UCBXGenBiol-Spring2015-1sppLect03 - Lecture 3 Cells Cell Membranes Cellular components and structure Cell membrane structure Lipid bilayer Membrane

UCBXGenBiol-Spring2015-1sppLect03 - Lecture 3 Cells Cell...

This preview shows page 1 - 11 out of 83 pages.

Lecture 3 Cells & Cell Membranes Cellular components and structure Cell membrane structure Lipid bilayer Membrane Proteins Cell membrane transport Carrier proteins & their functions Ion Channels & the membrane potential Campbell et al , Chap 6, 7
Image of page 1
All living creatures are made up of cells. Cells : - small membrane-bound units filled with a concentrated aqueous solution of chemicals - able to create copies of themselves by growing and dividing in two. - simplest collection of matter that can live - division of labor in organelles So far …. Organelle : membrane-enclosed structure with specialized function, suspended in the cytosol of eukaryotic cells
Image of page 2
Light microscope down to 200 nm Electron microscope down to 0.5 nm Frog Egg 3 mm (10 -3 , milli) Typical Plant Cell 10-100 ! m (10 -6 , microns) Human Red Blood Cells 7-8 ! m E. Coli (Bacterium) 1-5 ! m in length HIV virus 100 nm (10 -9 , nano) Molecules, DNA 2 nm Relative Size
Image of page 3
Light microscopes - magnify to about 1,000X size of specimen - enhance, contrast, stain, label cell components - Confocal microscopy Electron microscopes (EMs) – - to study subcellular structures - Scanning electron microscopes (SEMs) - focus beam of electrons onto specimen surface -> images that look 3-D - Transmission electron microscopes (TEMs) - focus beam of electrons through a specimen Fluorescence 10 ! m SEM 2 ! m TEM 2 ! m
Image of page 4
Cell fractionation: Technique 1. Breaking cells and tissues: sonication, mild detergent, pressure, homogenization Cell Breakage & Fractionation extract or homogenate
Image of page 5
Differential centrifugation Centrifuged at 1,000 g (1,000 times the force of gravity) for 10 min Supernatant poured into next tube 20 min 60 min Pellet rich in nuclei and cellular debris 3 hr Pellet rich in mitochondria (and chloro- plasts if cells are from a plant) Pellet rich in microsomes Pellet rich in ribosomes 20,000 g 80,000 g 150,000 g 2. Centrifugation - separation of components based on size and density
Image of page 6
Eukaryotic cells have internal membranes that compartmentalize their functions . Cell Fractionation Basic features of all cells - Plasma membrane - Cytosol: semifluid substance - Chromosomes (carry genes) - Ribosomes (make proteins) Prokaryotic cell Eukaryotic cell - No nucleus - DNA in unbound region (nucleoid) - No membrane-bound organelles - Cytoplasm bound by plasma memb - Nucleus, membrane bound - Membrane-bound organelles - Cytoplasm: region b/w PM & nucleus - Generally larger than prokaryotic cells
Image of page 7
Fimbriae Bacterial chromosome A typical rod-shaped bacterium Nucleoid Ribosomes Plasma membrane Cell wall Capsule Flagella (TEM) Thin section through bacterium Bacillus coagulans 0.5 μ m Prokaryotic cell
Image of page 8
Plasma membrane Selective barrier allowing passage of oxygen, nutrients and waste. Double layer of phospholipids . Outside of cell Inside of cell 0.1 μ m TEM of PM Hydrophilic region Hydrophobic region Hydrophilic region Carbohydrate side chains Proteins Phospholipid
Image of page 9
ENDOPLASMIC RETICULUM (ER) Rough ER Smooth ER Nuclear envelope Nucleolus Chromatin Plasma membrane Ribosomes Golgi apparatus Lysosome Mitochondrion Peroxisome Microvilli Microtubules Intermediate filaments Microfilaments Centrosome CYTOSKELETON: Flagellum NUCLEUS Eukaryotic Cell
Image of page 10
Image of page 11

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture