botany assignment 02

8/10/2019 Botany Assignment 02

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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.

botany assignment 02

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