This set of Protein Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Structure Function Relationships – Photosynthetic Reaction Center”.
1. Which of the following is responsible for the primary energy conversion reactions of photosynthesis?
a) Electron transport center
c) Photooxidation center
d) Photosynthetic reaction center
Explanation: The photosynthetic reaction center is responsible for the primary energy conversion reactions of photosynthesis. Photosynthetic reaction centers consist of several proteins, pigments, and co-factors. It contains an α helix bundle which is formed from two different protein subunits. The electron transport center, rhodopsin, and photooxidation center are not responsible for the primary energy conversion reactions of photosynthesis.
2. Which reaction is shown in the figure below?
a) Cellular respiration
b) Oxidation reaction
Explanation: The reaction shown in the figure above is photosynthesis. The process by which plants and other organisms convert light energy into chemical energy is called photosynthesis. It is vital to the survival of living organisms.
3. Photosynthetic reaction centers are present only in plants.
Explanation: The above statement is false. Photosynthetic reaction centers are present in plants and many bacteria and algae. Green plants have two reaction centers known as Photosystem I and Photosystem II.
4. Light is made up of small bundles of energy. What are these bundles called?
Explanation: Light is made up of small bundles of energy called photons. The photon is a type of elementary particle. Photons are massless, and they always move at the speed of light in a vacuum. If a photon with the right amount of energy hits an electron it will raise the electron to a higher level.
5. Which of the following is not an electron acceptor in the electron transport chain of plants?
Explanation: Phycobilins are not an electron acceptor in the electron transport chain of plants. In green plants, the electron transport chain that follows has many-electron acceptors including phaeophytin, quinone, plastoquinone, cytochrome bf, and ferredoxin that ultimately results in the reduced molecule NADPH.
6. Which of the following is used in the Calvin cycle to fix carbon dioxide into triose sugars?
a) Either ATP or NADPH
b) Only ATP
c) Only NADPH
d) Both ATP and NADPH
Explanation: Both ATP and NADPH are used in the Calvin cycle to fix carbon dioxide into triose sugars. The Calvin cycle or light-independent reactions are the chemical reactions that convert carbon dioxide and other compounds into glucose.
7. Which of the following is the site of photosynthetic light reactions in plants?
a) Mitochondrial membrane
b) Chloroplast membrane
c) Cellular membrane
d) Thylakoid membrane
Explanation: The Thylakoid membrane is the site of photosynthetic light reactions in plants. In the stroma of the chloroplast, there are tiny membrane sacs, called thylakoids. The thylakoid membranes are the site of photosynthetic light reactions. The thylakoid is thus the location for light absorption and ATP synthesis.
8. Electrons are most stable at their highest energy level.
Explanation: The above statement is false. The electrons are most stable at their lowest energy level or ground state, the orbit in which the electron has the least amount of energy.
9. Which of the following is not true for chloroplasts?
a) It holds 70S ribosomes
b) It is semi-autonomous
c) It divides by binary fission
d) It has linear ds DNA
Explanation: Chloroplast is a semi-autonomous structure and it divides by the process of binary fission, as it occurs in bacteria. It has a nucleoid region that contains the circular ds DNA. It also has 70S ribosomes.
10. Which of the following phenomenon is key to the conversion of light energy to chemical energy?
a) Proton transfer
b) Electron excitation
c) Electron degradation
d) Electron transfer
Explanation: Electron transfer is the phenomenon that is key to the conversion of light energy to chemical energy. In the photosynthetic reaction center, the photosensitive pigments absorb light energy. The photons present in the light transfer their energy to electrons, which then rises to higher energy levels. This pigment then achieves a tendency to donate electrons.
11. Which among the following is the central metal ion in chlorophyll?
Explanation: Mg+2 is the central metal ion in chlorophyll. Chlorophyll is the major photosynthetic pigment in plants. It contains a polycyclic, planar tetrapyrrole ring. It is a part of the photosynthetic reaction center.
12. Find the odd one out.
b) Chlorophyll b
d) Chlorophyll a
Explanation: Chlorophyll is an essential photosynthetic pigment. Phycobilins, chlorophyll b, and carotenoids are accessory photosynthetic pigments. Carotenoids and phycobilins absorb light in the wavelength region where chlorophylls do not absorb strongly.
13. The first role of carotenoids is as a “quencher”.
Explanation: The above statement is false. The first role of carotenoids is as an accessory light-harvesting pigment. The other role of carotenoids is as a quencher of triplet chlorophyll to protect against photo-oxidative damage.
14. Chlorophyll is the essential photosynthetic pigment.
Explanation: The above statement is true. Chlorophyll is the essential photosynthetic pigment. In a pure state, chlorophyll is blue-green. It absorbs more towards red wavelength than the violet-blue wavelength of light. The pyrrole ring II in chlorophyll contains a methyl group.
15. Which property is shown by a molecule whose electron is raised to a higher energy level?
a) Lesser tendency to accept an electron
b) Greater tendency to accept an electron
c) Lesser tendency to donate an electron
d) Greater tendency to donate an electron
Explanation: A molecule whose electron is raised to higher energy levels shows a greater tendency to donate an electron. When an electron rises to a higher energy level it increases the reduction potential of the molecule.
Sanfoundry Global Education & Learning Series – Protein Engineering.
To practice all areas of Protein Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.
Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!