil.
May not provide all the nutrients in required quantity.
Farmers cannot choose according to their water holding capacity, aeration
which improves microbial activity.
Do not cause soil or water pollution.
Chemical fertilizers:
Chemical fertilizers supply only nutrients to the soil.
Provide all the nutrients in specific ratios in readily usable form.
Farmers can choose according to their requirement.
Have the tendency to accumulate and alter the soil characteristic which harms
soil fauna.
Cause soil and water pollution and effect the aquatic organisms and their
habits.
4. List some agricultural practices that help to maintain the fertility of soil
some agricultural practices that help to maintain the fertility of soil are
17
1.
Crop rotation is growing several crops one after another in a regular sequence.
2.
Rotating the crops with legumes which enhance the nitrogen content.
3.
Mixed cropping in which crops utilize soil nutrients more evenly.
4.
Keeping land unused for a season and allowing goats and sheep to graze and
set over the land so that animal droppings will enrich the soil.
5.
Adding organic manure like compost.
6.
Adding bio fertilizers like rhizobium, azolla etc.
7.
Adding chemical fertilizers according to the requirement.
Ans:
Ans:







Ans:
5.How do you prepare compost manure?
Collect and stock up the organic material in a heap inside a pit or vessel. The
decomposition is more intense in a heap and cover it with a layer of soil.
Sprinkle water over the heap to keepthe matter moist go on heaping layer after
layer until the pit is full. keep adding water after each heap. Microbes break up
the organic matter into simpler forms. Adding earthworms also enriches the
manure.
6. List any three by which soil erosion occurs state two measures to reduce the
loss of top soil
The causes for erosion are:
Deforestation.
Over grazing of animals in grass lands.
Over irrigation by gravity methods.
Unscientific use of soil.
Measures to prevent soil erosion are
Growing grass and trees so that the roots bind the soil firmly.
Ploughing at right angles in slope.
Growing crops that grow closely together greatly help in preventing soil
erosion.
7. What are the advantages of organic farming?
1. Eco friendly agricultural products which do not harm health.
2. Bio magnification due to pesticides and fungicides can be prevented.
3. Water and soil pollution can be avoided since the organic manures are bio
degradable.
4. Soil productivity can be maintained.
8. What are the advantages of pressurized irrigation systems over gravity
drivensurface irrigation systems?
Ans:
1. Pressurized irrigation systems are highly efficient irrigation practices.
2.Optimum soil moisture can be maintained throughout the day.
3. Water logging due to excessive irrigation will not happen.
4. Water conservation to the maximum extent.
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8.
Ans:
Suggest measures to consume water in agriculture
1.Match the supply of irrigation water with crops demand.
2.Irrigation does not cause surface rain off or allow water to percolate below
root zone.
3. Awareness of root saturate zone of the crop and tolerance to soil water
depletion.
4. Use pressurized irrigation system such as drip irrigation and sprinkler
irrigation.
5. Use of better crops which needs less water supply.
6. Avoid over grazing so that water percolates when it rains.
Digestion and respiration
i.
Choose the right answer
1.
a.
The process of obtaining food and utilizing it in the body is
Respiration b. nutrition c. excretion d. reproduction
2.
a.
One of these is a product of photosynthesis
Starch b. glucose
c.maltose
d. sucrose
3.
a.
Insectivorous plants commonly grow in areas where soil is deficient in
Carbon b. nitrogen c. potassium d. phosphorus
4.
A person applies hydrogen peroxide on his wound this is to kill
Anaerobic bacteria
d. protozoa
5.
a.
Amylase converts starch to
Glucose
b.sucrose
b. aerobic bacteria
c. lactose
II.Answer the following
1.What are life processes?
19
c. fungi
d.maltose
Ans:
Different life activities nutrition, respiration, growth,movement, response to
stimuli, excretion and reproduction which are essential for living beings to
survive are called life processes.
2. Explain the method of testing a leaf for starch?
Ans:
A green leaf is kept in water for an hour and then dipped in spirit. After that
few drops of iodine are put on the leaf. If the leaf turns bluish it indicates the
presence of starch.
3. Explain an experiment to demonstrate that oxygen is released during
photosynthesis.
Ans:
Purpose of the experiment: To show that oxygen is released during
photosynthesis.
Materials required: Two troughs, crystals of sodium bicarbonate,
hydrilla(aquatic submerged plants), pieces of steel wool, water, two test tubes
and two glass funnels.
Methods: Fill both the troughs with water and add few crystals of sodium
bicarbonate. Place the hydrilla plants inside water and invert the funnels over
them. Place pieces of steel wool in the bottom of test tubes, fill them with the
water, and invert them over the narrow ends of the funnels. Place one of the
troughs in a bright sunny area and theother inside a dark room or cupboard for
about 48 hours.
Observation: The trough which is kept in sunlight shows accumulation of gas
in the test tube and the steel wool turns black. The trough which is kept in the
dark room doesn‟t show this change.
Inference: Oxygen is not release d in the trough kept in the dark because
photosynthesis does not take place.
4.Differentiate between the two phases of photosynthesis.
Ans:- Light dependent reaction :
1) Takes placeonly in the presence of sunlight.
2) Takes place in grana region of chloroplast.
3)water is decomposed to hydroxyl and hydrogen ions.
Dark reaction:
1) Takes place in the presence or absence of sunlight.
2) Take place in stroma region of chloroplast.
3) Carbon dioxide is reduced to starch.
5.What are parasites? Give 2 examples.
Ans:- The organisms which obtain nutrition from other organisms directly, but are of
no use to the host are parasites eg:-Tapeworm- Parasite inside the stomach.
Mosquito- External parasite.
6.
Amoeba cannot digest fats. Why?
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Ans:
The amoeba cell has lysosomes containing the enzyme amylase and protease to
digest carbohydrates and protein. But they do not have fat digesting enzymes.
Hence amoeba cannot digest fats.
7.
Explain respiration in cockroach?
Ans:-
Cockroach respires through tracheal system. The tracheal system includes the
stigmata or spiracles, trachea and tracheoles.
Stigmata are the ten pairs of respiratory openings which are present on lateral
side of the body. Trachea and tracheoles are the narrow tubes spread in the
body.
Air enters through the stigmata and carried through the trachea spread in the
body. From the air, oxygen diffuses into the blood to the air in trachea- and
passes out through the stigmata.
8.
Explain the respiration in human beings.
Ans:- Human respiratory system includes nose, pharynx trachea, bronchi and lungs.
Lungs consist the bronchioles and alveoli. Alveoli are surrounded by blood
capillaries.
Air passes through the nose to pharynx, trachea into bronchi and bronchioles
and enters into the air sacs called alveoli in the lungs.
Blood flowing in the capillaries around the alveoli collects oxygen from and give
carbon dioxide, to the alveoli.
Oxygenated blood reaches the cell, gives oxygen to the cell, where it is used to
oxidize glucose to release energy. Carbon dioxide released during energy
release is carried through the blood to the lungs.
9.
Draw a diagram of human digestive system and label the parts
Ans:
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Evolution of life
Choose the right answer :1.The term not dilute soup was used by
a.oparim
b.darwin
c.haldane
d.pasteaur
2.Which gas was absent in the atmosphere at the time of origin of life?
a.ammonia
b.hydrogen
c. oxygen
d.methane
3. The 1st organism on primitive earth were
a. autotrophic b. heterotrophic and anaerobic
c.parastic
d.prokaryotic&autophic
4. The greatest weakness in darwins theory was his failure to explain
a.over production
b.survival of the fittest
c.struggle for existence
d.variations
II.Fill in the blanks
1.
2.
earth
3.
Earth was hot revolving ball of gas about 4.8 billions of years ago
Lightest element hydrogen was found in the outer most layer of the earliest
Variations caused by sudden genetic changes are called mutation
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4.
Darwins explained the survival of the fittest,but not their arrival
III. Match the following:1.
2.
3.
4.
Lamarck
theory of inheritance of acquireCharacters
Darwin
theory of natural selection
Hugo devries
mutation theory
Oparin
theory of chemical evolution
IV.Answer the following
1.What is organic evolution?
Ans:
The slow and gradual process by which living organisms have undergone
changes from the single celled forms to the many celled forms of life is known
as organic evolution.
2.Explain Lamarck‟s theory of use and tissue of organs with suitable example
Ans:
Lamarck‟s theory is on three main ideas, use and disuse of organs and
inheritance of acquired characters. The appearance of new needs forces the
organism to put in additional efforts to fulfill. Thus by a differential over use
and disuse of various body parts, an organism would change to some extent
and acquire new characters.
For example :- For over use : Giraffe‟s ancestors were small as deer. Giraffes
started stretching their neck and forelimbs in order to reach the leaves of taller
plants due to the serve competition from other herbivores and drought. This
continued for generations and as a result neck and forelimbs became longer.
Example for disuse: The ancestors of snake had four well developed limbs.
Snakes were hunted by more advanced group of animals. In order to survive
they started crawling on the ground and spent most of their time hiding in
crevices and holes. This resulted in the limbs becoming degenerate and
ultimately disappears.
3.What is the role of variations in evolution?
Ans:
He found that generally the young ones of an organism show differences
compared to the parents he described the differences in variation. It is the rule
of nature. They help an organism to adjust better to the environment.
4.What is Mutation?
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Ans:
Sudden changes to the genetic makeup of an organism when it is subjected to
higher environmental temperature or high energy radiation is called as
mutation.
5.What is neo Darwinism?
Ans:
Neo Darwinism is the modern theory on organic evolution, the synthesis of
ideas from the theory of natural selection and mutation theory in the light if
present knowledge on how mutation occur.
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