Term
| The formation of ___ , due to it being a highly favorable reaction, tends to pull the pathway of glycolysis forward. |
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Definition
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Term
| ____ is limiting in glycolysis. Under aerobic conditions, it is regenerated during electron transport in the mitochondria. How is it regenerated under anaerobic conditions in animal muscle? |
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Definition
NAD+ Pyruvate --(Lactate dehyd)--> Lactate (NADH ---> NAD+) |
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Term
| Name the 2 kinds of fermentation pathways. Give an example of where each will occur. |
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Definition
Alcohol fermentation: yeast cells
Lactic acid fermentation: animal muscle |
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Term
| What causes animal muscles to undergo lactate fermentation? |
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Definition
| If O2 is being used faster than it can be produced. |
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Term
| A marathon runner collapses. What happened? |
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Definition
| High levels of lactic acid= acidic blood= muscles fail |
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Term
| In the Cori cycle, ___ , produced by fermentation in active muscle gets converted back into ____ in the liver. |
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Definition
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Term
| Fermentation in yeast occurs in 2 steps. What are these steps and what 2 products are formed and what do they contribute to the beer? |
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Definition
Pyruvate ---(^ CO2)->Acetaldehyde ---(NADH->NAD+)----> EtOH
EtOH- alcohol
CO2- carbonation |
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Term
| In aerobic respiration, pyruvate is converted to _____, which then enters the TCA cycle. What enzyme is involved in this step? |
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Definition
| Acetyl-CoA; Pyruvate dehydrogenase complex |
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Term
| In glycolysis, glu-6-P gets isomerized to fru-6-P. What are 2 other possible uses for glu-6-P other than entering glycolysis? |
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Definition
| Glycogen (storage) and Ribulose-5 (nucleotide synthesis) |
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Term
| PFK is the most highly regulated enzyme in glycolysis. It acts like a valve that is opened up (pos. reg.) by ____ and is closed by ____ (neg. reg.) |
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Definition
| ADP, AMP; ATP, citrate. If [ATP] is high, glycolysis is inhibited. If [ADP] is high, glycolysis proceeds. |
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Term
Draw the reaction catalyzed by the Pyruvate dehydrogenase complex. Include all reactants and products. What type of a reaction is this? |
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Definition
pyruvate --(+CoA-SH)-(NAD+ ->NADH)-Acetyl CoA (gives off CO2) Oxidative decarboxylation |
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Term
| The pyruvate dehydrogenase complex uses 5 cofactors. What are they? |
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Definition
| TPP, Lipoate, FAD, NAD+, CoA (last 2 are free) |
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Term
| The reaction catalyzed by the pyruvate dehydrogenase complex results in 3 products: Acetyl CoA, NADH, and CO2. Which enzyme (E1,E2 OR E3) is responsible for the production of each of the products? |
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Definition
| Acetyl CoA (E2), NADH(E3), CO2 (E1) |
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Term
| The TCA cycle is an amphibolic pathway. What is meant by this? |
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Definition
| It serves both anabolic and catabolic pathways. |
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Term
Where do the 4 regulatory proteins below fit into the TCA cycle? Give an example of an inhibitor of each. Are the reaction catalyzed by these enzymes exergonic or endergonic? Isocitrate dehydrogenase alpha-ketoglutarate citrate synthase pyruvate dehydrogenase complex |
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Definition
Isocitrate dehydrogenase- isocitrate to alpha-ketoglutarate (ATP inhibits) alpha-ketoglutarate-alpha-ket. to succinyl CoA (succinyl CoA inhib) citrate synthase- Acetyl CoA to citrate (ATP inhib) pyruvate to OAA (ATP inhib) The reactions are exergonic. |
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Term
| When TCA cycle components are used in biosynthetic pathways, they need to be replenished. These 'replenishing reactions' are called ____ reactions. Give an example of one of these replenishing reactions. |
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Definition
They are called anaplerotic reactions.
EX:
pyruvate---(ATP-->ADP)--> O.A.A. |
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Term
| Fats, rather than glucose, act as the main source of energy from our diet. Why is this? Is it true for all of our tissues? |
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Definition
| Fat is used because it stores a higher amount of energy. The brain requires glucose, not fat. |
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Term
| Why is fat a high energy molecule? |
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Definition
| Every bond in the hydrocarbon chain has e-s that can be given up to high E e- carriers. |
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Term
| What has to happen to fats (TGs) before they can enter the cells lining the intestine? How is this achieved? |
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Definition
| TG + bile salts ---> mixed micelles (promotes access to enzymes) ---(lipase)--> FAs + glycerol |
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Term
| In the epithelial cells lining the intestine, TGs are packaged into chylomicrons. What is the CM composed of and what is its function with respect to the TGs? |
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Definition
| It is composed of apoproteins, cholesterol, phospholipids and TGs. CMs are lipoproteins used to store fats. |
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Term
| Once in the capillaries of their target tissues, TGs are broken down to FAs and glycerol. These FAs can then move to their target cells. What are the 2 kinds of target cells and what is the fate of FAs in each? |
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Definition
Muscle cells- myocytes- (energy)
Adipose tissue- adipocytes- (storage) |
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Term
| The energy harvesting steps that occur in the mitochondrial matrix and make energy from fat are collectively referred to as _________. |
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Definition
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Term
| Concerning the regulation of FA catabolism, what dietary situation would drive the synthesis pathway forward while inhibiting the catabolic pathway? |
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Definition
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Term
| What are the 2 possible routes taken by acetyl CoA produced in the liver by oxidation of FAs? Which route predominates under conditions of starvation and diabetes? |
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Definition
1)Form ketone bodies, exported to other tissues (predominates) 2)TCA cycle (liver) |
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Term
| What condition results from ketone bodies being produced in amounts exceeding that which can be oxidized by the tissues? |
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Definition
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Term
| Malonyl CoA is an important regulator of FA metabolism. Describe the mechanism by which malonyl CoA inhibits FA catabolism. |
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Definition
| If there is a high amount of carbs, CAT1 will be inhibited. |
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Term
| FAs must be modified in order to pass into the mitochondrial matrix and be ready to be oxidized. What is the purpose of the last step? |
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Definition
| It produces an activated form to undergo oxidation. |
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Term
| In order to use proteins as an energy source, they must first be broken down into amino acids. This is achieved by ____. These enzymes are first made as zymogens. What is a zymogen? |
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Definition
| The enzymes are called pepsidases. A zymogen is an inactive precursor. |
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Term
| How are the products formed from amino acid oxidation used to provide energy? |
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Definition
| Pyruvate is used in the TCA cycle and glutamate is used in making N containing molecules. |
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Term
| What enzyme catalyzes the Phe-->Tyr step? What is the genetic disorder that results from its mutation? What is the major manifestation of the disease and how is it avoided? |
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Definition
| Phenylalanine hydroxylase is the enzyme. The disease is called Phenylketonuria and can cause brain damage/mental retardation. A diet low in Phe can prevent the effects. |
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Term
| Briefly describe how birds and mammals deal with the problem of ammonia toxicity. |
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Definition
| They must excrete it: Birds- uric acid Mammals- urea |
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Term
| NH4+ produced in non liver cells must be transported to the liver in order to be converted to urea. Glutamate cannot carry the NH4+ groups through the blood. Why is this? What 2 carriers are used? |
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Definition
| Glutamate cannot be a carrier bc it is acidic and can't move freely in the blood. Glutamine and alanine are used instead. |
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Term
| What is the ultimate goal of the urea cycle? |
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Definition
| To make urea for excretion |
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Term
| In beta-oxidation, what are the 4 steps and what molecules are present at each step? |
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Definition
1)oxidation- FAD/FADH2 2)Hydration-H2O 3)Oxidation- NAD+/NADH 4)Thiolysis- O R-C-S-CoA O H3C-C-S-CoA |
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Term
| What is the net reaction for the production of urea? How many high energy phosphate bonds are used? |
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Definition
2NH4+ + HCO3- + 3ATP + H2O --> 2ADP, AMP, 4Pi, 5H+
4 bonds used |
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Term
| How does the uncoupler DNP destroy the electrochem. gradient across the inner mitochondria membrane? |
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Definition
| It carries H+ across the inner mitochondrial membrane. |
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Term
What are the 7 electron carriers used in the ETC in mitochondria? Which is found in the cytochromes? |
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Definition
NADH- carries e- and H+ FADH2- carries e- and H+ FMNH2-carries e- and H+ Quinones- carries e- and H+ Heme-found in cyt. Carries e- Fe-S carriers-carries e- copper ions- carries e- |
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Term
| What is the overall reaction for the movement of e-s thru the NADH dehydrogenase complex? Does H+ pumping occur? What happens to the product carrying the e-s? |
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Definition
NADH + H+ + Q--> NAD+ + QH2
Yes, H+s are pumped. Electrons are transferred to the Q cycle. |
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Term
| What are 3 sources of e-s to quinone other than those from the NADH dehydrog. complex? |
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Definition
| Complex II, ETFP, glycerol dehydrogenase |
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Term
| Why is it that the e-s passed from FADH2 result in fewer ATPs synthesized than those from NADH? |
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Definition
| Because e-s from FADH bypass complex I and don't get H+ pumping. |
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Term
| Show the reaction for the terminal e- acceptor of cytochrome oxidase. Are H+s pumped as e-s move through this complex to this terminal? |
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Definition
4cyt (red) + O2 + 8H+ (matrix)-->2H2O + 4cyt (oxid) + 4H+ (ims)
Yes, H+s are pumped |
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Term
| Where does glycolysis occur? |
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Definition
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Term
| Several TCA cycle components can act as intermediates in biosynthetic processes. For example, ___ can be converted into glutamate. Another cmpnd ____, can be converted to glucose via a process called _____. |
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Definition
alpha-ketoglutarate
OAA
gluconeogenesis |
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Term
| Anaplerotic rxns often involve the addition of a carbon to a substrate. When this occurs, what molecule provides the carbon? What cofactor is often involved? Does the reaction require energy? |
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Definition
HCO3- provides carbon
Cofactor= biotin
Yes, E is required. |
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Term
| What are the roles of the 1st messenger (hormone) and the 2nd (cAMP) in the remobilization of fats from their reserves in adipose cells? What situation stimulates the cascade? |
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Definition
Glucagon- activates adenylyl cyclase (membrane protein), which makes cAMP cAMP- releases FAs |
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Term
| In the degradation of proteins in the digestive system, which enzymes are used and to what degree do they degrade proteins? |
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Definition
carboxyl peptidase & amino peptidase-
degrade sm. peptides to amino acids |
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Term
| Through what product of the splitting of argininosuccinate are the TCA and Urea cycles linked? |
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Definition
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Term
| Peter Mitchell's chemiosmotic theory states that electron flow thru an ETC is coupled to ATP synthesis in mitochondria. Through what are they coupled? How was this shown? |
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Definition
| They are coupled via an electrochem. gradient. The graph shows that after ADP was added, the line drops until ADP runs out, which is shown as a flatline. |
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Term
| What is the limiting step for the synthesis of ATP on the ATP synthase? What causes this step to go forward? |
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Definition
| Release of ATP from F1 is limiting step. Protons moving thru Fo make step proceed. |
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Term
| Glycolysis and gluconeogenesis are reciprocally regulated. What does this mean? |
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Definition
| If both pathways are on at the same time, ATP will be wasted. Only one can be on at one time. |
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Term
| What role does fructose-2,6 bis-P play in the reciprocal reglation of glycolysis and gluconeogenesis? How is its production affected by glucagon? Does this result in raising or lowering blood glucose levels? |
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Definition
| The role it plays is inhibiting fru-1,3 bis-P and glycolysis. An increase in glucagon results in a decrease in fru-2,6 bis-P. This raises blood glucose. |
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Term
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Definition
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Term
| What drives gluconeogenesis? |
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Definition
| hydrolysis of 2 phosphate bonds |
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Term
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Definition
| Different enzymes that catalyze the same rxn |
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