Which of the following statements about photosynthesis is true?

a. Photosynthesis is an energy consuming process

b. The light-dependent reactions produce the energy-rich compounds that are used up in the light-independent reactions.

c. The light independent reactions can only occur in night

d. Photosynthesis and respiration cannot take place together in plants

I think both c and d are incorrect, but I'm unsure whether a or b is the correct option.

The reason why I think a is correct is that sunlight is used during photosynthesis and b because the hydrogen of $NADPH$ produced during light phase is used to combine with $CO_2$ by utilizing ATP (which again was produced in the light phase ) to make $C_6H_{12}O_6$ in the presence of enzyme Rubisco.

Which of the following is true about photosynthesis?

a. Rate of photosynthesis is directly proportional to concentration of $CO_2$ in the air.

b. Photosynthesis takes place only in the visible spectrum of the electromagnetic radiations.

c. Rate of photosynthesis would be highest under the green light

d. Structure of leaf has no effect on the rate of photosynthesis

Here I am also stuck between either a and b.

The reason why I think a is correct is that when $CO_2$ concentration increases the rate of photosynthesis also increases until the concentration reaches 0.1 % and it could be b because photosynthesis takes place in the presence of sunlight, not any other radiation.

  • 3
    $\begingroup$ Perhaps you didn't read this meta post. $\endgroup$ – WYSIWYG May 31 '16 at 14:19
  • $\begingroup$ @WYISWYG edited ... Now is it ok ? $\endgroup$ – user23312 May 31 '16 at 14:23
  • 1
    $\begingroup$ Nope. Your title should convey the actual question. $\endgroup$ – WYSIWYG May 31 '16 at 14:29
  • $\begingroup$ @WYSIWYG i cant think of more .... can u suggest one please $\endgroup$ – user23312 May 31 '16 at 14:31
  • $\begingroup$ First one: (b) because photosynthesis is overall energy producing process. Second one: (b) since graph between rate of photosynthesis & $CO_2$ concentration is not linear and becomes stagnant after threshold concentration. $\endgroup$ – another 'Homo sapien' May 31 '16 at 14:41

First question:

B. The net gain of ATP in Photosynthesis is 0, so it cannot be A. C & D are obviously not true.

Second question: B. D is not true, C is not true (it is actually the opposite- Chloroplasts absorb all BUT green, so only green would be bad). Like another commentator said, the level of CO2 only aids the rate to a point, at which the rise is not great. http://www.rsc.org/learn-chemistry/content/filerepository/CMP/00/001/068/Rate%20of%20photosynthesis%20limiting%20factors.pdf

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