1. “VOLUME” Cytosol and Cytoplasm cytosol: viscous liquid in cell analogy: JELL-O cytoplasm: viscous liquid + cell organelles analogy: JELL-O w/ fruit Eukaryotic cells have compartmentalized organelles, meaning the organelles are separated from the rest of the cell by membranes. Of course, the cell itself is enclosed by a plasma membrane. The space between the organelles and the plasma membrane is filled with some gel-like, gooey stuff called cytosol. We can differentiate the cytosol from cytoplasm like this: * Cytosol is found between the organelles and the cell (plasma) membrane, but does not include the organelles and plasma membrane in its definition. Thus, only eukaryotic cells have cytosol in this sense because only eukaryotic cells have compartmentalized organelles. Cytosol is comprised of a lot of water, dissolved ions, large water soluble molecules, smaller molecules, and proteins. Metabolic processes and cell communication occur within the cytosol. Proteins are synthesized in the cytosol (translation). Metabolic (anabolism and catabolism) processes occur within the cytosol. * Cytoplasm refers to everything that is found within the plasma membrane. It includes the cytosol, endomembrane system, and cell organelles. Both eukaryotic cells and prokaryotic cells have cytoplasm. Cytoplasm is made of water up to 80% nucleic acids, enzymes, lipids, non-organic ions, amino acids, carbohydrates, and lightweight molecular compounds.

2. Flagella and 3. Cilia flagella: long extension of cell surface, ex. tail of a sperm cell analogy: people mover cilia: short extensions of cell surface, move cell, move substances across the cell, ex. surface of paramecium analogy: legs

4. Cytoskeleton cytoskeleton: “skeleton” of the cell, allows for movement within cell, made of microtubules and microfilaments analogy: human skeleton Microtubules (25 nm diameter) - moves stuff around the cell, make up cilia and flagella, assist during cell division Actin filaments (8 nm) – involved in muscle contraction, assist during cell division Intermediate filaments (10 nm) – provide structure and strength in the cell

5. Cell Membrane cell membrane: phospholipid and protein “skin” around cytoplasm, selectively permeable (allows certain materials into/out of cell analogy: security guard Draw and label the diagram on next slide. All cell membranes are dynamic, fluid structures. Most of their lipids and proteins are able to move about rapidly in the plane of the membrane. This has lead to the term “fluid mosaic model" as a description of the structure of cell membranes. Many membrane proteins are held in the bilayer by “hydrophobic" interactions with lipid molecules. Membrane proteins may be associated with the lipid bilayer in one of three ways: 1) Some proteins are known to extend across the bilayer (integral membrane proteins) 2) Some to be held by non-covalent interactions with other membrane proteins. 3) Recently, it has been shown that some membrane proteins have one or more covalently attached fatty acid chains that help anchor the protein in one monolayer or the other (these may or may not be integral membrane proteins).

Phospholipids Integral protein Peripheral protein Fatty acid “tails” (lipids) Phosphate Group

6. Nucleus nucleus: membrane-bound structure, contains genetic info, nuclear pores allow RNA and ribosomal subunits to leave nucleus analogy: brain

7. Nucleolus nucleolus: dark spot inside nucleus, where ribosomal subunits are made (leave through nuclear pores) analogy: Lego factory

8. DNA DNA: found in nucleus (eukaryotes) and in cytosol (prokaryotes) chromatin: unwound, “working DNA” (replication, repair, transcription) chromosomes: “copied DNA” (condense for cell division) analogy: information in an encyclopedia

9. Ribosomes ribosomes: most numerous organelle, protein synthesis, free-floating (cytosol), attached to rough ER analogy: Garage Band

10/11/12. Rough and Smooth Endoplasmic Reticulum and Vesicle rough ER: stores and transports proteins, sends proteins to Golgi analogy: highway smooth ER: detoxifies (lots in liver cells), phospholipid and steroid production, transport analogy: filter vesicle: membrane-bound, storage (ex. proteins from ribosome) analogy: Rubbermaid container smooth ER: (lacks ribosomes): steroid and phospholipid production, little smooth ER except in hepatocytes (liver cells), detoxification

13. Golgi Apparatus Golgi: receives raw material from ER, modifies, processes, and sorts material into vesicles to be sent to cytosol or out of cell analogy: post office

14. Lysosomes lysosomes: digest worn out cell parts (enzymes), digest food absorbed by the cell, mainly in animal cells (100s per cell) analogy: garbage disposal

15. Mitochondria mitochondria: makes the cell’s energy (ATP), folded inner membrane = increased surface area, has its own DNA analogy: power plant

16. Cell Wall cell wall: strong, outer covering of plant cells, contains cellulose, support, prevents dehydration analogy: castle wall

17. Vacuoles (animal cells) and Central Vacuole (plant cells) vacuoles: animal cells, small and numerous, accumulate toxic wastes, storage analogy: sponges (clean up and remove water) central vacuole: up to 90% of plant cell’s volume, keeps cell pressurized (“turgidity”) analogy: swimming pool

18. Chloroplast chloroplast: plant cells, type of plastid filled with chlorophyll, turns solar energy into chemical energy (glucose) analogy: oven

19. Centrosomes centrioles: animal cells, in pairs, organize chromosomes during cell division microtubule-organizing center (MTOC): plant cells, same function as centrioles