Harvesting the sun

Bundle sheath cells play a prominent role in what type of plants?

C4 plants

What element is bound to the center of plant chlorophyll?

Magnesium

The random transfer of induced excitation from one chlorophyll to neighboring chlorophylls is known as what? What is the efficiency of this energy transfer?

Random walk; approaching 99 to 100 percent efficient

What wavelength range of the light spectrum do plants use in photosynthesis?

What is this range called?

400 to 700 nm. Photosynthetically active radiation

Why do plant leaves appear green?

Plants don’t absorb green light (around 550 nm) as well as they absorb other ranges. Thus, some of this green light is reflected off the plant and the leaf appears to us as green.

In C3 plants, what is a characteristic of the first product of CO₂ fixation?

A three‐carbon compound

At what temperature range is photorespiration more prevalent?

Warmer temperatures (above 25C). It gets worse as temperature rises.

What is the general structure of the compound that reacts with CO₂ in the

Rubisco-catalyzed reaction?

a 5 carbon compound with 2 phosphates on either end

What protein is the most abundant in plants?

Rubisco

What is the process called where Rubisco reacts with oxygen? Typically, what is

the proportion of O₂ reaction to CO₂ reaction?

Photorespiration. About 25 percent of the time in normal air, or 1 out of every 4 reactions.

What are the benefits of PEP carboxylase in C4 plants?

PEP carboxylase is able to perform faster with lower CO₂. It does not react with

O₂

Why do we say C4 has a pump?

The transfer of compounds and decarboxylation boost up the CO₂ concentration in the bundle sheath, where Rubisco is located

PEP carboxylase forms what product during its first CO₂ reaction? Once this

product is formed, what is the next step in the CO₂ fixation process for C4 plants?

A four‐carbon compound; this four‐carbon compound then diffuses into bundle

sheath cells

In what situations are C4 plants more efficient?

Hotter climates.

In what situations are C3 more efficient?

Cool climates with adequate water

Give an example of at least two C4 species.

Maize, sorghum, sugarcane, millet, and red‐root pigweed.

Give an example of at least three C3 species.

Wheat, oats, barley, rye, rice, potato, banana, soybean, pea, pigeonpea, chickpea, lentil, alfalfa, cotton, and peanuts.

What is transpiration? What are some secondary functions of transpiration in

plants?

The process of evaporative water loss via the stomata of plants. Some secondary functions include cooling of the plant and the movement of mineral nutrients within the plant, specifically nutrients from root to leaf via the xylem.

What is the basic equation for photosyntesis?

H₂O + CO₂ → O₂ +CH₂O

What are limitations with Rubisco?

Confuses O₂ for CO₂, which results in wasteful photorespiration (Happens more at low CO₂ levels

how do CAM plants operate

C₃ pathway during the day

C₄ pathway at night