Class 10th Science Biology Experiment 12 To show that carbon dioxide is given out during respiration
Aim : To show that carbon dioxide is given out during respiration.
Requirements: A conical flask, beaker, test tube, KOH pellets, a tube bent at right angles, one hole rubberstopper, thread, soaked gram seeds, coloured water, cotton wool, etc.
Procedure :
- Soak gram seeds overnight in water and germinate them by placing the seeds in moist cotton wool for1 to 2 days.
- Place moist germinated seeds in conical flask so that respiration may continue for longer time.
- Suspend a test tube with KOH pellets in the conical flask.
- Fit the cork with bent glass tube to the conical flask. Keep the connection air tight.
- Dip the free end of the bent glass tube in a beaker containing coloured water. Mark the initial level of water in the bent tube.
- Keep this set up undisturbed for about 15 minutes and mark the final level of water in the bent tube.
- Note down the observations.
Diagram :
Observation :
Water in the bent tube rises / falls down. (Underline the correct option and justify your answer.)
Ans. The gas evolved during respiration of germinating seeds is absorbed by KOH pellets. This creates apartial vacuum in the conical flask due to which the water level in the bent tube rises.
Inference : Carbon dioxide gas is given out during respiration in plants.
Multiple Choice Questions
Choose the correct alternative and write its letter (A), (B), (C), (D) in the box :
1. Arrange the steps in correct order to demonstrate that carbon dioxide is produced during respiration. (i) Soak gram seeds overnight and place them in a conical flask. (ii) Fit a cork and U tube into the conical flask. (iii) Suspend a test tube containing KOH pellets in the conical flask. (iv) Keep the set up undisturbed for some time.
(A) i – ii – iii – iv
(B) i – ii – iv – iii
(C) i – iii – ii – iv
(D) i – iii – iv – ii
Answer: C
2. Fermentation is a type of .
(A) aerobic respiration (B) anaerobic respiration (C) endothermic reaction (D) none of these
Answer: B
3. Before setting up the experiment to show that seeds release CO2 during respiration, the seedsshould be .
(A) dried completely (B) boiled to make them soft (C) soaked in vinegar (D) kept moist till they germinate
Answer: D
4. The use of KOH pellets in the experiment is for .
(A) providing O2 required by the seeds for respiration (B) absorbing CO2 and creating partial vacuum in the flask (C) absorbing water from the seeds to make them dry (D) making the air present in the flask alkaline
Answer: B
5. The process of release of energy from the nutrients is called .
(A) respiration (B) photosynthesis (C) nutrition (D) absorption
Answer: A
6. The cellular respiration takes place in
(A) lysosome (B) mitochondrion (C) chlorophyll (D) ribosome
Answer: B