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Francine Antoinette M. Gonzales September 1, 2013
1F-PHAR Dr. Ross Vasquez
A. DEFINE THE FF:
1. Absorption spectrum
An absorption spectrum is a graph that shows which wavelengths
are most strongly absorbed by a pigment.
2. Action Spectrum
An action spectrum shows which wavelengths are most effectiveat powering a photochemical process.
3. Anabolic reactions
4. Anoxygenic photosynthesis
5. ATP synthetase
6. Bacteriochlorophylls
7. C3(Calvin/Benson) cycle
8. C4 metabolism
9. Chemiosmotic phosphorylation
The necessary ATP is also generated by the light reactions, but the
process is indirect. It is phosphorylation because light is involved.
10. Chlorophyll
11. Crassulacean acid metabolism (CAM)
12. Cyclic electron transport
13. Cytochromes
14. Electron transport chain
15. Entropy
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Entropy is the process by which plants absorb diffusely scattered
molecules, cells, tissues, and organs.
16. Gluconeogenesis
17. Greenhouse effect
18. Heterotrophs
19. Light compensation point
20. Light-dependent reactions
21. Noncyclic electron transport
22. Oxidation state
23. Oxidative phosphorylation
24. Oxidized compounds
B. ANSWER THE FF. QUESTIONS:
1. What is the meaning of the word entropy? Does the entropy of a plant
increase or decrease while it is alive? After it is dead?
Entropy is the process by which plants absorb diffusely scattered
molecules, cells, tissues, and organs. After death, decay is the process
by which an organisms molecules become more disordered and
scatteredtheir entropy increases.
2. Name several examples of autotrophs and several of heterotrophs.
How do phototrophs obtain energy? Can a plant be heterotrophic while
a seedling and photoautotrophic when older?
Photoautotrophs gather energy directly from light. No, a plant
cant be heterotrophic while a seedling and photoautotrophic when
older because heterotrophs cannot obtain energy from light, they
obtain energy from organic materials.
3. ATP is an important chemical involved in many of a plant and
animals metabolic reactions. Yet any plant has only a small amount of
it. Can you explain this? When ATP enters a reaction and forces it to
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proceed, what is the ATP converted into? What then happens to the
molecule?
ATP only constitutes a tiny fraction of the plant body because
each molecule is recycled and reused, repeatedly thousands of timesper second. ATP Is converted to ADP and phosphate by metabolic
reactions. Then each molecule is an energy carrier, shuttling between
reactions that release energy and consume it.
4. Name the three methods of phosphorylation.
The three methods for phosphorylation are
photophosphorylation, substrate-level phosphorylation and oxidative
phosphorylation.
5.What is a reduction reaction? Why does a reduction reaction always
occur simultaneously with an oxidation reaction?
A reduction reaction is one that reduces the positive charge on
an atom. Oxidized compounds often (but not always) contain a great
deal of oxygen while reduced compounds contain hydrogen. Oxygen
has a strong tendency to pull electrons away from an atom and raisethat atoms partial positive charge, but hydrogen becomes more
stable by giving up electrons, reducing its partners partial positive
charge thats why does a reduction reaction always occur
simultaneously with an oxidation reaction.
6.In organic molecules, we calculate the oxidation state of the carbon
by assuming that each oxygen has an oxidation state of -2 .
Each hydrogen has an oxidation state of +1 . Calculate the
oxidation state of carbon in each of the following: CO2, CH2O and
mallic acid.
The oxidation state of carbon in CO2 = +4, CH2O = 0 and mallic
acid = +4.
7. Two of the following are oxidizing agents and two are reducing
agents. Which are which: NAD+, NADP+, NADH and NADPH?
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The oxidizing agents are NAD+ and NADP+ while the reducing
agents are NADH and NADPH.
8. In photosynthesis, what is the ultimate source of electrons? What is
the benefits of this molecule in terms of its toxicity and the cost of theplant to obtain it?
The ultimate source of electrons to form carbohydrates in
photosynthesis is carbon dioxide with water. T he benefits of this
molecule is first, both carbon dioxide and water are abundant and
cheap, occurring almost everywhere in large quantities. Second is that
they are very stable and contain little chemical energy, so it is possible
to deposit a large amount of energy into them. And finally, both the
reactants and the products of photosynthesis are nontoxic.
9. Describe the absorption spectrum of chlorophyll. Why does it match
with the action spectrum of photosynthesis?
An absorption spectrum is a graph that shows which wavelengths
are most strongly absorbed by a pigment while an action spectrum
shows which wavelengths are most effective at powering a
photochemical process. And to initiate a photochemical process, light
must first be absorbed; therefore, the action spectrum of a process
must match the absorption spectrum of the pigments possible.
10. Chlorophyll does not use high energy quanta. Why not? What would
happen to the chlorophyll if it did? It also does not use long wavelength
radiation either. Why not?
Quanta with intermediate wavelengths pass right through the
pigment and photosynthesis is low. And because the absorption
spectrum and wavelengths of both chlorophylls differ, more
wavelengths are harvested. If the two match perfectly, one chlorophyll
would be useless.
11. The most common accessory pigments in the land plants are
chlorophyll b and the carotenoids . Algae that live deep
in water have other accessory pigments because only absorbing-
excessive light penetrate deeply into water.
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12. Name the electron carriers that transport electrons from
photosystem II to photosystem I. Which ones contain metal atoms, and
which do not?
The electron carriers that transport electrons from photosystem IIto photosystem I are FX, which contains iron and and sulfur atoms;
ferrodoxin, which also contains iron and and sulfur atoms; and
ferrodoxin-NADP+reductase.
13. When photosystem I produces NADPH, its reaction center P700
chlorophyll a loses electrons. What would happen if photosystem II did
not supply new electrons to P700?
Bonding orbitals would not be easily rearranged, and moleculeswould not be broken down and destroyed. There must be a
mechanism that adds electrons back to the P700, reducing it so that it
can work repeatedly.
14. When electrons are removed from water, protons are liberated.
Does this occur in the stroma or inside the thylakoid lumen? Can
protons move directly across the membrane? Describe the
chemiosmotic mechanism of ATP synthesis in chloroplasts.
It occurs in the thylakoid lumen and protons cannot move directly
across the membrane. The necessary ATP is also generated by the light
reactions, but the process is indirect. It is phosphorylation because light
is involved, but a more specific name is often used: chemiosmotic
phosphorylation.