Question

Fill in the blank.

___1___ of light energy strike the surface of leaves. They excite the electrons in ___2___ molecules found in the chloroplast of plant cells. These molecules are embedded in the ___3___ membrane of the chloroplast.

The electrons are so excited that they leave the chlorophyll molecule and are passed down a chain of molecules called a(n) ___4___ . This process leads to the formation of two high energy molecules called ___5___ and ___6___. Both of these molecules accumulate in the ___7___ of the chloroplast. These reactions make up the ___8___.

In order for these reactions to make more high energy molecules, the excited electrons that left the chlorophyll molecules must be replaced. This happens when ___9___ is split and the electrons are used to replace the chlorophyll electrons. This results in the formation of ___10___, a waste product of photosynthesis.

The high energy molecules are used in the ___11___ to produce sugar molecules in a series of reactions called the Calvin Cycle. The high energy molecules provide the energy to link a ___12___ to a 5C molecule. ___13___ , the enzyme that catalyzes this reaction, is the most abundant protein on Earth. The resulting 6C molecule immediately splits into two 3C molecules. These get rearranged and for every three turns of the cycle, excess 3C is made and can be used to form ___14___ . The remaining 3C molecules are used to regenerate ___15___, the starting molecule of the Calvin Cycle.

The ___16___ are openings in the leaf which allow ___17___ gas to leave the leaf and ___18___ gas to enter the leaf. The overall equation for photosynthesis is:

6___19___ + 6 H₂O + energy à ___20___ + 6 oxygen

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Answer 1

1. Photons : photons are the quantum of light energy .

2. Chlorophyll : these are pigment molecules that absorb light energy.

3. Thylakoid membrane : membrane of chloroplast .

4. Photosynthetic unit : a unit of chrolophyll molecuels.

5. ATP

6. NADPH

7. Grana of chloroplast

8. Light reaction.

9. Water (H2O)

10. Oxygen (O2).

11. Dark reaction

12. 3 C molecule

13. Ribulose-1,5- bisphisphate carboxylase/oxygenase (RuBisCo)

14. Glyceraldehyde 3-phosphate.

15. Ribulose 1,5-bisphisphate

16. Stomatal pore

17. Oxygen

18. Carbon dioxide (CO2).

19. 6 CO2

20. 6 (CH2O).