Question 14 Marks
Manoj adds some yeast to two test tubes containing sugar solution. He ties balloons on the mouth of each of test tube. One test tube is kept in ice and the other at room temperature. The picture shows what happens after three hours.
(i) What is Manoj investigating ?
$\quad$(a) Does yeast grow in sugar solution only ?
$\quad$(b) Does yeast convert sugar into alcohol ?
$\quad$(c) Does temperature affect the growth of yeast ?
$\quad$(d) Which gas is produced as yeast grows in sugar solution ?
(ii) How can Manoj confirm, if the gas produced in the test tube at room temperature was due to the yeast growing in it ?
$\quad$(a) He should repeat the same experiment
$\quad$(b) He should leave the test tube undisturbed for six hours
$\quad$(c) He should repeat the experiment with test tubes containing more sugar solution
$\quad$(d) He should keep an extra set of test tubes with sugar solution, but without the yeast
(iii) What should Manoj keep the same in both the test tubes for a fair experiment? Circle 'Yes' or 'No' for each row.
(iv) What type of organism is yeast ?
$\quad$(a) Fungi
$\quad$(b) Algae
$\quad$(c) Bacteria
$\quad$(d) Protozoa
(i) What is Manoj investigating ?
$\quad$(a) Does yeast grow in sugar solution only ?
$\quad$(b) Does yeast convert sugar into alcohol ?
$\quad$(c) Does temperature affect the growth of yeast ?
$\quad$(d) Which gas is produced as yeast grows in sugar solution ?
(ii) How can Manoj confirm, if the gas produced in the test tube at room temperature was due to the yeast growing in it ?
$\quad$(a) He should repeat the same experiment
$\quad$(b) He should leave the test tube undisturbed for six hours
$\quad$(c) He should repeat the experiment with test tubes containing more sugar solution
$\quad$(d) He should keep an extra set of test tubes with sugar solution, but without the yeast
(iii) What should Manoj keep the same in both the test tubes for a fair experiment? Circle 'Yes' or 'No' for each row.
| Should this be kept same for both the test tubes ? | Yes or No |
| (a) The concentration of sugar solution | Yes/No |
| (b) The colour of the balloons | Yes/No |
| (c) The amount of yeast added to each test tube | Yes/No |
(iv) What type of organism is yeast ?
$\quad$(a) Fungi
$\quad$(b) Algae
$\quad$(c) Bacteria
$\quad$(d) Protozoa
Answer
View full question & answer→(i) (c) Does temperature affect the growth of yeast?
(ii) (d) He should keep an extra set of test tubes with sugar solution without the yeast.
(iii) (a) Yes
(b) No
(c) Yes
(iv) (a) Fungi
(ii) (d) He should keep an extra set of test tubes with sugar solution without the yeast.
(iii) (a) Yes
(b) No
(c) Yes
(iv) (a) Fungi