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27 Cards in this Set
- Front
- Back
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What does the cell theory state? |
Cells are building blocks of all plants and animals.
All cells come from the division of previous cells. Cells are the smallest units that perform all vital functions. Each cell maintains homeostasis at cellular level |
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What are the two Classes of cells?
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Sex Cells Germ cells-
reproductive cells Sperm (male cells) Oocytes (female cells) Contain 23 chromosomes - Somatic cells All other cells within chromosome 46 chromosomes (23 pairs) |
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What is found in the cytoplasm |
Cell contents Subdivided into Cytosol: intracellular fluid Organelles: Intracellular structure |
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extracellular fluid?
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Surrounds cell Watery fluid
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What are the roles of membrane lipids |
Lipids (Fatty Acid Tails) form most of surface area (42%) Prevent water soluble molecules from passing through membrane Lipid soluable molecules CAN pass through Small gases and water can squeeze between fatty acid tails through membrane |
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Role ofMembrane Proteins |
Accounts for 55% of PM Anchoring Proteins -Attach to PM and other structures (cytoskeleton, extracellular fibers) Recognition Proteins- Often glycoproteins Help to ID normal vs abnormal cells Enzymes Catalyze membrane bound reactions Receptor Proteins Binds with ligand (hormones) triggers changes in cellular activity Carrier Proteins Bind solutes and transport across PM Channels Central Pore forms passageway- permits movement of water and small solutes across PM |
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What are the different types of membrane proteins? |
Integral Proteins=transmembrane Proteins Part of membrane, cannot be removed without damage to PM Most span width of PM Peripheral Proteins Bound to inner or outer surface Easily separated Fewer than integral |
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What are the roles of membrane carbohydrates? |
Accounts for only 3% of PM Components of more complex molecules such as: Proteoglycans, glycoproteins, and glycolipids Extend beyond outer surface of membrane forming a layer called: Glycolax Function as: Lubrication and protection of PM Anchoring and location of cell BINDS extracellular compounds altering cell surface and indirectly cell behavior Involved in Immune response |
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List the functions of the plasma membrane and the structural features that enable it to perform those functions |
Physical Isolation Regulation of Exchange within environment Eliminate waste controls entry of nutrients Sensitivity to environment Contains receptors to recognize molecules Structural Support Structural Features: Phosphate heads Hydrophilic Fatty Acid Tails Hydrophobic |
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What types of molecules can diffuse across plasma membrane? |
Non polar, hydrophobic molecules
Alcohols, fatty acids and steroids Dissolved gases: O2 and CO2 Soluble in lipids |
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What types of molecules cannot diffuse across plasma membrane? |
Polar molecules and ions Water soluable Require protein to aid in transportation |
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What types require a protein channel or protein transporter to cross plasma membrane?
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Polar molecules and ions Water soluable |
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What is it meant by having a cell membrane that is selectively permeable?
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Based on size, electrical charge, molecular shape lipid solubility Also based on PM structure |
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Describe the processes of cellular diffusion
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Random movement of molecules from high to low concentration Eventually eliminates concentration gradient and becomes evenly distributed |
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Describe process of cellular osmosis
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Movement of water molecules across membrane from HIGH WATER concentration to LOW WATER concentration Happens when membrane is selectively permeable to water, but not solutes Eliminates solute concentration differences faster than diffusion |
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What factors are involved in the diffusion rate across cell membrane?
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Shorter distance, faster diffusion Molecule size: Smaller size, faster diffusion Temperature: higher temp, faster diffusion Gradient size: greater concentration gradient, faster diffusion Electrical Forces: opposites attract |
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Describe carrier mediated transport
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Can be passive or active Requires integral memebrane proteins
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What are characteristics of carrier mediated transport?
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Each carrier protein binds and transports specific substances Saturation limits: Availibility of substrate molecules and carrier proteins limit transport rate When all carrier proteins are filled: saturation Regulation: Binding of other molecules can effect activity of carrier protein Two types: Facilitated Diffusion Active Transport |
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What is vesicular Transport? What are the to main types?
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Move materials in or out of cell in vesicles "bulk transport" 2 Main Types Endocytosis Pinocytosis: cell drinking Phagosytosis: cell eating Exocytosis Movement out of cell |
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What is active Transport? How is it different from other types of transport?
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Active transport is different because it requires ATP It moves substances against concentration gradient (from low to high) Details: Solute attaches to specific binding site on transport protein ATP phosphorylates the transport protein, causing it to change so solute is released on other side of protein Phosphate group detaches, transport protein returns to original shape, ready for more ACTIVE TRANSPORT!!! |
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Describe the Na/K- exchange pump. Which type of transport is it an example of?
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Na and K- are principle cations in body fluids Pump maintain resting ion levels Na high in the extracellular fluid (low in cytoplasm) K is high in INTRACELLULAR fluid (low in extracellular) Na diffuses in, K out As ions leak, pump restores required resting levels Takes 3 Na to outside Takes 2 K to inside One ATP per 3Na/2K |
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Na/K- exchange pump Pic
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What are the different types of endocytosis? How are they different from one another?
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Pinocytosis Endocytosis of extracellular fluid Common to most cells Phagocytosis Endocytosis of solid objects Common with WBC's Objects include bacteria, cell debris
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What is tonicity? And osmolarity
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Describes how a solution affects a cell Osmolarity is solute concentration in aqueous cell |
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What is an isotonic solution
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Intracellular environment and extra have equal osmolarity |
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Hypertonic solution?
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Solution has greater content than cell Water will leave cell via osmosis, shrinking and dehydrate |
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Hypotonic Solution?
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Solute has less solute concentration than cell Water will enter cell vis osmosis, swell, potential hemolysis |
