The document discusses the essential life processes that maintain the functions of living organisms, including nutrition, respiration, transportation, and excretion. It elaborates on the types of nutrition (autotrophic and heterotrophic), the process of photosynthesis, and the human digestive system, detailing how food is ingested, digested, and absorbed. Additionally, it covers respiration in both plants and animals, emphasizing the mechanisms of gas exchange and the importance of oxygen and energy production in living systems.

1. Life Processes
Class – 10th
PART – 1

2. What Are Life
Processes?
The maintenance functions of living organisms must go
on even when they are not doing anything particular.
The processes which together perform this maintenance
job are Life Processes.
Since these maintenance processes are needed to
prevent damage and break-down, energy is needed for
them.
This energy comes from outside the body of the
individual organism.
The four major Life Processes are: Nutrition,
Respiration, Transportation and Excretion.

3. NUTRITION
Nutrition is the process of taking food by an organism and its utilization by the body
to build the body, for growth, to repair the damaged parts of the body and for
energy.
Life on earth depends on carbon based molecules and most of the food are also
carbon based molecules.
The outside raw materials used by living organisms are food, water and air.
The two types of mode of nutrition are:
Autotrophic Organisms, such as Green Plants and Bacteria, use simple food
material obtained from inorganic sources in the form of carbon dioxide and water.
Heterotrophic Organisms, such as Fungi and Humans, utilize complex
substances. These substances have to be broken down into simpler ones before
they can be used for the growth of the body. To achieve this, organisms use bio-
catalysts called Enzymes.

4. Autotrophic Nutrition
Carbon and Energy needs of the autotrophic
organism are fulfilled by Photosynthesis.
It is the process by which autotrophs take in
substances from the outside and convert them
into energy.
This material is taken in the form of CO2 and
H2O which is converted into carbs in presence of
Sunlight and Chlorophyll.
Carbohydrates are not used immediately are
stored in the form of Starch, which serves as
the internal energy reserve to be used when
required by the plant.
In Human Body, carbs are stored as Glycogen.

5. Photosynthesis

6. Photosynthesis
The following events occur during Photosynthesis –
o Absorption of light energy by chlorophyll.
o Conversion of light energy to chemical energy and splitting of water molecules into
hydrogen and oxygen. (Hydrolysis)
o Reduction of carbon dioxide to carbohydrates.
These steps need not take place one after the other immediately.
For e.g. Desert plants take up carbon dioxide at night and prepare an intermediate
which is acted upon by the energy absorbed by the chlorophyll during the day.

7. ACTIVITY 5.1
Take a plant with variegated leaves – for e.g. Money Plant or Crotons.
Keep the plant in a dark room for three days so that all the starch gets used up.
Now keep the plant in sunlight for about six hours.
Pluck a leaf from the plant. Mark the green areas in it and trace them on a sheet of
paper.
Dip the leaf in boiling water for a few minutes. After this, immerse it in a beaker
containing alcohol.
Carefully place the beaker in a water-bath and heat till the alcohol begins to boil.
What happens to the color of the leaf? Now dip the leaf in a dilute solution of iodine
for a few minutes.
Take out the leaf and rinse off the iodine solution. Observe the color of the leaf and
compare this with the tracing of the leaf done in the beginning.

8. Conclusion

9. Cross – Section Of A Leaf
The cross – section of leaf contains 3 parts
majorly:
• Epidermis: protects the leaf surface and is
divided into Upper and Lower Epidermis.
• Mesophyll: refers to the inner tissues of the
leaf which contains Chloroplasts.
• Veins: provide support to the leaf and consist
of Xylem and Phloem vessels which
transport the Water and Photosynthates to
the whole plant body.

10. Stomata
Stomata are the tiny pores present on
the surface of the leaves.
Prevents water loss during transpiration
and maintains gaseous exchange
through pores used for
Photosynthesis.
The opening and closing of the pore is a
function of the Guard Cells.
The guard cells swell when water flows
into them, causing the stomatal pore to
open.
Similarly the pore closes if the guard
cells shrink.

11. ACTIVITY 5.2
Take two healthy potted plants which are nearly
the same size.
Keep them in a dark room for three days.
Now place each plant on separate plates. Place
a watch-glass containing Potassium
Hydroxide by the side of one of the plants. The
potassium hydroxide is used to absorb CO2.
Cover both plants with bell-jars, use Vaseline
to seal the bottom of the jars, so that the set-up
is air-tight.
Keep the plants in sunlight for about two hours.
Do both the leaves show the presence of the
same amount of starch?
(A) (B)

12. Absorption Of Minerals By Plants
Water used in photosynthesis is taken up
from the soil by the roots in terrestrial
plants.
Other materials like Nitrogen,
Phosphorus, Iron and Magnesium are
taken up from the soil.
Nitrogen is an essential element used in
the synthesis of proteins and other
compounds.
This is taken up in the form of inorganic
nitrates or nitrites.
Or it is taken up as organic compounds
which have been prepared by

13. Heterotrophic Nutrition
Each organism is adapted to its environment. The form of nutrition differs
depending on the type and availability of food material as well as how it is obtained
by the organism.
It is the mode of nutrition where the organism is unable to prepare its food and
depends on plants or other organisms for nutrition.
The three types of Heterotrophic Nutrition are:
o Holozoic Nutrition – It involves the ingestion of organic matter which is then
digested and absorbed into the body. For e.g. Amoeba, Human Beings, etc.
o Saprophytic Nutrition – Organisms feed on dead and decaying matter to fulfil their
energy requirements. For e.g. Fungi, Bacteria, etc.
o Parasitic Nutrition – Organisms obtain nutrition from living organisms, by living on
or inside the body of Host. For e.g. Tapeworm, Lice, etc.

14. Holozoic Nutrition Parasitic Nutrition
Saprophytic
Nutrition

15. Phagocytosis: Amoeba
Phagocytosis is the process by which the food is engulfed by
the organism. It involves the following steps:
Ingestion: Amoeba pushes out the pseudopodia to encircle
the food and engulfs it forming a food vacuole.
Digestion: The food vacuoles are transported deeper into
the cell and digestive enzymes breaks large insoluble
particles to simplest molecules.
Absorption: The nutrients from the digested food are
absorbed into the cell’s cytoplasm by leaving behind the
undigested particles.
Assimilation: Absorbed food is then utilized to produce
energy.
Egestion: It is carried out by rupturing the cell membrane
to remove the undigested food material from body.

16. Nutrition In Human Beings
Human Digestion is an essential process that converts huge food molecules into simpler ones, producing energy for bodily functions.
Ingestion: The food enters through the Buccal Cavity. The food is sliced, torn, chewed by teeth and digested in the mouth with the help of Saliva as it contains Salivary
Amylase. The lining of canal has muscles that contract rhythmically in order to push the food forward. These Peristaltic Movements occur all along the gut.
Digestion: The digestion in stomach is done by the gastric glands present in the wall of the stomach. These release HCl, a protein digesting enzyme called Pepsin, and
Mucus. The HCl creates an acidic medium which facilitates the action of pepsin. The mucus protects the inner lining of the stomach from the action of the acid under normal
conditions.
The exit of food from the stomach is regulated by a Sphincter Muscle which releases it in small amounts into the small intestine.
Absorption: Small Intestine is the longest part of the alimentary canal which is fitted into a compact space because of extensive coiling. It is the site of complete digestion of
carbs, proteins and fats. The food coming from the stomach is Acidic and has to be made Alkaline for the pancreatic enzymes to act.
Bile juice from the liver acts on fats, as they are present in the intestine in the form of large globules. Bile salts break them down into smaller globules increasing the
efficiency of enzyme action.
The pancreas secretes Pancreatic Juice which contains enzymes like Trypsin for digesting proteins and Lipase for breaking down emulsified fats. The walls of the small
intestine contain glands which secrete Intestinal Juice. The enzymes present in it finally convert the proteins to amino acids, complex carbs into glucose and fats into fatty
acids and glycerol.
Digested food is taken up by the walls of the intestine. The inner lining of the small intestine has numerous finger-like projections called Villi which increase the surface area
for absorption. The villi are richly supplied with blood vessels which take the absorbed food to each and every cell of the body, where it is utilized for obtaining energy, building
up new tissues and the repair of old tissues.
Egestion: The unabsorbed food is sent into the large intestine where its wall absorb more water from this material. The rest of the material is removed from the body via the
anus.
The exit of this waste material is regulated by the Anal Sphincter.

17. Human Digestive
System

18. Dental Caries
Dental Caries (tooth decay) causes gradual softening of enamel
and dentine.
It begins when bacteria acting on sugars produce acids that
softens or demineralizes the enamel.
Masses of bacterial cells together with food particles stick to the
teeth to form Dental Plaque.
Saliva cannot reach the tooth surface to neutralize the acid as
plaque covers the teeth.
Brushing the teeth after eating removes the plaque before the
bacteria produce acids.
If untreated, microorganisms may invade the pulp, causing
inflammation and infection.

19. Stages Of Tooth Decay

20. RESPIRATION
The food material taken in during the process of nutrition is used in cells to provide
energy for various life processes.
Diverse organisms use Oxygen to break-down Glucose completely into CO2 and
water.
The 1st step is the break-down of Glucose {6-carbon Molecule}, into a {3-carbon
molecule} called Pyruvate. This process takes place in the cytoplasm.
Anaerobic Respiration:
• Fermentation (yeast): the pyruvate may be converted into Ethanol and 𝐂𝐎𝟐.
• Cramps (muscles): the pyruvate may be converted into Lactic Acid and Energy.
Aerobic Respiration:
• Pyruvate converts into 𝐂𝐎𝟐, Water and Energy.

21. The Fate Of Pyruvic
Acid

22. Adenosine Triphosphate
ATP is the energy currency for most cellular processes.
The energy released during the process of respiration is
used to make an ATP molecule from ADP and Inorganic
Phosphate.
The energy released during cellular respiration is
immediately used to synthesize a molecule called ATP,
which is used to fuel all other activities in the cell.
In these processes, ATP (Adenosine Triphosphate) is
broken down giving rise to a energy which can drive the
endothermic reactions taking place in the cell.

23. ACTIVITY 5.4
Take some freshly prepared Lime Water in
a test tube.
Blow air through this lime water.
Note how long it takes for the lime water to
turn Milky.
Use a syringe to pass air through some
fresh lime water taken in another test tube.
Note how long it takes for this lime water to
turn milky.
What does this tell us about the amount of
Carbon Dioxide in the air that we breathe
out?

24. Respiration In Plants
Plants exchange gases through stomata, and the large inter-
cellular spaces ensure that all cells are in contact with air.
𝐂𝐎𝟐 and oxygen are exchanged by diffusion here.
The direction of diffusion depends upon the environmental
conditions and the requirements of the plant.
At night, when there is no photosynthesis occurring, 𝐂𝐎𝟐
elimination is the major exchange activity going on.
During the day, 𝐂𝐎𝟐 generated during respiration is used up for
photosynthesis, hence there is no 𝐂𝐎𝟐 release.
Instead, oxygen release is the major event at this time.

25. Cellular
Respiration

26. Respiration In Animals
Terrestrial Animals can breathe the oxygen in the
atmosphere, but Aquatic Animals need to use the oxygen
dissolved in water.
Since, the amount of dissolved oxygen is low compared to
the amount of oxygen in the air, the rate of breathing in
aquatic organisms is much faster than that seen in
terrestrial organisms.
All the organs have a structure that increases the surface
area for absorption of oxygen. Since the exchange of
oxygen and 𝐂𝐎𝟐 has to take place across it and this
surface is very Fine and Delicate.
In order to protect this surface, it is usually placed within
the body, so there have to be passages that will take air to
this area. In addition, there is a mechanism for moving the

27. Respiration In Animals

28. Pulmonary Respiration In Humans
• Air is drawn into the body through the Nostrils.
• The air from the nasal cavity passes to the pharynx, which leads to the trachea, through a slit called
Glottis.
• The trachea runs down the neck and divides into two bronchi, which further divide into smaller
bronchioles. The smallest Bronchioles terminate into Alveoli.
• The walls of the alveoli are thin and covered by blood capillaries to facilitate the exchange of gases
in the lungs.
• In the alveoli, the exchange of gases takes place, CO2 from the blood is replaced with O2 and CO2 is
removed out of the body.
• In humans, for the process of respiration, air is drawn into the lungs by the process of Breathing.
• When an individual inhales, the diaphragm moves down, and the chest cavity expands and
the oxygen rich air is drawn into the lungs.
• When the individual exhales, the diaphragm relaxes and the chest cavity moves back to its relaxed
position and the carbon dioxide rich air is expelled out of the body.

29. Human Respiratory System

30. Respiratory Reserve
Volume
• During the breathing cycle, when air is taken in and out, the
lungs always contain a Residual Volume of air so that there is
sufficient time for O2 to be absorbed and for the CO2 to be
released.
• When the body size of animals is large, the diffusion pressure
alone cannot take care of oxygen delivery to all parts of the body.
• Instead, respiratory pigments take up oxygen from the air in the
lungs and carry it to tissues which are deficient in oxygen before
releasing it.
• In human beings, the respiratory pigment is Haemoglobin which
has a very high affinity for oxygen. This pigment is present in the
Red Blood Corpuscles.
• CO2 is more soluble in water than oxygen is and hence is mostly
transported in the dissolved form in our blood.

31. TO BE CONTINUED…