BIO CH 6

Which of the following is a coenzyme?

NADP+

The _______ from the light reactions is used to reduce CO2 to a carbohydrate using energy derived from ______.

NADPH; ATP

What of the following is a disadvantage of C4 photosynthesis relative to C3 photosynthesis?

need for energy to move fixed carbon in C4 compound into bundle sheath cells

In a high latitude rainforest, the dominant type of photosynthesis is most likely to be

not C3 and CAM or CAM C3 plants are generally more successful in environments with moderate temperatures and plentiful water. Under these conditions, it is not necessary to close stomata during the daytime to minimize water loss.

ATP and NADPH are both used during the Calvin cycle. What is the function of each?

ATP supplies energy and NADPH supplies electrons for reducing power.

How many times must the Calvin cycle turn to yield a single molecule of glyceraldehydes-3-phosphate (G3P).

3

A poison that disrupts the H+ gradient in the thylakoid space would most likely cause which of the following to accumulate during the Calvin cycle reactions?

3-phosphoglycerate (3PG)

How many turns of the Calvin cycle would be required for a plant to make one molecule of glucose?

6

Which of the labeled cells of a C3 leaf does not perform photosynthesis?

A and D

In which of the labeled cells of a C4 leaf are the Calvin cycle reactions performed?

C only

A small, low-growing plant found on the surface of a sun-exposed rock on a dry hillside would most likely use which type of photosynthesis?

CAM

As climate change leads to drier and drier summers in the southeastern U.S., more and more homeowners find that they have crabgrass growing in their yards. The reason for this is that

Crabgrass is a type of C4 plant that does well in dry climates.

Which compounds link the light reactions with the Calvin cycle reactions?

ATP and NADPH

The light reactions act much as a battery to power the reactions of the Calvin cycle. This energy is stored as

ATP and NADPH.

The light reactions produce __________, which are used in the Calvin cycle. The Calvin cycle produces __________, which are in turn used in the light reactions.

ATP and NADPH; ADP and NADP

Grana are

Flattened sacs of thylakoid membrane.

Not all molecules contain the same amount of chemical energy. The energy relationship between G33P and CO2 is

G3P has more energy than CO2.

Sucrose, cellulose, amino acids, and starch are all made from what starter molecule in plants?

Glyceraldehyde-3-phosphate (G3P)

What two things are added to NADP+ to convert it into NADPH?

H+ and electrons

Energy to drive the formation of ATP in photosynthesis is derived from ____________.

H+ gradient

Replacement electrons for the reaction center of photosystem II are derived from __________.

H2O

The O2 given off during photosynthesis is derived from which compound?

H2O

The light reactions of photosynthesis are said to be similar to a battery because they form a current. In which direction do the electrons of this circuit flow?

H2O → PSII → electron transport chain → PSI → electron transport chain → NADPH

How does ATP synthase obtain the energy to produce ATP?

Hydrogen ions flow down a concentration gradient from the thylakoid space to the stroma through ATP synthase, releasing energy that can be used to produce ATP from ADP + Pi.

In C4 plants, the light reactions will stop during the daytime when the supply of what compound is limited?

NADP+

Which of the following is not derived from G3P?

NADP+

Which complex or enzyme of photosynthesis consumes H2O?

Photosystem II

Why do plants contain other pigments besides chlorophyll?

The additional pigments are able to absorb other light wavelengths that chlorophyll cannot.

ATP synthase derives energy for the generation of ATP from

The movement of hydrogen ions down their concentration gradient from the thylakoid space to the stroma.

The chlorophyll a molecules in the reaction center of a photosystem participate directly in the capture of solar energy. What is the purpose of the accessory pigments?

They funnel solar energy to chlorophyll a in the reaction center.

A coenzyme is defined as

a non-protein helper that works with an enzyme.

Which of the following organisms can perform photosynthesis?

algae

In photosynthesis, the light reactions ____________ while the Calvin cycle ____________.

capture solar energy; converts the captured energy to chemical potential energy

The reaction center of photosystem I consists of what type of molecule?

chlorophyll a

The reaction center of each photosystem

funnels electrons to a central chlorophyll a molecule.

In a redox reaction, reduction means _________, and oxidation means _________.

gain of electrons; loss of electrons

Before being converted into sucrose, starch, or cellulose, G3P must first be converted into which compound?

glucose phosphate

The end product of the Calvin cycle reactions is ___________.

glyceraldehyde-3-phosphate (G3P)

A plant that uses CAM photosynthesis is most likely to be successful in what type of environment?

hot, dry

In C4 plants, chloroplasts are located

in both mesophyll and bundle sheath cells.

What is the major disadvantage of CAM photosynthesis relative to C3 or C4 photosynthesis?

lower G3P yield

CAM photosynthesis limits CO2 fixation to nighttime hours in order to

open stomata only at night, limiting water loss because of heat and low humidity.

RuBP carboxylase (rubisco) is able to bind with both

oxygen and carbon dioxide

During photosynthesis, ___________ is oxidized, while ___________ is reduced.

water; carbon dioxide

Which of the following events does NOT take place in the light reactions?

conversion of 3PG to G3P

The difference between bundle sheath cells in C3 and C4 plants is that

the bundle sheath cells in C4 plants have chloroplasts while those in C3 plants do not.

The localization of the electron transport chains to the thylakoid membrane ensures that

the energy released can be used to establish an H+ ion gradient.

Inside the chloroplasts, chlorophyll is found in the

thylakoid membrane

The light-harvesting complexes of a chloroplast are located in the ______; the enzymes of the Calvin cycle reactions are located in the _________.

thylakoid membrane; stroma

The innermost compartment of a chloroplast formed by the interconnected thylakoids is the

thylakoid space.

The Calvin cycle reactions only occur in bundle sheath cells in a C4 plant

to shield the Calvin cycle reactions from O2 in the leaf spaces.

The three stages of the Calvin cycle reactions are

CO2 fixation, CO2 reduction, and RuBP regeneration.

Which stages of the Calvin cycle reactions require the use of energy from ATP?

CO2 reduction and RuBP regeneration

Carotenoids are found in high concentrations in yellow and orange leaves or vegetables. This color is seen because the carotenoid pigments

Reflect and transmit yellow and orange wavelengths of light.

Chlorophyll is to the light reactions as ___ is to the Calvin cycle.

RuBP

Which of the following correctly describes CO2 fixation in a C3 plant?

Rubisco combines CO2 with RuBP to form a 6-carbon compound that then breaks down into two 3-carbon compounds.

A new species of plant is discovered and you are asked to help classify it. Upon examination under a microscope, you find that there is a layer of bundle sheath cells containing chloroplasts around the vein of the leaf of the plant. What can you tell about the plant from this?

This plant very likely carries out C4 photosynthesis.

The production of glyceraldehyde-3-phosphate (G3P) in the Calvin cycle requires 6 molecules each of ATP and NADPH. Another 3 molecules of ATP are then used in the cycle. What is the purpose of the 3 additional ATP molecules?

To regenerate the starter molecule RuBP.

The enzyme-rich solution found within the chloroplast is called the ________.

stroma