Chapter 7 Biology

What is the name given to organisms that can make their own food and thus sustain themselves without consuming organic molecules derived from other organisms?

autotrophs

Thylakoids are arranged in stacks called

grana

Where is chlorophyll found in a plant cell?

thylakoid membranes

The oxygen released into the air as a product of photosynthesis comes from

water

Which of the following molecules is a reactant of photosynthesis?

CO2

A redox reaction involves the transfer of

an electron

Which of the following statements concerning the role of redox reactions in photosynthesis and cellular respiration is true?

In photosynthesis, carbon dioxide is reduced to form sugar, whereas in respiration, sugar is oxidized to form carbon dioxide.

What is the source of energy that provides the boost for electrons during photosynthesis?

light

Which of the following statements comparing photosynthesis and cellular respiration is false?

ATP is not produced during photosynthesis; it is produced only during cellular respiration.

The light reactions occur in the ________, while the Calvin cycle occurs in the ________.

thylakoid membranes; stroma

Photoautotrophs

produce organic molecules from inorganic molecules.

Which of the following are produced during the light reactions of photosynthesis?

ATP, NADPH, O2

Which of the following is part of the light reaction?

formation of waste products in the form of O2

Which of the following are produced during the Calvin cycle?

glucose, ADP, NADP+

Carbon fixation

occurs when carbon atoms from CO2 are incorporated into an organic molecule.

Sunlight is a type of ________ energy.

electromagnetic

Why are most plants green?

Chlorophyll a reflects green light.

Which of the following colors contributes the least energy to photosynthesis?

green

Chlorophyll b

passes absorbed energy to chlorophyll a.

Which of the following is an example of a photoautotroph?

algae in freshwater and marine ecosystems

Plant cells are protected from the harmful effects of excessive light energy and reactive oxidative molecules by

carotenoids

A packet of light energy is called a

photon

Which of the following photosynthetic pigments can be found at the photosystem reaction center?

chlorophyll a

Which of the following molecules is a product of photosynthesis?

glucose and O2

Clusters of light-gathering pigments in a photosystem

pass energy to the reaction center.

In a photosystem, clusters of chlorophyll a, chlorophyll b, and carotenoid pigments function most like

an antenna.

The energy that excites the photosystems is supplied by

photons.

The electron transport chains of the light reactions

shuttle electrons from photosystem II to photosystem I.

Autotrophs that utilize light as their energy source are

photoautotrophs.

As a result of the cascade of electrons down the electron transport chains of the light reactions,

NADP+ is reduced to NADPH.

The electrons lost from the reaction center of photosystem I are replaced by electrons from

photosystem II.

The electrons lost from the reaction center of photosystem II are replaced by electrons from

H2O

Photophosphorylation during photosynthesis differs from oxidative phosphorylation during cellular respiration in that

the final electron acceptor is NADP+ and not oxygen.

In photophosphorylation, energy from electron flow is used to transport ________ from the ________ to the thylakoid compartment, generating a concentration gradient of ________.

H+; stroma; H+

In chloroplasts, ATP synthase

phosphorylates ADP to ATP.

Mitochondria transfer ________ energy from ________ to ATP; chloroplasts transform ________ energy into the chemical energy of ATP.

chemical; food; light

Photosynthetic organisms derive their carbon from

carbon dioxide.

What is the likely origin of chloroplasts?

photosynthetic prokaryotes that lived inside eukaryotic cells

ATP and NADPH

power sugar synthesis during the Calvin cycle.

To produce one glucose, the Calvin cycle needs to be run ________ times.

six

The Calvin cycle constructs ________, an energy-rich molecule that a plant cell can then use to make glucose or other organic molecules.

G3P

The addition of oxygen instead of carbon dioxide to RuBP results in

photorespiration.

What is the main adaptive advantage of the C4 and CAM photosynthesis strategies over the C3 strategy?

They help the plant synthesize glucose efficiently under dry conditions.

Plants use sugars as

a fuel for cellular respiration and a starting material for making other organic molecules.

In most green plants, chloroplasts are

concentrated in a zone of leaf tissue called the mesophyll.

Put the following steps of the light reactions in the correct order:
1. Light excites an electron from photosystem I.
2. Light excites an electron from photosystem II.
3. Electrons reduce NADP+ to NADPH.
4. Electrons pass through an electron transport chain, which generates a H+ gradient used to make ATP.

2, 4, 1, 3

Put the following steps of the Calvin cycle in the correct order:
1. Carbon fixation
2. Regeneration of RuBP
3. Release of G3P
4. Reduction

1, 4, 3, 2

________ cells in leaves are specialized for photosynthesis.

Mesophyll

CO2 enters and O2 escapes from a leaf via

stomata

In the chloroplast, sugars are made in a compartment that is filled with a thick fluid called the

stroma