CELL-dictate our structureI. BASIC CELL COMPOSITIONA. Plasma membrane = Cell membrane – surrounds cell & gives it form.1. Structure: 2 layers of phospholipids with proteins scattered throughout (bilayer).a. Proteins: In membrane or “float” on surface.b. Glycoproteins: Proteins with carbohydrate attached. 2. It is selectively permeable. Determined primarily by size, charge, and solubility.3. Functionsa. Passive Transport (no energy)i. Diffusion: Some SMALL materials may diffuse/pass through the cell membraneb. Active Transport (energy required) LARGE particles must be transported actively:i. Exocytosis: process by which cellular materials EXIT the cell- Materials are packed within vesicles (small sacs)- vesicles fuse w/cell membrane and release contents outside of cellii. Endocytosis: process by which materials are brought INTO the cell. (3 types) - Phagocytosis: “cell eating”; ingestion of large particles. - Pinocytosis: “cell drinking”; ingestion of fluid& small particles. - Receptor-mediated endocytosis: substances bindto receptors where the membrane is indented = coated pit, & a clathrin (protein) – coated vesicle is formed.4. Specializations of plasma membrane:a. Microvilli: non-motile, help increase surface rea.b. Cilia: motile, move substances over the surface of stationary cells.c. Flagellum: motile, whip-like structure that moves cells.B. Cytoplasmic Organelles1. Mitochondriona. Makes ATP (adenosine triphosphate, energy molecule)2. Ribosomes - involved in protein synthesis (production)a. Two kinds: #1. Free Ribosomes: makes protein for cell.#2. Ribosomes attached to the ER: make proteins for export.3. Endoplasmic Reticulum (ER) - a network of tubules used to transport & synthesize (produce) materialsa. Rough ER - has ribosomes on walls. Transports and modifies proteins made by ribosomesb. Smooth ER – no ribosomes- synthesizes lipids, mainly steroids- detoxify drugs and alcohol4. Golgi Apparatus: several C-shaped sacs near the nucleusa. Packages material for secretion.b. Forms lysosomes. 5. Lysosomes - contain digestive enzymesa. Enzymatically breaks down internalized material & old organelles. “Garbage men” of the cell. 6. Centrioles – needed for cell divisionC. Nucleus1. Nuclear Envelope (Nuclear Membrane): It has nuclear pores and is selectively permeable2. Nucleolus – contains protein & RNA-Based on size: whether a substance goes in or out.3. Chromatin - coiled mass of DNA (1/2) wrapped around proteins(1/2) wrapped around histonesII. DNA (= deoxyribonucleic acid) COMPOSITION/REPLICATIONA. It’s made up of nucleotides (each consists of a phosphate group, sugar & base)B. Shape: double helixC. Prior to cell division, the DNA "unzips"1. free nucleotides will attach to the two half-ladders, forming twoidentical DNA strands = replicationWhich of the following is responsible for protein production?a. Mitochondrionb. Lysosomec. Smooth endoplasmic reticulumd. Rough endoplasmic reticulume.