Unit 4 Review in AP Biology

This video reviews Unit 4 of the AP Biology curriculum, focusing on cell communication and the cell cycle. It covers how cells communicate through direct contact and signaling molecules, including hormones and local regulators. The video explains signal transduction pathways, emphasizing the role of receptors and kinases. Feedback mechanisms, such as insulin and glucagon in maintaining homeostasis, are discussed. The video also covers cell division processes, including mitosis and meiosis, and the regulation of the cell cycle through checkpoints and proteins like p53.

What percentage of the AP bio test is made up by unit 4?

• 30 to 35%

• 10 to 15%

• 5 to 10%

• 20 to 25%

Which type of cell communication involves direct contact between cells?

• Endocrine signaling

• Local signaling

• Long-distance signaling

• Cell-to-cell contact

What is the role of local regulators in cell communication?

• They travel long distances to signal cells

• They are used for cell-to-cell contact

• They signal cells over short distances

• They do not participate in signaling

What type of molecule is used as a second messenger in signal transduction pathways?

• Lipids

• Carbohydrates

• DNA

• Cyclic AMP

Which type of receptor is involved in the transduction signal when a ligand attaches?

• Ion channels

• G-protein coupled receptors

• Enzyme-linked receptors

• Nuclear receptors

What is the function of ligand-gated ion channels?

• To amplify cell signals

• To open and allow ions to flow into the cell

• To replicate DNA

• To produce hormones

What can cause apoptosis in cells?

• Overproduction of growth factors

• Signaling for cell self-destruction

• Absence of any mutations

• Healthy DNA replication

What is the role of p53 in the cell cycle?

• It stops cells with damaged DNA from dividing

• It assists in the attachment of spindle fibers

• It increases the mutation rate in cells

• It promotes DNA replication

What is the main purpose of feedback mechanisms in organisms?

• To initiate cell division

• To maintain homeostasis

• To stop all cell communications

• To disrupt homeostasis

Which process ensures the transfer of a complete genome during cell division?

• Endocytosis

• Apoptosis

• Exocytosis

• Mitosis