Gas Exchange in Plants

Question 1

Which are the two main organs in plants that exchange gases with the environment?

Answer 1

roots and leaves.

Question 2

What is the word equation for photosynthesis?

Answer 2

carbon dioxide + water = glucose + oxygen

Question 3

Photosynthesis produces nutrients for which life processes?

Answer 3

respiration, metabolism and growth.

Question 4

What are the names of the differentiated cells that surround stoma?

Answer 4

guard cells

Question 5

Describe the process of gas exchange through the stomata.

Answer 5

1. receptor proteins absorb sunlight, causing membrane channel proteins to open.
2. chloride and potassium ions diffuse into guard cells.
3. Water diffuses into guard cells by osmosis, causing guard cells to swell and become turgid.
4. Turgid guard cells expose stomata and allow gases to diffuse between atmosphere and leaf.

Question 6

Name the two types of mesophyll cells

Answer 6

palisade and spongy

Question 7

Name the tissue and cells that carbon dioxide and oxygen are exchanged through

Answer 7

ground tissue

mesophyll cells

Question 8

How is the diffusion path shortened in mesophyll cells?

Answer 8

large air spaces around mesophyll cells increase surface area to volume ratio, and they have thin cell walls.

Question 9

What is transpiration?

Answer 9

where water moves through organs and is evaporated through stem and leaves.

Question 10

Describe the process of transpiration.

Answer 10

Water diffuses into roots and is transported to the stem and leaves in vascular tissue. part of the the water diffuses into plant cells for metabolism, respiration, photosynthesis and growth. the rest diffuses into the atmosphere through stomata.

Question 11

Name a factor that influences the rate of transpiration

Answer 11

light (stomata open) 
temperature
movement of air (diffusion down concentration gradient)
number of leaves
size of leaves
density of stomata
humidity (diffusion cannot happen)
lack of air movement