Cell Signalling (& Homeostasis)

Question 1

Homeostasis

Answer 1

Homeostasis is the maintenance of a dynamically constant internal environment by an organism irrespective of changes in the external environment.

Question 2

Self-regulation

Answer 2

Self-regulation involves the control mechanism that is triggered by the very parameter / entity that it serves to regulate.

Question 3

Negative feedback

Answer 3

Negative feedback is a corrective / regulatory mechanism in which a stimulus as a result of a deviation from the set point triggers a response.

Question 4

Receptor

Answer 4

Receptors are proteins that bind and transduce the message of the signal molecule into a cellular response.

Question 5

Signal transduction

Answer 5

Signal transduction refers to the series of changes in cellular proteins that converts extracellular chemical signals to a specific intracellular response.

Question 6

Phosphorylation cascade

Answer 6

A phosphorylation cascade is a sequence of events where one enzyme phosphorylates another, causing a chain reaction leading to the phosphorylation of thousands of proteins.

Question 7

Kinase

Answer 7

Kinase is an enzyme which adds phosphate groups from ATP to the protein (phosphorylation).

Question 8

Phosphatase

Answer 8

Phosphatase is an enzyme that removes phosphate groups from proteins by hydrolysis (dephosphorylation). This action is directly opposite to that of kinase.

Question 9

Signal amplification

Answer 9

Signal amplification produces a large number of an intracellular mediator, and subsequently a large response, from a relatively small number of extracellular signals.

Question 10

Protein kinase

Answer 10

A protein kinase is a class of enzyme that adds phosphate groups from ATP to proteins.

Question 11

Domain

Answer 11

A domain is a distinct functional and / or structural unit in a protein.