AP Biology Unit 4 Review

Front

What are cyclins and CDKs, and how do they function in the cell cycle?

Back

Cyclins are proteins that regulate the cell cycle by activating cyclin-dependent kinases (CDKs). CDKs, once activated by cyclins, phosphorylate target proteins to drive the cell cycle forward, facilitating processes such as cell division.

Front

What is the role of secondary messengers in cell signaling?

Back

Secondary messengers are molecules that relay signals received at receptors on the cell surface to target molecules inside the cell, amplifying the signal and triggering a cellular response.

Front

What is positive feedback in biological systems?

Back

Positive feedback is a process where the output of a system enhances or amplifies the initial stimulus, leading to an even greater response. An example is the release of inflammatory cytokines by immune cells.

Front

How do cancerous cells differ from healthy cells in terms of cell cycle?

Back

Cancerous cells typically have a much shorter cell cycle compared to healthy cells, allowing them to divide uncontrollably and proliferate.

Front

What triggers the release of glucagon in the body?

Back

Glucagon is released when blood glucose levels are low, particularly when there is a low cellular ATP concentration, signaling the need for energy.

Front

What is the function of insulin in blood sugar regulation?

Back

Insulin lowers blood sugar levels by facilitating the uptake of glucose into cells and promoting the storage of glucose as glycogen in the liver.

Front

What is the difference between autocrine and paracrine signaling?

Back

Autocrine signaling occurs when a cell targets itself, while paracrine signaling involves a cell communicating with nearby cells through the release of signaling molecules.

Front

What is the significance of density-dependent inhibition in cell growth?

Back

Density-dependent inhibition is a regulatory mechanism where cell growth and division are inhibited when cells become too crowded, preventing overgrowth and maintaining tissue organization.

Front

How do receptor tyrosine kinases function in cell signaling?

Back

Receptor tyrosine kinases are a class of cell surface receptors that, upon binding to a ligand, undergo dimerization and autophosphorylation, activating downstream signaling pathways.

Front

What is the role of apoptosis in multicellular organisms?

Back

Apoptosis is programmed cell death that eliminates damaged or unnecessary cells, playing a crucial role in development and maintaining homeostasis.