PRATIBHASTHALI GYANODAYA VIDYAPEETH
LIFE PROCESS - NOTES
1. Nutrition
The process of consuming food to obtain energy.
Autotrophic nutrition : Plants make their own food through photosynthesis .
Heterotrophic nutrition : Organisms that depend on others (e.g. humans , dodder , fungi).
Human Digestive System :
Mouth (Ingestion + Salivary Amylase) → Oesophagus (Peristalsis) → Stomach (Mixing with
HCl + Pepsin) → Small Intestine (Bile & Pancreatic juice added → Absorption) → Large
Intestine (Water absorption) → Anus (Egestion)
2. Respiration
The process of releasing energy from digested food.
Aerobic respiration : In the presence of oxygen (more energy).
Anaerobic respiration : In the absence of oxygen (such as the formation of lactic acid in
yeast or in our muscles).
Nostrils (Filtering by hair and mucus) → Pharynx & Larynx (The throat and voice box) →
Trachea (Windpipe supported by cartilage rings) → Bronchi & Bronchioles (Branching
network) → Alveoli (Site of diffusion: O2 into blood, CO2 out)
3 . Transportation
substances (oxygen , food , waste) from one place to another in the body.
In humans : main organs There is a heart .
o Blood consists of plasma , RBCs, WBCs and platelets.
Double Circulation : Blood passes through the heart twice in one cycle.
Pulmonary Loop (Oxygenation):
Right Ventricle → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium
Systemic Loop (Distribution):
Left Ventricle → Aorta → Body Tissues → Vena Cava → Right Atrium
In plants :
o Xylem : Transport of water and minerals.
o Phloem : Transport of food (sucrose).
4. Excretion
Removing harmful metabolic waste from the body .
Human excretory system: A pair of kidneys , ureters , urinary bladder and urethra.
Nephron : The structural and functional unit of the kidney. It filters blood to form urine.
, Renal Artery (Dirty blood enters) → Glomerulus (High-pressure filtration) → Bowman's Capsule
(Collection of filtrate) $\downarrow$ Nephric Tubule (Selective reabsorption of Glucose/Water)
→ Ureter (Transports urine to bladder) → Urinary Bladder (Storage) → Urethra (Release)
in plant: They excrete waste through falling leaves , gum , resin or stomata .
Main 'Reasoning' Questions:
1. What is emulsification? ( Smalling of large globules of fat by bile juice).
2. What is ATP ? ( Energy currency of the cell ) .
3. Difference between artery and vein ? ( Artery carries pure blood and is thick ; vein carries
impure blood)
and has valves ). Section A: Structure and Function (Reasoning)
1. Why is the left ventricle much thicker than the right ventricle?
Answer : The right ventricle needs to pump deoxygenated blood only to the lungs (low
pressure, short distance). The left ventricle needs to pump oxygenated blood throughout
the body (high pressure, long distance). Therefore, it needs thick muscular walls to
generate the necessary force.
2. Role of cartilage rings in the human trachea.
Answer: The rings of cartilage ensure that the air passages remain closed even when there
is little or no air in the windpipe, thus maintaining a
continuous flow of air.
3. How does the design of the alveoli maximize gas exchange?
Answer: 1. Large surface area: Their balloon-like
structure provides a wide area for exchange.
2. Thin walls: They are one-cell thick, allowing for rapid
diffusion .
3. Blood supply: They are surrounded by a large network of blood capillaries .
Section B: Practical Skills
4. Why is the leaf boiled in alcohol (in water)?
Answer : To change the color of the leaf, it is boiled in alcohol, which removes/dissolves the
chlorophyll. This results in a clear color change in the iodine test (blue-black for starch). Note:
Water is used for boiling because alcohol is highly flammable.
5. What changes occur in lime water when we exhale?
Answer: Lime water turns milky . The gas responsible for this is carbon dioxide (CO2) .
Section C: Data Interpretation
6. Comparison Table: Xylem vs. Phloem
LIFE PROCESS - NOTES
1. Nutrition
The process of consuming food to obtain energy.
Autotrophic nutrition : Plants make their own food through photosynthesis .
Heterotrophic nutrition : Organisms that depend on others (e.g. humans , dodder , fungi).
Human Digestive System :
Mouth (Ingestion + Salivary Amylase) → Oesophagus (Peristalsis) → Stomach (Mixing with
HCl + Pepsin) → Small Intestine (Bile & Pancreatic juice added → Absorption) → Large
Intestine (Water absorption) → Anus (Egestion)
2. Respiration
The process of releasing energy from digested food.
Aerobic respiration : In the presence of oxygen (more energy).
Anaerobic respiration : In the absence of oxygen (such as the formation of lactic acid in
yeast or in our muscles).
Nostrils (Filtering by hair and mucus) → Pharynx & Larynx (The throat and voice box) →
Trachea (Windpipe supported by cartilage rings) → Bronchi & Bronchioles (Branching
network) → Alveoli (Site of diffusion: O2 into blood, CO2 out)
3 . Transportation
substances (oxygen , food , waste) from one place to another in the body.
In humans : main organs There is a heart .
o Blood consists of plasma , RBCs, WBCs and platelets.
Double Circulation : Blood passes through the heart twice in one cycle.
Pulmonary Loop (Oxygenation):
Right Ventricle → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium
Systemic Loop (Distribution):
Left Ventricle → Aorta → Body Tissues → Vena Cava → Right Atrium
In plants :
o Xylem : Transport of water and minerals.
o Phloem : Transport of food (sucrose).
4. Excretion
Removing harmful metabolic waste from the body .
Human excretory system: A pair of kidneys , ureters , urinary bladder and urethra.
Nephron : The structural and functional unit of the kidney. It filters blood to form urine.
, Renal Artery (Dirty blood enters) → Glomerulus (High-pressure filtration) → Bowman's Capsule
(Collection of filtrate) $\downarrow$ Nephric Tubule (Selective reabsorption of Glucose/Water)
→ Ureter (Transports urine to bladder) → Urinary Bladder (Storage) → Urethra (Release)
in plant: They excrete waste through falling leaves , gum , resin or stomata .
Main 'Reasoning' Questions:
1. What is emulsification? ( Smalling of large globules of fat by bile juice).
2. What is ATP ? ( Energy currency of the cell ) .
3. Difference between artery and vein ? ( Artery carries pure blood and is thick ; vein carries
impure blood)
and has valves ). Section A: Structure and Function (Reasoning)
1. Why is the left ventricle much thicker than the right ventricle?
Answer : The right ventricle needs to pump deoxygenated blood only to the lungs (low
pressure, short distance). The left ventricle needs to pump oxygenated blood throughout
the body (high pressure, long distance). Therefore, it needs thick muscular walls to
generate the necessary force.
2. Role of cartilage rings in the human trachea.
Answer: The rings of cartilage ensure that the air passages remain closed even when there
is little or no air in the windpipe, thus maintaining a
continuous flow of air.
3. How does the design of the alveoli maximize gas exchange?
Answer: 1. Large surface area: Their balloon-like
structure provides a wide area for exchange.
2. Thin walls: They are one-cell thick, allowing for rapid
diffusion .
3. Blood supply: They are surrounded by a large network of blood capillaries .
Section B: Practical Skills
4. Why is the leaf boiled in alcohol (in water)?
Answer : To change the color of the leaf, it is boiled in alcohol, which removes/dissolves the
chlorophyll. This results in a clear color change in the iodine test (blue-black for starch). Note:
Water is used for boiling because alcohol is highly flammable.
5. What changes occur in lime water when we exhale?
Answer: Lime water turns milky . The gas responsible for this is carbon dioxide (CO2) .
Section C: Data Interpretation
6. Comparison Table: Xylem vs. Phloem
