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75 Cards in this Set
- Front
- Back
What is an essential component of energy usage and metabolism?
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ATP
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ATP's production linked to the _________ of food.
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oxidation
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What is NAD?
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It is an intermediate in the production of ATP
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What is another name for what NAD serves as?
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Enzyme Cofactor
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What is NAD?
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Niacin
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When NAD is reduced you get what?
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NADH
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What is NAD involved in primarily?
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Electron transport chain
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What is produced via the ETC?
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ATP
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What is the name of another version of NAD that has a phosphate added, and what is this other compounds primary function?
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NADP is the compound, and its primary involvement is as a reducing agent, which means it gets oxidized
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What else is NADP involved in?
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It is involved in biosynthesis
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FAD is what?
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Another important compound that gets reduced
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NAD and FAD have adenine and sugar ________ connections.
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ribose
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What does FAD do?
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It is a compound that we reduce via NAD and then it transfers its electrons.
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ATP is involved in many different things. Name 3 ATPases that in part produce ATP
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Sodium ATPase, Calcium ATPase, and Myosin ATPase
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These ATPases function where (99% of the time)?
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In the mitochondria
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If you are measuring oxygen consumption, what are you really measuring?
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ATP production
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Where does most ATP production occur, and is oxygen involved?
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Most occurs inside the mitochondria. This occurs aerobically
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Is ATP produced anywhere outside the mitochondria, and if so, is oxygen involved?
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ATP is produced outside the mitochondria, and when this occurs it is done anaerobically
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What are all enzymes?
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Catalysts
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Catalysts are or are not consumed in a reaction?
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They are not consumed in reaction
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What is the major function of catalysts?
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To allow things to occur very rapidly
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Could most reactions that occur with enzymes work without enzymes, and if they could, how would they do this?
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Most could occur, but many would take weeks to months to occur without enzymes
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Are all enzymes proteins?
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The vast majority are, but there is evidence now that ribozymes work catalytically and are not proteins
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How do enzymes work?
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They lower the activation energy, and in doing so this increases the rate of reaction
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So what's the difference between bioenergetics and kinetics?
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Bioenergetics says if the reaction will occur, while kinetics says how fast it will occur
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Do enzymes change the equilibrium constant?
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No
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Will a reaction that is irreversible become reversible if an enzyme is used?
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No
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Do enzymes have high or low specificity?
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Very high specificity
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Specificity refers to what do things?
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The kinds of reactions enzymes catalyze as well as how substrate specific they are
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Do enzymes require anything else to function?
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Oftentimes, they require coenzymes
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What are coenzymes?
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Many are vitamins
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What are 3 examples of coenzymes?
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NAD and FAD are examples, as well ATP, which is thought of as a vitamin
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Is allosteric regulation used in enzymes?
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Yes. For example, hormones use this type of regulation
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What are Ribozymes?
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They are one of the few if not only things that are enzymes but not proteins, and they act as enzymes
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How do they work?
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They are bits of RNA's that have the ability to catalyze a limited number of reactions
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On the surface of the enzyme, what is the region called that the substrate binds to?
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The active site
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What is this new thing called once they've hooked up?
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Enzyme-substrate complex
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Now what happens?
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The ES complex catalyzes the reaction
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What are enzyme inhibitors?
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They are things that bind to the enzyme to prevent it from working
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What is an example of an enzyme inhibitor?
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Many drugs are enzyme inhibitors
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Once the substrate binds, then the _______ occurs.
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catalysis
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After the catalysis occurs, you form what?
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A product, known as an enzyme substrate complex (EP)
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What happens to these two things?
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The product is released and the enzyme is released
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Can the enzyme be used over again?
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Yes, in fact, what often happens in metabolism is you can have one compound converted into another, and then a second, into a third, and fourth, until you get the product you want
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What happens if you heat a molecule kinetically?
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It can allow the molecule to obtain enough energy to reach over the energy barrier. It doesn't lower it though.
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What are the 6 major classes of reactions?
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Oxidoreductases, Transferases, Hydrolases, Lyases, Isomerases, and Ligases
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What are oxidoreductases?
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They involve oxidations and reductions, and with these are a transfer of electrons
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How common are oxidoreductases?
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They are very common
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What are transferases?
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They transfer functional groups
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What are hydrolases?
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They catalyze cleavages via water
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Lyases do?
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They are responsible for the addition of a group across a double bond, ie. forms a double bond.
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What are isomerases?
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They allow production of isomers
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What are ligases responsible for?
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They form bonds between things using energy derived from ATP
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What is the surface element called on enzymes that the substrate binds to?
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Active site
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Once its bound, what does it form?
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An enzyme substrate complex
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How does the substrate know to bind there?
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The site has a 3D conformation to allow it to bind
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This site is made up of what?
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Amino acid sidechains
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When a protein folds up, and it brings the amino acid sidechains together, what does it form?
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A pocket or active site
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The kinds of residues found on the active are dependent on what?
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They are dependent on the nature of the substrate
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If we have a positively charged substrate, what we will have somewhere on the active site?
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An electrically charged residue
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Is binding dependent on pH?
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Yes
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What is an alternative to the lock and key theory?
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It is clear that very often when a substrate binds to the enzyme, it may cause a conformation change in the enzyme
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How is it supposed glucose does this?
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Once glucose binds to the active site, parts of the chain (on active site) will move
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How is the idea of conformation change in enzyme function related to mutation?
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Any mutation in a protein, which changes an amino acid, may affect folding, ability of the substrate to bind, and the conformation, and this may lead to a prevention of the correct conformation, so it may look like minor changes in the amino acid may mess up the ability of the acid to function
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Where do cofactors bind if they exist?
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They bind where the enzyme substrate complex is
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When the substrate is bound with cofactors, what does the enzyme do?
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It catalyzes the change in substract to the product
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Where is glucokinase found, and what does it do?
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It is found in the liver and pancreas, and is responsible for converting glucose to glucose-6-phosphate
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Whats the difference between glucokinase interacting with glucose and interacting with galactose
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Glucokinase does not react with galactose because it has an added hydroxyl group at carbon 4 which is oriented towards where galactose would hydrogen bond with glucokinase
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What does trypsin do?
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It hydrolizes peptide bonds in digestion
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What does trypsin work on?
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Lysine or arginine
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What does this show?
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It is highly specific, an dhydrolizes many proteins, and is highly specific for the type of bond in a protein
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What is a model classical curve for a pH curve?
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It shows there is no activity at low or high pH, but in the middle you have maximum activity
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What is the top activity level called?
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pH optima
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What are high ends to this maximum pH range?
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Some go as high as 10, and some are lower
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What is a functional example of why this doesnt work pertaining to carboxyl groups and low pH?
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If an enzyme required charge from a carboxyl group, it wouldn't function at low pH because the carboxyl would be deprotonated
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