BIOCHEM 523 Lecture Notes - Lecture 20: Light-Dependent Reactions, Mitochondrial Matrix, Light-Independent Reactions

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cerisebuffalo390

1 Jan 2018

School

UMASS-Amherst

Department

Biochemistry & Molecular Bio.

Course

BIOCHEM 523

Professor

James Staros

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Document Summary

6co2 + 6h2o c6h12o6 + 6o2 (net) Mechanistically, co2 + 2h2o ch2o + o2 + h2o, because the o atoms in o2, all come from h2o, not co2. Photosynthesis requires a reductant, usually h2o, to reduce co2 to the carbohydrate. In the first subprocess, in a series of steps called the light reactions, energy from sunlight level is used to carry out the photochemical oxidation of h2o. First, the oxidizing agent nadp+ is reduced to nadph and o2 is released. In the second subprocess, the so-called dark reactions of photosynthesis, the nadph produce atp (photophosphorylation) and atp produced by the light reactions are used in the reductive synthesis of carbohydrate from co2 and water. Chloroplasts: the photosynthetic organelle of green plants and algae. In all higher plants and algae, photosynthetic processes are localized in chloroplasts. There is an outer, freely permeable membrane and an inner membrane that is.

Related Questions

1. All of the following are correct descriptions of photosynthesis except:

A) The Calvin Cycle is endergonic.

B) Electrons are supplied to the reaction center via the splitting of water, which yields O2 as a byproduct

C) Chlorophyll and accessory pigments capture energy from the sun in the form of electrons, which they use to drive the electron transport chains of photosystems I and II.

D) ATP and NADPH generated in the light-dependent reactions are used to power CO2 fixation via the Calvin cycle in the light-independent reactions.

2. In glycolysis and the TCA cycle, glucose is _____ down to CO2; this process _____ lots of ATP and reducing power. In photosynthesis, CO2 is ______ back to sugar by the _______ of lots of ATP and reducing power.

A) reduced; requires; oxidized; production

B) oxidized; requires; reduced; production

C) oxidized; produces; reduced; input

D) reduced; produced; oxidized; input

3. Which description accurately compares cellular respiration and photosynthesis?

A) Photosynthesis uses energy captured from sunlight to power the reduction of carbon dioxide to sugars; cellular respiration oxidizes sugars to yield energy for the cell.

B) The ATP produced via cellular respiration is needed to power the reactions of photosynthesis

C) The pathways of photosynthesis are those of cellular respiration run in reverse.

D) Photosynthesis captures energy from sunlight to oxidize carbon dioxide to sugars; cellular respiration reduces these sugars to yield energy for the cell.

Question 1 The membrane structures inside the chloroplast are called the ______, while the fluid surrounding the stacks of membrane is called the ______.
a. stroma; thylakoid
b. thylakoid; cytosol
c. thylakoid; stroma
d. thylakoid; matrix
e. matrix; thylakoid

Question 2 What is considered the ultimate source of energy for living things on Earth?
a. the sun
b. electrons
c. green plants
d. oxygen
e. ATP

Question 3 Why do most plant leaves appear green?
a. They contain a lot of starch which has a green color.
b. They have chloroplasts which absorb green light for photosynthesis.
c. During the light reaction phase carbon dioxide is converted to oxygen which emits green light.
d. They have chloroplasts which absorb all colors of light except for green, which is reflected.
e. During the dark reaction phase water is converted to oxygen which emits green light.

Question 4 Plants perform only photosynthesis, not respiration. True False

Question 5 What is the primary purpose of the light reactions of photosynthesis?
a. to create oxygen gas
b. to produce glucose
c. to convert solar energy to chemical energy (in the form of ATP and NADPH) to power the dark reactions
d. to remove carbon dioxide gas from the atmosphere
e. to create water

Question 6 The light dependent reactions occur in the:
a. mitochondrial membrane.
b. mitochondrial matrix.
c. stroma.
d. thylakoid membrane.
e. cytosol.

Question 7 The energy to run the dark reactions of photosynthesis is produced _________.
a. by the CO2 initially used in the dark reactions.
b. during glycolysis
c. during the light reaction phase
d. during the Krebs cycle
e. during anaerobic respiration

Question 8 Which of the following substances could be totally eliminated and not interfere with the process of photosynthesis?
a. O2
b. H2O
c. light
d. CO2

Question 9 What product(s) do plants produce during photosynthesis that is/are used by humans and other animals?
a. carbon dioxide
b. carbon dioxide and water
c. glucose and oxygen
d. glucose
e. oxygen

Question 10 Only plants can carry out photosynthesis. True False

Question 11 During the light reactions of photosynthesis, ...
a. oxygen is produced from H2O.
b. glycolysis occurs.
c. the Krebs cycle occurs.
d. CO2 is combined into glucose.
e. ATP is broken down to ADP + P

Question 12 The reactants of photosynthesis are:
a. sugar.
b. sugar and water.
c. O2 and CO2
d. O2 and sugar.
e. CO2 and water.

Question 13 During the dark reaction phase of photosynthesis in plants...
a. ATP is created.
b. H+ ions are moved into the stroma from the matrix.
c. molecules of CO2 are combined into sugar.
d. H2O is split into oxygen and H+.
e. solar energy is converted to chemical energy.

coffeelion96

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

BIOCHEM 523 Lecture Notes - Lecture 20: Light-Dependent Reactions, Mitochondrial Matrix, Light-Independent Reactions

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