8th standard science notes nutrition and respiration lesson
Answers
Question 7.
What are epiphytes?
Answer:
The photosynthetic plants which take shelter in the host tree are called epiphytes, example: orchids
Explanation:
Question 1.
The process of obtaining food and utilizing it in the body is …………………………
(a) respiration
(b) nutrition
(c) excretion
(d) reproduction
Answer:
(b) nutrition
KSEEB Solutions for Class 8 Science Chapter 19 Nutrition and Respiration
Question 2.
One of these is a product of photosynthesis …………………………
(a) starch
(b) glucose
(c) maltose
(d) sucrose
Answer:
(a) starch
Question 3.
Insectivorous plants commonly grow in areas where soil is deficient in …………………………
(a) carbon
(b) nitrogen
(c) potassium
(d) phosphorus
Answer:
(b) nitrogen
Question 4.
A person applies hydrogen peroxide on his wound. This is to kill …………………………
(a) anaerobic bacteria
(b) aerobic bacteria
(c) fungi
(d) protozoa
Answer:
(c) fungi
KSEEB Solutions for Class 8 Science Chapter 19 Nutrition and Respiration
Question 5.
Amylase converts starch to …………………………
(a) glucose
(b) sucrose
(c) lactose
(d) maltose
Answer:
(d) maltose
II. Answer the following:
Question 1.
What are life processes?
Answer:
The processes Such as respiration, nutrition, growth movement response to Stimuli excretion and reproduction called as life processes.
Question 2.
Explain the method of testing a leaf for starch.
Answer:
Collect a few leaves from a plant. Put them it in water for some time and then take out. Then dip them in a spirit and then in iodine solution. Observe that the leaf turns blue-black, showing the presence of starch.
Question 3.
Explain an experiment to demonstrate that oxygen is released during photosynthesis.
KSEEB Solutions for Class 8 Science Chapter 19 Nutrition and Respiration 1
Beaker kept In cupboard – Beaker kept in sun
Answer:
Take two beakers filled with water. Add a few crystals of sodium bicarbonate to both. Place Hydriila plants in both beakers kept in sun and invert large funnels over them. Take two test tubes.
KSEEB Solutions for Class 8 Science Chapter 19 Nutrition and Respiration
Place small pieces of steel wool into the bottom and fill the test tubes with water and invert them over the narrow ends of each, of the funnel. Place one of the beakers in a bright sunny area and the other in a dark cupboard for about 48 hours.
Take the test tube. Test the gas collected in the test by introducing splinters. The splinter burns brightly in the gas collected in the test tube which is kept outside, but not in the one kept in the cupboard.
Also, the steelwool in the test tube kept in sun turns brown due to oxidation. From this experiment, we can show that the gas released during photosynthesis is oxygen.
Question 4.
Differentiate between the two phases of photosynthesis.
Answer:
Light-dependent reaction
Takes place in the presence of sunlight
Takes place in the grana region of the chloroplast
During this reaction, water is decomposed into hydroxyl and hydrogen ions by the help of light energy
Oxygen is given out in this reaction
light energy is converted into chemical energy and stored in the form of ATP
known as photochemical reaction Light independent reaction
takes place in the without using sunlight
takes place in the stroma region of the chloroplast.
in this reaction, C02 is reduced to starch utilizing the energy released during the light-dependent reaction.
known as Calvin cycle
KSEEB Solutions for Class 8 Science Chapter 19 Nutrition and Respiration
Question 5.
What are parasites? Give two examples.
Answer:
The organisms which obtain food from other organisms are called parasites. There are two types namely, semi parasites, and total parasites.
Semiparasite example:- Viscum
Total parasite example:- Cuscuta, intestinal worms like Tapeworm, roundworm, etc.
Question 6.
Amoeba cannot digest fats, why?
Answer:
Amoeba has no enzyme to digest fats, like lipase to convert fats into simple fats. Therefore amoeba cannot digest fats.