ExamGOAL
Books
PreviousNext
17
Cyanobacteria and some other photosynthetic bacteria don't have chloroplasts. How do they conduct photosynthesis?
Explanation
The cyanobacteria and photosynthetic bacteria are prokaryotes. They do not have well defined membrane bound cell organelles, but these organisms have photosynthetic pigments in a membranous form, which are primitive in nature but can trap and use solar energy. So, they can carry out photosynthesis.
18

(a) NADP reductase enzyme is located on .............. .

(b) Breakdown of proton gradient leads to release of ............ .

Explanation

(a) NADP reductase enzyme is located on the outer side of thylakoid membrane. It is bounded to the thylakoid membrance in light and becomes free in stroma during dark.

(b) ATP Molecules The movement of $\mathrm{H}^{+}$ions across the membrane is coupled with the formation of ATP synthesis in presence of enzyme ATP synthase.

19
Can girdling experiments be done in monocots? If yes, How? If no, why not?
Explanation
The girdling experiment cannot be done in monocots. The monocot stem has vascular bundles scattered all over the width of stem so, we cannot reach that specific band of the phloem tissues as we get in dicots.
20

$$\begin{aligned} 3 \mathrm{CO}_2+9 \mathrm{ATP}+6 \mathrm{NADPH}+\text { water } \longrightarrow & \text { Glyceraldehyde } 3-\text { phosphate } \\ + & 9 \mathrm{ADP}+6 \mathrm{NADP}^{+}+8 \mathrm{Pi} . \end{aligned}$$

Analyse the above reaction and answer the following questions

(a) How many molecules of ATP and NADPH are required to fix one molecule of $\mathrm{CO}_2$ ?

(b) Where in the chloroplast does this process occur?

Explanation

(a) 2 molecules of ATP for phosphorylation and two molecules of NADPH for reduction are required per $\mathrm{CO}_2$ molecule fixed.

(b) The calvin cycle occurs in the stroma of the chloroplast.

21
Does moonlight support photosynthesis? Find out.
Explanation
Plants cannot carry out photosynthesis in moonlight because it does not carry enough energy to excite chlorophyll molecule, i.e., reaction centres PS I and PS II, so light dependent reactions does not get initiate. Thus, no photosynthesis occurs in presence of moonlight.
PreviousNext