Carotenoids are often found in foods that are considered to have
antioxidant properties in human nutrition. What related function do
they have in plants?
Answers:
They serve as accessory pigments to increase light
absorption. They protect against oxidative damage from
excessive light energy. They shield the sensitive
chromosomes of the plant from harmful ultraviolet radiation.
They reflect orange light and enhance red light absorption by
chlorophyll.

2

In a plant, the reactions that produce molecular oxygen
(O2) take place in _____.
Answers:
the light reactions alone the Calvin cycle alone
the light reactions and the Calvin cycle neither the
light reactions nor the Calvin cycle

1

Carbon dioxide is split to form oxygen gas and carbon compounds _____.
Answers:
during photosynthesis during respiration
during photosynthesis and respiration in neither
photosynthesis nor respiration

4

A flask containing photosynthetic green algae and a control flask
containing water with no algae are both placed under a bank of lights,
which are set to cycle between 12 hours of light and 12 hours of dark.
The dissolved oxygen concentrations in both flasks are monitored.
Predict what the relative dissolved oxygen concentrations will be in
the flask with algae compared to the control flask. The dissolved
oxygen in the flask with algae will _____.
Answers:
always be higher always be lower be higher
in the light, but the same in the dark be higher in the
light, but lower in the dark

4

The process of photosynthesis probably originated _____.
Answers:
in plants in prokaryotes in fungi
three separate times during evolution

2

Where does the Calvin cycle take place?
Answers:
stroma of the chloroplast thylakoid membrane
interior of the thylakoid (thylakoid space) outer
membrane of the chloroplast

1

Plants photosynthesize _____.
Answers:
only in the light but respire only in the dark only
in the dark but respire only in the light only in the light
but respire in light and dark and respire only in the
light

3

What wavelength of light in the figure is most effective in driving photosynthesis?
Answers:
420 mm 575 mm 625 mm 730 mm

1

What is the primary function of the Calvin cycle?
Answers:
use NADPH to release carbon dioxide split water and
release oxygen transport RuBP out of the chloroplast
synthesize simple sugars from carbon dioxide

4

When oxygen is released as a result of photosynthesis, it is a direct
by-product of _____.
Answers:
splitting water molecules chemiosmosis the
electron transfer system of photosystem I the electron
transfer system of photosystem II

1

Early investigators thought the oxygen produced by photosynthetic
plants came from carbon dioxide. In fact, it comes from _____.
Answers:
water glucose air electrons from
NADPH

1

What compound provides the reducing power for Calvin cycle reactions?
Answers:
ATP NADH NADP+
NADPH

4

What is the relationship between the wavelength of light and the
quantity of energy per photon?
Answers:
They have a direct, linear relationship. They are
inversely related. They are logarithmically related.
They are separate phenomena.

2

In the thylakoid membranes, the pigment molecules in a
light-harvesting complex _____.
Answers:
split water and release oxygen from the reaction-center
chlorophyll absorb and transfer light energy to the
reaction-center chlorophyll synthesize ATP from ADP and P
i transfer electrons to ferredoxin and then
NADPH

2

What event accompanies energy absorption by chlorophyll (or other
pigment molecules of the antenna complex)?
Answers:
ATP is synthesized from the energy absorbed. A
carboxylation reaction of the Calvin cycle occurs.
Electrons are stripped from NADPH. An electron is
excited.

4

In autumn, the leaves of deciduous trees change colors. This is
because chlorophyll is degraded and _____.
Answers:
carotenoids and other pigments are still present in the
leaves the degraded chlorophyll changes into many other
colors water supply to the leaves has been reduced
sugars are sent to most of the cells of the leaves

1

In its mechanism, photophosphorylation is most similar to _____.
Answers:
substrate-level phosphorylation in glycolysis
oxidative phosphorylation in cellular respiration the
Calvin cycle reduction of NADP+

2

Which of the following are products of the light reactions of
photosynthesis that are utilized in the Calvin cycle?
Answers:
CO2 and glucose H2O and
O2 ADP, Pi, and NADP+
ATP and NADPH

4

The final electron acceptor associated with photosystem I is _____.
Answers:
oxygen water NADP NADPH

3

If pigments from a particular species of plant are extracted and
subjected to paper chromatography, which of the following is most likely?
Answers:
Paper chromatography for the plant would isolate a single band
of pigment that is characteristic of that particular plant.
Paper chromatography would separate the pigments from a
particular plant into several bands. The isolated pigments
would be some shade of green. Paper chromatography would
isolate only the pigments that reflect green light.

2