CBSE Revision Notes

Respiration in Organisms Class 7 Extra Questions

Respiration releases energy from food
The oxygen that we inhale breaks down glucose into carbon dioxide and water. This releases the energy
Aerobic respiration uses oxygen to breakdown the food. Anaerobic respiration does not use oxygen
Breathing is a process of respiration during which oxygen is inhaled and carbon-dioxide is exhaled. Please refer Respiration in Organisms Class 7 Extra Questions for more information.

Soil is one of the most important natural resources
Soil is the home for many organisms and it is essential for agriculture
The rotting dead matter in soil is called humus
Soil is formed by the process of weathering
The mixture of rock particles and humus is called the soil
Soil is of different types clayey, loamy and sandy. Please refer Soil Class 7 Extra Questions for more information.

Air exerts pressure and expands on heating and contracts on cooling
Warm air rises up, and the comparatively cool air tends to sink towards the earth’s surface
When warm air rises up, the air pressure at that place becomes less and cooler air moves toward that place
Air moves from a region of high pressure to a region of low pressure
Moving air is called wind. Please refer Winds, Storms and Cyclones Class 7 Extra Questions for more information.

Weather describes the condition of the atmosphere. it might be sunny, hot, windy or cloudy, raining or snowing
The temperature, humidity and other factors are called the elements of weather
Climate is the average weather conditions temperature, pressure, precipitation and humidity – expected for a certain place.
Climate is based on the average weather experienced over 30 years or more. Please refer Weather, Climate and Adaptations of Animals to Climate Class 7 Extra Questions for more information.

There are two types of changes namely physical and chemical changes
Physical changes refers to the changes in the physical properties of substances
Chemical changes refers to the changes in the chemical properties of substances
No new substances are formed in physical changes
A new substance is formed in chemical changes
Rusting of iron is an example of chemical changes. Please refer Physical and Chemical Changes Class 7 Extra Questions for more information.

Substances that tastes sour contains acids and chemical nature of such substances is acidic
Substances which are bitter in taste and feel soapy on touching are bases and chemical nature of such substances is basic
Indicators are used to taste whether a substance is acidic or basic
Litmus is the most commonly used natural indicator. Please refer Acids, Bases and Salts Class 7 Extra Questions for more information.

A reliable measure of an object is its temperature
Thermometer is used to measure the temperature of an object, the temperature that measures our body temperature is called a clinical thermometer
The normal temperature of human body is 37 °C, although the temperature of every person is not 37 °C, it may be slightly higher or lower. Please refer Heat Class 7 Extra Questions for more information.

Some fibres are obtained from plants while some other fibres like wool and silk are obtained from animals
Wool comes from yak, sheep, goat and some other animals
In India, mostly sheep are reared for getting wool
Sheep hair is sheared off from its body, scoured, sorted, dried, dyed, spun and woven to yield wool. Please refer Fibre to Fabric Class 7 Extra Questions for more information.

Carbohydrates, proteins, fats, vitamins and minerals are essential components of food, these components are called nutrients
Humans and animals are dependent directly or indirectly on plants for food
Nutrition is the mode of taking food by an organism and its utilisation by the body
Animals and most other organisms are called heterotrophs as they take in ready-made food prepared by the plants
Animal nutrition includes nutrient requirement, mode of intake of food and its utilisation in the body. Please refer Nutrition in Animals Class 7 Extra Questions for more information.

Carbohydrates, proteins, fats, vitamins, and minerals are essential components of food, these components are called nutrients
Humans and animals are dependent directly or indirectly on plants for food
Nutrition is the mode of taking food by an organism and its utilization by the body
Green plants are called autotrophs as they prepare their own food from simple substances. Please refer Nutrition in Plants Class 7 Extra Questions for more information.