Food and its Constituents
Choose the correct answer and Fill in the blanks
1. One of the following is not an energy source for our body
Ans
roughage
2. The number of molecules of simple sugars in an oligosaccharide is
Ans
2 to 10,
3. In our body , the principle energy source is
Ans
glucose
4. The constituents of food which serve as thermal insulators
Ans
fats
Q II
Fill in the blanks
1. A simple lipid which remains a solid at room temperature
is fats.
2. An example of conjugated protein is haemoglobin.
3. In carbohydrates , hydrogen and oxygen are present in a ratio of
2:1
4. Protiens are made up of aminoacids.
5. An example of animal starch is glycogen.
Q III
Match the following
A
1. Fructose
2. Glycosidic bond
3. Cellulose
B
a) monosaccharide
b) linkage between two single sugar
c) roughage
4. Proteins that yield only
Amino acids
5. Vegetable oil
Q IV
d) simple proteins
e) simple lipid
Answer the following
1. Name any 3 constituents of our food.
Constituents of food are carbohydrates, proteins and lipids
2. Which of the two constituents of food provide energy for our
body?
Carbohydrates and proteins provide energy for our body.
3. What are carbohydrates? Give two examples.
Carbohydrates are commonly as saccharides. They are made up of
Carbon , hydrogen and oxygen Ex. Glucose and fructose
4. Write the difference between monosaccharide and
oligosaccharides. Give one example for each
Monosaccharide
Contain one simple sugar
Oligosaccaharide
Formed by the linkage of two
molecule.
to ten monosaccharide units.
Eg. Glucose, fructose
eg. Lactose and sucrose
5. Mention the importance of the following
Carbohydrates,
Protiens,
Lipids
Carbohydrates----1) Glucose is the principle source of energy for all
our activities . 2)starch and glycogen serve as energy storage
products .
Proteins ---- 1) They increase the rate of chemical processes in our
body. 2) They help in blood clotting and prevent bleeding
Lipids ---- 1) Lipids (fats ) also provide energy. 2) Fats acts as
thermal insulators and help in maintaining body temperature.
6. Name the storage carbohydrate in plants and the storage
carbohydrates in animals.
Storage carbohydrates in plants -----Starch.
Storage carbohydrates in animals ----glycogen.
7. Differentiate an amino acid from a protein.
Proteins are made up of amino acids . Where as amino acids are
linked by peptide bonds to form proteins.
8. What are proteins? Give two examples.
Proteins are made up of amino acids. Eg pulses and milk
9. Define simple proteins. Give an example
Simple proteins are made up of only amino acids. Example egg
white part.
10. What do you mean by a conjugated protein? Give an example.
Proteins which are made up of a protein and a non- protein are
called conjugated proteins. Ex haemoglobin.
11. What are lipids ? Give two examples.
Lipids are made up of carbon , hydrogen and oxygen. But they
contain less oxygen than in carbohydrates. Ex. Ghee, coconut oil.
12. Write a difference between fat and oil . Give an example for each.
Fats are solid at room temperature. Ex. Cheese
Oils are liquid at room temperature. Ex. Groundnut oil.
13. What are simple lipids? Give an example
Fats and oils are made up of fatty acids and glycerol are called
simple lipids. Ex. Ghee
FRICTION
Q I
Fill in the blanks
1. Friction is caused mainly due to irregularities of the surfaces.
2. Proper arrangement of frictions in their decreasing order is
Static, sliding, rolling
3. The increasing order of friction in the following substances is
Glass, wood, sand
Q II
Choose the world from the list and fill in the blanks.
( less, heat, opposite, reduce, greater, more )
1. Fraction always acts in the direction opposite to the direction of
the applied force.
2. Friction produces heat.
3. Stastic friction is more than the sliding friction.
4. Frictional force is less in smooth surface.
5. Lubricant reduce the friction between the surfaces in contact.
Q II
Match the following
A
1.
2.
3.
4.
5.
Q IV
B
Spikes
Treads
Talcum power
Grease
Stream lining
Answer the following
a) shoes
b) tyres
c) carom board
d) ball bearing
e) air crafts
1. What is friction ? Explain how it is caused.
Ans Friction is a force which tends to slow down or stop the moving
bodies. Friction is caused due to interlocked irregularities of the
surfaces in contact.
2. Name the two important factors which effect friction?
Ans Factors effecting friction
1) Frictional force vary in strength according to how hard the two
surfaces are pressed against one another and how slippery or how
rough the surfaces are. 2) Frictional force is more for rough
surfaces and less for smooth surfaces.
3. Make a list of the effects of friction .?
Ans Effects of friction 1) Friction opposes motion
2) Friction produces heat.
3) Friction causes wear and tear
4. Why friction is called a necessary evil ?
Ans Advantages----- We can not write on anything without friction.
Without friction the pulley of a motor can not move the conveyor belt
to run a machine. Disadvantages ---Friction brings wear and tear in
moving bodies and worn out tyers of machines. So friction is both
useful and harmful at different situations and hence it is called a
necessary evil.
5
State two advantages of friction.
Ans 1) Match stick catches fire because of heat produced by the
friction. 2) Without friction the pulley of a motor can not move the
conveyor belt to run a machine.
6. State two disadvantages of friction.
Ans Disadvantages of friction 1) Friction reduces the speed of
machine. 2) Force of friction worm out soles of shoes.
7. What is lubricant ? Give two examples.
Ans Lubricant is a substance which reduces friction between surfaces
in contact. Example Oil, grease , graphite
8. How does a lubricant reduce friction?
Ans A thin layer of lubricant separates two moving surfaces, So they
do not rub against each other directly.
9. How can you say that sliding friction is greater than the rolling
friction ?
Ans The force of friction acting between the two bodies when they
are sliding upon each other, but rolling reduces the friction. By this we
can say that sliding friction is greater than the rolling friction.
10 . Explain why objects moving in fluids must have stream-lined
shape ?
Ans Fluids like water offer friction to the moving bodies. Modern boats
and ships are given a stream-lined shape. So that they offer least
friction to the water.
QV
Give reason
1. A ball rolling over the ground slows down.
Ans A moving ball slows down because of the friction between the
surfaces of the ball and the ground
2. The surface of a conveyor belt is made rough and tight.
Ans Because to increase friction the surfaces in contact are made
rough and tight belt helps to run a machine.
3. The worn out tyres are discarded.
Ans Because worn out tyres of the vehicles may skid on the sharp turns
of the road due to less friction, and can cause serious accident.
Cellular Organization
QI
Choose the correct answer
1. Microscope was invented by