Class 10 Chapter 5 Life Processes

5.2 Nutrition

Energy Requirement:

All living organisms need energy to perform various functions, including movement and maintaining body order.
The source of energy and materials comes from the food we eat.

Types of Nutrition:

Organisms can be classified based on their method of nutrition into autotrophs and heterotrophs.

Autotrophic Nutrition:

Autotrophs, such as plants, use photosynthesis to convert light energy into chemical energy.
The main materials for photosynthesis are carbon dioxide and water, which are converted into carbohydrates in the presence of sunlight and chlorophyll.
The stored carbohydrates (like starch in plants) serve as an energy reserve.

Heterotrophic Nutrition:

Heterotrophs, including animals and fungi, depend on complex substances derived from other organisms.
These organisms break down complex food into simpler forms using enzymes.
Examples include animals that consume plants or other animals, and fungi that decompose organic material.

Human Digestive System:

The process of digestion begins in the mouth and involves the alimentary canal.
Food is broken down by enzymes at different stages in the stomach, small intestine, and other parts of the digestive system.
The end products of digestion are absorbed by the villi in the small intestine and transported throughout the body for energy and growth.

5.3 Respiration

Purpose of Respiration:

Respiration is the process by which energy is released from food, primarily glucose, for various life activities.
Respiration can be aerobic (using oxygen) or anaerobic (without oxygen).

Aerobic Respiration:

In aerobic respiration, glucose is completely broken down into carbon dioxide and water in the presence of oxygen, producing a large amount of energy.
This process mainly occurs in the mitochondria of cells.

Anaerobic Respiration:

Anaerobic respiration occurs in the absence of oxygen.
In this process, glucose is broken down into ethanol and carbon dioxide (in yeast) or lactic acid (in muscles), producing less energy than aerobic respiration.

Energy Storage – ATP:

The energy released during respiration is stored in the form of ATP (Adenosine Triphosphate), which acts as an energy currency for the cell.
ATP is used to power various cellular functions.

Human Respiratory System:

The respiratory system involves the lungs, where gas exchange occurs in small air sacs called alveoli.
Oxygen is absorbed into the blood from the alveoli, and carbon dioxide is released from the blood into the alveoli to be exhaled.

Respiratory Pigments:

In humans, the respiratory pigment hemoglobin in red blood cells binds to oxygen, transporting it to tissues and returning carbon dioxide to the lungs.

MCQs

What is the main source of energy for all living organisms?
(A) Water
(B) Air
(C) Food
(D) Light
Answer: (C) Food
Which type of nutrition involves organisms producing their own food using sunlight?
(A) Heterotrophic
(B) Autotrophic
(C) Parasitic
(D) Saprophytic
Answer: (B) Autotrophic
What is the main pigment involved in the process of photosynthesis?
(A) Chlorophyll
(B) Hemoglobin
(C) Amylase
(D) Myoglobin
Answer: (A) Chlorophyll
Which gas is required for photosynthesis in plants?
(A) Nitrogen
(B) Oxygen
(C) Carbon dioxide
(D) Hydrogen
Answer: (C) Carbon dioxide
In what form is energy stored in plants after photosynthesis?
(A) Starch
(B) Protein
(C) Lipid
(D) Vitamin
Answer: (A) Starch
Which of the following is an example of heterotrophic nutrition?
(A) Photosynthesis
(B) Eating a plant or animal
(C) Absorbing sunlight
(D) Making food from inorganic compounds
Answer: (B) Eating a plant or animal
What is the role of enzymes in digestion?
(A) Absorb food
(B) Break down complex food
(C) Transport food
(D) Store food
Answer: (B) Break down complex food
What is the site for the absorption of digested food in humans?
(A) Stomach
(B) Small intestine
(C) Large intestine
(D) Liver
Answer: (B) Small intestine
Which structure in the small intestine increases the surface area for absorption?
(A) Villi
(B) Cilia
(C) Microvilli
(D) Alveoli
Answer: (A) Villi
Which of the following is the process of breaking down glucose in the presence of oxygen?
(A) Fermentation
(B) Aerobic respiration
(C) Anaerobic respiration
(D) Glycolysis
Answer: (B) Aerobic respiration
Where does aerobic respiration take place in the cell?
(A) Cytoplasm
(B) Nucleus
(C) Mitochondria
(D) Ribosomes
Answer: (C) Mitochondria
What is the end product of anaerobic respiration in yeast?
(A) Lactic acid
(B) Ethanol and carbon dioxide
(C) Oxygen and water
(D) Glucose
Answer: (B) Ethanol and carbon dioxide
Which molecule acts as the energy currency in cells?
(A) ADP
(B) ATP
(C) DNA
(D) RNA
Answer: (B) ATP
In humans, where does the exchange of gases take place during respiration?
(A) Stomach
(B) Lungs
(C) Skin
(D) Liver
Answer: (B) Lungs
What is the role of hemoglobin in respiration?
(A) Transporting oxygen
(B) Breaking down glucose
(C) Producing energy
(D) Storing energy
Answer: (A) Transporting oxygen
Which process releases more energy, aerobic or anaerobic respiration?
(A) Anaerobic respiration
(B) Aerobic respiration
(C) Fermentation
(D) Photosynthesis
Answer: (B) Aerobic respiration
Where in the body does anaerobic respiration usually take place during vigorous exercise?
(A) Liver
(B) Muscles
(C) Lungs
(D) Heart
Answer: (B) Muscles
Which of the following products is formed during anaerobic respiration in human muscles?
(A) Alcohol
(B) Oxygen
(C) Lactic acid
(D) Carbon dioxide
Answer: (C) Lactic acid
What is the function of the diaphragm in the respiratory system?
(A) Absorbs nutrients
(B) Pumps blood
(C) Contracts and expands during breathing
(D) Transports oxygen
Answer: (C) Contracts and expands during breathing
Why do aquatic organisms breathe faster than terrestrial organisms?
(A) They need more oxygen
(B) Less oxygen is dissolved in water
(C) They have larger lungs
(D) They breathe through their skin
Answer: (B) Less oxygen is dissolved in water