ap bio unit 4

What are the three steps of cell signaling?

Reception, Transduction, Response.

What is short distance signaling?

Signaling that occurs when cells are touching, the fastest type of signaling, happens in spaces between cell membranes.

What are ligands in long distance signaling?

Molecules that are released to travel short distances through diffusion or long distances in the bloodstream.

What happens during the Reception step in cell signaling?

Ligand binds to receptor embedded in cell membrane, causing a shape change that transmits the signal into the cell.

What is transduction in cell signaling?

The process of moving the signal from the cell membrane to the nucleus, often involving phosphorylation of proteins.

What role do kinases play in cell signaling?

They transfer phosphates from ATP to other molecules during the transduction step.

What are the two types of feedback in response to signals?

Negative Feedback and Positive Feedback.

What is Negative Feedback?

A reaction that causes the cell to force changes to stop the effect of a signal, such as insulin in response to blood sugar.

What is Positive Feedback?

A reaction that amplifies the effect of a signal until it is stopped, like contractions during birth.

What occurs in the S phase of the cell cycle?

DNA Replication, where the cell goes from 2n to 4n.

What is the role of cyclins and cyclin-dependent kinases (CdK’s) in the cell cycle?

They regulate the progression through the cell cycle.

What are the 5 parts of Mitosis?

Prophase, Metaphase, Anaphase, Telophase, Cytokinesis.

What happens during Prophase in Mitosis?

The nuclear membrane dissolves, nucleolus dissolves, and DNA condenses into chromosomes.

What does cytokinesis achieve?

Cuts the cell in two, leading to the formation of two separate cells.

What characterizes cancer in terms of the cell cycle?

Uncontrolled mitosis caused by random mutations affecting cyclins and CdK’s.

How does cancer affect the duration of interphase?

It causes cells to spend less time in interphase.

How do mutations in signaling proteins affect cell signaling?

They can alter or stop signal pathways, affecting cellular responses.

What is a chromatid?

Condensed DNA structure, each chromatid is identical in mitosis.

What is the purpose of the cell cycle?

To coordinate cell growth, DNA replication, and cell division.