Question

Notes of Ch 6 of class 10 in cbse

Answer 1

➣ Life processes – The processes that are necessary for an organism to stay alive. Eg. Nutrition,respiration, etc.
➣ Criteria of life- (i) Growth (ii) Movement
➣ Nutrition- The process in which an organism takes in food, utilizes it to get energy, for growth, repair and maintenance, etc. and excretes the waste materials from the body
Types of nutrition
1. Autotrophic nutrition (Auto =self: trophos = nourishment) E.g. Plants, Algae, blue green bacteria.
o Process – Photosynthesis (Photo=light; Synthesis= to combine)
o Raw materials- (i) Carbon dioxide (ii)Water
o Equation-



o Energy conversion- Light/Solar energy to Chemical energy
o Role off Chlorophyll- To trap the sun‘s energy for photosynthesis
o Factors for Autotrophic nutrition -
(i) Carbon dioxide
(ii) Water
(iii) Light
(iv) Temperature
o Events/ Steps of photosynthesis-
(i) Absorption of light energy by chlorophyll
(ii) Conversion of light energy to chemical energy & Splitting of water molecule into Hydrogen & oxygen
(iii) Reduction of Carbon dioxide to Carbohydrate
o Gaseous exchange-
(i) Gas used- Carbon dioxide
(ii) By product - Oxygen
o Source of raw materials-
(i) Carbon dioxide –Land plants- Air, Aquatic plants- Water
(ii) Water & Minerals - Soil
2. Heterotrophic nutrition (Hetero =others: trophos =ourishment) Eg. Animals, plants lacking chlorophyll like fungi.
(a) Saprophytic nutrition: Organisms feeds on dead decaying plants or animals material. E.g. Fungi, Bacteri
(b) Parasitic nutrition: Organisms obtain food from the body of another living (host)
o Endoparasite : Parasite lives inside the body of the host e.g. tapeworm, roundworm.
o Exoparasite : Parasite lives on the body of the host. E.g. lice, leech.
Note- The parasite benefits while the host is usually harmed e.g. Cuscutta-plant parasite (amar bel), plasmodium (malarial parasite).
(c) Holozoic nutrition: Organism (mostly animals) take in whole food and then digest it into smaller particles with enzyme. Eg.Amoeba, Paramoecium. Animals, human beings.
o Steps in Holozoic nutrition
(i) Ingestion: taking in of food.
(ii) Digestion: breaking down of complex food into simpler, absorbable form.
(iii Assimilation: Utilization of digested food from the body.
(iv)Egestion: Removing undigested food from the body
o Nutrition in human beings
♦ Alimentary canal-
Mouth Oesophagus Stomach Small intestine Large intestine
♦ Important gland/juices
(Refer to figure 6.6 page no.97 of N.C.E.R.T Text book)

Organ
Gland
Enzyme/Juice
Function
Mouth
Salivary
glands
Salivary Amylase
Converts starch into sugar
Stomach
Gastric glands
Gastric juice-
(i) Hydrochloric
acid

(a) Kills harmful bacteria that enters with the food.

(b) Makes the medium alkaline for the action of Pepsin


(ii) Pepsin
Digests proteins




(iii) Mucus
Protects the inner lining of the stomach from the corrosive action of Hydrochloric acid.
Small
intestine
1) Liver



(i) Bile juice



(a) Makes the medium acidic
for the action of Pancreatic enzymes.

(b) Breaks down large fat molecules into smaller globules so that enzymes can act upon them.


2) Pancreas

( ii) Pancreatic
Juice
♦ Amylase

Converts Carbohydrates to glucose


♦ Trypsin
Converts Proteins to Amino acids


♦ Lipase
Converts Fats into Fatty acids & Glycerol


Aerobic respiration
Anaerobic respiration
-

♦ Terrestrial animals- take Oxygen from the atmosphere.
♦ Aquatic animals- take Oxygen dissolved in water. (Oxygen content is low in water, therefore they breathe faster.

o Human Respiratory system-
External nostrils → Nasal cavity → Trachea→ Bronchi → Bronchioles →Alveoli

♦ Blood-
(i) It is a fluid connective tissue.
(ii) Components-
(1) Fluid medium- Plasma (2) Red blood corpuscles (3) White blood corpuscles
(4) Platelets suspended in plasma
(iii) Plasma transports food, Oxygen, Carbon dioxide, Nitrogenous wastes, etc.


➣ Important diagrams-

1. Open & close stomata
2. Steps of nutrition in Amoeba
3. Alimentary canal of human beings/ Digestive system of human beings
4. Respiratory system of human beings
5. Structure of heart.
6. Excretory system of human beings
7. Structure of nephron

➣ Important activities-

1. To prove that chlorophyll is necessary for photosynthesis.
2. To prove that Carbon dioxide is necessary for photosynthesis.
3. To prove that light is necessary for photosynthesis.
4. To prove that product of fermentation is Carbon dioxide.
5. To prove that leaves lose water by transpiration.
6. To study the action of salivary amylase on starch.
7. To demonstrate that Carbon dioxide is present in exhaled air.
8. To demonstrate the process of transpiration in plants.