Unit 4 AP Bio Study Guide

Topic 1: Vocab ●​ Direct Contact- communication through cell junctions where cells physically touch to exchange signals ●​ Gap Junctions- Protein channels connecting cytoplasm of adjacent animal cells, allowing direct passage of ions and small molecules (like second messengers) for rapid communication. ●​ Plasmodesmata- microscopic channels that connect adjacent plant cells, allowing for direct communication and the transport of water, nutrients, and other molecules between their cytoplasm. This is through cell walls. ●​ Hormones- chemical messengers in the body that are secreted by glands in the endocrine system and travel through the bloodstream to regulate and coordinate various bodily functions Q&A 1.​ In direct contact communication, animal cells communicate through _______ junctions and plant cells communicate through _______. Animal cells communicate through gap junctions and plant cells communicate through plasmodesmata. 2.​ What do animals and plants use for long distance signaling? ​ They both use hormones for long distance signaling. 3.​ Differentiate between animals and plants when they use hormones to communicate. ​ Plants hormones travel into the vascular tissue or the air to get to the target cell while long distance signaling. Meanwhile, animals have specialized cells that release the hormones into their circulatory system to the target cell. 4.​ Differentiate between paracrine signaling and synaptic signaling. ​ Paracrine signaling can happen in plants or animals, it has more to do with the body (growth factors and local regulators). Synaptic signaling can only happen in animal cells and has more to do with the brain (neurons and nervous system). 5.​ True or false: insulin signaling is an example of local signaling. ​ False 6.​ What is Quorum sensing? Bacterial cell communicating, for example, tells cells to not divide because supplies could be low. 7.​ What is better for a message that you want closely contained? Polar Topic 2: Vocab: ●​ Reception- first step in cell to cell messages where the ligand binds to the receptor. ●​ Transduction- second step in cell to cell messages where signal is converted into another. ●​ Receptor- a specialized molecule (usually a protein) on or inside a cell that binds to specific signaling molecules (ligands like hormones, neurotransmitters) to trigger a specific cellular response. ●​ Ligand- a molecule that binds to another, larger molecule, often a protein like a receptor, to transmit a signal and cause a functional change ●​ Second messengers- small, intracellular molecules or ions that amplify and relay signals from a cell's surface to its interior ●​ GPCR- G protein-coupled receptor, a large family of proteins on the cell surface that transmit signals from outside the cell to the inside. They are activated by hormones. ●​ Ligand-gated ion channel- a type of membrane protein that opens or closes in response to a specific chemical messenger, called a ligand. When the ligand, such as a neurotransmitter, binds to the channel, it triggers a change in the channel's shape, which in turn opens it and allows ions to pass through the cell membrane ●​ Protein Kinase- an enzyme that regulates a cell's activity by adding a phosphate group to a protein, a process called phosphorylation. ●​ Protein phosphatase- enzymes that remove phosphate groups from proteins, which is a crucial process for regulating many cellular functions. They act as the counterpart to protein kinases, which add phosphate groups ●​ cAMPQ&A 1.​ Summarize the three stages of cell signaling in one sentence each. ​ The first step is reception, where the ligand binds to the receptor. Then the second is transduction where the signal gets converted. The last step is the response, where the cell process is altered. 2.​ If you were given a problem on the AP exam that described a water-soluble (polar) receptor, where would it be located in the cell? ​ The plasma membrane. 3.​ Receptors that bind to estrogen, a hormone would be found where in the cell? ​ Inside the cell. 4.​ What do second messengers do, and why is this role so important in some cells? ​ Second messengers amplify the response of the signal and relay the message. 5.​ Molecules that help to relay and amplify messages during the signal transduction pathway? cAMP and Calcium 6.​ Identify 3 different responses that can be seen in cells, when the last stage of the signal transduction pathway. Cell growth, turning genes off and on, or the cell can die. Topic 7 1.​ Describe what will happen to a cell if it does not pass the G1 checkpoint? G1 checks if the cell is growing or not, if they are not growing they go back to G0. 2.​ What is G0? What types of cells are in G0? Nerves and muscle cells are in G0, they do not rejuvenate. 3.​ Describe what will happen to a cell if it does not pass the G2 checkpoint? The cell will go through apoptosis. 4.​ True or False: the concentration of cyclins remains constant throughout the cell cycle? True 5.​ List the three types of external cell regulators. 6.​ Describe at least two ways a cancer cell differs from a normal cell. 7.​ Explain how sun damage can potentially lead to skin cancer. Proto-oncogenes tells cell cycle to go Tumor suppressor- tells cell cycle to stop