AP Biology Unit 4

What are the two main types of cell signaling?

Local signaling and long-distance signaling.

What are growth factors an example of in cell signaling?

Local signaling, where cells communicate over short distances.

What is the role of hormones in cell signaling?

Hormones are chemical messengers that regulate functions like growth, metabolism, and mood.

What occurs during the reception stage of cell signaling?

The target cell detects a signal molecule (ligand) when it binds to a receptor.

What is a signal transduction pathway?

A sequence of processes where a signal outside the cell is converted into a functional response inside the cell.

What type of receptor is activated when a ligand binds and changes shape?

G-Protein-Coupled Receptors.

What do receptor tyrosine kinases do?

Attach phosphate groups to tyrosine on proteins, initiating multiple signaling pathways.

What is the function of secondary messengers?

They relay signals inside the cell and amplify the response.

What is apoptosis?

A process of programmed cell death vital for development and maintaining health.

What are the phases of the cell cycle?

G1 phase, S phase, G2 phase, and M phase.

What occurs during the S phase of the cell cycle?

DNA is replicated, forming sister chromatids.

What is the spindle apparatus and its function?

A structure made of microtubules that helps separate chromosomes during cell division.

What is the difference between benign and malignant tumors?

Benign tumors are non-cancerous and don’t spread, while malignant tumors are cancerous and can metastasize.

What is the definition of homeostasis?

Maintaining a stable internal environment.

What role does the hypothalamus play in the body?

It helps regulate homeostasis, including temperature and hunger.

What distinguishes endothermic from ectothermic animals?

Endothermic animals generate their own heat, whereas ectothermic animals rely on external sources.

What is thermoregulation?

The process of maintaining body temperature through mechanisms like sweating or shivering.

Define basal metabolic rate (BMR).

The energy used at rest in a neutrally temperate environment.

What is meant by density-dependent inhibition?

Cells stop dividing when they are crowded.

What is a key characteristic of cancer growth compared to normal growth?

Cancer cells grow uncontrollably, ignoring signals that regulate the cell cycle.

What is acclimatization in biological terms?

Short-term adjustment to environmental changes.

What is the primary function of epithelial tissue?

To cover and protect surfaces.

What happens during the anaphase of mitosis?

Sister chromatids are pulled apart to opposite poles.