Question

1. by which process does carbon dioxide enter the stomata of leaves? * 1 point

osmosis
diffusion
transpiration
active transport

1. which option in the table below tells us what will happen to plant cells * 1 point

and animal cells placed into water for a few hours?
plant cells burst; animal cells become turgid
plant cells become turgid; animal cells shrink
plant cells become turgid; animal cells burst
plant cells shrink; animal cells shrink

Explanation:

• For question 13:
• Osmosis is the movement of water molecules across a semi - permeable membrane. Carbon dioxide is a gas, not water, so osmosis is not relevant.
• Diffusion is the movement of molecules (including gas molecules like carbon dioxide) from an area of higher concentration to an area of lower concentration. Carbon dioxide in the atmosphere (higher concentration outside the leaf compared to inside the leaf's photosynthetic cells) enters the stomata by diffusion.
• Transpiration is the loss of water vapor from plants (mainly through stomata). It is not the process for carbon dioxide entry.
• Active transport requires energy (usually in the form of ATP) and is used for moving molecules against a concentration gradient. Carbon dioxide moves down its concentration gradient into the leaf, so active transport is not needed.
• For question 14:
• When plant cells are placed in water (hypotonic solution), water enters the cell by osmosis. Plant cells have a rigid cell wall. As water enters, the cell swells and becomes turgid (the pressure of the cell contents against the cell wall).
• Animal cells do not have a cell wall. When placed in water (hypotonic solution), water enters the animal cell by osmosis. Since there is no cell wall to withstand the increasing internal pressure, the animal cell will burst (lysis).

Answer:

1. B. diffusion
2. C. plant cells become turgid; animal cells burst