Free NCERT Solutions for Class 10 Science Chapter 6 Life Processes in PDF form to download. NCERT Solutions for class 10 all subjects are also given in PDF. Download answers of Life Processes ( Page 95, Page 101, Page 105, Page 110, Page 112, Exercises) or study online.
NCERT Solutions for Class 10 Science Chapter 6
Important questions with answers – Frequently Asked in CBSE Board Exams
Some finger like projection are present in the inner wall of small intestine. Write their name. Why are they important?
The fingers-like structure present on the inner surface of the small intestine are called Villi. About five millions of villi are present in the intestines, thus they increase the absorptive surface of the intestine considerably and facilitate quick absorption of the digested food. Each villi contains a network of blood capillaries with a central lacteal vessel (lymph vessel).
Which is the internal energy reserve in plants? Do the animals have the same energy reserve? Justify your answer.
Carbohydrates are utilised for providing energy to the plants and are stored in the form of starch, which serves as the internal energy reserve to be used as and when required by the plant. In animals, carbohydrates are reserved in the form of glycogen, as internal energy reserve. The carbohydrates like starch (in plants) and glycogen (in animals) serve as the internal energy reserve because they are polymer of glucose and their hydrolysis provide glucose molecules to provide energy at the time of need.
Differentiate between Inhalation and Exhalation. “The breathing cycle is rhythemic whereas exchange of gases is a continuous process” Justify the statement.
The blood brings CO_2 form the body parts to be released into the alveoli, and the oxygen in the alveolar cavity is taken up in the alveolar blood vessels to be transported to all the cells in the body. This forms the breathing cycle (taking in air and given out air) is rhythmic. But during breathing cycle, when air is taken in and let out. The lungs always contain a residual volume of air. So that there is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released. Thus, there is some gap in between inspiration (taking in air) and expiration (given out air) during breathing cycle but exchange of gases continuous.
What are nutrients?
Nutrients are substances which an organism obtains from its surroundings and uses it either as an energy source or source of material required for growth and maintenance of the body.
What are the basic materials used during photosynthesis? Write chemical equation for photosynthesis.
Materials used in photosynthesis are (a) Carbon Dioxide and (b) Water. Chemical equation of photosynthesis.
Explain the structure of stomata. Write functions of guard cells.
- The outermost layer of cell i.e., usually the epidermis is not continuous at some place e.g., on the surface of leaves or green herbaceous stems. The epidermis of the young shoot and leaves contains numerous minute pores called stomata. Each stomata opening is surrounded by two semilunar cells known as the guard cells. The term ‘stomata’ (plural – stomata) is applied to the stomatal opening plus the guard cells. The guard cells are living and contains chloroplast. Their inner walls (wall towards opening) are thicker and outer walls thinner.
- Function of guard cells: the guard cells regulate the opening and closing of the stomatal pore. The guard cells swell when water flows into them causing the stomatal pore to open. Because inflow of water in guard cells causes the stretching and bulging of outer thin walls in converse shape. This drags thick walls apart leading to opening of the pore. When there is outflow of water from guard cells, the outer thin walls come to their original position resulting in closure of stomatal pore.
Write major functions of stomata present in the epidermis.
Write two functions of stomata.
Major functions of stomata are:
- Stomata are essential for exchange of gases between the plants and the atmosphere-Oxygen and carbon dioxide.
- Normally, plants eliminate excessive water in the form of vapour through stomatal openings. The process is called transpiration.
- When there is shortage of water, stomatal openings get closed. Thus, reduce water lose. Stomatal opening also close down during night. Thus, stomata regulate water lose from plants i.e., they regulate transpiration.
Stomata remains closed during the day in desert plants. How they get carbon dioxide for photosynthesis?
In desert, temperature is very high so stomata are closed to reduce the loss of water due to transpiration. Therefore, desert plants are adapted to take up carbon dioxide at night when stomata are open. This CO2, taken up in night, prepare an intermediate compound. This intermediate compound is acted upon by the energy absorbed by the chlorophyll during the day to prepare food.
Explain parasitic mode of nutrition with two examples.
Parasitic mode of nutrition: Some organisms derive their nutrition from other plants or animals (hosts). This is known as parasitic mode of nutrition and such organisms are called parasites. Some parasites are ectoparasite. They lived outside of the body of the host and derive their nutrition, the host such as cuscuta, leech, blood sucking mosquitoes etc. are ectoparasite. Some parasites live in the body of the host called endoparasites. For example: tapeworm, some fungi, etc.
Explain the process of nutrition in amoeba with the help of diagrams.
Engulfing of Food: Amoeba obtains food by phagocytosis (a type of holozoic nutrition). Amoeba engulfs the food by forming pseudopodia.
- Two pseudopodia start growing from opposite sides of food particle. They completely encircle the food and their lips touch each other.
- The membranes of both the pseudopodia dissolve at the point of touching and the food is encaptured into the Amoeba (one cell body) in a bag known as food vacuole.
- Digestion of food: Inside the food vacuole, complex substances of the food are broken down into simpler ones. The digested simple substances diffuse from food vacuole into cytoplasm.
- The remaining undigested material is moved near the surface of the single-celled body of amoeba and thrown out.
Example of other unicellular organisms are Paramoecium and Euglena. Pseudopodia also help amoeba in locomotion.
How does nutrition takes place in Paramoecium?
Explain how does Paramoecium obtain its food.
Paramoecium is unicellular animal which has a definite shape (slipper – like).
Paramoecium takes in food at a specific point (through oral groove to mouth to gullet). Food such as bacteria or very small organisms are moved to the specific spot (ingestion point) by the movement of cilia which are present all over the single-celled body.
From the gullet a food vacuole is formed which starts circulating in the endoplasm. During circulation food is digested by enzymes. The digested food diffuses into the cytoplasm and undigested food is thrown out through the pore.
What is emulsification?
Emulsification means a fine dispersion of one liquid in another. In reference to digestion of food, breakdown of large fat globules in the small intestine by the bile juice from liver into fine smaller fat globules so to increase the efficiency of enzyme action, is called emulsification.
a) Where are salivary glands located in human beings?
b) Name the enzyme found in saliva. State the role of saliva in the digestion of food.
Salivary glands secrete their secretion called saliva in the mouth cavity. There are three pairs of salivary glands located in the mouth. Saliva Amylase enzyme.
Role Or Function of saliva:
- Saliva moisten the food thus help in chewing of food by the teeth.
- Human saliva contains an enzyme called salivary amylase that converts starch into maltose (a sugar)
- Saliva also helps in swolling and passage of food chewed food through the food canal which has soft lining.