AP Biology--Cell Communication & Feedback

Front

What is a feedback loop?

Back

A feedback loop is a biological mechanism in which the output of a system influences its own operation, often to maintain homeostasis.

Front

What is the difference between positive and negative feedback loops?

Back

Positive feedback amplifies a response or process, while negative feedback reduces or dampens it to maintain stability.

Front

Define 'ligand'.

Back

A ligand is any signal molecule that binds to a receptor to initiate a cellular response.

Front

What are secondary messengers?

Back

Secondary messengers are molecules, such as cyclic AMP (cAMP), that relay and amplify intracellular signals after the initial signal is received.

Front

What is phosphorylation?

Back

Phosphorylation is the addition of a phosphate group to a molecule, often used in signal transduction to activate or deactivate proteins.

Front

Explain the role of protein kinases in signal transduction.

Back

Protein kinases are enzymes that transfer phosphate groups from ATP to specific substrates, playing a crucial role in amplifying cellular signals.

Front

What is an example of a positive feedback response in the human body?

Back

An example is the release of oxytocin during childbirth, which intensifies contractions until delivery.

Front

What is an example of a negative feedback loop in the human body?

Back

An example is the regulation of blood glucose levels, where insulin lowers blood sugar and glucagon raises it.

Front

What is the significance of amplification in signal transduction?

Back

Amplification allows a small initial signal to produce a large cellular response, enhancing the effectiveness of the signal.

Front

Define 'receptor'.

Back

A receptor is a protein molecule that receives and responds to a signal molecule (ligand) to trigger a cellular response.