Download Outline for Cell structure and membranes

Outline for Cells and Cell Membranes - Chap 7
Biology 520 -- Mr. Ausema
Main class page | cells links
I. History of cell-related discoveries
A. 1600’s Hooke – first to describe cells (dead plant cells in cork)
B. 1600’s Van Leewenhoek – first to describe one-celled microorganisms
C. 1800’s Schleiden and Schwan – proposed the theory that all living things are
made of cells.
D. 1800’s Virchow – proposed the theory that all cells come from pre-existing
cells (how does this tie in with Redi and his maggots?)






Why are living things organized into cells?
We will explore the answer to this question in lab.
why are cells so small? - see links
Tutorial on Scanning Electron Microscopes
Virtual microscope
Interactive cell
iCell - free app for Apple or Android
II. Cell organization: organelles - Also overview diagram p. 196




fact sheet on cells - what we know and what we hope to learn in the future.
Interactive cell
animated cell anatomy and how it works
iCell - free app for Apple or Android
A. manufacture
1. nucleus – fig 7-7
2. ribosomes
3. endoplasmic reticulum (rough and smooth)
4. golgi apparatus – fig 7-11
5. flow of manufacture and processing
B. breakdown/catabolism
1. lysosomes - p. 198
2. vacuoles – fig 7-8
C. Energy processing – fig 7-12
1. chloroplast
2. mitochondria
D. Support and movement
1. walls
2. cytoskeleton – p. 199
3.junctions
4. cilia/flagella
III. Membrane structure: (see p. 204) | animated membrane structure
A. phospholipid bilayer - fig 7-13
B. proteins – for transport and other functions
C. glycoproteins (carbo/protein combination) - serve as cell markers
IV. Movement across the membrane: compare the membrane to a chain link fence (see p. 208213 in your book)
Pictures and diagrams of movement across the membrane and membrane structure
A. diffusion - fig 7-15
1. definition: movement of particles across the membrane; results
explained by kinetic molecular theory
2. goes in the direction of the "gradient" – from higher to lower
concentration.
3. only small, uncharged particles diffuse without assistance
(examples: water, carbon dioxide, oxygen)
B. osmosis - diffusion of water
1. also goes in the direction of higher to lower concentration; note
that this means water tends to flow toward areas where solutes are
more concentrated. (see fig 7-17, p. 210)
2. note results when cells are in solutions of greater or lesser
concentration – sometimes the cells burst or collapse. (see p. 211,
fig 7-18)
C. Facilitated diffusion (passive transport)
1. involves particles moving across the membrane in the natural
direction (high to low)
2. particles move through the protein "gates" because they are too
large or too polar to diffuse through the lipid layer.
3. examples: sugar, some hormones, ions such as K+ and Na+
D. Active transport (see fig. 7-19, p. 212)
1. involves movement of any particle from low to high
concentration ("against the gradient"), using the protein gates
2. called "active" because energy is needed
E. Phagocytosis/Pinocytosis
IV. Variety of cells

not all cells look like the "model cells" shown in your book. Some examples follow, see
also p. 190-193 on cell specialization:
A. Secretory cells (such as in stomach and intestines)
B. Red blood cells
C. Muscle cells
D. Fat cells
E. Nerve cells
F. Leaf "pallisade" cells – photosynthesis
G. Leaf transport cells
V. Eukaryotic vs. Prokaryotic cells (see p. 194, fig 7-5)
A. Prokaryotic – bacteria – no "membrane-bound" organelles
B. Eukaryotic – everything else.

did mitochondria and chloroplasts used to be bacteria?
VI. Enzymes
A. enzymes are proteins, so they are made of amino acids and have complex
three-dimensional structure
B. enzymes are biological catalysts. They lower the "activation energy" needed to
start a reaction, so they make the reactions go faster. Enzymes control every
chemical reaction that takes place inside living things.
C. enzymes are specific for particular reactions. Each step in a reaction process
has its own enzyme. For example, getting the energy out of sugar (respiration)
requires more than 20 separate enzymes.
D. Enzymes can be sped up or slowed down by changing conditions such as
temperature, pH, and concentration of reactants and products.
Back to top