Subject: Science
Topic: Life processes
Grade: X
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LIFE
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NUTRITIO
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NUTRITIO
Nutrition is the process of acquiring food byN
an organism and its utilization by the body for
growth, to repair the damaged parts of the body and for energy.
Modes of nutrition
Autotrophic Heterotrophic
(Auto = self: trophos = (Hetero = other: trophos = nourishment)
nourishment) E.g. Animals, Birds, Fish, Humans
E.g. Plants, Algae, Blue green bacteria
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Autotrophic Nutrition
Autotrophs are organisms that produce their own food by the
process of photosynthesis.
Photosynthesis is the process used by plants to create
their own food. Plants use sunlight, water, and carbon
dioxide to create food (glucose) and oxygen.
Site of Photosynthesis - Chloroplasts in the leaf
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The Carbon
Dioxide
Ingredients
Carbon dioxide is taken in by plants
through tiny openings on leaves called
stomata.
Water is absorbed from the soil through
the roots and is transported to the
leaves.
Water
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Cross Section Of A Leaf
Cross section of a leaf under the microscope
shows that some cells contain green dots.
They are cell organelles called chloroplasts.
Chloroplasts contain chlorophyll pigments.
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Events During Photosynthesis
• Absorption of light energy by chlorophyll.
• Conversion of light energy to chemical energy
and splitting of water molecules into hydrogen
and oxygen.
• Reduction of carbon dioxide to carbohydrates.
These steps need not take place one after the other immediately.
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The Photosynthesis
The photosynthesis reaction
Reaction
converts carbon dioxide and
water into glucose and oxygen.
Chloroplasts
The
Equation:
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Heterotrophic Nutrition
It is the nutrition in which an organism depends on other living organisms for food.
TYPES OF HETEROTROPHIC NUTRITION
Feed on dead plants, dead and Organisms that obtain nutrition from Organisms that feed by ingesting solid
decaying animal bodies. other living organisms (in return harm organic matter which is then digested
Examples them). and absorbed into their bodies.
• Fungi (such as mushrooms) Examples Examples
• Tapeworm • Human beings
• Lice • Amoeba
(Saprotrophic nutrition) (Parasitic nutrition) (Holozoic nutrition)
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Nutrition In Amoeba
Amoeba takes in food using temporary finger-like extensions of
the cell surface which fuse over the food particle forming a food-
vacuole.
Inside the food vacuole, complex substances are broken down into
simpler ones which then diffuse into the cytoplasm.
The remaining undigested material is moved to the surface of the
cell and thrown out.
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Nutrition In Human Beings
• Being more complex, humans have a very
complicated nutrition system.
• The digestive system has an alimentary canal and
associated digestive glands, which together
function to nourish the body.
• There are five stages in human nutrition;
Ingestion, Digestion, Absorption, Assimilation and
Egestion.
• Four stages i.e. ingestion, digestion, absorption
and egestion take place in the alimentary canal
while assimilation of food takes place in the whole
body.
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MOUTH
Food is ingested through the mouth. Digestion of food begins in the mouth.
Teeth helps to chew and crush the food.
Salivary amylase present in saliva breaks the starch into simple sugar.
OESOPHAGUS
From the mouth, the food is taken to the stomach through the food-pipe or oesophagus
STOMACH
The muscular walls of the stomach help in mixing the food thoroughly with more digestive juices
Wall have gastric glands that release hydrochloric acid, pepsin and mucus.
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SMALL INTESTINE
Site of complete digestion of carbohydrates, proteins and fats.
Receives bile from the liver and pancreatic juice from the pancreas.
Bile salts break larger fat globules into smaller globules.
The pancreas secretes pancreatic juice, which contains:
-Trypsin – Digests proteins
-Lipase – Breaks down emulsified fats
The walls of the small intestine have glands that secrete intestinal juice.
The enzymes in in intestinal juice complete digestion by converting:
- proteins to amino acids
- complex carbohydrates into glucose
- fats into fatty acids and glycerol.
Has numerous finger-like projections called villi which increase the surface area for absorption.
LARGE INTESTINE
The unabsorbed food is sent into the large intestine where its wall absorbs water from this material.
The rest of the material is removed from the body via the anus.
ANUS
It is the opening at the end of the large intestine.
The waste from digestion (faeces) is removed from the body through the anus.
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TRANSPORTATIO
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Transportation In Humans
Heart pumps the blood all over the body.
It has two upper chambers – the right
atrium and the left atrium.
It has two lower chambers- the right
ventricle and the left ventricle.
Left chambers carry oxygen rich blood
Deoxygenated blood reaches the heart to
remove carbon dioxide.
Oxygenated blood from the lungs is
brought back to the heart and then
pumped to the rest of the body.
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Transportation In Humans
Why do ventricles have thicker muscular valves than atria?
Since ventricles have to pump blood to various organs, they have thicker
walls than the atria.
Significance of valves:
Valves ensure that blood does not flow backwards
when the atria or ventricles contract.
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Transportation In Fishes
Single Circulation
1. Fishes have single circulation.
2. They have a two-chambered heart comprising an
atrium and a ventricle.
3. In fishes, the heart pumps out the deoxygenated
blood which undergoes oxygenation in the gills.
4. Thus, blood goes only once through the heart in the
fish during one cycle of passage through the body
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Transportation In Humans
Double Circulation
Blood passes twice through the heart, hence called
double circulation.
• The oxygenated blood flows from the left ventricle to all
body parts.
• The deoxygenated blood returns from the tissue to the
right atrium.
• The right ventricle pumps blood into the pulmonary artery,
while the left ventricle pumps blood into the aorta.
• The deoxygenated blood pumped into the pulmonary artery is
delivered to the lungs, where it is replaced by oxygenated
blood carried into the left atrium via the pulmonary veins.
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Difference Between Arteries, Veins &
Arteries Capillaries
Veins Capillaries
Transports blood from the heart Transports blood from various Connects both arteries and
to other parts of the body. regions of the body to the heart. veins.
Carry oxygenated blood except Carry deoxygenated blood Transports both oxygenated
Exception: pulmonary artery Exception: pulmonary vein and deoxygenated blood.
Thick walled. Thin walled Walls only one celled thicker to
facilitate exchange of gases
Blood flows under high pressure Blood flows under low pressure ---
as the lumen is narrow. as the lumen is large.
Valves absent Valves present Valves absent
Blood flows with high speed Blood flow with slow speed ---
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Transportation In
Lymph (Tissue Fluid)
Humans
Through the pores in the capillary walls some amount
of plasma, proteins and blood cells escape into
intercellular spaces in the tissues to form the tissue
fluid or lymph.
It is similar to blood plasma but colourless and contains
less proteins.
Lymph carries digested and absorbed fat from intestine
and drains excess
fluid from extra cellular space back into the blood.
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