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SYLLABUSSCIENCE (CLASS - VII)
Questions Key Concepts Resources Activities/Processes
1. Food (Periods - 22)
Food from where
How do plants get their food?
Autotrophic and heterotrophic nutrition; parasites, saprophytes; photo synthesis.
Coleus or any other plant with variegated leaves, alcohol, iodine solution, kit materials.
Need for light, green leaf for photosynthesis, looking at any saprophyte/parasite and noting differences from a green plant.
Utilisation of food
How do plants and animals utilise their food?
Types of nutrition, nutrition in amoeba and human beings, Digestive system – human, ruminants; types of teeth; link with transport and respiration.
Model of human teeth, charts of alimentary canal, types of nutrition etc., chart and model of amoeba. The story of the stomach with a hole.
Effect of saliva on starch, permanent slide of Amoeba.Role play with children.
2. Materials (Periods - 38)
Materials of daily use
Do some of our clothes come from animal sources?
Which are these animals? Who rears them?
Which parts of the animals yield the yarn? How is the yarn extracted?
What kinds of clothes help us to keep warm?
What is heat? What is the meaning of
‘cool’/‘cold’ and ‘warm’/ ‘hot’?
Howdoesheatflowfrom/to our body to/from the surroundings?
Wool,silk–animalfibres.
Process of extraction of silk; associated health problems.
Heatflow;temperature.
Samples of wool and silk; brief account of silkworm rearing and sheep breeding.
Potassium per manganate, metal strip or rod, wax, common pins, spirit lamp, matches, tumblers, thermometer etc.
Collection of different samples of woollen and silk cloth. Activities to differentiate naturalsilkandwoolfromartificialfibres.
Discussion.
Experiment to show that ‘hot’ and ‘cold’ are relative.Experiments to show conduction, convection and radiation.Reading a thermometer.
Different kinds of materials
Why does turmeric stain become red on applying soap?
Classificationofsubstancesinto acidic, basic and neutral; indicators.
Common substances like sugar, salt, vinegar, etc., test tubes, plastic vials, droppers, etc.
Testing solutions of common substances like sugar, salt, vinegar, lime juice etc. with turmeric, litmus, china rose.Activity to show neutralisation.
How things change/react with one another
What gets deposited on a tawa/khurpi/kudal if left in a moist state?
Why does the exposed surface of a cut brinjal become black?
Why is seawater salty? Is it possible to separate salt from seawater?
Chemical substances; in a chemical reaction a new substance is formed.
Substances can be separated by crystallization.
Test tubes, droppers, common pins, vinegar, baking powder, CuSO4, etc.
Urea, copper sulphate, alum etc, beaker, spirit lamp, watch glass, plate, petridish etc.
Experiments involving chemical reactions like rusting of iron, neutralisation (vinegar and baking soda), displacement of Cu from CuSO4 etc.Introduce chemical formulae without explaining them.
Making crystals of easily available substances like urea, alum, copper sulphate etc. using supersaturated solutions and evaporation.
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Questions Key Concepts Resources Activities/Processes
3. The World of the Living (Periods - 42)
Surroundings affect the living
Why are nights cooler? How does having winters and summers affect soil? Are all soils similar? Can we make a pot with sand? Is soil similar when you dig into the ground? What happens to water when it falls on the cemented/bare ground?
Climate, soil types, soil profile,absorption of water in soil, suitability for crops, adaptation of animals to different climates.
Data on earth, sun–size, distance etc, daily changes in temperature, humidity from the newspaper, sunrise, sunset etc.
Graph for daily changes in temperature, day length, humidity etc.; texture of various soils by wetting and rolling; absorption/percolation of water in different soils, which soil can hold more water.
The breath of life
Why do we/animals breathe?
Do plants also breathe? Do they also respire? How do plants/animals live in water?
Respiration in plants and animals. Lime water, germinating seeds, kit materials.
Experiment to show plants and animals respire; rate of breathing; what do we breathe out? What do plants ‘breathe’ out? Respiration in seeds; heat release due to respiration. Anaerobic respiration, root respiration.
Movement of substances
How does water move in plants? How is food transported in plants?
Why do animals drink water? Why do we sweat? Why and how is there blood in all parts of the body? Why is blood red? Do all animals have blood? What is there in urine?
Herbs, shrubs, trees; Transport of food and water in plants; circulatory and excretion system in animals; sweating.
Tw ig , s t a i n ; improv i sed stethoscope; plastic bags, plants, egg, sugar, salt, starch, Benedicts solution, AgNO3 solution.
Trans loca t ion o f water i n s tems , demonstration of transpiration, measurement of pulse rate, heartbeat; after exercise etc.
Discuss ion on dia lys is , importance; experiment on dialysis using egg membrane.
Multiplication in plants
Why are some plant parts like potato, onion swollen – are they of any use to the plants?
What is the function of flowers? How are fruits and seeds formed? How are they dispersed?
Vege t a t i ve , a sexua l and s e x u a l r e p r o d u c t i o n i n plants, poll ination – cross, self pollination; pollinators, fertilization, fruit, seed.
Bryophyllum leaves, potato, onion etc.; yeast powder, sugar.
Study of tuber, corm, bulb etc; budding in yeast; T.S./L.S. ovaries, w.m. pollen grains; comparison of wind pollinated and insect pollinatedflowers;observingfruitandseeddevelopment in some plants; collection and discussion of fruits/seeds dispersed by different means.
4. Moving Things, People and Ideas (Periods - 16)
Moving objects
Why do people feel the need to measure time?
How do we know how fast something is moving?
Appreciation of idea of time and need to measure i t . Measurement of time, using periodic events.Idea of speed of moving objects–slow and fast motion along a straight line.
Daily-life experience; metre scale, wrist watch/stop watch, string etc.
Observing and analysing motion (slow or fast) of common objects on land, in air, water and space.
Measuring the distance covered by objects moving on a road in a given time and calculating their speeds. Plotting distance vs. time graphs for uniform motion. Measuring the time taken by moving objects to cover a given distance and calculating their speeds. Constancy of time period of a pendulum.
5. How things work (Periods - 14)
Electric current and circuits
How can we conveniently represent an e lectr ic circuit?
Why does a bulb get hot?
Electric circuit symbols for different elements of circuit.
Heating effect of current.
Recollection of earlier activities. Pencil and paper.
Cells, wire, bulb.
Drawing circuit diagrams.
Activities to show the heating effect of electric current.
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Questions Key Concepts Resources Activities/Processes
How does a fuse work?
How does the current in a wire affect the direction of a compass needle?
What is an electromagnet?
How does an electric bell work?
Principle of fuse.
A current-carrying wire has an effect on a magnet.
A current-carrying coil behaves like a magnet.
Working of an electric bell.
Cells , wire, bulb or LED, aluminium foil.
Wire, compass, battery.
Coil, battery, iron nail.
Electric bell.
Making a fuse.
Activity to show that a current-carrying wire has an effect on a magnet.
Making a simple electromagnet.Identifying situations in daily life where electromagnets are used.
Demonstration of working of an electric bell.
6. Natural Phenomena (Periods - 24)
Rain, thunder and lightning What causes storms? What
are the effects of storms? Why are roofs blown off ?
High-speed winds and heavy r a i n f a l l h a ve d i s a s t r ou s consequences for human and other life.
Exper ience ; news-paper reports. Narrativess stories.
Making wind speed and wind direction indicators. Activity to show “lift” due to moving air.Discussion on effects of storms and possible safety measures.
Light Can we see a source of
light through a bent tube? How can we throw sulight
on a wall?
What things give images that are magnif ied or diminished in size?
How can we make a coloured disc appear white?
Rectilinear propagation of light.
Reflection, certain surfaces reflectlight.
Real and virtual images.
White light is composed of many colours.
Rubber/plastic tube/straw, any source of light.Glass/metal sheet/metal foil, white paper.
Convex/concave lenses and mirrors.
Newton’s disc.
Observation of the source of light through a straight tube, a bent tube.Observingreflectionoflightonwallorwhitepaper screen.
Open ended activities allowing children to explore images made by different objects, and recording observations. Focussed discussions on real and virtual images.Making the disc and rotating it.
7. Natural Resources (Periods - 24) Scarcity of water Where and how do you
get water for your domestic needs? Is it enough? Is there enough water for agricultural needs? What happens to plants when there is not enough water for plants? Where does a plant go when it dies?
Water exists in various forms in nature.Scarcity of water and its effect on life.
Experience; media reports; case material.
Discussions.Case study of people living in conditions of extreme scarcity of water, how they use water in a judicious way.Projects exploring various kinds of water resources that exist in nature in different regions in India; variations of water availability in different regions.
Forest products What are the products we
get from forests? Do other animals also benefit fromforests? What will happen if forests disappear?
Interdependence of plants and animals in forests. Forests contributetopurificationofairand water.
Case material on forests. Case study of forests.
Waste Management Where does dirty water
from your house go? Have you seen a drain? Does the water stand in it sometimes? Does this have any harmful effect?
Sewage; need for drainage / sewer systems that are closed.
Observation and experience; photographs.
Survey of the neighbourhood, identifying locations with open drains, stagnant water, and possible contamination of ground water by sewage. Tracing the route of sewage in your building, and trying to understand whether there are any problems in sewage disposal.
Prelims_7.indd 5 11/23/2015 12:58:27 PM
1
Nutrition in Plants
1
Unit: Food
CHAPTER IN A NUTSHELL
IMPORTANT TERMS AND DEFINITIONS
All living organisms require food for energy, growth and repair of damaged tissues.
The process of consuming or providing food and its utilisation by the body is called nutrition.
Nutrition can be classified into two types: autotrophic and heterotrophic nutrition.
The mode of nutrition by which green plants make their own food from simple substances is called
autotrophic nutrition (‘auto’ means ‘self’ and ‘troph’ means ‘nourishment’).
Green plants prepare their own food using carbon dioxide and water in the presence of chlorophyll
and sunlight. This process is called photosynthesis and the green plants are known as autotrophs.
Animals and non-green plants depend directly or indirectly on green plants for their food. This
mode of nutrition is known as heterotrophic nutrition. (‘hetero’ means ‘other’, and ‘troph’ means
‘nourishment’). Such animals and plants are known as heterotrophs.
Heterotrophic plants are of four kinds: parasitic, saprophytic, insectivorous and symbiotic plants.
A parasite is an organism, which lives inside or on another organism (host) and derives nutrition
from its host.
Plants which derive their nutrition from dead or decaying organic matter are called saprophytes.
The condition of living together for mutual benefits such as sharing shelter and nutrients is called
symbiosis.
Symbiotic association of Rhizobium bacteria and leguminous plants is a natural way of replenishing
nitrogen in the soil.
Nutrients: Components of food—carbohydrates, proteins, fats, vitamins and minerals that are
necessary for our body are called nutrients.
Cell: The basic structural and functional unit of all living organisms is known as the cell.
Cell membrane: The thin outer boundary, which encloses a cell and is selectively permeable in
nature is known as the cell membrane.
Nucleus: A spherical structure usually located in the centre of a cell and containing the genetic material
is known as the nucleus.
CONCEPTS
1.1 Types of Nutrition
1.2 Autotrophic Nutrition
1.3 Heterotrophic Nutrition
1.4 Replenishing Nutrients
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Super RefresherAll chapters as per NCERTSyllabus and Textbook
Every chapter divided into Sub-topics
Chapter in a Nutshell and Important Terms and Definitions provide a complete and comprehensive summary of the chapter
Highlights essential information which must be remembered
MBD Super Refresher Science - VII
2
1.1 Types of NutritionWe get nutrition from the food we eat. There are two modes of nutrition: autotrophic and heterotrophic
nutrition. Green plants, which prepare their own food, are known as autotrophs. All the other organisms
that depend on green plants for their food are known as heterotrophs. Objective Type Questions 1 mark each
A. State whether the following statements are true or false. 1. Food provides nutrition for energy, growth and repair of damaged tissues.
2. All plants are autotrophs.3. Substances which provide nourishment to living organisms are known as nutrients.
4. An organism that can make its own food from simple, non-living substances is known as a
heterotroph.5. There are two modes of nutrition: autotrophic and heterotrophic nutrition.
Answers: 1. True 2. False 3. True 4. False 5. TrueShort Answer Type Questions
2–3 marks each
A. Differentiate between autotrophs and heterotrophs.Autotrophs
Heterotrophs
They are the organisms, which can make their own food.
These are the organisms, which cannot make their own food.They prepare their food from carbon dioxide and water in the presence of sunlight and chlorophyll.
These organisms depend directly or indirectly on autotrophs for their food.
All green plants are autotrophs.All animals and non-green plants are heterotrophs.1.2 Autotrophic NutritionThe mode of nutrition by which green plants make their own food from simple substances is called autotrophic
nutrition (‘auto’ means ‘self’ and ‘troph’ means ‘nourishment’). Green plants prepare their own food by the
process of photosynthesis. A green pigment called chlorophyll present in the leaves of green plants traps
sunlight. Plants take in carbon dioxide from air and water and nutrients from the soil. They convert carbon
dioxide and water into carbohydrates and oxygen. Carbohydrates form the food for plants and oxygen is
released into the air.
Carbon dioxide + Water
→Sunlight
Chlorophyll Carbohydrate + OxygenExchange of gases takes place through tiny pores called stomata, which are present on the surface of leaves.
Guard cells surround the stomata and help in opening and closing them.
Cytoplasm: A jelly-like substance present inside the cell is called the cytoplasm.
Stomata: Tiny pores present on the under surface of leaves through which exchange of gases take
place are called stomata.
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Nutrition in Plants
3
(a) Leaf
Stomata
Guard cells
Stomatal opening
Desert plants like Opuntia has thorn-like leaves but their stems are green and fleshy. Instead of the leaves,
these stems carry out photosynthesis. Certain plants can synthesise nutrients such as proteins and fats along
with carbohydrates by absorbing nitrogen present in the soil.
NCERT Activity 1 – Pages 3 – 4
Aim: To show that sunlight is necessary for photosynthesis
Procedure: 1. Take two identical, healthy potted plants.
2. Place one plant in a place, which does not receive any sunlight.
3. Place the other plant in a place, where it will receive sunlight.
4. Water both plants every day.
5. On the fourth day, using the iodine test, test the leaves of both the plants for the presence
of starch.
6. Record your observations.
Observation: The leaf of the plant kept in the sunlight turned blue-black, whereas the leaf of the plant
kept in the dark did not show any change.
Conclusion: Starch is present only in the leaf of the plant kept in the sunlight. This shows that sunlight
is necessary for photosynthesis.
Objective Type Questions
1 mark each
A. State whether the following statements are true or false.
1. Tiny pores present on the surface of leaves are known as guard cells.
2. Sunlight is necessary for photosynthesis to take place.
3. Oxygen formed during photosynthesis is released into the air.
Answers: 1. False 2. True 3. True
B. Fill in the blanks.
1. Green plants require _________, _________ and _________ for photosynthesis.
2. Plants take in carbon dioxide through _________ present on their leaves.
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Important Questions fromexamination point of viewto ensure passing marks
Each sub-topic dealt with as a complete unit
Includes NCERT Textbook Activities and Exercises with answers
MBD Super Refresher Science - VII
6
1.4 Replenishing NutrientsPlants absorb nutrition from the soil. Farmers add manure and fertilisers to the soil to replenish its
nutrients.. Fertilisers are rich in potassium, nitrogen and phosphorous. Rhizobium, a bacterium, helps plants
by fixing atmospheric nitrogen into the soil. It lives in the root nodules of leguminous plants such as peas
and beans.
Objective Type Questions 1 mark each
A. Fill in the blanks.1. _________ and _________ are leguminous plants.2. The main nutrients provided by fertilisers are _________, _________ and _________.
3. Farmers add _________ and _________ to the soil.4. _________ bacterium fix atmospheric nitrogen into the soil.Answers: 1. Peas, beans 2. Nitrogen, potassium, phosphorous 3. Manure, fertilisers
4. RhizobiumShort Answer Type Questions
2–3 marks each
A. Why are nitrogenous fertilisers not added to the soil in which leguminous plants grow?
A bacterium known as Rhizobium lives in the root nodules of leguminous plants. These bacteria
convert atmospheric nitrogen into soluble form and fix nitrogen into the soil. They make the soil rich
in nitrogen and hence, nitrogenous fertilisers are not required. NCERT TEXTBOOK EXERCISES 1. Why do organisms need to take food?Organisms need food to grow, repair damaged body parts, get energy for doing physical work and
protect themselves from diseases. 2. Distinguish between a parasite and a saprophyte.Differences between a parasite and a saprophyte are:Parasites
Saprophytes
Parasites depend on other living organisms for thier food.They live on or inside the body of other organism called the host.
Saprophytes obtain their food from dead and decaying matter.They do not live on or inside the body of other organisms.
They have special organs such as suckers. They secrete enzymes to decompose complex molecules into simpler forms.
Examples of parasites include Cuscuta, tapeworms, roundworms, etc. Examples of saprophytes include fungi, bacteria,
mushrooms, etc. 3. How would you test the presence of starch in leaves?
Steps to test the presence of starch in leaves:(a) Take a green leaf and boil it in water for 5–6 minutes.(b) Now place it in warm alcohol for some time. This will remove the green pigment.
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Nutrition in Animals
21
D. Fill in the blanks.
1 mark each
1. Fatty acids and glycerol are the structural units of ________.
2. ________ is the approximate length of the large intestine in human beings.
3. Pancreas is a _______ coloured gland situated below the ________.
4. The process by which absorbed food is transported to different organs to form complex substances
is called ___________.5. The four front teeth are known as ________.
Answers: 1. Fats 2. 1.5 metre 3. Cream, stomach 4. Assimilation 5. Incisors
E.Whatisdiarrhoea?Howisitcaused?Howcanitbetreated?
3markseach
Diarrhoea is a condition in which a person passes watery stools frequently. It may be caused by intake
of unhygienic food and water, which may cause food poisoning or indigestion. This may also result in
excessive loss of water and salts from the body, which can even lead to death. It can be treated by
taking Oral Rehydration Solution (ORS). ORS is a mixture of water, sugar and a pinch of salt.
SELF ASSESSMENT A. Fill in the blanks.1. Nutrients absorbed in the process of digestion are ____________________ in the body.
2. Saliva breaks down the starch into ________.
3. The food in Amoeba is trapped in the ________.
4. Liver secretes ________ that is stored in ________.
B. State whether the following statements are true or false.
1. The total number of canines in human beings are 6.
2 Proteins get converted into amino acids during digestion.
3. Rectum is the last part of the small intestine.
4. Stomach is a J-shaped muscular bag.5. The number of milk teeth in human beings are 20.
6. The undigested solid waste is stored in the anus.
C. Multiple Choice Questions.1. The digestive juice secreted by the pancreas will act on which of the following components?
a) Fats b) Proteins
c) Carbohydrates d) All of these
2. What is the total number of permanent teeth in an adult human being?
a) 28 b) 30
c) 32 d) 20
3. Which of the following animals can digest cellulose?
a) Human beings b) Dogs c) Buffaloes
d) Monkeys
4. In which of the following organisms would you find food vacuoles?
a) Human beings b) Hydra c) Amoeba
d) Cows
D. Short Answer Type Questions. 1. Name all the digestive glands in human beings.
2. What are the functions of pseudopodia in Amoeba?
Untitled-4 21
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220
Term-1
Model Test Paper – 1
Duration – 1.5 hrClass VII
Maximum Marks – 90
-_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
SECTION A
A. Multiple Choice Questions.
1 × 20 = 20
1. Insectivorous
plantstrapinsects
tofulfiltherequir
ementofwhicho
fthefollowingmin
erals?
a) Nitrogen
b) Oxygen
c) Potassium
d) Phosphorus
2. Whichofthefollowin
gdoesnotsecrete
digestivejuices?
a) Oesophagus
b) Stomach
c) Smallintestine
d) Allofthese
3. Whichfibreisagood
insulator?
a) Woolb) Silk
c) Nylon
d) Cotton
4. Whatistheprimary
modeofheattran
sferinliquids?
a) Conduction
b) Convection
c) Radiation
d) Allofthese
5. Whatistheeffectof
acidsonbluelitm
uspaper?
a) Itturnsred
b) Itturnsgreen
c) Itturnsblack
d) Itturnsyellow
6. Throughwhic
hofthefollowing
processescrystals
ofapuresubstan
ceareobtained?
a) Galvanisation
b) Precipitation
c) Crystallisation
d) Noneofthese
7. Whichzoneliesarou
ndtheequator?
a) Frigidzone
b) Torridzone
c) Temperatezo
ne d)Allofthe
se
8. Whichmethodisus
edtopreventsoil
erosion?
a) Buildingdams
b) Afforestation
c) Terracefarmin
g d) Allofthese
9. Whatisthesitefore
xchangeofgases
inhumanbeings?
a) Skinb) Bron
chusc) Trach
ead) Alveo
li
10.Whichofthefollowin
gelementwillbe
mostaffectedbya
irandmoisture?
a) Chromium
b) Copper
c) Iron
d) Zinc
11.Whichliquidisagoo
dconductorofhe
at?
a) Waterb) Oil
c) Mercury
d) Alcohol
12.Whatiswashingofs
hearedfleececalle
d?
a) Shearing
b) Grading
c) Scouring
d) Dyeing
13.Whichisthelargest
chamberofthest
omachofarumin
ant?
a) Rumen
b) Reticulum
c) Omasum
d) Abomasum
14.Inwhichparto
fthedigestivesyst
emdigestiondoes
nottakeplace?
a) Mouth
b) Stomach
c) Smallintestine
d) Largeintestine
15.Whataretheendpro
ductsofphotosyn
thesis?
a) Carbondioxid
eandglucose
b) Oxygenandg
lucose
c) Oxygenandc
arbondioxide
d) Starchandcar
bondioxide
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MBD Super Refresher Science - VII
20
13. Canwesurv
iveonlyonraw,lea
fyvegetables/gras
s?Discuss.
Raw, leafy vegetables are a rich source of minerals, cellulose, water and vitamins. But besides these, our
body needs a balanced diet which also includes carbohydrates, proteins and fats. Therefore, survival on
only raw, leafy vegetables is not possible.
HOTS CORNER
A.Whatcausescougho
rchokingsensatio
nwhilehavingfoo
dinahurry?
The windpipe and the food pipe share a common passage inside the throat. When the food is
swallowed, a small flap closes the windpipe. This prevents the food from entering into it. However,
if you laugh or talk while eating or eat in a hurry, food particles may enter the windpipe. This causes
cough or a choking sensation.
B. The inner lining of the stomach releases hydrochloric acid that kills many bacteria which come
alongwiththefoo
d.Canthisacidca
usedamagetothe
stomachwall?
Stomach also secretes mucous along with hydrochloric acid and digestive juices. The mucous protects
the inner lining of the stomach from the acid. However, sometimes the acid does attack the inner
lining of the stomach and damages it. If it is not treated, it may cause ulcers in the stomach.
PRACTICE EXERCISE
Maximum Marks–20
A. Circle the odd one out:
1 mark each
1. Ingestion, digestion, absorption, food vacuole, assimilation
2. Mosquito, housefly, butterfly, Amoeba
3. Molars, milk teeth, premolars, canines, incisors
4. Stomach, gall bladder, small intestine, liver
5. Cow, sheep, deer, cat
Answers: 1. Food vacuole 2. Amoeba 3. Milk teeth 4. Gall bladder 5. Cat
B. Give one word for each of the following.
1 mark each
1. Name the gland that secretes insulin.
2. Name the organ that stores undigested food.
3. Name the organ of locomotion in Amoeba.
4. Name the part of the stomach in ruminants that stores cud.
5. Name one animal that swallows its whole food.
6. Name one animal that sucks its food.
Answers: 1. Pancreas 2. Rectum 3. Pseudopodia 4. Rumen 5. Snake
6. Mosquito/butterfly
C. State whether the following statements are true or false.
1 mark each
1. The small intestine is highly colied and is about 7.5 m in length.
2. Liver is the largest gland in our body.
Answers: 1. False 2. True
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Science
Variety of Objective Type, Value-Based and HOTS, questions with answers in every chapter
Self Assessment at the end of each chapter
Four Model Test Papersof 90 marks each (two per term)
Practice Exercise equaling 20 marks for every chapter
Prelims_7.indd 7 11/24/2015 3:07:46 PM
1 Nutrition in Plants 1–10
2 Nutrition in Animals 11–22
3 Fibre to Fabric 23–31
4 Heat 32–44
5 Acids, Bases and Salts 45–55
6 Physical and Chemical Changes 56–66
7 Weather, Climate and Adaptations of Animals to Climate 67–75
8 Winds, Storms and Cyclones 76–87
9 Soil 88–100
10 Respiration in Organisms 101–111
11 Transportation in Animals and Plants 112–122
12 Reproduction in Plants 123–133
13 Motion and Time 134–150
14 Electric Current and its Effects 151–164
15 Light 165–177
16 Water: A Precious Resource 178–186
17 Forests: Our Lifeline 187–197
18 Wastewater Story 198–208
Answers for Self Assessments 209–219 Model Test Papers (1–2) 220–230
CONTENTS
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1
Nutrition in Plants1Unit: Food
CHAPTER IN A NUTSHELL
IMPORTANT TERMS AND DEFINITIONS
All living organisms require food for energy, growth and repair of damaged tissues. The process of consuming or providing food and its utilisation by the body is called nutrition. Nutrition can be classified into two types: autotrophic and heterotrophic nutrition. The mode of nutrition by which green plants make their own food from simple substances is called
autotrophic nutrition (‘auto’ means ‘self’ and ‘troph’ means ‘nourishment’). Green plants prepare their own food using carbon dioxide and water in the presence of chlorophyll
and sunlight. This process is called photosynthesis and the green plants are known as autotrophs. Animals and non-green plants depend directly or indirectly on green plants for their food. This
mode of nutrition is known as heterotrophic nutrition. (‘hetero’ means ‘other’, and ‘troph’ means ‘nourishment’). Such animals and plants are known as heterotrophs.
Heterotrophic plants are of four kinds: parasitic, saprophytic, insectivorous and symbiotic plants. A parasite is an organism, which lives inside or on another organism (host) and derives nutrition
from its host. Plants which derive their nutrition from dead or decaying organic matter are called saprophytes. The condition of living together for mutual benefits such as sharing shelter and nutrients is called
symbiosis. Symbiotic association of Rhizobium bacteria and leguminous plants is a natural way of replenishing
nitrogen in the soil.
Nutrients: Components of food—carbohydrates, proteins, fats, vitamins and minerals that are necessary for our body are called nutrients.Cell: The basic structural and functional unit of all living organisms is known as the cell.Cell membrane: The thin outer boundary, which encloses a cell and is selectively permeable in nature is known as the cell membrane.Nucleus: A spherical structure usually located in the centre of a cell and containing the genetic material is known as the nucleus.
CONCEPTS
1.1 Types of Nutrition1.2 Autotrophic Nutrition1.3 Heterotrophic Nutrition1.4 Replenishing Nutrients
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MBD Super Refresher Science - VII2
1.1 Types of Nutrition
We get nutrition from the food we eat. There are two modes of nutrition: autotrophic and heterotrophic nutrition. Green plants, which prepare their own food, are known as autotrophs. All the other organisms that depend on green plants for their food are known as heterotrophs.
Objective Type Questions 1 mark each A. State whether the following statements are true or false.
1. Food provides nutrition for energy, growth and repair of damaged tissues.2. All plants are autotrophs.3. Substances which provide nourishment to living organisms are known as nutrients.4. An organism that can make its own food from simple, non-living substances is known as a
heterotroph.5. There are two modes of nutrition: autotrophic and heterotrophic nutrition.Answers: 1. True 2. False 3. True 4. False 5. True
Short Answer Type Questions 2–3 marks each
A. Differentiate between autotrophs and heterotrophs.
Autotrophs HeterotrophsThey are the organisms, which can make their own food.
These are the organisms, which cannot make their own food.
They prepare their food from carbon dioxide and water in the presence of sunlight and chlorophyll.
These organisms depend directly or indirectly on autotrophs for their food.
All green plants are autotrophs. All animals and non-green plants are heterotrophs.
1.2 Autotrophic NutritionThe mode of nutrition by which green plants make their own food from simple substances is called autotrophic nutrition (‘auto’ means ‘self’ and ‘troph’ means ‘nourishment’). Green plants prepare their own food by the process of photosynthesis. A green pigment called chlorophyll present in the leaves of green plants traps sunlight. Plants take in carbon dioxide from air and water and nutrients from the soil. They convert carbon dioxide and water into carbohydrates and oxygen. Carbohydrates form the food for plants and oxygen is released into the air.
Carbon dioxide + Water
→SunlightChlorophyll Carbohydrate + Oxygen
Exchange of gases takes place through tiny pores called stomata, which are present on the surface of leaves. Guard cells surround the stomata and help in opening and closing them.
Cytoplasm: A jelly-like substance present inside the cell is called the cytoplasm.Stomata: Tiny pores present on the under surface of leaves through which exchange of gases take place are called stomata.
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Nutrition in Plants 3
(a) Leaf
Stomata
Guard cells
Stomatal opening
Desert plants like Opuntia has thorn-like leaves but their stems are green and fleshy. Instead of the leaves, these stems carry out photosynthesis. Certain plants can synthesise nutrients such as proteins and fats along with carbohydrates by absorbing nitrogen present in the soil.
NCERT Activity 1 – Pages 3 – 4
Aim: To show that sunlight is necessary for photosynthesisProcedure:
1. Take two identical, healthy potted plants.2. Place one plant in a place, which does not receive any sunlight. 3. Place the other plant in a place, where it will receive sunlight.4. Water both plants every day.5. On the fourth day, using the iodine test, test the leaves of both the plants for the presence
of starch.6. Record your observations.
Observation: The leaf of the plant kept in the sunlight turned blue-black, whereas the leaf of the plant kept in the dark did not show any change.Conclusion: Starch is present only in the leaf of the plant kept in the sunlight. This shows that sunlight is necessary for photosynthesis.
Objective Type Questions 1 mark each
A. State whether the following statements are true or false. 1. Tiny pores present on the surface of leaves are known as guard cells.2. Sunlight is necessary for photosynthesis to take place.3. Oxygen formed during photosynthesis is released into the air.Answers: 1. False 2. True 3. True
B. Fill in the blanks.1. Green plants require _________, _________ and _________ for photosynthesis.
2. Plants take in carbon dioxide through _________ present on their leaves.
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MBD Super Refresher Science - VII4
3. A green pigment called _________ is present in the leaves of green plants.Answers: 1. Carbon dioxide, water, sunlight 2. Stomata 3. Chlorophyll
C. Multiple Choice Questions.1. In which plants does photosynthesis occur? a) All plants b) All green plants c) Only desert plants d) Only water plants2. Which of the following pigments is found in green plants? a) Haemoglobin b) Myoglobin c) Xanthophyll d) Chlorophyll 3. What are the end products of photosynthesis? a) Oxygen and carbonhydrate b) Oxygen and carbon dioxide c) Carbon dioxide and glucose d) Starch and carbon dioxide4. Which of the following components can be synthesised by plants? a) Carbohydrates b) Proteins c) Fats d) All of the theseAnswers: 1. b) All green plants 2. d) Chlorophyll 3. a) Oxygen and carbohydrate 4. d) All of these
Short Answer Type Questions 2–3 marks each
A. Write the chemical equation for photosynthesis.The chemical equation for photosynthesis is
Carbon dioxide + Water →SunlightChlorophyll Carbohydrate + Oxygen
B. How do plants with red, brown or yellow leaves photosynthesise?Certain plants have red, brown, yellow, or other colour leaves. These leaves contain large amounts of red, brown and other pigments. These pigments mask the green colour of the chlorophyll. Since they contain chlorophyll, they can photosynthesise.
1.3 Heterotrophic Nutrition
Animals and non-green plants depend directly or indirectly on green plants for their food. This mode of nutrition is known as heterotrophic nutrition. (‘hetero’ means ‘other’, and ‘troph’ means ‘nourishment’). Heterotrophic plants are of four kinds: parasitic, saprophytic, insectivorous and symbiotic plants.
l Parasitic Plants: A parasite is an organism, which lives inside or on another organism (host) and derives nutrition from the host. Cuscuta (Amarbel) and mistletoe are two very common parasitic plants.
l Insectivorous Plants: Plants that feed on insects are called insectivorous plants. Examples of insectivorous plants are venus flytrap, sundew and pitcher plant.
l Saprophytic Plants: Plants like mushroom, mould and yeast feed on dead and decaying organic matter. They are called saprophytic plants.
l Symbiotic Plants: Some fungi like mushrooms live in association with other plants and share shelter and nutrients, thereby mutually benefiting from each other. They are known as symbiotic plants.
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Nutrition in Plants 5
NCERT Activity 2 – Page 6
Aim: To grow bread mould (fungi)Procedure:
1. Take a piece of bread and moisten it with water.2. Keep it in a closed box for 2 – 3 days. 3. After 2 – 3 days, observe it with a magnifying glass.
Observation: Whitish, green or brown patches appear on the bread. When seen with a magnifying glass, they are thread-like structures.Conclusion: Whitish or greenish, thread-like structures growing on moistened bread are fungi. Fungus grows in moist and warm conditions.
Objective Type Questions 1 mark each
A. Fill in the blanks.
1. The plants on which parasitic plants grow are known as _________.2. Mushroom has _________ mode of nutrition.3. Parasitic plants do not contain _________ and are hence, not able to photosynthesise.4. Venus flytrap is a / an _________ plant.5. _________ plants share shelter or nutrition or both and thus, mutually benefit from each other.Answers: 1. Host 2. Saprotrophic 3. Chlorophyll 4. Insectivorous 5. Symbiotic
B. Match the items in column A with those in column B.
Solved
Column A Column B
Cuscuta Parasite
Fungi Saprophyte
Lichens Symbiotic relationship
Green algae Autotroph
Venus flytrap Insectivorous plant
Unsolved
Column A Column B
Cuscuta Saprophyte
Fungi Symbiotic relationship
Lichens Parasite
Green algae Insectivorous plant
Venus flytrap Autotrophs
Short Answer Type Questions 2–3 marks each
A. Why do whitish or greenish patches appear on leather shoes or bags during rainy season? The whitish or greenish patches that appear on leather shoes or bags during rainy season are due to the growth of fungi on them. Fungal spores are present in the air and they grow fast on wet and warm things during the rainy reason.
B. Insectivorous plants contain chlorophyll and can photosynthesise. Why do they still need to feed on insects?Insectivorous plants feed on insects because they grow in soil that is deficient in nitrogen. They fulfil their nitrogen requirement by eating insects.
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MBD Super Refresher Science - VII6
1.4 Replenishing Nutrients
Plants absorb nutrition from the soil. Farmers add manure and fertilisers to the soil to replenish its nutrients.. Fertilisers are rich in potassium, nitrogen and phosphorous. Rhizobium, a bacterium, helps plants by fixing atmospheric nitrogen into the soil. It lives in the root nodules of leguminous plants such as peas and beans.
Objective Type Questions 1 mark each
A. Fill in the blanks.1. _________ and _________ are leguminous plants.2. The main nutrients provided by fertilisers are _________, _________ and _________.3. Farmers add _________ and _________ to the soil.4. _________ bacterium fix atmospheric nitrogen into the soil.Answers: 1. Peas, beans 2. Nitrogen, potassium, phosphorous 3. Manure, fertilisers 4. Rhizobium
Short Answer Type Questions 2–3 marks each
A. Why are nitrogenous fertilisers not added to the soil in which leguminous plants grow?A bacterium known as Rhizobium lives in the root nodules of leguminous plants. These bacteria convert atmospheric nitrogen into soluble form and fix nitrogen into the soil. They make the soil rich in nitrogen and hence, nitrogenous fertilisers are not required.
NCERT TEXTBOOK EXERCISES 1. Why do organisms need to take food?
Organisms need food to grow, repair damaged body parts, get energy for doing physical work and protect themselves from diseases.
2. Distinguish between a parasite and a saprophyte.Differences between a parasite and a saprophyte are:
Parasites SaprophytesParasites depend on other living organisms for thier food.
They live on or inside the body of other organism called the host.
Saprophytes obtain their food from dead and decaying matter.
They do not live on or inside the body of other organisms.
They have special organs such as suckers. They secrete enzymes to decompose complex molecules into simpler forms.
Examples of parasites include Cuscuta, tapeworms, roundworms, etc.
Examples of saprophytes include fungi, bacteria, mushrooms, etc.
3. How would you test the presence of starch in leaves?Steps to test the presence of starch in leaves:(a) Take a green leaf and boil it in water for 5–6 minutes.(b) Now place it in warm alcohol for some time. This will remove the green pigment.
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MBD CBSE Super Refresher ScienceClass 7
Publisher : MBD GroupPublishers
Author : Jaya Sharma
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