Physiology Sept. 26th

These flashcards cover essential vocabulary and concepts related to plant photoreceptors and their functions in response to light.

Photorespiration

A process that captures protective effects by dissipating excess energy during high light conditions.

Chromophore

A light-absorbing molecule that undergoes structural changes upon light absorption, playing a crucial role in photoreception.

Phytochrome

A photoreceptor in plants that senses red and far red light, existing in two distinct forms (PR and PFR).

Photoreversibility

The ability of certain plant responses to be reversed by changing the wavelength of light.

Law of Reciprocity

The principle that the magnitude of the response in plants depends on the total number of photons received, regardless of the duration.

Cryptochromes

A class of blue light receptors in plants that undergo conformational changes upon blue light absorption, influencing various physiological responses.

Phototropin

A type of photoreceptor in plants that functions as a kinase, regulating responses such as stomatal movement through phosphorylation and chloroplast movement within cells

Stomata

Tiny openings in plant leaves that allow for gas exchange and are regulated by light conditions.

UVR8

A UV light receptor in plants that does not require a chromophore and can regulate gene expression in response to UV light.

NADH

A molecule that generates more ATP than FADH by donating electrons to complex one in the electron transport chain.

R:FR Ratio

Used by plants to gain critical info abt their environment. If ratio is low, this signals shade and phototropism is prioritized (growing towards optimal light source)

Seed germination

Red light stimulates seed germination (plant growing from seed). A pulse of far red light can revert this response.

Cryptochrome functions

Controls de-etiolation. In contact with light (blue light) cryptochromes stop hypocotyl elongation, signaling the seedling has emerged from the soil.