BIOL 111 Chapter 6
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Begin Exam 2 Contents
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A Tour of the Cell
Tools
- Microscopes (Appendix D)
- Light microscope (1,000x)
- Electron microscope (2,000,000x)
- Cell Fractionation
- break cells open
- use centrifuge to separate components of different densities
Three domains of life
- Common Ancestor of all life
- Bacteria
- (non-bacteria)
- Eukarya
- Archaea
Prokaryotes (Bacteria and Archaea)
Prokaryote = "before nucleus"
- No central nucleus (nucleoid is genetic material)
- All single-celled
- Cell wall around cell membrane
- Only organelle is ribosome
Eukaryotes
Eukaryote = "True nucleus"
- plants
- Cell walls made of cellulose, vacuoles, chloroplasts
- fungi
- can have multiple nuclei, cell wall made of chitin
- animals
- lysosomes, no cell wall, cilia or flagella, centrosomes in nucleus
Tuesday, September 14, 2010
Components of a Cell
- Extracellular Matrix
- Stuff outside the cell
- Plasma Membrane
- Phospholipid bilayer with proteins and cholesterol embedded
- Cytoskeleton (refer to Table 6.1)
- Microtubules: hollow tubes made of tubulin monomers
- Intermediate filaments: keratin proteins supercoiled into thick cables
- Microfilaments: two twisted actin polymers
- Mitochondrion
- Two membranes: inner and outer
- Endosymbiosis theory: mitochondrion prokaryotic cell was once engulfed by larger cell[1]
- produce ATP for energy via cellular respiration
- Nucleus
- Double membrane nuclear envelope
- Chromatin (units called Chromosomes) = Protein + DNA
- Nuclear pores allow material to enter and exit
- Nucleolus produces ribosomes; contains protein and rRNA[2]
- Ribosomes
- Two units: Large and small
- Makes proteins
- free-floating in cytosol or bound to rough ER[3]
Endomembrane system
- Endoplasmic Reticulum (ER)
- attached to nuclear envelope
- regulates protein processing
- metabolic functions
- Smooth ER
- Synthesizes lipids, detoxification
- Breaks down carbohydrates
- Rough ER
- synthesizes and modifies proteins
- constructs cell membrane
- Golgi Apparatus
- modifies proteins
- produces polysaccharides like cellulose and glycogen
- cis side "receives" raw proteins
- trans side "ships" modified proteins
- Lysosomes
- break down large molecules in an acidic environment (phagocytosis)
- EX: White blood cells
- break down old and worn-out organelles (autophagy)
- Cytosol
- fluid substance around organelles
- Cytoplasm
- region between nucleus and plasma membrane including organelles
- Peroxisomes
- Dense core of enzymes that take H atoms from poisons and create H2O2 (Hydrogen Peroxide)
- Hydrogen peroxide used to break down fatty acids
Plant-specific structures
- Cell Wall
- composed of cellulose fibrils
- plasmodesmata go through membrane and cell wall to connect adjacent cells
- Central Vacuole
- stores various compounds like sugars, starch, water
- important for cell growth
- Chloroplast
- Endosymbiotic organelle[4]
- 3 membranes: outer, inner, and thylakoid