Question

exit ticket
sc.912.l.18.9 - explain the interrelated nature of photosynthesis and cellular respiration.

1. underline the question (1 pt)
2. highlight key terms (1 pt)
3. why are the other 3 choices wrong (2pts)
4. answer question (1 pt)

1. earth’s atmosphere is about 21 percent oxygen. this percentage has remained about the same throughout human history and even earlier. how have cellular respiration and photosynthesis helped maintain relatively constant oxygen levels?

a. cellular respiration helps maintain oxygen levels, while photosynthesis has no effect.
b. photosynthesis helps maintain oxygen levels, while cellular respiration has no effect.
c. cellular respiration removes oxygen from the atmosphere, while photosynthesis adds oxygen to the atmosphere.
d. photosynthesis removes oxygen from the atmosphere, while cellular respiration adds oxygen to the atmosphere.

1. plant cells have mitochondria, which use glucose to produce atp. where does the glucose originate?

a. photosynthesis, which occurs in chloroplasts
b. fermentation, which occurs in the absence of oxygen
c. exocytosis, which transports the glucose into cells
d. diffusion, which transports the glucose from the digestive tract

1. many processes within the cell require atp. which of the following does not require atp?

a. active transport of molecules across the cell membrane
b. the contraction of a heart muscle to pump blood
c. the movement of water across a cell membrane
d. transcription of an mrna molecule

1. atp synthase is an enzyme that helps convert adp into atp in muscle cells. which of the following would be increased by increasing atp synthase?

a. the amount of energy available
b. the amount of energy released
c. the number of mitochondria
d. the number of cell divisions

Explanation:

Question 1

To solve this, we analyze each option:

• Option a: Photosynthesis produces oxygen, so it has an effect. Eliminate a.
• Option b: Cellular respiration consumes oxygen, so it has an effect. Eliminate b.
• Option c: Cellular respiration (uses glucose, releases CO₂, consumes O₂) and photosynthesis (uses CO₂, releases O₂) balance O₂. This is correct.
• Option d: Photosynthesis adds O₂, cellular respiration removes O₂. This is reversed. Eliminate d.

• Option a: Photosynthesis in chloroplasts makes glucose (using CO₂, light, H₂O). Mitochondria use this glucose for ATP. Correct.
• Option b: Fermentation is an anaerobic process, not the source of glucose for mitochondria in plants (which do photosynthesis). Eliminate.
• Option c: Exocytosis is for transporting out of cells, not bringing glucose in for mitochondria. Eliminate.
• Option d: Plants don't have a digestive tract. Diffusion isn't the source of glucose here. Eliminate.

• Option a: Active transport needs ATP (against concentration gradient). Requires ATP.
• Option b: Muscle contraction (like heart) needs ATP for myosin-actin interaction. Requires ATP.
• Option c: Water movement across cell membrane is osmosis (passive, no ATP needed). Does NOT require ATP.
• Option d: Transcription (making mRNA) needs ATP (for enzymes, nucleotide activation). Requires ATP.

Answer:

c. Cellular respiration removes oxygen from the atmosphere, while photosynthesis adds oxygen to the atmosphere.

Question 2