BIOL 1000 Chapter Notes - Chapter 7: Light-Dependent Reactions, Photosystem Ii, Photosynthetic Reaction Centre

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17 Mar 2016

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Photosynthesis: the use of light energy to convert carbon dioxide into organic compounds such as carbohydrates. Photosynthetic organisms are photoautotrophs, but some are chemoautotrophs. [endif]the light reactions: involve the capture of light energy by pigment molecules (green- chlorophyll, yellow/ orange- carotenoids) and the utilization of that energy to synthesize both nadph and atp. The electrons needed to reduce the nadp+ come from the oxidation of water, resulting in the release of o2. The pigment molecules are precisely bound to specific proteins, and these pigment- proteins are organized into complexes called photosystems: composed of a large antenna. Complex and a reaction centre: has a small number of proteins that bind a special chlorophyll a molecule and an electron accepting molecule called the primary electron acceptor. The function of the photosystem is to trap photons and use the energy to oxidize a reaction centre chlorophyll and the electron is transferred to the primary electron acceptor.

Related Questions

Photosynthesis

Light Reactions:

Photosynthesis is the process of reducing/oxidizing (circle one) _____________________ to produce ___________________. This overall reduction-oxidation reaction requires _________________ to begin the flow of __________________. Photosynthetic ____________________ absorb light energy and are located in ___________________ found embedded within the membranes of __________________. The most prevalent one include the ___________________ which reflect ________________ light and absorb the other wavelengths of light. Accessory pigments include ___________________. When light energy is absorbed in photosynthesis, electrons of pigment molecules become _________________ and move into higher potential energy _______________. When the electrons return to their previous position, _____________ is passed to the ______________________ pigment molecule. Electrons within this pigment molecule move to a high potential energy state and are âgrabbedâ by _________________________ chains. Electrons from photosystem II are passed to ______________________. Electrons from photosystem I are passed to _________________. As electrons move in the electron transport chain associated with photosystem I/II (circle one), the energy released is used to power ___________ pumps and __________ is produced via a process known as ________________________. Photosystem I/II (circle one) electrons must be replaced to continue the reaction so ____________ is split for its electrons. The products _______________ & _______________ then proceed to the ______________________ cycle.

Calvin Cycle:

The Calvin Cycle can be broken into 3 main series of reactions. In the first group, known as the __________________ step, ______________________ combines with 3 molecules of ____________________ to form 6 molecules of _____________________. This reaction is catalyzed by ___________________. ________________ can act as a competitive inhibitor of this enzyme, shutting down this step in a process known as ______________________________. In the second series of reactions known as the __________________ steps, the molecules produced in the previous step get oxidized/reduced (circle one). The source of electrons is _________from the light reactions. This step is endergonic/exergonic (circle one) and thus requires _______ from the light reactions. Six molecules of _____________________ are produced, ______ (#) of which will continue in biosynthetic pathways to produce __________________. The remaining molecules will then enter the ______________________ steps which require _____________ from the light reaction. In this step, 3 molecules of _______________ are produced so that this cyclic reaction can continue.

The complete set of reactions carried out by an organism is called:

a. anabolism

b. catabolism

c. metabolism

Value: 2

The breakdown of starch is broken down to glucose is an example of:

a. anabolism

b. catabolism

c. metabolism

Value: 3

For the following statement, determine which description best describes the process: DNA is synthesized from free nucleotides.

a. anabolism

b. catabolism

c. metabolism

Value: 4

Fill in the blank: Catabolic reactions result in the synthesis of molecules of .............via cellular respiration. This is then used to power anabolic reactions.

Value: 5

The energy in organic molecules is released in a series of steps because:

a. it is not possible to release it in a single step.

b. more total energy is released in multiple steps than would be released in a single step

c. less total energy is released in multiple steps than would be released in a single step.

d. more energy can be harvested for cellular use in multiple steps than from a single step.

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photosynthesis

1-The light reaction of photosynthesis does not include

a. chemiosmosis

b. oxygen liberation

c. glucose synthesis

d. electron transport

Value: 2

Photosynthesis takes place in the membranes of small sacs called

a. thylakoids

b. photosystems

c. stroma

d. photons

Value: 3

During what stage of photosynthesis is O2 produced?

a. the light-dependent reactions involving photosystems I and II

b. carbon fixation

c. the Krebs cycle

d. O2 is not produced during photosynthesis

Value: 4

The pigment molecules responsible for photosynthesis are located in the

a. mitochondria

b. cytoplasm of the cell

c. stroma of the chloroplast

d. thylakoid membrane of the chloroplast

Value: 5

During what stage of photosynthesis are ATP and NADPH converted to ADP + Pi and NADP+?

a. the light-dependent reactions

b. the light-independent reactions

c. both of the above

d. none of the above

Value: 6

What energy-rich organic compound is produced as a result of the Calvin cycle?

a. ATP

b. NADPH

c. glucose

d. H2O

Value: 7

During photosynthesis, photons raise electrons to higher energy levels. These excited electrons belong to what compound?

a. water

b. ATP

c. chlorophyll

d. electron transport chain

Value: 8

Which of the following statements accurately describes the relationship between photosynthesis and cellular respiration?

a. photosynthesis occurs only in autotrophs; cellular respiration occurs only in heterotrophs

b. photosynthesis uses solar energy to convert inorganics to energy-rich organics; respiration breaks down energy-rich organics to synthesize ATP

c. photosynthesis involves the oxidation of glucose; respiration involves the reduction of CO2

d. the primary function of photosynthesis is to use solar energy to synthesize ATP; the primary function of cellular respiration is to break down ATP and release energy

35. During the complete catabolism of glucose, CO2 is released during ____ (note: Krebs cycle = citric acid cycle)
A. glycolysis only
B. Krebs cycle only
C. Krebs cycle and oxidation of pyruvate
D. oxidation of pyruvate only
E. Krebs cycle, glycolysis and oxidation of pyruvate

36. A reaction center, a primary electron acceptor and many chlorophyll molecules are all components of a/an _________ .
A. fluorescence center
B. photosystem
C. electron transport chain
D. carbon-fixation unit
E. electromagnetic spectrum

37. Which of the following generates the most reducing power?
A. anabolism of isoleucine
B. Calvin cycle
C. glycolysis
D. citric acid cycle
E. Hobbes reactions

38. After completion of the citric acid cycle (Krebs cycle), most of the usable energy from the original glucose molecule is in the form of _____.

A. acetyl CoA
B. ATP
C. NADH
D. CO2
E. FADH2

39. The light reactions of photosynthesis occur in:
A. all membranes of the chloroplast
B. the stroma
C. the matrix
D. the tonoplast membrane
E. thylakoid membranes

40. When chloroplasts are illuminated with white light, chlorophyll primarily absorbs:
A. photons of all wavelengths
B. green light only
C. red light only
D. blue light only
E. red and blue light

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BIOL 1000 Chapter Notes - Chapter 7: Light-Dependent Reactions, Photosystem Ii, Photosynthetic Reaction Centre

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