Draw the Lewis structures for each of the following molecules or ions. Which do not obey the octet rule? (a) NO, (b) BF3, (c) ICI2¯, (d) OPBr3 (the P is the central atom), (e) XeF4.
BSCI105 Week 3 Notes Bulk transport, metabolism, energy & the membrane 02/15 Video Lecture 7 — Bulk Transport Bulk transport occurs because the cell has to transport larger molecules, and excrete many molecules at the same time - In bulk transport, the membrane itself is used - There are 2 types: - Endocytosis - Exocytosis Endocytosis: used to bring things into the cell - Phagocytosis: “cell eating” - Allows the cell to consume large things at once - Macrophage digests unwanted material - Amoeba surrounds other cells with arms from the cell membrane to connect and digest things - Pinocytosis: “cell drinking” - Brings in water (and solutes dissolved in water) without diluting cytoplasm, by using membrane vesicles - Receptor-Mediated Endocytosis - more speciﬁc - Brings in a particular molecule from the environment - Uses receptors to recognize speciﬁc molecules - Occurs in clathrin-coated pits; uses 2 types of protein: - 1. Receptor — recognizes something speciﬁc and bonds to it - 2. Clathrin (peripheral) — bends and creates a force bubble of membrane Exocytosis: reversed endocytosis; used for secretion - Cell makes a vesicle of membrane which goes to the plasma membrane protein - The plasma protein fuses them and the vesicle dumps its contents into the outside environment. - Membrane trasport: - Multiple membranes operate at the same time - Important because what happens with one mechanism could impact other mechanisms 02/19 In Class Lecture 8 —