Question

question 6 (multiple choice worth 4 points) (02.06r mc) why does darkness affect the light - independent reactions of photosynthesis? plants stop their daytime activities and rest during the night, much like animals do. light independent reactions need more heat energy than nighttime temperatures often provide. mitochondria produce sugars more effectively in the darkness than chloroplasts do. light independent reactions require the energy gathered in the thylakoids. question 7 (multiple choice worth 4 points)

Explanation:

To solve this, we analyze each option:

• Option 1: Plants don't "rest" like animals; they still perform processes (e.g., respiration) at night. Eliminate.
• Option 2: Light - independent reactions (Calvin cycle) don't need heat energy from temperatures; they need ATP and NADPH from light - dependent reactions. Eliminate.
• Option 3: Mitochondria do cellular respiration (break down sugars), and chloroplasts (with light - dependent reactions) produce the starting materials for light - independent reactions. Mitochondria don't produce sugars more effectively in darkness. Eliminate.
• Option 4: Light - independent reactions (Calvin cycle) require ATP and NADPH, which are produced in the thylakoids during light - dependent reactions (which need light). In darkness, light - dependent reactions stop, so the products (ATP, NADPH) needed for light - independent reactions are not made, affecting the light - independent reactions. This is correct.

Answer:

The correct option is the one stating "Light independent reactions require the energy gathered in the thylakoids." (The option with the text "Light independent reactions require the energy gathered in the thylakoids.")