| Term | Definition |
|---|
| Cell Theory | 1. Organisms consist of 1 or more cells, 2. Cell is the smallest unit of life, 3. Continuity of life comes from growth and division of cells |
| What is a cell? | Made of C, H, O, N, and trace elements, has all the properties of life, differ in size, structure and function |
| Cell Function | Performs all vital physiological functions, maintains homeostasis, building blocks of all organisms |
| Generalized cell structure | Plasma membrane, Cytoplasm, region of DNA |
| Cell (plasma) membrane | semi-permeable barrier between interior of cell and external environment |
| Fluid mosaic model | lipid bilayer, dyanmic pattern of proteins, scattered carbohydrates |
| Lipid bilayer consists of: | phospholipids, glycolipids, sterols and lipid rafts |
| Membrane Lipids: Phospholipids | Amphipathetic, hydrophilic head, hydrophobic tail |
| Membrane Lipids: Glycolipids | Phospholipids with sugar groups |
| Membrane Lipids: Sterols | 20% of membrane lipids, wedged between phospholipid tails, in animal cells as cholesterol |
| What do the sterols act as an maintain? | Act as temperature buffers and maintains fluidity |
| Membrane lipids: Lipid Rafts | 20% of membrane lipids, found only on outer membrane surface |
| What are lipid rafts made of? | saturated lipids and proteins |
| What are lipid rafts used for? | concentration platforms for cell signalling molecules |
| What does the cell membrane consist of? | The Lipid bilayer and membrane proteins |
| Membrane proteins | carry out most membrane functions, can be intergral or peripheral |
| Integral proteins | most are transmembranal, have both hydrophobic and hydrophilic regions, used mainly for transport |
| Peripheral proteins | Attach to integral proteins or membrane lipids |
| Functions of peripheral proteins | structural support, enzymatic action, joining cells, changing cell shape |
| Major Membrane proteins | Adhesion protein, enzyme, receptor protein, recognition protein, passive transporter, active transporter |
| Adhesion proteins | Allow cells of same type to stick to each other or to other substances |
| Enzymes | Carry out necessary chemical reactions as needed |
| Receptor Proteins | Binding sites for particles and allow changes in cell activities |
| Recognition Proteins | In multicellular organisms, identify cells as foreign or self, |
| Communication Proteins | form channels between cytoplasm of 2 cells to allow signals to flow between cells |
| Transport Proteins | Have interior channels, involves shape-change of transporter, can be active or passive, one-way or bi-directional and may be gated |
| Membrane is mostly _____ allowing small, ____ molecules to cross | nonpolar; nonpolar |
| Concentration Gradient | Chemical potential energy, difference in concentration of ions or molecules between 2 adjacent areas |
| Movement mechanisms | Passive Transport, active transport, exocytosis, endocytosis |
| Simple diffusion | Movement of molecules down concentration gradient |
| What type of molecules use simple diffusion? | non-polar, lipid-soluble and small molecules |
| Facilitated diffusion | Substances transported passively via transport proteins |
| Factors Affect diffusion rate | steepness of concentration gradient, temperature, size of ions, electrochemical and pressure gradients |
| Active Transport | Pumps solutes against concentration gradient |
| Example of active transport | sodium-potassium pump |
| Osmoregulation | Control of water balance: prevents excessive uptake and loss of water |
| Example of osmoregulation | fish have gills and kidneys |
| Osmosis | diffusion of water across semi-permeable membrane from high water to low water |
| The more _____ a solution is, the more _____ the water is | dilute; concentrated |
| Tonicity | Relative solute concentrations of two fluids |
| What does tonicity determine? | The direction and how much movement will occur across the membrane |
| In animal cells, a hypotonic solution will | Lyses: burst |
| In animal cells, a hypertonic solution will | Crenate: Shrivel up |
| In Animal cells, a isotonic solution will: | have no net loss or gain of water |
| In plant cells, an isotonic solution will: | make the plant flaccid and wilt |
| In plant cells, a hypertonic solution: | Shrivals |
| In plant cells, a hypotonic solution: | will become turgid, net flow of water = happy |
| Exocytosis | OUT: Vesicle within cytoplasm moves to cell membrane, fuses with the membrane, and releases contents to exterior cell |
| Endocytosis: | IN: Outer membrane inpouches |
| Three forms of using endocytosis | Receptor mediated Endocytosis, phagocytosis, bulk-phase endocytosis |
| Receptor Mediated Endocytosis | somewhat selective, Receptors grab particles and bring them into the vesicle |
| Phagocytosis | Type of Endocytosis: food or bacteria selective: "cell eating," uses pseudopods, "fake feet" |
| Bulk phase | non-selective, "cell drinking," vesicle grabs whatever is outside and brings it in |
| Cell Junctions | Plasmodesmata, tight junction, anchoring junction and gap junction |
| Plasmodesmata | Only in plant cells; connect cytoplasms of 2 adjacent cellls= allows rapid exchange of materials |
| Tight Junction | In animal cells, Cells firmly stuck together |
| Example of a tight junction | stomach cells (so that acid isn't released into the body) |
| Anchoring Junction | Zipper-seal--with a bit of elasticity. |
| Example of an anchoring junction | uterus (so that it doesn't tear) |
| Gap Junction | enables materials to flow quickly via connected channels of two cells |
| Example of gap junction | cardiac muscles |
| Cell-Environment Interactions | Contact signalling and chemical signalling |
| Contact signalling | physical contact between cells; glycocalyx |
| Chemical Signalling | LIGANDS= signalling chemicals that bind to membrane receptors |
Combine with other sets
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