Given below are some activities that will help you to relate the content of topics related to ‘Nutrition and Respiration’ to your daily lives. These activities will make you understand the various processes that take place in the living organisms. Perform theses activities and answer the questions given at the end of each activity.
Activity no.1
Apply a coat of Vaseline/cooking oil on a leaf of a potted plant, observe the leaf for 4-5 days.
Q.1. What happens to the leaf after 4-5 days?
Q.2. What is the reason for these observations.
Q.3. Which processes are effected when you coat the leaf with Vaseline?
Activity no.2
Chew a piece of bread for 3-4 minutes. Note the change in taste as you chew it.
Q.1. Describe the change in taste observed.
Q.2. Why is there a change in taste.
Q.3. Try to write a chemical equation to show the reaction due to which there is a change in taste.(Chemical formulae are not required)
Activity no.3
Take some starchy water that is obtained after boiling rice. Add 2-3 drops of this water to 4 glass bowls (small transparent katories or glasses), you can name them as A, B, C and D. Add a teaspoon of water to each glass bowl. Now add a teaspoon of your saliva to bowl B. Boil a teaspoon of your saliva over a candle flame for 20 seconds and add this to bowl- C. After 10 minutes add 4-5 drops of iodine in each bowl, except bowl D. Tabulate your observations in the following manner-
| Glass Bowl | Quantity of Starchy water | Quantity of water | Quantity of saliva | Colour change observed after 10 minutes. |
| A | | | | |
| B | | | | |
| C | | | | |
| D | | | | |
Give reasons for your observations.
Activity no.4
Take a ripe fruit (orange or mango) and place it in a poly-bag. Tie or paste the open end of the bag so that no air can get inside the bag. Leave it at room temperature for 3-4 days. Take out the fruit and observe.
Q.1. The fruit may be spoilt and may smell of alcohol. Give a reason for this observation.
Q.2. Which type of microorganisms could be responsible for spoiling the fruit. Do they respire in presence of oxygen of absence of oxygen.
Q.3. Try to write a chemical equation to show the reaction due to which there is a change in smell.(Chemical formulae are not required)
2. Answer the following questions:
2.1 What would happen if :
a) Amoeba did not have pseudopodia
b) Liver did not secrete bile juice
c) Rings of cartilage were not present in the throat.
d) Blood did not have haemoglobin
e) There was no transpiration in plants
f) Villi in small intestine did not have blood vessels.
2.2 Differentiate between:
a) Arteries and veins
b) Large intestine and small intestine
c) Aerobic and anaerobic respiration
d) Blood and lymph
e) Mesophyll cells and epidermal cells of a leaf
f) Respiration in man and fish.
No comments:
Post a Comment