Which of the following best explains the main difference between photoautotrophs and chemoautotrophs?

• Photoautotrophs use chemical compounds for energy, whereas chemoautotrophs use sunlight.

• Photoautotrophs require organic molecules for growth, but chemoautotrophs do not.

• Photoautotrophs use sunlight to produce organic molecules, while chemoautotrophs harvest energy from inorganic chemicals.

• Chemoautotrophs are found only in plants, while photoautotrophs exist only in bacteria.

Why are autotrophs considered the producers of the biosphere?

• They break down organic matter from other organisms.

• They consume energy from other organisms to survive.

• They produce organic molecules from inorganic sources.

• They rely on animals for their energy needs.

Where does photosynthesis primarily occur in plants?

• Roots

• Stem

• Leaves

• Flowers

What pigment is responsible for the green color of leaves?

• Carotene

• Xanthophyll

• Chlorophyll

• Anthocyanin

What structure allows CO₂ to enter and O₂ to exit the leaf?

• Veins

• Mesophyll

• Chloroplast

• Stomata

How does the structure of a leaf facilitate efficient gas exchange for photosynthesis?

• Leaves have thick outer walls to trap gases.

• Stomata allow the movement of CO₂ in and O₂ out.

• Veins carry gases into the mesophyll cells.

• Chloroplasts absorb gases from the air directly.

What is the name of the organized sacs in the chloroplast that contain chlorophyll?

• Lamella

• Grana

• Thylakoids

• Stroma

What is a stack of thylakoids called?

• Photosystem

• Cluster

• Stroma

• Granum

What surrounds the thylakoid and grana inside the chloroplast?

• Cytoplasm

• Pigment cluster

• Stroma

• Intermembrane space

Why are thylakoid membranes essential in photosynthesis?

• They store oxygen produced during photosynthesis.

• They capture light energy using pigments to produce ATP.

• They provide support to the outer membrane.

• They transport glucose through the plant.