Biology: Plant Photoreceptors and Enzyme Activity

Which photoreceptor is responsible for sensing red and far red light?

Which photoreceptor is sensitive to blue light and includes phototropism responses?

Which photoreceptor is solely responsible for detecting blue light but not involved in phototropism?

Which photoreceptor is not involved in detecting blue light?

Which of the following is NOT a known photoreceptor?

What are plant hormones also known as?

Which of the following is NOT one of the major groups of plant hormones?

Which plant hormone is associated with the abbreviation IAA?

What three aspects does the study of plant hormones generally involve?

What are brassinosteroids classified as?

Which of the following is an environmental signal?

What type of receptor is involved in signal transduction?

Which of the following is a type of second messenger in signal transduction?

Which is NOT a component of signal transduction?

What is a possible cellular response to signal transduction?

Environmental Stimuli

Plants respond to light through photoreceptors, including:
- Phytochrome, which responds to red and far-red light
- Cryptochrome, which responds to blue light
- Phototropin, which responds to blue light
Enzyme activity is affected by the orientation of hydrogen

Introduction to Plant Hormones

Plant hormones are also known as Plant Growth Regulators (PGRs).
They are chemical signals that move within the plant, affecting the physiology or development of other parts.

Major Groups of Plant Hormones

The five major groups of plant hormones are: auxins, gibberellins, cytokinins, ethylene, and abscisic acid.
The later-discovered plant hormones include brassinosteroids, jasmonic acid, and salicylic acid.

Key Topics to be Covered

Biosynthesis of plant hormones
Physiological effects of plant hormones
Molecular modes of action of plant hormones

Signal Transduction

Components of Signal Transduction:
Environmental or physiological signal (stimulus)
Receptor (detects the signal)
Signal transduction pathway (transmits the signal)
Response (cell's reaction to the signal)

Types of Signals:

Environmental Signals:
Light
Temperature
Touch
Physiological Signals:
Hormones
Nutrients

Types of Receptors:

Kinase receptors
G-protein coupled receptors

Messengers:

Kinases (enzymes that add phosphate groups)
Calcium (ions that regulate various cellular processes)
Lipids (molecules that participate in signaling pathways)

Response:

Gene Expression (alteration of gene transcription and translation)
Cellular Structure (changes in cell shape, organization, or adhesion)
Enzyme Activity (alteration of enzyme function or activity)

This quiz assesses knowledge of plant photoreceptors such as phytochrome, cryptochrome, and phototropin, as well as enzyme activity related to hydrogen orientation.