I. Cell theory II. Eukaryotic vs. prokaryotic cells III. Cell structure IV. Cell-cell communication V. Plant vs. animal cells Cells: structure and function

I. Cell theory All living things are composed of cells and cells form a unifying structural basis of organization (1838). -- Structure and function (1900s) -- All cells come from preexisting cells (1862)

-- no nucleus-- have a nucleus -- have membrane bound organelles -- no membrane bound organelles -- plant and animal cells-- bacterial cells II. Eukaryotic vs. prokaryotic cells EukaryotesProkaryotes

Fig. 3.4, p. 33 Remaining organelles Cytoplasm = Protoplasm = Cell = III. Cell Structure: Subunits of the cell Cell wall Cytosol = fluid of the cell Vacuole Nucleus

A. Cell wall -- defines the shape of the cell Secondary cell wall Primary cell wall Middle lamella Intercellular space

A. Cell wall Rigidity = strength, support, and protection “cellulose fibrils” 2. Primary cell wall: network of cellulose, hemicellulose, pectin, glycoproteins 3. Secondary cell wall: derived from primary wall, include lignin 1. Middle lamella: layer of pectin

B. Plasma membrane: -- selectively permeable: regulates the movement of substances into and out of the cell -- Composed of lipids, protein and carbohydrates Fig. 3.7, p. 37 carbohydrates lipids proteins

C. Organelles 1. Nucleus (pl. nuclei) -- Stores hereditary material (DNA) -- “Control center” of the cell

2. Vacuole -- Stores water, nutrient reserves, excess minerals, and toxic waste -- Recycles cellular materials -- Maintains pressure

3. Mitochondria (sing.: mitochondrion) -- “Powerhouses” of the cell; site of cellular respiration Fig. 3.13, p. 42

4. Endoplasmic reticulum (ER): -- Network of membrane channels; carry material around the cell ribosomes -- Rough ER: protein synthesis -- Smooth ER: lipid secretion, membrane assembly

5. Ribosomes -- responsible for protein synthesis

6. Plastids a. Chloroplast: “green” -- Photosynthesis -- Chlorophyll pigment b. Chromoplast: “color” -- Carotenoid pigment (yellow, orange, red) c. Leucoplast: “colorless” -- Store starch and oils

7. Dictyosomes (Golgi bodies) -- Flattened membrane sacs -- Process products of the ER -- “post offices” of the cell vesicles

-- through secretion of specific compounds IV. Cell-cell communication -- through plasmodesmata (sing.: plasmodesma): cytoplasmic channels between adjacent cells Fig. 3.20, p. 50

V. Plant vs. animal cells Plasma membrane = Cell membrane Nucleus Nucleus ERER Ribosomes Ribosomes Mitochondria Mitochondria Dictysomes= Golgi Cell wall Large central vacuole Plastids (ex. chloroplast) Plasmodesmata Plant cellsAnimal cells