Photosynthesis and Plant Adaptations

This set of vocabulary flashcards covers the process of photosynthesis, including the anatomical structures of the chloroplast, light-dependent reactions, the Calvin cycle, and specialized plant pathways.

Photosynthesis overall equation

$$6CO_{2} + 6H_{2}O + \text{Light energy} \rightarrow C_{6}H_{12}O_{6} + 6O_{2}$$

Photoautotrophs

Organisms that are self-feeders (autotrophs) using light as an energy source.

Stoma

The pore on a leaf through which $CO_{2}$ enters and $O_{2}$ exits.

Stroma

The thick fluid within the chloroplast surrounding the thylakoid membrane, where the Calvin cycle occurs.

Grana

Stacks of thylakoids within the chloroplast; the singular form is granum.

Thylakoid

A flattened membrane sac inside the chloroplast, whose membranes contain chlorophyll and are the site of light reactions.

Chlorophyll

A light-absorbing pigment located on the membranes of thylakoids.

Photosystem II

A protein-pigment complex in the thylakoid membrane that utilizes the $P680$ reaction center to initiate the electron transport chain.

Photosystem I

A complex in the thylakoid membrane that uses the $P700$ reaction center and contributes to the generation of NADPH.

Chemiosmosis

The process by which an electron transport chain provides energy for the synthesis of ATP.

Noncyclic electron flow

The pathway during light reactions that generates both ATP and NADPH.

Cyclic electron flow

A pathway in the chloroplast that produces additional ATP without producing NADPH.

Calvin Cycle

The second stage of photosynthesis that uses $CO_{2}$, ATP, and NADPH to produce sugar (G3P) in the stroma.

Rubisco

The enzyme in the Calvin cycle that catalyzes the addition of $CO_{2}$ to RuBP during carbon fixation.

3-PGA

The three-carbon intermediate produced immediately after carbon fixation in the Calvin cycle.

G3P

The carbohydrate output of the Calvin cycle used to build glucose and other organic compounds.

Carbon fixation

The initial step of the Calvin cycle where inorganic carbon ($CO_{2}$) is incorporated into an organic molecule (RuBP).

C4 pathway

A biochemical adaptation used by some plants to conserve water while maintaining photosynthesis.

CAM plants

Plants that utilize a specific biochemical adaptation to conserve water by opening their stomata only at night.

Global warming

The phenomenon of radiant heat being trapped by $CO_{2}$ and other gases in the atmosphere, which photosynthesis helps ameliorate.