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Virchow Hypothesis (1858): All cells arise from pre-existing cells (all-cells-from-cells theory) Hypothesis of spontaneous generation: organisms arise spontaneously under certain conditions |
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| Modern Tenents of the Cell Theory |
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Definition
1) All organisms are made of cells 2) cells are derived from pre-existing cells 3) cells contain hereditary infromation which is passed from cell to cell during cell division 4) All cells are basically the same in chemical composition 5) All energy flow of life occurs within cells |
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have a cell membrane contain genetic information in chromosomes protein synthesis occurs via ribosomes have an aqeous cytoplasm lack nucleus and membrane-bound organelles less than 10 micrometers unicellular circular DNA create "capsule" to attach to other organisms |
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Definition
have a cell membrane contain genetic information in chromosomes protein synthesis occurs via ribosomes have an aqeous cytoplasm have a nucleus and membrane-bound organelles larger than 10 micrometers hellical DNA primarily multicellular |
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| Adaptive Advantages to organelle compartmentalization |
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Definition
1) Molecules in chemical reactions do not need to diffuse across large distances 2) Allows incompatible chemical reactions to be separated 3) Increases the efficiency of chemical reactions |
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Definition
| darker, dense part of nucleus that forms ribosomes |
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| Rough Endoplasmic Reticulum (RER) |
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Definition
Exterior: ribosome attached to membrane-produces proteins Interior: (lumen) new proteins are modified |
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| Smooth Endoplasmic Reticulum (SER) |
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Definition
smooth sac-like structure lacking ribosomes produces lipid structures and breaks down hydrophobic molecules |
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modify, store, ship, and route products of the ER comprised of cisternae |
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| closest to the ER-"recieving department" |
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farthest from ER-"Shipping Department" sorts and sends products wherever they need to go |
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| aid in intracellular digestion by phagocytosis (engulfing cell and digesting), enzymes dismantling and consuming, and autophagy (hydrolytic enzumes recycle the cells' own organic material) |
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| formed by phagocytosis and its enzymes digest food |
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| pump excess water out of freshwater protist's cells maintaining suitable concentrations of ions and molecules inside the cell |
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Definition
| holds reserves of important organic compounds and is the cell's main repository of inorganic ions |
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| The site of cellular respiration |
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| the site of photosynthesis |
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| the metabolic process generating ATP by extracing energy from sugars, fats, and other fuels with the help of oxygen |
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Definition
the process of converting solar energy to chemical energy by absorbing sunlight to drive the synthesis of organic compounds such as sugars from carbon dioxide and water |
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| Three compartments in the chloroplast |
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Definition
the intermembrane space the stroma the thalakoid space |
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Definition
| contain enzymes that transfer hydrogen from various substrates to O2 producing H2O |
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Definition
| a network of fibers extending throughout the cytoplasm |
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Definition
- hollow tubes, walls consist of 13 columns of tubulin molecules
- for maintenance of cell shape, cell motility, chromosome movements in cell division, and organelle movements
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Definition
- two intertwined strands of actin
- used for maintenance of cell shape, changes in cell shape, muscle contraction, cytoplasmic streaming, cell motility, and cell division
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Definition
- fibrous proteins supercoiled into thicker cables. Made of one of several different proteins of the keratin family depending on cell type
- used for maintenance of cell shape, anchorage of nucleus and certain other organelles, and formation of nuclear lamina
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Definition
channels through the cell wall of plants allowing for things to pass through |
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Definition
act like "rivits" poping cells together to provide anchorage |
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Definition
| tie cells together and help with intercellular communication |
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| act like belts "sewing" the cells together |
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Definition
| amphipathic because they have a hydrophillic head and hydrophobic tails. |
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| Components of the cell membrane |
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Definition
- integral proteins
- peripheral proteins
- phospholipid bilayer
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Affect of Temperature on membrane fluidity |
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Definition
when the temperature raises things expande therefore lessoning permeability. cholesterol is present in cells to help regulate this |
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| Cholesterol's role in maintaining membrane fluidity |
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Definition
In warm temperatures, it restrains the movement of phospholipids, reducing fluidity In cool temperatures, it maintains fluidity by preventing the packing of molecules too tightly |
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| Perepheral membrane proteins |
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Definition
| loosely bound to the surface of the molecule, connecting to integral proteins |
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| Integral membrane proteins |
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Definition
| penetrate the hydrophobic come of the lipid bilayer spanning the membrane |
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| Major membrane protein functions |
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Definition
- transport
- enzymatic activity
- signal transduction
- cell-cell recognition
- intercellular joining
- attachment to the cytoskeleton and extracellular matrix (ECM)
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| Membrane Cabohydrates and Cell-Cell Recognition |
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Definition
| cells recognize one another by binding to surface molecules, which are often carbohydrates, on the plasma membrane |
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| Hydrophobic Molecules Crossing The Cell Membrane |
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Definition
| they dissolve easily into the lipid bilayer and are able to cross it easily |
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Definition
| protiens built into the membrane and regulate transport |
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Definition
| have a hydrophyllic channell that certain molecules or atomic ions use as a tunnel through the membrane |
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Definition
| the movement of molecules of any substance so that they spread out evenly into the available space |
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| Why is diffusion a spontaneous process? |
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Definition
| because diffusion moves things from a higher concentration into something with a lower concentration which is the way this naturally occurs |
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Definition
| The region along which the density of a chemical substance decreases. Allows only a certain amount to diffuse, so this amount is the potential. |
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Definition
| the solution with a higher concentration of solute |
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| the solution with a lower concentration of solute |
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| same concentration of solute in both or all substances |
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Definition
| The diffusion of water across a selectively permeable membrane. Water diffuses from the area with lower solute concentration to the area with higher solute concentration because this will head toward an equal concentration in both areas. |
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Definition
| polar molecules and ions impeded by the lipid bilayer of the memmbrane to diffuse passively are able to span the membrane with the help of transport proteins |
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Definition
| the cell must expend energy to help this substance through the membrane. Transport proteins aid in this process |
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| Electrochemical gradient is produced by: |
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Definition
- chemical force-the ion's concentration gradient
- electric force-the effect of the membrane potential on the ion's movement
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Definition
| the cell "gulps" droplets of extracellular flluid into tiny vesicles |
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Definition
| a cell engulfs a particle by wrapping around it and packaging it within a membrane-enclosed sac that can be large enough to be classified as a vacuole |
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| receptor-mediated endocytosis |
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Definition
| enables the cell to acquire bulk quantities of specific substances |
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Definition
| the cell's secretions of certain biological molecules by the fusion of vesicles with the plasma membrane |
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Definition
| a transport protein that generates voltage across a membrane |
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Definition
| a single ATP-powered pump that transports a specific solute can indirectly drive the active transport of several other solutes in this mechinism |
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Definition
| metabolic pathway that releases energy by breaking down complex molecules into simpler compounds |
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Definition
| consumes energy to build complicated molecules from simpler ones |
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Definition
| energy associated with relative motion of objects |
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Definition
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Definition
| kinetic energy associated with the random movement of atoms or molecules |
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Definition
| potential energy available for release in a chemical reaction |
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First Law of Thermodynamics |
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Definition
| Energy can be transferred and transformed, but it cannot be created or destroyed |
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| Second Law of Thermodynamics |
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Definition
| Every energy transfer or transformation increases the entropy of the universe |
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Term
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Definition
| energy and matter can be transformed between the system and its surroundings |
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| closed or isolated system |
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Definition
| unable to exchange energy or matter with its surroundings |
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Definition
| proceeds with a net release of free energy. ΔG is negative. Magnitude of ΔG is the maximum amount of work the reaction can perform. |
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Definition
| Absorbs free energy from its surroundings and stores free energy in molecules. ΔG is positive. These reactions are nonspontaneous. |
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Definition
| a measure of disorder or randomness |
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| Three Main kinds of Cellular Work |
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Definition
- Chemical work
- Transport work
- Mechanical work
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Definition
| the pushing of endergonic reactions which would not occur spontaneously |
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Definition
| the pumping of substances across membranes against the direction of spontaneous movement |
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Definition
| the beating of cilia, the contraction of muscle cells, or the movement of chromosomes during cellular reproduction are examples |
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Term
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Definition
adenosine triphosphate - contains the sugar ribose, with the nitrogenous base adenine and a chain of three phosphate groups conded to it
- belongs to the hydroxyl group
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Term
How does ATP perform cellular work? |
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Definition
With the help of enzymes, the cell is able to use the energy released by ATP hydrolysis directly to drive the chemical reaction. |
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Term
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Definition
Enzymes act as catalysts, speeding up a reaction without being consumed. |
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| How do enzymes lower activation energy? |
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Definition
- bring substances closer together
- induce shape changes
- provide favorable orientation
- displace water
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Definition
| chemical compound or structure that is being acted upon by the enzyme |
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Definition
| area where the substrate can bind |
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Term
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Definition
| Enzyme-Substrate Complew-the enzyme wwith a substrate bound to it |
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Term
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Definition
| nonprotein molecules that stabilize the transitional state-coenzymes |
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Term
| How do pH and temperature affect enzymatic activity? |
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Definition
enzymes have optimum themperature and pH ranges, so when they are in that range, the enzymatic activity will be greater than when it is unfavorable conditions |
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Term
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Definition
| block substrate binding that the active site |
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Term
| Non-competitive Inhibitors |
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Definition
| bind to an alternative site on the enzyme changing the structural configuration |
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Term
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Definition
| protein's funtion at one site is affected by the binding at an alternative site |
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Definition
| causes a reaction because it makes the enzyme more stable |
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Definition
| stabilizes the inactive form of enzyme |
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Definition
| product binding into the ehzyme allowing the reactant to build up and the product to be used (negative-feedback loop) |
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