Photosynthesis Unit Test Review

How many molecules of CO2 must enter the Calvin cycle for the synthesis of one molecule of glucose?

6

Which of the following is the balanced equation for the generation of sugar from sunlight, water, and CO2?

6 CO2 + 6H2O → C6H12O6 + 6 O2

The light reactions of photosynthesis provide the Calvin cycle with

ATP and NADPH

Photosynthetic activity can be measured using choloroplasts suspened in a buffered solution containing DCPIP, a dye that can accept electrons from the electron transport chain of photosyntheis. Transfer of electrons to DCPIP decreases the relative absorbance of a specifice wavelength of light (605 nm) by a solution that contains the dye. A buffered solution containing the cholorplasts and DCPIP was divided equally among six identical samples. The samples were placed at various distances from a lamp, and then all samples were exposed to white light from the lamp for 60 minutes at room temperature. Sample 3 was wrapped in foil to prevent any light from reaching the solution. At 20-minute intervals, the photosynthetic activity in each sample was determined by measuring the relative absorbance of 605 nm light. The results of the experiment are provided below. Which of the following provides the best indication that light is required for the activation of electron transfer reactions in chloroplasts?

Comparing the observed results from sample 2 and sample 3

In what respect are the photosynthesis adaptations of C4 plants and CAM plants similar?

In both cases, an enzyme other than Rubisco carries out the first step in carbon fixation

Which of the following can be reasonably concluded from the experiment results?

Light from a lamp can subsitute for sunlight in stimulating chloroplast processes

What is the final electron acceptor during the light reactions?

NADP+

Which of the following statements is NOT correct?

Plant cells do not usually have mitochondria because ATP is made by chloroplasts

Which of the following statements is NOT correct?

Sugar production in CAM plants can continue throughout the night

In addition to the pigments commonly associated with photosynthesis, a certain photosynthetic species contains two additional pigment types. Which of the following best supports the claim that this species is better adapted to environmental changes than other photosynthetic species are?

The additional pigments allow the species containing them to harvest energy from wavelenths of light that the other photosynthetic species cannot use

If an additional sample containing the chloroplasts/DCPIP solution was placed at a distance of 90 cm from the lamp, which of the following predictions would be most consistent with the experimental results?

The change in absorbance over time in the solution will be less than that of the other non-control samples

The first pathway of photosynthesis, in which light energy is converted into chemical energy in the form of ATP and NADPH, is referred to as the

light reactions

Trays of young plant seedlings are intially grown in a greenhouse under natural light conditions. The seedlings moved to a room with only a green light source. The figure below shows the absorption spectrum for the pigment chlorophyll a, which the seedlings possess. Based on the figure, which of the following best predicts the effect of the green light on seedling growth rate?

The seedling will exhibit an increased growth rate because chloropyll a fail to absorb green light efficiently

Plants are green because

chlorophylls absorb blue and orange-red wavelengths of light and not green

The NADPH required for 3PG reduction is formed

during the light reactions

In both photosynthesis and cellular respiration, protons are pumped across a membrane during

electron transport chain

Compared to long-wavelength photons, short-wavelength photons have

more energy

During carbon fixation, CO2 combines with

ribulose-1, 5-biphosphate

As a photon is absorbed by chlorophyll,

the chlorophyll becomes "excited" or energized

When a suspension of algae is incubated in a flask in the presence of light and CO2 and then transferre to the dark, the reduction of 3-phosphoglycerate 3-phosphate is blocked. This reaction stop in the dark because

the reaction requires ATP and NADPH

In photosystem II during the noncyclic electron flow, electrons from ________ replenish chlorophyll a molecules in the reactive center after they have given up electrons to the primary acceptor molecule.

water

The O2 gas produced during photosynthesis is derived from

water