Question

1. What is the overall outcome of the light reactions in photosynthesis?

3. Describe the pathway of electron transfer from photosystem II to photosystem I in light dependent reactions.

4. How and why would the end products of photosynthesis be changed if a plant had a mutation that eliminated its photosystem II complex?

5. Which part of the light-independent reactions would be affected if a cell could not produce the enzyme RuBisCO?

6. Why does it take three turns of the Calvin cycle to produce G3P, the initial product of photosynthesis?

7. Figure 10.6 Which of the following is the correct order of events in mitosis? a. Sister chromatids line up at the metaphase plate. The kinetochore becomes attached to the mitotic spindle. The nucleus reforms and the cell divides. Cohesin proteins break down and the sister chromatids separate. b. The kinetochore becomes attached to the mitotic spindle. Cohesin proteins break down and the sister chromatids separate. Sister chromatids line up at the metaphase plate. The nucleus reforms and the cell divides. c. The kinetochore becomes attached to the cohesin proteins. Sister chromatids line up at the metaphase plate. The kinetochore breaks down and the sister chromatids separate. The nucleus reforms and the cell divides. d. The kinetochore becomes attached to the mitotic spindle. Sister chromatids line up at the metaphase plate. Cohesin proteins break down and the sister chromatids separate. The nucleus reforms and the cell divides.

8. ___________ are changes to the order of nucleotides in a segment of DNA that codes for a protein.

9. Identical copies of chromatin held together by cohesin at the centromere are called _____.

10. List some reasons why a cell that has just completed cytokinesis might enter the G0 phase instead of the G1 phase.

11. What cell-cycle events will be affected in a cell that produces mutated (non-functional) cohesin protein? 1

2. Describe the general conditions that must be met at each of the three main cell-cycle checkpoints.

13. Explain the difference between a proto-oncogene and a tumor-suppressor gene.

14. p53 can trigger apoptosis if certain cell-cycle events fail. How does this regulatory outcome benefit a multicellular organism?

15. Describe how the duplicated bacterial chromosomes are distributed into new daughter cells without the direction of the mitotic spindle.

Answer 1

Question

1. The overall outcome of the light reaction of photosynthesis is the conversation of light energy into chemical energy (ATP, NADPH) that are used by plant to synthesize glucose.

3. The electron transport chain transfer electron from PSII to PSI. These transport of electron develop a proton gradient in the chloroplasts which further change light energy into chemical energy.

4. The PSII of the light reaction is responsible for the splitting of water molecule to generate electrons and production of oxygen gas. But if mutation take place in PSII, it will lead to no evolution of oxygen and no synthesis of glucose molecules.

5. Without the RUBISCO enzyme , Calvin cycle will not able to take place and it will result in no synthesis of carbohydrates.

6. The each cycle of Calvin cycle take one  carbon molecule of carbon dioxide and G3P have three carbon atom, so it take three turns of Calvin cycle to produce G3P.

8. Gene mutation

9. Sister -chromatids

10. The reason could be:

I. Have error in DNA replication.

II. Improper attachment of spindle fibers to the kinotochore.

III. No cell growth

11. Mutated cohesin protein will result in the non-packaginh of chromosomes after DNA replication in the S phase of the interphase.

13. Protooncogene is a normal gene in the body which when mutated with any mutagen like X-ray convert into a oncogene which cause cancer. On the other hand, tumour suppressor gene inactivate any extra growth in the body.

15. The chromosomes are attached to the membrane with the help of specific proteins that help in the duplicated bacterial chromosomes are distributed into new daughter cells.