Week 7 Quiz

A houseplant sits on a sunny windowsill. Which set lists the reactants it uses in photosynthesis?

Select one.

• Glucose, oxygen, and light
• Carbon dioxide, water, and light
• Carbon dioxide, glucose, and soil minerals
• Oxygen, water, and light

In which part of the chloroplast do the light-dependent reactions run?

Select one.

• The stroma, the fluid around the stacks
• The mitochondrial matrix
• The cytoplasm outside the chloroplast
• The thylakoid membrane, where chlorophyll sits

Why do most leaves look green?

Select one.

• Chlorophyll absorbs red and blue light and reflects green
• Chlorophyll absorbs green light and stores it as sugar
• The stroma is green and colors the whole leaf
• Green light is the only light a leaf receives

True or false: because none of its steps absorbs light, the Calvin cycle keeps building sugar all night in a dark closet.

True or false.

• True
• False

Where do the atoms of the oxygen gas (O₂) that a plant releases come from?

Select one.

• From carbon dioxide, split apart in the Calvin cycle
• From glucose, broken down in the stroma
• From water, split in the light-dependent reactions
• From minerals the roots draw out of the soil

A redwood grows from a tiny seed into a towering tree. Where does most of the tree's mass come from?

Select one.

• Soil pulled up through the roots over many years
• Carbon from carbon dioxide in the air, plus water
• Sunlight turned directly into wood
• Minerals dissolved in rainwater

In the floating leaf disk example (illustrative data constructed for this course), the light cup has 0, 2, 5, 8, and 10 disks floating out of 10 at 0, 3, 6, 9, and 12 minutes. What is the light average across the five readings?

Select one.

• 5.0 disks, from 25 ÷ 5
• 6.25 disks, from 25 ÷ 4
• 10 disks, the last reading
• 25 disks, the sum of the readings

In the floating leaf disk example, one cup of spinach disks sits under a lamp and an identical cup sits in the dark. What is the dark cup?

Select one.

• The independent variable
• The dependent variable
• A failed trial to throw out
• The control group, the no-light baseline

Which statements about a plant leaf cell are accurate? Select all that apply.

Select every option that applies.

• Its chloroplasts make sugar in the light.
• Its mitochondria respire day and night.
• It photosynthesizes instead of respiring.
• It stops respiring whenever the sun is up.
• Photosynthesis and respiration are roughly mirror processes in it.

Which choice gives the two stages of photosynthesis in the correct order, each with its location?

Select one.

• Calvin cycle (thylakoid membrane), then light-dependent reactions (stroma)
• Calvin cycle (stroma), then light-dependent reactions (thylakoid membrane)
• Light-dependent reactions (thylakoid membrane), then Calvin cycle (stroma)
• Light-dependent reactions (stroma), then Calvin cycle (thylakoid membrane)