AP Biology 4.1-4.3

How do cells communicate with other cells over short distances?

By direct contact or local signaling molecules.

How do cells communicate with other cells over long distance?

By hormones carried through the bloodstream.

How is the process of distance communication different from the process of communicating during cell-to-cell contact?

Direct physical contact between cells.

What is a signal transduction pathway?

A series of steps that converts a signal into a cellular response.

Why do cells use signal transaction pathways?

To receive, amplify, and respond to signals accurately.

How does a signal transduction pathway begin?

When a signaling molecule binds to a receptor.

What is the roles of protein modification in signal transduction pathways?

They activate or deactivate proteins to pass the signal.

What is the role of phosphorylation cascades in signal transduction pathways?

They amplify and transmit the signal inside the cell.

What role does the environment play in eliciting cellular responses?

It provides signals that trigger cellular responses.

How are signal transductions pathways used to influence cellular responses where there are changes in the environment?

They detect environmental changes and activate pathways to adjucts cell behavior.

How can mutations in the receptor protein or any component affect the transduction of a signal?

They can block, reduce, or misdirect the signal, disrupting the response.

How can chemicals activate a pathway?

By binding to a receptor and triggering the signaling cascade.

How can chemicals inhibit a pathway?

By blocking the receptor or interfering with signaling components.

What are feedback mechanisms?

Processes that regulate a system by increasing or decreasing its activity.

How does negative feedback maintain homeostasis?

It reduces a response when conditions return to normal.

How does positive feedback affect homeostasis?

It amplifies a response, moving conditions away from normal.

What is the role of interphase?

It allows the cell to grow, replicate its DNA, and prepare for division.

What occurs during interphase?

The cell grows, performs normal functions, and replicates its DNA.

What is the role of mitosis?

To divide the nucleus and produce two genetically identical cells.

What occurs during mitosis?

Duplicated chromosomes separate and the nucleus divides.

What is the role of cytokinesis?

Divide the cytoplasm, forming two separate cells.

What occurs during prophase?

Chromosomes condense, the spindle forms, and the nuclear envelope begins to break down.

What occurs during metaphase?

Chromosomes line up at the center (equator) of the cell.

What occurs during anaphase?

Sister chromatids separate and move to opposite poles of the cell.

What occurs during telophase?

Nuclear membranes reform around each set of chromosomes, and the chromosomes begin to decondense.

When does cytokinesis occur?

During late telophase.

What are cell checkpoints?

Control points where the cell checks for errors before moving to the next phase.

What is the role of checkpoints in regulating the cell cycle?

They ensure the cell only divides when conditions are correct and DNA is undamaged.

How are proteins involved in checkpoints?

Proteins monitor cell conditions and can stop or allow the cell cycle to continue.

What happens if the cell cycle is disrupted?

Cells may divide uncontrollably or die.