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91 Cards in this Set
- Front
- Back
What are the two classes of chemical reactions that metabolism can be divided into? |
those that release energy and those that require energy. |
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What two enzyme-regulated processes are involved in digestion? |
Anabolism + Catabolism |
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This enzyme-regulated chemical reaction releases energy by breaking down complex organic compounds into simpler ones: |
Catabolism |
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Give an example of Catabolism: |
when cells break down sugars into carbon dioxide and water. |
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This enzyme-regulated reaction, requires energy to build complex organic molecules from simpler ones: |
Anabolism |
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Examples of anabolic processes are: |
the formation of proteins from amino acids, nucleic acids from nucleotides, and polysaccharides from simple sugars. |
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The coupling of energy-requiring (anabolism) and energy-releasing (catabolism) reactions is made possible through what molecule? |
ATP |
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How does ATP play the role in coupling anabolic and catabolic reactions? |
ATP stores energy obtained from catabolic reactions and releases it later to drive anabolic reactions and perform other cellular work. |
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What group of proteins are involved in almost all biologically important chemical reactions? |
Enzymes |
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A cell's ________________ are determine by its enzymes, which are in turn determined by the cell's genetic makeup. |
metabolic pathways (sequences of chemical reactions) |
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Explain the collision theory: |
the collision theory states that chemical reactions can occur when atoms, ions, & molecules collide |
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What factors determine whether a collision will cause a chemical reaction? |
the velocities of the colliding particles, their energy, and their specific chemical configurations. |
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The collision energy required for a chemical reaction, which is also the amount of energy needed to disrupt the stable electronic configuration of any specific molecule so that the electrons can be rearranged is called what? |
activation energy |
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The frequency of collisions w/enough energy to bring about a reaction |
reaction rate |
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What is one way to increase the reaction rate of a substance and how does it do so? |
Raising its temperature, increases both frequency of collisions and the number of molecules that attain activation energy. |
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Substances that can speed up a chemical reaction without being permanently altered themselves are called ____________. |
catalysts |
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In living cells, these serve as biological catalysts... |
enzymes |
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Enzymes act on a specific substance, called its what? |
substrate (substrates, when there are two or more reactants) |
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The surface of the substrate contacts a specific region of the surface of the enzyme molecule, called what? |
The active site |
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What are the factors that influence enzymatic activity? |
temperature, pH, substrate concentration, state of subdivision, and the prescience or absence of inhibitors |
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Give two examples of electron transfer: |
*oxidation *reduction |
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What is Oxidation? |
*Loss of electrons *Loss of Hydrogen *Addition of Oxygen |
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What is reduction? |
*Gain of electrons *Gain of Hydrogen *Loss of Oxygen |
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What is the fully reduced form of Carbon? |
Methane |
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What is the fully oxidized form of Carbon? |
CO2 |
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What is the pairing of oxidation and reduction reactions are called? |
oxidation-reduction or a redox reaction |
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Since oxidation/reduction reactions are often coupled, what occurs each time a substance is oxidized? |
Another substance is reduced. |
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____________ from transfer of electrons (oxidation) of one compound to another (reduction) is used to generate ATP in the electron transport chain |
Energy released |
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Energy released from transfer of electrons (oxidation) of one compound to another (reduction) is used to ______________________________ |
generate ATP in the ELECTRON TRANSPORT CHAIN |
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First considering their energy source, we generally classify all organisms as what? |
Either Chemotrophs (chemical) or phototrophs (light) |
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Phototrophs |
Use light as their primary energy source. |
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Chemotrophs |
depend on redox reactions of inorganic or organic compounds for energy. |
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For their principal carbon source, autotrophs (self-feeders) use________________. |
Carbon dioxide |
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For their principal carbon source, heterotrophs (feeders on others) require_________________. |
an organic carbon source. |
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If we combine the energy and carbon sources, we derive the following nutritional classifications for organisms: |
*photoautotrophs *photohetertrophs *chemoautotrophs *chemoheterotrophs |
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Name some characteristics of photoautotrophs: |
*they use light as energy source and CO2 for carbon source *they include green and purple sulfur bacteria, green algae, green plants, and cyanobacteria |
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What is the photosynthetic process of cyanobacteria, algae, and green plants? |
The hydrogen atoms of water are used to reduce CO2, and oxygen gas is given off. |
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When a photosynthetic process produces O2, it is sometimes called what? |
oxygenic |
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Do green and purple sulfur bacteria produce oxygen after photosynthesis? |
NO |
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Since green and purple sulfur bacteria do not produce oxygen after photosynthesis they are considered what? |
anoxygenic photoautotrophs |
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anoxygenic photoautotrophs cannot: |
use H2O to reduce CO2 and don't produce O2 |
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Green and purple sulfur bacteria use what to to reduce CO2? |
They use sulfur compounds (H2S) or hydrogen. |
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Give some characteristics of photoheterotrophs: |
*they use light for energy but can't convert CO2 to sugar *sources of carbon: alcohols, fatty acids, and carbs *they are anoxygenic *green and purple NONsulfur bacteria are photoheterotrophs |
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Give some characteristics of chemotautotrophs: |
*use electrons from inorganic sources as energy and CO2 for carbon *inorganic sources of energy include: H2S, Sulfur, ammonia, nitrite (NO2-) * energy is stored as ATP |
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Give some characteristics of chemoheterotrophs: |
*use electrons from hydrogen atoms in organic compounds for both energy and carbon source *we are chemohetertrophs, b/c we eat organic molecules |
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The two most common sources of energy and carbon sources are: |
photoautotrophs and chemoheterotrophs |
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The mechanism of enzymatic action is also known as: |
the lock and key mechanism |
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The general sequence of the lock and key mechanism: |
1) the substrate contact the active site on enzyme to form 2) an enzyme-substrate complex 3) the substrate is then transformed into products, 4) the products are released, and 5) the enzyme is recovered unchanged. |
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As a result of the events of the lock and key mechanism, what occurs? |
an enzyme speeds up a chemical reaction |
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An effective way to control the growth of bacteria is to control their enzymes with what? |
enzyme inhibitors |
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Enzyme inhibitors are classified as either: |
competitive or noncompetitive inhibitors |
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A competitive inhibitor does what? |
*fills the active site of the enzyme *competes with normal substrate (molecule that binds to enzyme) for the active site. |
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What does a noncompetitive inhibitor do? |
*doesnt compete with the substrate for the active site *has own extra binding site (allosteric inhibition) *binds to site other than substrates binding site called allosteric site *the binding causes the active site to change its shape, making it nonfunctional |
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How would one test for inhibition? |
Measure rate of reaction vs substrate concentration Plot 1/Velocity of reaction rate vs 1/ [S] concentration of substrate |
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After plotting, you get all lines intercepting on the y-axis, what does this indicate? |
This indicates a competitive inhibitor |
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After plotting, you get all lines intercepting on the x-axis, what does this indicate? |
This indicates that you have a noncompetitive inhibitor |
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What is feedback inhibition? |
an inhibitor that blocks the pathway that made it |
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What is respiration? |
An ATP generating process in which molecules are oxidized and the final electron acceptor is (almost always) an inorganic molecule. |
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An essential feature of respiration is the operation of an electron transport chain which consist of: |
*glycolysis (breaking down glucose) * Krebs Cycle and *oxidative phosphorylation |
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What are the two types of respiration? |
Aerobe which uses oxygen and anaerobe which does not use oxygen and may even be killed by it. |
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What is the final electron acceptor in aerobic respiration? |
O2 |
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What is the final electron acceptor in anaerobic respiration? |
an inorganic molecule other than O2 or, rarely an organic molecule. |
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What is glycolysis (splitting of sugar) ? |
it is the oxidation of glucose to pyruvic acid, which is usually the first stage of carbohydrate catabolism |
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What is glycolysis also called? |
the Embden-Meyerhof pathway. |
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Does glycolysis require energy? |
No, it can occur wether energy is present or not. |
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What are the starting and ending products of glycolysis? |
Glucose and pyruvic acid. |
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What are the 3 enzymes involved in glycolysis and what are their functions? |
*kinase- enzyme that transfers phosphate groups *isomerase- enzyme that changes the shape of molecules *aldolase -splits Fructose-1, 6 di-PO4 into two separate molecules |
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Step 1 of glycolysis: |
Is the conversion of Glucose into Glucose-6-PO4, catalyzed by the enzyme glucokinase. This step is considered the activating reaction because ATP is breaking down to form ADP, preparing the phosphate transfer. |
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Step 2 of glycolysis: |
is the conversion of Glucose-6-PO4 into Fructose-6-PO4, catalyzed by the enzyme isomerase. The purpose here is to free up the #1 carbon moving it out of the ring. |
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Step 3 of glycolysis: |
is the conversion of Fructose-6PO-4 into Fructose-1, 6-di-PO4 through the enzyme phosphohexokinase. The purpose here is to add phosphate to #1 carbon for symmetry, you want a phosphate on both sides |
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Step 4 of glycolysis: |
The enzyme aldolase splits Fructose-1, 6-di-PO4 into 2 separate molecules that are isomers of each other, each being 3 carbon molecules. One is Dihydroxy acetone phosphate (DHAP) and Glyceraldehide (GAP). |
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Step 5 of glycolysis: |
By the enzyme isomerase, it will reorganize DHAP into GAP and you will now have two GAPs. |
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What are the name of the coenzymes that appears in the glycolytic chain? |
NAD and NADH *NAD+ is reduced to NADH |
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How many ATPs are being produced in glycolysis? |
4 ATPs are being produced but we lose 2 to get glycolysis started. So there is a net gain of 2 molecules of ATP for each molecule of glucose that is oxidized. |
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What is lactic acid? |
it is the reduced form of pyruvic acid and pyruvic acid is the oxidized form of lactic acid. |
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Why is lactic acid not a part of respiration? |
because it is not permanent, sooner or later it will oxidize back to pyruvic acid. |
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Is glycolysis aerobic or anaerobic breathing and why? |
Glycolysis is anaerobic breathing because an anaerobic organism can only produce 2 ATPs from glucose. |
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Where does glycolysis occur? |
in the cytoplasm |
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How many ATPs can aerobic organisms produce from glucose? |
38 ATPs |
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After respiration, pyruvic acid moves into mitochondria, now making everything... |
aerobic |
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What 3 transition steps does pyruvic acid endure to be able to enter the Krebs Cycle? |
1)removal of H 2) removal of the rest of the carboxyl group in form of CO2 3) binding of coenzyme A to form acetyl group, CoA the cargo carrier, carries acetyl group into Krebs Cycle drops it off and exits. |
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What is the first molecule of the Krebs cycle? |
Oxaloacetic acid (OAA) |
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How does OAA become citric acid? |
As CoA enters Krebs cycle, it detaches from the 2 carbon acetyl group, which then combines with the 4 carbon compound OAA to form the 6 carbon citric acid. |
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At what points in the Krebs Cycle do the CO2s come out? |
In transition and in Krebs Cycle |
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How many ATP's are being produced in Krebs Cycle and how? |
*each pyruvic acid is producing 15 ATPs (3 in transition phase and 12 in Krebs) *we have 2 pyruvic acids from glycolysis=30 ATPs *+2 more from glycolysis=32 ATPs * +2 NADH (3ATPs each)=38ATPS total |
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Since 38 ATPs are being produced in Krebs Cycle what type of respiration is this? |
Aerobic respiration |
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What is oxidative phosphorylation and the electron transport system (ETC or ETS)? |
A series of electron transfers and redox reactions, giving up energy with every transfer. |
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what is ATP synthase? |
this is the process of gathering energy lost from electron transfer |
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In the ETC how many ATPs are being made? |
2 ATPS by FADH |
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What is the final electron acceptor in ETC? |
O2 |
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What is the reduced form of O2 and the final product of ETC? |
H2O (water) |