AP Biology - Unit 2 Study Guide Questions with Verified Answers

AP Biology - Unit 2 Study Guide Questions with Verified Answers Describe diffusion and give some specific examples of molecules which move by diffusion. - The random thermal motion of particles of liquids, gases, or solids. In the presence of a concentration or electrochemical gradient, diffusion results in the net movement of a substance from a region where it is more concentrated to a region where it is less concentrated. - The movement of particles of any substance, so that they tend to spread out into the available space. - Ex. of molecules that move by diffusion: carbon dioxide (CO2) & oxygen (O2). Describe how animal and plant cells differ in their present/absence of cellular organelles. In Animal cells, but not Plant cells: - lysosomes - centrosomes, w/centrioles - flagella (but present in some plant sperm) - small vacuoles In Plant cells, but not Animal cells: - chloroplasts - cell wall - plasmodesmata - central vacuole - tonoplast Describe some examples of how each is used in the body. - Ex. of Phagocytosis: white blood cells (it engulfs a bulk transport of bacteria). - Ex. of Pinocytosis: bacteria, human egg cell (that matures in the ovary that's surrounded by other cells). Describe the process that occurs to activate protein membranes? Reception: the signal molecule (ligand) bonds with receptor molecule, fitting like a lock & key, changing the receptor protein's confirmation (shape). * Explain 2 examples of bulk transport into a cell. - Pinocytosis: "cellular drinking"... aka Pina Coladas - Phagocytosis: "cellular eating" Explain how a hormone can have so many effects in a body. - These ligands can fit into different proteins on different cells, which causes the cells to do different things. - The cells of ligands causes different effects. - It is the same molecule, but in a different cell, so a different response occurs each time. - The same ligand could have 1,000's of different responses. Explain how steroid receptors work. - The steroid is the molecule that gets through the membrane. These intracellular receptors/hormones passes