Term
| what do fireflies use light for? |
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Definition
| to send signals to potential mates |
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Term
| what makes fireflies light up? |
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Definition
| the fluorescent chemical in them |
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Term
| what does the light in fireflies come from? |
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Definition
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Term
| what do female fireflies look for in males? |
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Definition
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Term
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Definition
| the capacity to perform work |
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Term
| what is an example of potential energy? |
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Definition
|
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Term
|
Definition
| study of energy transformations |
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Term
| First Law of Thermodynamics |
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Definition
| 1. energy can be transferred or transformed; 2. energy cannot be created/destroyed |
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Term
| Second Law of Thermodynamics |
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Definition
| energy transformations increase disorder or entropy, and some energy is lost as heat |
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Term
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Definition
| absorb energy & yield products rich in potential energy |
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Term
|
Definition
| release energy & yield products that contain less potential energy than their reactants |
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Term
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Definition
| uses exergonic reactions to fuel endergonic reactions |
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Term
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Definition
| shuttles chemical energy & drives cellular work |
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Term
| where is the energy in an ATP molecule? |
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Definition
| it lies in the bonds between its phosphate groups |
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Term
| how does ATP drive energonic reactions? |
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Definition
| by phosphorylation [the transferring of a phosphate group to make molecules more reactive] |
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Term
|
Definition
| the transferring of a phosphate group to make molecules more reactive |
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Term
| why can cellular work be sustained (prolonged)? |
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Definition
| b/c ATP is a renewable resource that cells generate |
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Term
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Definition
| speed up the cell's chemical reactions by lowering energy barriers (also regulate a chemical reaction) |
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Term
| what must happen for a chemical reaction to begin? |
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Definition
| reactants must absorb some energy, called the energy of activation |
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Term
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Definition
| energy needed for a chemical rxn to begin |
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Term
| what can a protein catalyst called an enzyme do? |
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Definition
| it can decrease the energy of activation needed to begin a reaction |
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Term
| does the net change in energy change whether an enzyme is used or not? |
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Definition
|
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Term
| what does an enzyme's shape determine? |
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Definition
| which chemical rnxs occur in a cell |
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Term
| what affects enzyme activity? |
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Definition
|
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Term
| which THREE factors affect enzyme activity? |
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Definition
| temperature, salt concentration & pH |
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Term
| what are examples of nonprotein cofactors? |
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Definition
|
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Term
| what is the name for organic molecules that enzymes might require? |
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Definition
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Term
| what blocks enzyme action? |
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Definition
|
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Term
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Definition
| takes the place of a substance in the active site |
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Term
| a noncompetitive inhibitor |
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Definition
| alters an enzyme's function by changing its shape of active site |
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Term
| where does a noncompetitive inhibitor attach itself? |
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Definition
| to somewhere on the enzyme |
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Term
| what else are enzyme inhibitors? |
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Definition
| poisons, pesticides & drugs |
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Term
| what do membranes to for the cells? |
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Definition
| organizes the chemical activities |
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Term
| what do membranes provide for metabolism? |
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Definition
|
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Term
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Definition
| controls the flow of substances in/out the cell |
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Term
| what thing is selectively permeable? |
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Definition
|
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Term
| what do membrane phospholipids form? |
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Definition
|
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Term
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Definition
| have a hydrophilic head (polar) & 2 hydrophobic tails (nonpolar); main structural components of membranes |
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Term
| what do phospholipids form? |
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Definition
|
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Term
|
Definition
| a 2-layer sheet with the polar heads facing outward & nonpolar tails facing inward |
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Term
| the membrane is a _____ of ____ and _____ |
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Definition
| the membrane is a fluid mosaic of phospholipids and proteins |
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Term
| are other molecules embedded into a phospholipid bilayer? |
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Definition
|
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Term
|
Definition
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Term
| why is the membrane NOT identical top -> bottom in the bilayer? |
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Definition
| different structure & functions throughout it |
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Term
| what makes the membrane a mosaic of function? |
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Definition
|
|
Term
| what do many membrane proteins function as? |
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Definition
|
|
Term
| what do OTHER membrane proteins function as? |
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Definition
| receptors for chemical messages from other cells |
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Term
| what is an example of a receptor working in the membrane? |
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Definition
| insulin triggering something to open the cells up for glucose to go by |
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Term
| how do membrane proteins function in transport? |
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Definition
| they move substances across the membrane |
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Term
| why is ATP sometimessss needed for transport? |
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Definition
| energy is needed to move molecule to outside the cell |
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Term
| what is passive transport (vaguely) |
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Definition
| diffusion across the membrane |
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Term
| what happens in passive transport |
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Definition
| substances diffuse through membranes without work by the cell |
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Term
| how does passive transport work? |
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Definition
| by spreading from areas of high concentration to areas of low concentration |
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Term
| what is net movement in passive transport? |
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Definition
| more molecules going to one side |
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Term
| what is equilibrium in passive transport? |
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Definition
| # going to left = # going to right |
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Term
| what type of molecules diffuse easily across phospholipid bilayer of membrane? (&examples) |
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Definition
| small, nonpolar molecules such as O2 and CO2 |
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Term
| what MAY transport proteins do? |
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Definition
| facilitate diffusion across membranes |
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Term
| what do transport proteins do? |
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Definition
| provide passage across membranes through a process called facilitated diffusion |
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Term
| how does water travel in osmosis? |
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Definition
| when water travels from a solution of lower solute concentration to one of higher solute concentration |
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Term
| what is the diffusion of water across a membrane |
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Definition
|
|
Term
| what is equilibrium in osmosis? |
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Definition
| when there are equal # of free water molecules on both sides |
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Term
| describe the MODERN fluid mosaic model (2) |
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Definition
| 1. there is a double layer of lipids which are arranged w/ tails facing inwards. this bilayer is possibly fluidy with proteins floating in it; 2. the mobile proteins are thought to have a # of functions, including a role in active transport |
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Term
| how does the MODERN fluid mosaic model differ from the earlier DAVSON-DANIELLI model? |
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Definition
| the fluid mosaic suggests that there are proteins floating within the membrane while the Davson-Danielli suggests that the proteins "coat" the bilayer |
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Term
| purpose of cholesterol in plasma membranes |
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Definition
| helps regulate memb fluidity & important for memb stability. does this by disturbing close-packing of phospholipids |
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Term
| why do marine organisms living in polar regions have a very high proportion of cholesterol in their membrane |
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Definition
| since they live in a wet environment, they need cholesterol to regulate the membrane fluidity b/c water easily passes through membrane |
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Term
| name four organelles made of membrane systems |
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Definition
| nucelus, mitochondria, GA & ER |
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Term
| pH of pepsin; trypsin; urease |
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Definition
|
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Term
| enzyme concentration vs. rate of reaction |
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Definition
| as enzyme concentration increases, rate of reaction increases |
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Term
| how might a cell vary in the amount of enzyme present in the cell? |
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Definition
| it may make more of enzyme or make molecules to break the enzymes |
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Term
| concentration of substrate vs rate of reaction |
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Definition
| as concentration of subs. first increases, the rate of the reaction DRAMATICALLY increases then overtime - rate of reaction SLOWLY increases |
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Term
| what is the optimum temp for enzyme activity? |
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Definition
| the temp at which the enzyme will speed up rxns fastest w/o denaturing itself |
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Term
| why do most enzymes perform poorly at low temps (2) |
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Definition
| 1. b/c their shape changes as bonds break from low temps; 2. not enough energy for reactants to reach activation energy |
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Term
| why is pepsin's optimum pH well suited for its environment? |
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Definition
| b/c the stomach has a low pH so by pepsin having a low pH as well, it is able to work in the stomach's environment |
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Term
four heavy metals toxic to humans
[andrew can love me] |
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Definition
| arsenic, cadmium, lead & mercury |
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Term
| why are heavy metals toxic to life? |
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Definition
| they bind to groups of a protein & destroy the enzyme's ability to function. they are retained in the body & then lost slowly |
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Term
| common poison that is an enzyme inhibitor but NOT a heavy metal |
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Definition
|
|
Term
| how does cyanide interfere w/ enzyme function? |
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Definition
| it combines w/ copper & iron in active site of enzyme; it blocks cellular respiration |
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Term
| competitive inhibitor vs noncompetitive inhibitor |
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Definition
| C - competes for active site; N - attaches itself to somewhere else on enzyme |
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Term
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Definition
| protein that water passes through in memb. they do a better job of moving the water across than just letting it pass through |
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Term
| what does osmosis cause cells to do in hypertonic/hypotonic solutions?? |
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Definition
| shrink in hypertonic solutions (solutions w/ a lot of solution); swell in hypotonic solutions (has less solution) |
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Term
| what happens in isotonic solutions for plant vs animal cells? |
|
Definition
| animal cells are normal, but plant cells are limp |
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Term
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Definition
| stay up right; plants have to be turgid; this is why we water them |
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Term
|
Definition
| the control of water balance |
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Term
| why do cells expend energy |
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Definition
|
|
Term
| what can transport proteins do w/ solutes? |
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Definition
| move solutes against a concentration gradient (move solution from low conc to high conc) |
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|
Term
| what does active transport require? |
|
Definition
|
|
Term
| what is active transport also referred to as? |
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Definition
| a PUMP b/c solutes & ions are being pumped |
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Term
|
Definition
|
|
Term
| what do exocytosis & endocytosis do? |
|
Definition
|
|
Term
|
Definition
| a vesicle may fuse /w the membrane & expel its contents & the membrane may fold inward |
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Term
|
Definition
| enclosing mat'l from the outside |
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|
Term
| three ways endocytosis can occur in |
|
Definition
| phagocytosis: cell eating; pinocytosis: cells takes in LARGE quantities of a liquid; receptor-mediated endocytosis: a trap (ex. cholesterol) |
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|
Term
| how do faulty membranes affect cholesterol levels? |
|
Definition
| if the membranes lack cholesterol, then harmful levels of cholesterol can accumulate in the blood |
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Term
| why do HIV attack white blood cells? |
|
Definition
| b/c it has evolved to have a protein that matches the T-Cell (specific kind of white blood cell) |
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Term
| what is central to the process of making energy |
|
Definition
|
|
Term
|
Definition
| the way that essential endergonic reactions typically get their energy from exergonic reactions |
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|
Term
| why is ATP an ex. of a nucleotide? |
|
Definition
| b/c it is composed of sugar, at least one phosphate, & a nitrogenous base |
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Term
|
Definition
| the main structural lipid of a membrane |
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|
Term
|
Definition
|
|
Term
|
Definition
| circulates in the blood mainly as a molecule called a low density lipoprotein (LDL) |
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Term
|
Definition
|
|
Term
| what is energy converted into in most energy transformations? |
|
Definition
|
|
Term
| name of enzyme in fireflies that makes them light up |
|
Definition
|
|
Term
|
Definition
|
|
Term
| do enzymes alter the potential energy (chemical energy) of the reactants/products in a chemical reaction? |
|
Definition
|
|
Term
|
Definition
| the tendency of a cell in a given solution to gain or lose water |
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|
Term
|
Definition
|
|
Term
| why is the plasma memb referred to as a fluid mosaic? |
|
Definition
| b/c it is composed of various materials |
|
|
Term
| what can some proteins act as for hormone messengers? |
|
Definition
|
|
Term
| what happens when a dye reaches equilibrium |
|
Definition
| there will be no NET motion but particles will continue to move equally in all directions |
|
|
Term
| does diffusion normally occurdown a concentration gradient (how much something changes as you move from one region to another) |
|
Definition
|
|
Term
| the generation of nerve signals in a human depends upon the concentration of............... |
|
Definition
| both sodium and potassium ions |
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|
Term
| what type of inhibitors are poisons? |
|
Definition
| irreversible inhibitors (noncompetitive) |
|
|
Term
| which metal is a COMPETITIVE inhibitor? |
|
Definition
|
|
Term
| what type of energy are photons of light? |
|
Definition
|
|
Term
|
Definition
| amt of disorder in a system |
|
|
Term
|
Definition
| when a metabolic reaction is blocked by one of its products |
|
|
Term
how is most of the energy that ATP transfers to some other molecule transferred? |
|
Definition
| by phosphorylating the molecule |
|
|
Term
| the name of the things that are outside the system we are studying |
|
Definition
|
|
Term
inhibitor is bound to enzyme by covalent bonds...
reversible or irreversible? |
|
Definition
|
|
Term
|
Definition
| disease when one has no LDL receptors on their plasma membrane |
|
|
Term
| do hormones have to enter the cell in order to affect the metabolism of the cell? |
|
Definition
| no b/c this can happen in the plasma memb |
|
|
Term
| what is bonded to proteins & lipids in the outer surface of the memb? |
|
Definition
|
|
Term
| what is diffusion the result of? |
|
Definition
| random motion of atoms & molecules |
|
|
Term
| facilitated diffusion (facilitated transport) |
|
Definition
| a process of diffusion, facilitated by transport proteins. it is the spontaneous passage of molecules/ions across a membrane passing through a specific transmembrane transport protein |
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