Plant Structure and Function - Exam 2 - The Stomata and the Carbon Fixation Reactions

Carbon fixation reactions

\-used to be called the dark reactions

\-energy from light reactions drives the conversion of CO2 to carbohydrate in the chloroplast stroma

CO2

The carbon fixation reactions need what

the stomata

Where does the CO2 enter through?

True

True or False

Stomata are on all vascular and some nonvascular plants

Subsidiary cell

Non-flowering plants have these cells next to their guard cells

False

True or False

Plants can control what moves through their stomata

\

Osmosis

What process do stomata use to move potassium and water?

Potassium is pumped out of guard cell

What is happening to potassium when a stomata goes from open to closed?

Potassium is pumped into the guard cell

What is happening to potassium when a stomata goes from closed to open?

False

True or False

The inside of the cell wall of the guard cell is thin

Determinants of whether the guard cell is open or closed?

What are these determinants of?


1. Amount of photosynthesis
2. Blue light

Calvin-Benson Cycle

What cycle is the carbon fixation reactions called?

Sucrose or Starch

Most carbon running through the Calvin-Benson cycle is converted to either __ or ____

Sucrose

major transport sugar

Starch

major storage carbohydrate

Carboxylation of the CO2 acceptor molecule

Step 1: of the Calvin-Benson Cycle

* 3 CO2 enter and are catalyzed by Rubisco

Carboxylation

combining of carbon to get 3 phosphoglycerates

Reduction of 3 phsophoglycerates

Step 2: of the Calvin-Benson Cycle

* ATP and NADPH come from the light reactions

Regeneration of the CO2 acceptor ribulose 1,5-biphosphate

Step 3: of the Calvin-Benson Cycle

Triose phosphate

The ____ ________ that go to make stuff balance out the initial carbon input

Photorespiration

* uptake of atmospheric O2 with c concomitant release of CO2 by leaves in the light
* molecular oxygen serves as a substrate for Rubisco, producing 2-phosphoglycolate that enters the photo respiratory cycle
* the activity of the cycle recovers some of the carbon found in 2-pohophoglycolate, but some is lost to the atmosphere
* this is also called the “salvage” pathway

True

True or False

Rubisco can act as either a carboxylase or an oxygenase?

The C4 Carbon Cycle

What else is this known by?

Operation Concentrate CO2 Strategy 1: Prevent Rubisco from being an oxygenase

Crassulacean Acid Metabolism (CAM)

What else is this known by?

Operation Concentrate CO2 Strategy 2: to prevent Rubisco from being an oxygenase

CAM Plants

What type of plants are these?

* Pineapples
* Orchids
* Agave
* these typically have a thick cuticle on leaves

The presence of the bundle sheath chell

What is the main difference between a C4 and CAM plant?