The exercise

Three questions. The second is the one worth slowing down for — four of its five statements are false, and each is false for a different reason.

1. Underline the correct answer

(i) What is the main product produced in photosynthesis? 1. glucose 2. starch 3. sucrose 4. oxygen
(ii) Through which tissue is the product of photosynthesis transported to the storage sites? 1. xylem 2. phloem 3. parenchyma 4. collenchyma
(iii) As which type of food is the product of photosynthesis translocated? 1. sucrose 2. glucose 3. starch 4. cellulose
(iv) The by-product in photosynthesis is: 1. carbon dioxide 2. nitrogen 3. oxygen 4. carbon monoxide
(v) In photosynthesis, solar energy is converted into: 1. heat energy 2. light energy 3. chemical energy 4. potential energy

2. True or false

Mark each statement with a tick if it is correct and a cross if it is wrong.

(i) When the starch test is carried out on a leaf of a plant kept in the dark for 48 hours, a colour change is seen.
(ii) In carrying out the starch test, the leaf must be boiled in water in order to dissolve the chlorophyll.
(iii) Photosynthesis takes place only inside plant leaves.
(iv) When plant leaves are boiled in water, the permeability of the leaf cell membranes increases.
(v) Photosynthesis is a process that takes place only in green plants.

3. Design an experiment

"Grass that has been covered for about three days turns yellow." Design an experiment to verify this occurrence. Write down the observation and the conclusion.

A note on statement 2(v)

The answer turns on which sentence of this chapter you take as the definition. The chapter defines photosynthesis as taking place inside cells containing chlorophyll — not inside plants. On that definition, any organism whose cells carry chlorophyll can photosynthesise, and grade 10 already told you that algae do, and that algae are Protista rather than plants. The summary’s looser phrase "green plants" describes where most of it happens, not where all of it can.

Question 3 is the whole chapter in one task

It is asking you to design a destarching experiment on a plant that is not in a pot. Think about what you would cover, what you would leave uncovered and why, how long you would wait, and what you would then do to a blade of grass from each area. The answer is activity 2.3 with the polythene replaced by whatever you put over the grass.