Lecture Outline - Chapter 2

2.1 Cell Size (p. 40)
	1.	All living things are composed of cells, and new cells arise only from preexisting ones.
		a.	Cells are the fundamental unit of all living things.
		b.	Cells are small to maintain an optimal surface area to volume ratio. 
	2.	Microscopy Reveals Cell Structure (p. 40, Fig. 2.2 a-c)
		a.	The compound light microscope passes light rays through specimens and uses glass lenses to view objects.
		b.	The transmission electron microscope passes electrons through a specimen, focuses with magnetic lenses, and projects images onto a fluorescent screen or photographic film. 
		c.	The scanning electron microscope passes a beam of electrons over the surface of a metal-coated specimen, collecting them to produce a television-type picture on a screen.
2.2 Cellular Organelles (p. 42, Table 2.1, Fig. 2.3)
	1.	Plasma Membrane Is a Bilayer (p. 44, Fig. 2.4)
		a.	In the fluid-mosaic model, the plasma membrane is a bilayer of phospholipids with embedded or attached proteins.
		b.	Glycoproteins and glycolipids serve as identification markers.
		c.	Embedded proteins may serve as hormone receptors, transport channels, and enzymes in metabolic reactions. 
		d.	How the Plasma Membrane Functions (p. 45, Figs. 2.5, 2.6; Table 2.2)
			i.	Diffusion is the random movement of molecules from an area of higher concentration to one of lower concentration. 
			ii.	Osmosis is the diffusion of water across a plasma membrane. 
			iii.	Transport by carriers occurs in two manners. In facilitated transport a protein carrier helps a molecule across the membrane, using no energy. In active transport, a protein carrier transports a molecule but requires energy (Fig. 2.6). 
			iv.	Endocytosis occurs as the plasma membrane forms a vesicle around a particle. Exocytosis is the reverse process.
	2.	Nucleus Controls the Cell (p. 47, Fig. 2.7)
		a.	The nucleus DNA directs protein synthesis in the cytoplasm.
		b.	The nucleus contains one or more nucleoli, where ribosomal RNA (rRNA) is manufactured.
		c.	The nuclear envelope is a double membrane with nuclear pores. 
	3.	Granule-like Particles (p. 47)
		Ribosomes are a mix of rRNA and proteins. They are the site of protein synthesis in the cytoplasm.
	4.	Membranous Canals and Vacuoles (p. 48)
		a.	Endoplasmic Reticulum Produces, Modifies, and Transports (p. 48, Fig. 2.8)
			i.	The endoplasmic reticulum (ER) is a series of membranes that form tubular channels within the cytoplasm.
			ii.	Rough ER (with ribosomes) specializes in protein synthesis.
			iii.	Smooth ER produces different compounds in different cells. 
			iv.	Peroxisomes house drug-detoxifying enzymes.
		b.	Golgi Apparatus Modifies, Processes, and Packages (p. 48, Fig. 2.9)
			The Golgi apparatus, a stack of flattened vacuoles with vesicles near the edges, packages, stores, and distributes the proteins the ER produces.
		c.	Vacuoles Store Substances (p. 48)
			Large, membrane-bound sacs are vacuoles; smaller ones are vesicles. 
		d.	Lysosomes Digest (p. 49)
			The Golgi apparatus produces lysosomes, which contain hydrolytic enzymes that digest unwanted materials inside the cell, including worn-out cell parts.
	5.	Mitochondria Convert Energy (p. 50, Fig. 2.10)
		a.	Mitochondria are organelles bounded by a double membrane. The inner membrane is folded into cristae. The gel-like material between the cristae is matrix.
		b.	Mitochondria convert the energy stored in glucose into ATP molecules in a process called aerobic cellular respiration.
	6.	Cytoskeleton Maintains Cell Shape (p. 50, Fig. 2.11)
		a.	Filamentous protein structures, microtubules, and actin filaments form a cytoskeleton that serves as a framework for the cell's interior.
		b.	Centrioles and Microtubules (Fig. 2.12)
			i.	Centrioles are short cyclinders with a 9 + 0 arrangement of microtubules. They occur in pairs.
			ii.	Centrioles duplicate prior to cell division and function as part of a microtubule organizing center. Centrioles also give rise to basal bodies that direct the formation of cilia and flagella.
		c.	Cilia and Flagella Make Cells Move (p. 52, Fig. 2.13)
			Cilia and flagella are hairlike projections of cells responsible for locomotion.
2.3 Cellular Metabolism (p. 52)
	1.	Enzymes and Coenzymes (p. 52, Table 2.3, Fig. 2.14)
		a.	Cellular metabolism includes all the chemical reactions that occur in a cell.
		b.	Every cellular reaction requires a specific enzyme.
		c.	Metabolic pathways require enzymes to catalyze a series of reactions in sequence.
		d.	Enzymes are named for their substrates and have an active site specific for the substrate.
		e.	Many enzymes have nonprotein molecules, called coenzymes, to assist them. Some coenzymes, like NAD, remove hydrogen from substrates.
	2.	Cellular Respiration Uses Metabolic Pathways (p. 53)
		a.	Aerobic Cellular Respiration Uses Oxygen (Fig. 2.15, Table 2.4)
			i.	Glucose breaks down into carbon dioxide and water during aerobic cellular respiration.
			ii.	Glycolysis, the Krebs cycle, and the electron transport system are three subpathways of cellular respiration.
			iii.	Glycolysis needs no oxygen and takes place in the cytoplasm of the cell. During glycolysis, glucose breaks down into two molecules of pyruvate, with a net gain of 2 ATP.
			iv.	A transition reaction converts pyruvate to active acetate that can enter the mitochondrion and the Krebs cycle.
			v.	The Krebs cycle takes place in the matrix and requires oxygen. Two ATP and 4 CO2 molecules form as the cycle turns twice, once for each pyruvate molecule. 
			vi.	NADH2 carries hydrogen atoms from glycolysis and the Krebs cycle to electron carriers (electron transport system) embedded in the cristae. As electrons pass down the system of carriers, energy is released to generate 32 ATP.
	b.	Fermentation Is Anaerobic (p. 55)
		i.	When no oxygen is present for pyruvate to enter the Krebs cycle, pyruvate is converted to lactic acid through fermentation, producing few ATP. 
		ii.	Lactic acid is toxic to many cells and leads to muscle fatigue.