Chapter 27.2- Carbon dioxide gain and water loss

Question 1

What is the main site of photosynthesis?

Answer 1

Leafs

Question 2

What are the main major tissues of a leaf?

Answer 2

1. Sheets of epidermal cells in the lower surfaces
2. packed photosynthetic the mesophyll
3. the system of vascular conduits veins connect to the rest of the leaf

Question 3

How is a supply of carbon dioxide constantly resupplied into Leafs?

Answer 3

They are air spaces inside of leaves that surround mesophyll cells that , as carbon dioxide within the cell is being used by photosynthesizes more carbon dioxide enters cell. Because carbon dioxide travels from high to low concentration.

Question 4

What is the cost of cells resupplying carbon dioxide to Leafs and what is the risk?

Answer 4

As carbon dioxide enters the cell water vapors leave the cell and the lightness of water makes it get diffused faster into the cell. Transpiration occurs which is the loss of water vapor.

Question 5

How does leaves try to prevent too much water loss?

Answer 5

epidermal cells create a waxy cuticle on their surface to limit water loss. But also prevents carbon dioxide from entering the cell.

Question 6

What are stomatas? why are the helpful to epidermal cells?

Answer 6

They are small pores in the epidermal cell help diffuse carbon dioxide. They help combat the effect of the wax cuticle

Question 7

What is the structural component of stomatas cells? What is the process of them opening and closing?

Answer 7

• they have valves that can open or close
• they have two guard cells that surround the central pore and having the ability to shrink or swell

Opening:
light stimulates the opening
Closing:
high levels of carbon dioxide makes it close they become dehydrated and shrink in volume

Question 8

How does CAM plants prevent water loss?

Answer 8

A Crassulean acid metabolism enzyme PEP carboxylase stores carbon dioxide overnight

Night: stomatat is open to capture co2

Day: it is closed

Question 9

How is Crassulean acid metabolism stored at night ?

Answer 9

1. enzyme PEP carboxylase combines carbond dioxide with PEP
2. creating a 4 carbon organic compound that is stored in the vacoule

Question 10

How is Crassulean acid metabolism stored in the day?

Answer 10

1. When the sun is out the stomatata closes storing water
2. the 4 carbon organic compound decarboxylates releasing carbon dioxide in closed vacoule
3. carbon dioixde diffuses into the chlorpolast and enters the calvin cycle

Question 11

What are c4 plants and why are they important?

Answer 11

they suppress photorespiration by increasing the amount of carbon dioxide in rubisco

Question 12

In c4 cells where is carbon dioxide captures? Where does the calvin cycle take place?

Answer 12

1. mesophyll
2. bundle sheath which is cells that surround the veins

Question 13

What are the steps of c4 synthesis?

Answer 13

Step 1: captures carbon dioxide through PEP carboxylease the 4 carbon organic compound diffuses into the bundle shealth
Step 2:
then the 4 carbon compound decarboxylate and releases carbon dioxide into the calvin cycle
Step 3: 3 carbon molecules then diffuse back to the mesophyll so ATP can reform PEP