Cell Organization

1. Cell theory
1. all living things made of cells
2. all cells come from other cells

Sizes:

"orders of magnitude"

m meters

mm millimeters

(µm) microns (millionth)

(nm) nanometers (billionth)

() angstrom

(ten-billionth 1x10^-10 m)

Scientists

a) Robert Hooke - cells (1665)

b) van Leeuwenhoek -microscope (1683)-animalcules

c) Robert Brown - nucleus (1831)

d) Schleiden - plant cells (1838)

e) Schwann - animal cells (1839)

f) Virchow - all cells from preexisting cells (1858)

Dutrochet-parts of organisms are made of cells

Dujardin-recognizes 1 celled organisms

Schultze-defines protoplasm

Margulis-endosymbiotic theory (recent)

Prokaryotic versus Eukaryotic cells

Endosymbiotic theory of Eukaryotic cell formation

Multicellularity:-hierarchy of organization

Universal Hierarchy

Each layer of organization requires more free energy input for its maintenance than the one above it:

Sub-atomic particles

atoms

molecules

macromolecules

compound molecules

organelles

cells

tissue

organs

systems

organisms

populations

communities

ecosystems

biosphere

Simplest cells-

bacteria

(kingdom=monera)

no cell organelles

Specialized cells-

Simplest examples

Volvox

Hydra

Sponge

Division of labor

regulation - coordination

larger organisms (diffusion limits size of a single cell)-transport

M&M Lab-let

Problem:

Why do small M&M's taste different from regular sized M&M's?

Hypothesize

Taste

Record observations

Conclusions

Cell parts

cell wall

cell membrane

semipermeable phospho-lipid bilayer with embedded proteins

also called plasma membrane

hydrophobic and hydrophilic regions

1) Fluid mosaic

2) Lipid bi-layer

3) Trans- membrane proteins

4) Selectively permeable

{model}

cytosol / cytoplasm

fluid-like

-Cyclosis

1. nucleus

1) Directs cell activities

2) Contains chromosomes (genes)

-) Nuclear membrane

1) Surrounds nucleus

2) Completely permeable

-) Nucleolus

1) Found in nucleus

2) Synthesis of ribosomes

3) Synthesis of m-RNA

II. endoplasmic reticulum

Folded membrane channels

1) Intra-cellular transport

2) Rough - ribosomes

3) Smooth - no ribosomes

I

1. ribosomes

1) Site of protein synthesis

2) On endoplasmic reticulum (rough ER)

IV golgi apparatus

[Golgi complex (body)]

Packaging of material for export into vesicles

V Vacuoles

1) Membrane-bound storage

2) Food - intracellular digestion

3) Contractile - water balance

4) Lysosomes (lytic enzymes) break up/digestion

VI centrioles

(animal cells only)

1) Function in mitosis

2) Control microtubules (structure and movement)

VII microtubules

VIII mitochondrion

1) Site of aerobic cellular respiration

2) Site of ATP synthesis

3) Folded membranes - cristae

4) Contain DNA (cytoplasmic inheritance)

5) "Powerhouse of the cell"

IX chloroplast

(plant cells only)

1) Site of photosynthesis

2) Contain DNA (cytoplasmic inheritance)

3) Contain chlorophyll (pigment)

X flagella

1. cilia

Animal vs Plant cells

chloroplasts (photosynthesis)

centrioles

Cell Wall (plants only)

1) Cellulose (pectin - lignin) (PLANTS)

2) Chitin (FUNGI)

3) Turgor pressure - support

4) Completely permeable

Multicellular -division of labor

Transport

Diffusion

• facilitated diffusion
• Osmosis

diffusion of water

for a plant the pressure of water going into the cell against the cell wall is called turgor pressure-holds a plant up

• passive transport



• active transport

takes energy

concentration gradient

transport proteins