Term
- __: the standard free energy of hydrolysis - is a means of comparing the tendency of organic molecules to transfer __ to an acceptor molecule
- atp has a __:
1.__ potential
2.__ stabilization
3.stabilization due to __ |
|
Definition
- phosphoryl-transfer potential; phosphoryl group
- high phosphoryl transfer potential
1. electrostatic potential
2. resonance stabilization
3. stabilization due to hydrogen |
|
|
Term
| atp has an __ which enables atp to function efficiently |
|
Definition
| intermediate phosphoryl transfer potential |
|
|
Term
exercise depends on various means of generating atp
- muscle contains only enough atp to power muscle contraction for __
- __ can regenerate atp from adp, allowing a short burst of activity as in a sprint
- once the __ stores are depleted, atp must be generated by __ pathways |
|
Definition
- less than a second
- creatine phosphate
- creatine phosphate; metabolic |
|
|
Term
the oxidation of carbon fuels is an important source of cellular energy
- atp is the immediate donor of __ for biological activities
- atp turnover is __ and the amount of atp is __
- atp must be constantly __ to provide energy to power the cell |
|
Definition
- free energy
- very high; very limited
- recycled |
|
|
Term
carbon oxidation is paired with reduction
- __ reactions involve loss of electrons, and are pair with reactions that gain electrons, these combos are called __
- the carbon atoms in fuels are __ to yield __, and the electrons are ultimately accepted by __ to form __
- the more __ a carbon atom is, the more __ is released upon oxidation
- __ are a more efficient food source than glucose because they are more __ |
|
Definition
- oxidation; redox reactions
- oxidized; CO2; oxygen; h2o
- reduced; more free energy
- fats; reduced |
|
|
Term
compounds with high phosphoryl transfer potential can couple __ to __
- the essence of catabolism is capturing the energy of carbon oxidation as __
- energy of oxidation is initially trapped as a __ compound than used to form __ |
|
Definition
carbon oxidation; atp synthesis
- atp
- high-phosphoryl transfer potential; atp |
|
|
Term
- __ is an activated carrier of phosphoryl groups. other activated carriers are common in biochemistry, and they are often derived from __
1. activated carriers of __ for fuel __
2. activated carriers of __ for the synthesis of __
3. an activated carrier of __ |
|
Definition
- atp; vitamins
1. electrons; oxidation
2. electrons; biomolecules
3. two carbon fragments |
|
|
Term
1. activated carriers of electrons for fuel oxidation
- __ and __ carry activted electrons derived from the oxidation of fuels
- reactive part of NAD+ is the __: __ derivative synthesized from the vitamin __
- during oxidation of substrates, __ accepts __ and __
- __ is the electron acceptor and __ is the reduced form
- reactive part of FAD is the __: a derivative synthesized from the vitamin __
- isoalloxazine ring accepts __ and __ |
|
Definition
- NAD+; FAD
- nicotinamide ring; pyridine; niacin
- nicotinamide ring; 1 hydrogen; 2 electrons (NADH)
- FAD; FADH2
- isoalloxazine ring; riboflavin
- 2 protons; 2 electrons (FADH2) |
|
|
Term
activated carriers of electrons for the synthesis of biomolecules
- __ is the electron donor for reduction biosynthesis
- __ is used primarily for reductive biosynthesis while __ is used for generation of ATP |
|
Definition
|
|
Term
an activated carrier of two carbon fragments
- __ is an activated carrier of acyl groups such as the acetyl group
- vitamin __ is a key component
- reactive site is terminal __ group
- the transfer of acyl group is __ because the __ is unstable |
|
Definition
- coenzyme a
- pantothenate
- sulfhydryl
- exergonic; thioester |
|
|
Term
many activated carriers are derived from vitamins
- vitamins must be modified before they can serve as __ or __
- the __ function as coenzymes
- vitamins __ play a variety of roles but do not serve as coenzymes |
|
Definition
- coenzymes; cofactors
- b vitamins
- a, c, d, e, k |
|
|
Term
metabolism is regulated by controlling
1. amount of __
2. __ activity
3. accessibility of __ |
|
Definition
1. enzyme
2. catalytic
3. substrates |
|
|
Term
the amount of enzymes are controlled
- the quantity of enzyme present can be regulated at the level of __ |
|
Definition
|
|
Term
catalytic activity is regulated
- catalytic activity is regulated __ or by __
- __ coordinate metabolic activity, often by mediating the reversible covalent modification of allosteric enzymes
- the __ of the cell is often an important regulator of enzyme activity
- two common means are used to assess energy status: __ and __ |
|
Definition
- allosterically; covalent modification
- hormones
- energy status
- energy charge; phosphorylation potential |
|
|
Term
the accessibility of substrates is regulated
- __, such as fatty acid synthesis and degradation, may occur in different cellular compartments
- regulating the __ of substrates between compartments is used to regulate __ |
|
Definition
- opposing reactions
- flux; metabolism |
|
|
Term
Why is glucose such a prominent fuel in all life forms?
1. Glucose may have been available for primitive biochemical systems because it can form under ___ conditions.
2. Glucose is the most stable __.
3. Glucose has a low tendency to nonenzymatically __ |
|
Definition
1. prebiotic
2. hexose
3. glycosylate proteins |
|
|
Term
Why is Glycolysis Important ?
Central pathway for production of:
- __
- __ for biosynthetic pathways (__ and __) |
|
Definition
- energy (ATP)
- carbon; (fatty acids; amino acids) |
|
|
Term
1 molecule glucose is converted into 2 molecules of __ and 2 molecules of __ via 10 enzymatic steps.
-present in all organisms and is an __ process
-In mammals, __ and __ can only use glucose as carbon and energy source.
- In eukaryotic cells, glycolysis takes place in the __. |
|
Definition
pyruvate; atp
- anaerobic
- brain; red blood cells
- cytoplasm |
|
|
Term
Glycolysis consists of 2 stages:
Stage 1 - traps glucose in the cell and modifies it so that it can be cleaved into a pair of __ compounds
Stage 2 - oxidizes the __ to __ while generating 2 molecules of __ |
|
Definition
- phosphorylated 3-carbon
- 3-carbon compound; pyruvate; atp |
|
|
Term
__ Traps Glucose in the Cell and Begins Glycolysis
- glucose is phosphorylated to __ by __
- important step for two reasons:
1. __ cannot diffuse through membrane
2. the __ destabilizes glucose for further metabolism |
|
Definition
hexokinase
- glucose 6-phosphate; hexokinase
1. glucose 6 phosphate
2. phosphoryl group |
|
|
Term
- kinases transfer __ from __
- binding of glucose to hexokinase causes a large __; __ fit
- purpose:
-- makes the environment around the glucose more __
-- __ is excluded as a substrate
- __ is a general feature of kinases |
|
Definition
- phosphoryl groups; atp
- conformational change; substrate-induced
-- non-polar
-- h2o
- substrate induced cleft closing |
|
|
Term
___ is Generated from Glucose 6-phosphate
- second step is the __ of glucose 6 phosphate to ___
- The isomerization of glucose 6-phosphate to fructose 6-phosphate is a conversion of an __ into a __, catalyzed by the __ |
|
Definition
fructose 1,6 bisphosphate
- isomerization; fructose 6-phosphate
- aldose; ketose; phosphoglucose isomerase |
|
|
Term
- Fructose 6-phosphate is phorylated to ___
- This irreversible reaction is catalyzed by __, an allosteric enzyme, that determines the flux through the glycolysis |
|
Definition
- fructose 1,6-bisphosphate
- phosphofructokinase (PFK) |
|
|
Term
The Six-Carbon Sugar Is Cleaved into __
- Hydrolysis of fructose 1,6-bisphosphate into __ and __
-This reaction is catalyzed by __ and is __ |
|
Definition
two three-carbon fragments
- glyceraldehyde 3-phosphate (GAP); dihydroxyacetone (DHAP)
- aldolase; reversible |
|
|
Term
-Dihydroxyacetone phosphate (is a __) and glyceraldehyde 3-phosphate (is a _) are __ and can be __.
The isomerization is catalyzed by __. This reaction is rapid and __. |
|
Definition
- (ketose); (aldose); isomers; interconverted
- triose phosphate isomerase (TPI); reversible |
|
|
Term
The Oxidation of a __ to an __ Powers the Formation of a Compound with High Phosphoryl-Transfer Potential
- in the second stage of glycolysis, energy is produced as __
- Glyceraldehyde 3-phosphate is converted into __, catalyzed by __
- __ is an __ with a __ |
|
Definition
aldehyde; acid
- atp
-1,3-bisphosphoglycerate (1,3-BPG); glyceraldehyde 3-phosphate dehydrogenase
-1,3-Bisphosphoglycerate; acyl phosphate; high phosphoryl-transfer potential.
- |
|
|
Term
__ catalyzes a two-step process:
1. Highly exergonic oxidation of the __ to a __ by NAD+
2. Highly endergonic formation of __. |
|
Definition
Glyceraldehyde 3-phosphate dehydrogenase
1. aldehyde; carboxylic acid
2. acyl-phosphate |
|
|
Term
ATP Is Formed by __ Transfer from __
-__ catalyzes the transfer of the phosphoryl group from the acyl-phosphate of 1,3-BPG to ADP to form __ and __.
- this reaction is called __
- __ has a greater phosphoryl transfer potential than __ |
|
Definition
Phosphoryl Transfer; 1,3-Bisphosphoglycerate
- phosphoglycerate kinase; 3-phosphoglycerate; atp
- substrate level phosphorylation
- 1,3 BPG; atp |
|
|
Term
Additional ATP Is Generated with the Formation of ___
- 3-Phosphoglycerate is converted into
__ by __
- __ is converted to __ by a dehydration reaction catalyzed by __
- the last reaction is the formation of __ and __, catalyzed by __. this reaction is __ |
|
Definition
pyruvate
- 2-phosphoglycerate; phosphoglycerate mutase.
- 2 phosphoglycerate; phosphoenolpyruvate; enolase
- pyruvate; atp; pyruvate kinase; irreversible |
|
|
Term
| net reaction in the conversion of glucose to pyruvate: |
|
Definition
| glucose + 2Pi + 2ADP + 2NAD+ > 2 pyruvate + 2 ATP + 2NADH + 2H+ + 2H2O |
|
|
Term
__ is regenerated from the metabolism of pyruvate
- Conversion of glyceraldehyde 3-phosphate to 1,3-bisphospho-glycerate by the __ leads to reduction of __ to __
- there are only limited amounts of __ in the cell, and it must be __ for glycolysis to proceed |
|
Definition
NAD+
- glyceraldehyde 3-phosphate dehydrogenase; NAD+; NADH
- NAD+; regenerated |
|
|
Term
fermentations are a means of __
Ethanol - alcoholic fermentation
- yeast and several other microorganisms convert __ to __ in 2 steps
1. decarboxylation of __ catalyzed by the __
2. reduction of __ to __ by __, catalyzed by __. this process regenerates __ |
|
Definition
oxidizing NADH
1. pyruvate; ethanol
2. acetaldehyde; ethanol; NADH; alcohol dehydrogenase; NAD+ |
|
|
Term
Lactate- Lactic acid fermentation
- __ is formed in many microorganisms and in muscle when oxygen is limited
- the reduction of pyruvate by __ to form __ is catalyzed by __ |
|
Definition
- lactate
- NADH; lactate; lactate dehydrogenase |
|
|
Term
| Regeneration of __ by reduction of pyruvate to lactate or ethanol sustains the continued operation of glycolysis under __ conditions |
|
Definition
|
|
Term
- __ is the main metabolic fuel in most organisms
- Other sugars are converted to glycolytic __
- __ and __ are major sweeteners in many foods and beverages
- ___ from milk lactose |
|
Definition
- glucose
- intermediates
- fructose; sucrose
- galactose |
|
|
Term
- fructose is converted to __ and __
- most of fructose is metabolized by the __ using the __
- In other tissues, fructose can be phosphorylated to __ by __. |
|
Definition
-glyceraldehyde 3 phosphate; dihydroxyacetone phosphate
- liver; fructose 1-phosphate pathway
- fructose 6-phosphate; hexokinase |
|
|
Term
Galactose enters Glycolysis as __
- Galactose is converted into __ by the __, which begins with the phosphorylation of galactose by __ into __.
- Galactose 1-phosphate is then converted to __ and __ catalyzed by __
- UDP-galactose is epimerized to __ by __.
- glucose 1-phosphate is isomerized to __ by __. |
|
Definition
Glucose 6-phosphate
- glucose 6 phosphate; galactose glucose conversion pathway; galactokinase; galactose 1 phosphate
- UDP galactose; glucose 1-phosphate; galactose 1-phosphate uridyl transferase
- glucose; udp galactose 4 epimerase
- glucose 6 phosphate; phosphoglucomutase |
|
|
Term
__ Is Highly Toxic If the Transferase Is Missing
- Galactosemia is an inherited deficiency in __.
- Galactose is converted into ___ by aldose reductase. |
|
Definition
galactose
-galactose 1-phosphate uridyl transferase.
- galactitol |
|
|
Term
major reactions in glycolysis
1. __ – __ – Transfer of phosphoryl group from ATP
2. __ – __ - Shift of phosphoryl group
3. __ – __ – Aldose is converted to a ketose or vice versa
4. __ – __ – Elimination of water
5. __ - __ – Split of carbon-carbon bound |
|
Definition
1. phosphoryl transfer - kinase
2. phosphoryl shift - mutase
3. isomerization - isomerase
4. dehydration - dehydrogenases
5. aldol cleavage - aldolase |
|
|
Term
the glycolytic pathway is tightly controlled
- enzymes catalyzing __ are potential sites of metabolic control
- in glycolysis, there are 3 irreversible steps catalyzed by __, __, and __ |
|
Definition
- irreversible reactions
- hexokinase; phosphofructokinase 1; pyruvate kinase |
|
|
Term
These enzymes are controlled mainly by three different mechanisms:
1. Reversible __ control - milliseconds
2. Regulation by __ - seconds
3. __ control - hours |
|
Definition
1. allosteric
2. phosphorylation
3. transcriptional |
|
|
Term
how is glycolysis controlled in skeletal muscle and liver
1. skeletal muscle
- __ for contraction
- __ important
2. liver
- regulation of __ levels
- __ levels important |
|
Definition
- atp production
- energy status
- blood glucose
- blood glucose |
|
|
Term
glycolysis in muscle is regulated by __ to meet the need for atp
- __ is the most important control element of glycolysis
- it is inhibited by high levels of __
- __ then becomes the signal for the low energy state
- the activity of the enzyme increases when the __ is __ |
|
Definition
feedback inhibition
- phosphofructokinase (PFK)
- ATP
- amp
- atp/amp ratio; lowered |
|
|
Term
Glycolysis in Muscle Is Regulated by Feedback Inhibition to Meet the Need for ATP
- __ is allosterically inhibited by __
- __ is inhibited allosterically by atp and alanine, and stimulated by __, the product of the __.
- in muscle, __ is regulated to meet the energy needs of contraction |
|
Definition
- hexokinase; glucose 6-phosphate
- pyruvate kinase; fructose 1,6-bisphosphate; phosphofructokinase reaction
- glycolysis |
|
|
Term
The Regulation of Glycolysis in the Liver Corresponds to the Biochemical Versatility of the Liver
- __ is allosterically inhibited by high levels of __ like in skeletal muscle
- the key regulators of phosphofructokinase in liver are __, which reports on the status of the __, and __
- __ inhibits phosphofructokinase while __ is a powerful activator |
|
Definition
- phosphofructokinase; atp
- citrate; citric acid cycle; fructose 2,6 bisphosphate
- citrate; fructose 2,6 bisphosphate |
|
|
Term
- liver has a special hexokinase called __, which is not inhibited by __
- __ phosphorylates glucose only when it is abundant after a __ and has a __ for glucose than hexokinase
- when glucose supply is limited, glucose goes first to the __ and __ |
|
Definition
- glucokinase; glucose 6 phosphate
- glucokinase; meal; 50 fold lower affinity
- brain; muscle |
|
|
Term
- __ in the liver is regulated allosterically as it is in muscle. However, liver pyruvate kinase is also regulated by ___.
-__ leads to the phosphorylation and inhibition of liver pyruvate kinase |
|
Definition
- pyruvate kinase; covalent modification
- low blood glucose |
|
|
Term
| - Five __, termed __, facilitate the movement of glucose across the cell membrane. |
|
Definition
| glucose transporters; GLUT 1-5 |
|
|
Term
1) __ and __ are present in nearly all mammalian cells and are responsible for __ (KM=1mM). At normal blood glucose levels (4-8mM) they continually __ into cells.
2) __ is present in liver and pancreatic beta-cells and has a very high KM for glucose (15-20mM).
3) __ has a KM of 5mM and mediates the entry of glucose into __ and __ cells.
__ promotes the uptake of glucose by muscle and fat. __ is the insulin-responsive glucose transporter
4) __ is present in the small intestine and functions as a __ transporter. |
|
Definition
1. glut1; glut3; basal glucose uptake; transport glucose
2. glut 2
3. glut 4; muscle; fat; insulin; glut 4
4. glut 5; fructose |
|
|
Term
cancer and exercise affect glycolysis similarly
-Rapidly growing tumors obtain ATP by metabolizing glucose to __ even in the presence of oxygen, a process termed __ or the Warburg effect.
-During hypoxia, the __ increases the expression of most glycolytic enzymes and the glucose transporters GLUT1 & GLUT3.
-Exercise training also stimulates ___, which enhances the ability to generate ATP anaerobically. |
|
Definition
- lactate; aerobic glycolysis
- hypoxia inducible transcription factor (HIF-1)
- HIF-1 |
|
|
Term
- Insulin is secreted by __ of the pancreas in response to high blood levels of __. This secretion is stimulated by the metabolism of glucose by the __.
- Glucose enters β cells through __ and is metabolized to __, which is subsequently oxidized to CO2 and H2O.
- the influx of __ stimulates the release of insulin |
|
Definition
- beta cells; glucose; beta cells
- glut 2; pyruvate
- calcium ions |
|
|
Term
- genetic mutations in glycolytic genes result in __
- red blood cells lack __
- exercise induced __ and __ |
|
Definition
- hemolytic anemia (destruction of erythrocytes)
- mitochondria
- muscle cramps; weakness |
|
|
Term
| __ is the synthesis of glucose from non-carbohydrate precursors |
|
Definition
|
|
Term
- major sites of gluconeogenesis are __ and __
- gluconeogenesis is important for maintaining normal __ during __
- most of the newly formed glucose is used by __ and __ |
|
Definition
- liver; kidneys
- blood glucose levels; starvation
- brain; contracting muscle |
|
|
Term
- the gluconeogenic pathway converts __ into __
- __ can be formed form muscle derived __ in the liver by __
- the carbon skeletons of some __ can be converted into gluconeogenic intermediates |
|
Definition
- pyruvate; glucose
- pyruvate; lactate; lactate dehydrogenase
- amino acids |
|
|
Term
| __, derived from the hydrolysis of triacylglycerols, can be converted into __, which can be processed by __ or __. |
|
Definition
| glycerol; dihydroxyacetone phosphate; gluconeogenesis; glycolysis |
|
|
Term
| gluconeogenesis is not a complete reversal of glycolysis, the three irreversible reactions of glycolysis are bypassed in gluconeogenesis by new steps: |
|
Definition
1. glucose + ATP (e:hexokinase)> glucose 6 phosphate + ADP
2. fructose 6 phosphate + ATP (e:phosphofructokinase)> fructose 1,6 bisphosphate + adp
3. phosphoenolpyruvate + adp (e: pyruvate kinase) > pyruvate + atp |
|
|
Term
The conversion of pyruvate into phosphoenolpyruvate begins with the formation of __
- the pyruvate kinase reaction of glycolysis is bypassed by __ and __
- first step in gluconeogenesis is the __ of __ to __. pyruvate carboxylase requires vitamin __ as a cofactor. |
|
Definition
oxaloacetate
- pyruvate carboxylase; phosphoenolpyruvate carboxykinase
- carboxylation; pyruvate; oxaloacetate; biotin (B7) |
|
|
Term
oxaloacetate is shuttle into the __ and converted into __
- __ is a mitochondrial enzyme
- oxaloacetate is reduced to __ inside the mitochondria for transport to the __
- when malate is in the __, it is reduced to __
- oxaloacetate is converted to __ in the cytosol by the enzyme __ |
|
Definition
cytoplasm; phosphoenolpyruvate
- pyruvate carboxylase
- malate; cytosol
- cytosol; oxaloacetate
- phosphoenolpyruvate (PEP); PEP carboxykinase |
|
|
Term
- __ bypasses the phosphofructokinase reaction
- metabolically __ reaction
- __ enzyme and controls the flux through the gluconeogenesis pathway |
|
Definition
- fructose 1,6-bisphosphatase (FBPase)
- irreversible
- allosteric |
|
|
Term
the generation of __ is an important control point
- free glucose is generated mainly in the __
- __ converts glucose 6-P to __ and is present only in __ and __
- glucose 6 phosphate is hydrolized to __ in the __ by membrane bound __ |
|
Definition
free glucose
- liver
- glucose 6-phosphatase; free glucose; liver; kidney
- glucose; lumen of the er; glucose 6-phosphatase |
|
|
Term
-the stoichiometry of gluconeogenesis:
- __ nucleotide triphosphate molecules are required for synthesis of glucose from pyruvate, while only __ molecules of atp are generated in glycolysis |
|
Definition
2 pyruvate + 4 ATP + 2 GTP + 2 NADH + 2H+ + 6 H2O > glucose + 4 ADP + 2 GDP + 6 Pi + 2 NAD+
- six; 2 ATP |
|
|
Term
| deficiencies in __, __, __, and __ lead to lactic acidosis (accumulation of lactic acid in blood) and hypoglycemia (low blood glucose levels) |
|
Definition
| pyruvate carboxylase, phosphoenolpyruvate carboxykinase, fructose-1,6-bisphosphatase and glucose-6-phosphatase |
|
|
Term
- gluconeogenesis and glycolysis are coordinated so that only __
- the rate of glycolysis is determined by the __, while the rate of gluconeogenesis is dependent on the concentration of __ and __ |
|
Definition
- one pathway is active at the same time
- glucose concentration; lactate; other precursors |
|
|
Term
- the interconversion of __ and __ is a key regulatory site
- __ stimulates phosphofructokinase (__ is turned on), but inhibites 1,6 bisphosphatase (__ is turned off)
- high levels of __ and __ inhibit phosphofructokinase and thereby turn off __
- __ is an activator of fructose 1,6 bisphosphatase and promotes __ |
|
Definition
- fuctose 1,6 bisphosphate; fructos 6-phosphate
- high levels of AMP; (glycolysis); (gluconeogenesis)
- atp; citrate; glycolysis
- citrate; gluconeogenesis |
|
|
Term
- the glycolytic enzyme pyruvate kinase is inhibited by __ and __
- pyruvate carboxylase is inhibited by __
- phosphoenolpyruvate carboxykinase; adp
- __ activates pyruvate carboxylase
- if atp is required, __ predominates. if glucose is required, __ is favored |
|
Definition
- atp; alanine
- adp
- adp
- acetyl coa
- glycolysis; gluconeogenesis |
|
|
Term
- __ levels regulate glycolysis and gluconeogenesis in liver by alteration of __ levels
- __ stimulates __ and inhibits __ |
|
Definition
- blood glucose; fructose 2,6 bisphosphate
-fructose 2,6 bisphosphate; phosphofructokinase; fructose 1,6 bisphosphatase |
|
|
Term
- when blood glucose is low, __ is converted to __
- at high blood glucose levels, __ levels increase |
|
Definition
- fructose 2,6 bisphosphate; fructose 6 phosphate
- fructose 2,6 bisphosphate |
|
|
Term
- __ and __ are controlled reciprocally by __ of a single serine residue
- phosphorylation activates __ and inhibits __, lowering the level of __, thereby __ metabolism by the liver is stopped. __ predominates. |
|
Definition
-PFK2; FBPase2; phosphorylation
- FBPase2; PFK2; F-2,6-BP; glucose; gluconeogenesis |
|
|
Term
- when glucose is scarce, __ levels rise in the blood and trigger a cyclic __ cascade, leading to phosphorylation by __, __ is inactive
- when glucose is abundant, the enzyme becomes dephosphorylated, which activates __ and inhibits __, increasing the __ levels and __ metabolism is stimulated, therefore __ is active. |
|
Definition
- glucagon; AMP; protein kinase A; glycolysis
- PFK2; FBPase2; F-2,6-BP level; glucose; glycolysis |
|
|
Term
- insulin normally inhibits __. in type 2 diabetes, __ fails to act, a condition called __
- the enzymes of __, especially __, are active leading to abnormally high levels of blood glucose
- exercise and diet can enhance insulin sensitivity |
|
Definition
gluconeogenesis; insulin; insulin resistance
- gluconeogenesis; pepck |
|
|
Term
- muscle and liver display inter-organ cooperation in a series of reactions called the __
- __ produced by muscle during contraction is released into the blood
- __ removes lactate and converts it into __, which can be released into the blood |
|
Definition
- cori cycle
- lactate
- liver; glucose |
|
|
Term
three major factors control glycolysis and glyconeogenesis:
1.
2.
3. |
|
Definition
1. energy levels (ATP)
2. abundance of biosynthetic precursors
3. blood glucose levels |
|
|
Term
- under aerobic conditions, __ enters the mitochondria where it is converted into __
- __ is the fuel for the citric acid cycle, which processes the two carbon acetyl unit to 2 molecules of __, while generating __ that can be used to form atp. |
|
Definition
- pyruvate; acetyl CoA
- acetyl CoA; CO2; high energy electrons |
|
|
Term
- oxidative decarboxylation of pyruvate and the reactions of the citric acid cycle occur within the __
- the mitochondria consist of an __, an __, and a __ |
|
Definition
- mitochondrial matrix
- outer membrane; inner membrane; mitochondrial matrix |
|
|
Term
| - __ transports pyruvate produced during glycolysis in the cytoplasm into the mitochondria in symport with H+. |
|
Definition
|
|
Term
- the __, a mitochondrial matrix enzyme, oxidatively decarboxylates pyruvate to form acetyl CoA. This formula is as follows:
- this reaction is __, and is the link between __ and __ |
|
Definition
- pyruvate dehydrogenase complex; Pyruvate + CoA + NAD+ > acetyl CoA + CO2 + NADH + H+
- irreversible; glycolysis; citric acid cycle |
|
|
Term
the synthesis of acetyl CoA from pyruvate requires __ and __
- give the enzymes and their prosthetic group |
|
Definition
3 enzymes; five coenzymes
- pyruvate dehydrogenase component (E1), TPP; dihydrolipoyl transacetylase (E2), lipoamide; dihyrolipoyl dehydrogenase(E3), FAD |
|
|
Term
1. decarboxylation
- __ catalyzes the decarboxylation reaction.
- pyruvate combines with the ionized form of the __ |
|
Definition
- pyruvate dehydrogenase component
- coenzyme thiamine pyrophosphate (TPP) |
|
|
Term
2. oxidation:
- the two carbon fragment is oxidized and transferred to __ to form __ on __ in a reaction also catalyzed by __ |
|
Definition
| - dihyrolipoamide; acetyllipoamide; E2; E1 |
|
|
Term
formation of acetyl CoA:
- __ catalyzes the transfer of the acetyl group from acetyllipoamide to coenzyme A to form acetyl CoA |
|
Definition
|
|
Term
| To participate in another reaction cycle, __ must be reoxidized. this reaction is catalyzed by __. |
|
Definition
| dihydrolipoamide; dihydrolipoyl dehydrogenase (E3) |
|
|
Term
- formation of acetyl CoA from pyruvate is a key __ step in animals
- acetyl CoA has two principle fates: metabolism by the __, or incorporation into __ |
|
Definition
-irreversible
- citric acid cycle; fatty acids |
|
|
Term
- enzyme __ is a key site of regulation. a kinase associated with the complex __ and __ the enzyme
- a __, also associated with the complex, removes the phosphate and thereby __ the enzyme |
|
Definition
- phosphorylates; inactivates
- phosphatase; activates |
|
|
Term
- the pyruvate dehydrogenase complex is also regulated by __
- __, __, and __ inhibit the complex
- __ and __ stimulate the complex |
|
Definition
- energy charge
- atp, acetyl coa, NADH
- adp; pyruvate |
|
|
Term
- in people with phosphatase deficiency, PDH is always __ and thus __
- pyruvate is converted to __, which leads to __ and malfunctioning of the cns |
|
Definition
- phosphorylated; inactive
- lactate; lactic acidosis |
|
|
Term
- beriberi is a neurological and cardiovascular disorder caused by the dietary deficiency of __ or __
- __ is the prosthetic group for pyruvate dehydrogenase (PDH)
- the activity of PDH in beriberi is __ and results in __ |
|
Definition
- thiamine; vitamin B1
- thiamine pyrophosphate (TPP)
- very low; accumulation of pyruvate |
|
|
Term
- exposure to __ or __ results in symptoms similar to those of Beriberi
- arsenite and mercury bind to __ and inhibit the __
- the sulfhydryl reagent __ relieves the inhibition by forming a complex with arsenite that can be excreted. |
|
Definition
- mercury; arsenite
- dihydrolipoamide
-2,3 dimercaptopropanol |
|
|
Term
- the citric acid cycle is the final common pathway for the __ of fuel molecules
- the citric acid cycle oxidizes the __ of __ to __
- the function of the citric acid cycle is to harvest __ from carbon fuels in the form of __ and __
- the citric acid cycle is strictly __ |
|
Definition
- oxidation
- acetyl fragment; acetyl CoA; CO2
- high energy electrons; nadh; fadh2
- aerobic |
|
|
Term
the cac consists of two stages
- stage 1: __ enter the cycle as __ and two molecules of __ leave the cycle
- stage 2: regeneration of __
- both stages generate __ that are used in oxidative phosphorylation |
|
Definition
- 2 carbons; acetyl CoA; CO2
- oxaloacetate
- high energy electrons |
|
|
Term
- citric acid cycle removes electrons from __ and uses these electrons to form __ and __
- electrons released in the __ of nadh and fadh2 contribute to __ during oxidative phosphorylation |
|
Definition
- acetyle CoA; nadh; fadh2
- reoxidation; atp synthesis |
|
|
Term
stage 1
- __ catalyzes the condensation of acetyle CoA and oxaloacetate to form __
- the intermediate of the reaction is __ |
|
Definition
- citrate synthase; citrate
- citryl CoA |
|
|
Term
the mechanisms of __ prevents undesirable reactions
- __ exhibits induced fit
- __ binding induces structural changes that lead to the formation of the acetyl CoA binding site |
|
Definition
citrate synthase
- citrate synthase
- oxaloacetate |
|
|
Term
citrate is isomerized to __
- __ catalyzes the formation of __ from citrate
- the intermediate of this reaction is __ |
|
Definition
isocitrate
- aconitase; isocitrate
- cis-aconitate |
|
|
Term
isocitrate is oxidized and decarboxylated to __
- __ catalyzes the oxidative decarboxylation of isocitrate, forming __ and capturing high energy electrons as __
- __ is the unstable intermediate of this reaction |
|
Definition
alpha ketoglutarate
- isocitrate dehydrogenase; alpha ketoglutarate; nadh
- oxalosuccinate |
|
|
Term
__ is formed from the oxidative decarboxylation of alpha ketoglutarate
- this is catalyzed by __
- this reaction also produces __ and __ |
|
Definition
succinyl CoA
- alpha ketoglutarate dehydrogenase complex
- CO2; NADH |
|
|
Term
stage two regenerates __ and harvests __
- a compound with __ is generated from succinyl coenzyme A
- __ catalyzes the cleavage of a thioester linkage and concomitantly forms __ |
|
Definition
oxaloacetate; high energy electrons
- high phosphoryl transfer potential
- succinyl coa sythetase; atp |
|
|
Term
oxaloacetate is regenerated by the oxidation of succinate
- __ oxidizes __ to __ and produces fadh2
- __ is hydrated to __ catalyzed by __
- __ is then oxidized to form __ and nadh catalyzed by ___ |
|
Definition
- succinate dehydrogenase; succinate; fumarate
- fumarate; malate; fumarase
- malate; oxaloacetate; malate dehydrogenase |
|
|
Term
| the citric acid cycle produces __, __, and __ |
|
Definition
| high transfer potential electrons; a nucleoside triphosphate; carbon dioxide |
|
|
Term
- __ atp per nadh, and __ atp for fadh2
- Only __ ATP per acetyl unit is directly formed in the citric acid cycle. __ more ATP are formed when __ NADH and __ FADH2 are oxidized. Thus 1 acetyl unit generates __ molecules of ATP. |
|
Definition
- 2.5; 1.5
- 1; 9; 3; 1; 10 |
|
|
Term
- citric acid cycle is the final common pathway for __ of fuel molecules and is a source of __
- since it is an important __ of the cell, the entry into the cycle and the rate of the cycle are strictly controlled
- the key control points are catalyzed by __ and __ |
|
Definition
- aerobic oxidation; building blocks
- metabolic hub
- isocitrate dehydrogenase; alpha ketoglutarte dehydrogenase |
|
|
Term
- isocitrate dehydrogenase is allosterically stimulated by __ and inhibited by __ and __
- a-ketoglutarate dehydrogenase is inhibited by __, __, and __
- rate of citric acid cycle is reduced when the cell has high levels of __ and __ |
|
Definition
- adp; nadh; atp
- succinyl coa; nadh; atp
- atp; nadh |
|
|
Term
| many of the components of the citric acid cycle are precursors for biosynthesis of key ___ |
|
Definition
|
|
Term
- the citric acid cycle __ must be replenished if any are drawn off for biosynthesis
- these replenishing reactions are called __ |
|
Definition
- intermediates
- anapleurotic reactions |
|
|
Term
| an example of anapleurotic reaction is the carboxylation of __ by __ |
|
Definition
| pyruvate; pyruvate carboxylase |
|
|
Term
- the glyoxylate cycle is similar to the citric acid cycle by bypasses the __, allowing the synthesis of carbs from fats
- succinate can be converted into __ and then into __ |
|
Definition
- two decarboxylation steps
- oxaloacetate; glucose |
|
|
Term
__ is the process by which atp is formed as a result of the transfer of electrons from nadh or fadh2 to o2 by a series of electron carriers
- the process takes place in __, and is the major source of energy for __ organsisms
- complete oxidaton of glucose to co2 and h2o yields __ molecules of atp, __ of which are generated by oxidative phosphorylation |
|
Definition
oxidative phosphorylation
- mitochondria; aerobic
- 30; 26 |
|
|
Term
- the flow of electrons from nadh and fadh2 to o2 occurs in the __ aka __
- this exergonic set of redox reactions generates a __ which is used to power the __
- collectively the citric acid cycle and oxidative phosphorylation are called __ aka __ |
|
Definition
- electron transport chain; respiratory chain
- proton gradient; synthesis of atp
- cellular respiration; respiration |
|
|
Term
mitochondria are bounded by a __
- the outer mitochondrial membrane is permeable to most __ and molecules because of the channel protein mitochondrial __
- the inner membrane is folded into ridges called __, and is __ to most molecules
- the __ is the site of electron transport and atp |
|
Definition
double membrane
- small ions; porin
- cristae; impermeable
- inner membrane |
|
|
Term
- mitochondria are __ organelles and contain their own dna and encode a variety of proteins
- mitochondria also contain __ that are encoded by nuclear dna
- __: sequence data suggest that all mitochondria are descendants of an ancestor of rickettsia prowazekii, which was engulfed by another cell |
|
Definition
- semiautonomous
- proteins
- endosymbiosis |
|
|
Term
| the electron transport chain is a series of coupled __ that transfer electrons from nadh and fadh2 to oxygen |
|
Definition
|
|
Term
- the __ is a measure of a molecule's tendency to donate or accept electrons
- a __ readily donates electrons and has a __
-- formula:
- formula for energy change: |
|
Definition
- redox potential
- strong reducing agent (NADH); negative Eo
- strong oxidizing agent (O2); positive Eo
- oxidizing agent + e- = reducing agent
- delta G = -n F delta E |
|
|
Term
- energy is released when high energy electrons are transferred to __
- the energy is used to establish a __ |
|
Definition
- oxygen
- proton gradient |
|
|
Term
| the carriers include: __, __, __, and a mobile electron carrier called __ |
|
Definition
| FMN; iron-sulfur proteins; cytochromes; coenzyme q |
|
|
Term
- coenzyme q, or __, is derived from __ and is an important mobile electron carrier
- coenzyme q binds __ as well as __, and can exist in several __ states
- oxidized and reduced q are present in the __ in what is called the __ |
|
Definition
- ubiquinone; isoprene
- protons; electrons; oxidation
- inner mitochondrial membrane; Q pool |
|
|
Term
the respiratory chain consists of __ and a physical link to the citric acid cycle
- electrons flow from __ to __ is mediated through three large protein complexes
- these complexes __ out of the mitochondria, thus generating a __
- the complexes are: |
|
Definition
proton pumps
- nadh; o2
- pump protons; proton gradient
- NADH-Q oxidoreductase (Complex I); Q-cytochrome c oxidoreductase (Complex III); Cytochrome c oxidase (Complex IV) |
|
|
Term
- An additional complex, __, delivers electrons from FADH2 to Complex III.
__ is not a proton pump.
Electron flow within the complexes in the __-mitochondrial membrane generate a proton gradient.
These complexes appear to be associated with one another in what is called the __. |
|
Definition
- succinate q-reductase (complex II)
- succinate q-reductase
- inner
- respirasome |
|
|
Term
- the electrons from nadh enter the chain at __
- __ are simulataneously pumped out of the mitochondria by __ |
|
Definition
- nadh-q oxidoreductase (complex I)
- 4 protons; complex I |
|
|
Term
-The citric acid cycle enzyme __ which generates FADH2 is part of the succinate-Q reductase complex (Complex II).
-The ___ generated in the citric acid cycle reduces Q to QH2, which then enters the Q pool. |
|
Definition
- succinate dehydrogenase
- fadh2 |
|
|
Term
-__ is the second proton pump in the respiratory chain and catalyzes the transfer of electrons from __ to __.
This electron transfer is coupled to -the pumping of __ from the matrix. |
|
Definition
- q-cytochrome c oxidoreductase (complex III)
- two protons |
|
|
Term
-QH2 carries __ electrons while cytochrome c carries only __ electron.
-The mechanism for coupling electron transfer from QH2 to cytochrome c is called the __.
-Two molecules of __ are reduced and two __ removed from the mitochondrial matrix. |
|
Definition
- two; one
- q cycle
- cytochrome c; two protons |
|
|
Term
- Cytochrome c oxidase (complex IV) catalyzes the reduction of __ to two molecules of __
- cytochrome c oxidase pumps __ from the matrix to the cytoplasmic side
- oxidative phosphorylation occurs under __ conditions because this reaction requires oxygen |
|
Definition
- o2; h2o
- four protons
- aerobic |
|
|
Term
- partial reduction of o2 generates highly reactive oxygen derivatives called __
- ROS are implicated in many __ conditions
- ROS include __, __, and __
- _ of oxygen molecules consumed by mitochondrial are converted into __ |
|
Definition
- reactive oxygen species (ROS)
- pathological
- superoxide ion, peroxide ion, hydroxyl radical
- 2-4%; superoxide ions |
|
|
Term
- __ and __ can help protect against ros damage
- __ converts superoxide radicals to hydrogen peroxide and water
- __ converts hydrogen peroxide into water and oxygen
- defenses against oxidative damage include __ and __ |
|
Definition
- superoxide dismutase; catalase
- superoxide dismutase
- catalase
- antioxidant vitamins; exercise |
|
|
Term
- __: electron transport and atp synthesis are coupled by a proton gradient across the inner mitochondrial membrane.
- atp synthesis is powered by the __
-- the formula for this is ___ |
|
Definition
- chemiosmotic theory
- proton motive force
- proton motive force = chemical gradient + charge gradient |
|
|
Term
- heterologous experimental systems confirmed that proton gradients can power __
- etc and atp synthase are separate systems, linked only by a __ |
|
Definition
- atp synthesis
- proton-motive force |
|
|
Term
- atp synthase (complex 5): __ and __ unit
- __ subunit protrudes into the mitochondrial matrix and contains the catalytic activity of the synthase
- __ subunit spans the inner mitochondrial membrane and contains the proton channel
- the __ subunit connects the F1 and Fo components |
|
Definition
- proton conducting Fo; ATP synthesizing F1
- F1
- Fo
- y |
|
|
Term
- the __ accounts for the synthesis of atp in response to proton flow
- __ forms readily in the absence of a proton motive force. however, __ does not leave the catalytic site unless protons flow through the enzyme
- __ does not directly participate in the formation of ATP, but promotes the release of ___ |
|
Definition
- binding change mechanism
- enzyme bound atp; atp
- proton gradient; atp |
|
|
Term
binding change mechanism: changes in the properties of __ of __ allows sequential adp and pi binding, atp synthesis and release.
- __: nucleotides can bind to or be released from the beta subunit
- __: nucleotides are trapped in the beta subunit
- __: atp is synthesized from adp and pit to atp, however atp cannot be released
- the interconversion of these three forms is driven by __ |
|
Definition
three beta subunits; F1
- O or open form
- L or loose form
- T or tight form
- y subunit rotation |
|
|
Term
| the hydrolysis of a single atp powered the __ by ___ |
|
Definition
| y subunit rotation; 120 degrees |
|
|
Term
proton flow around the __ powers atp synthesis
- proton flow requires the __ and __ subunits of __.
- subunit __ forms a pair of __ that span the membrane and has an __ residue in the middle
- the __ subunit has two channels that reach halfway into the subunit. one half channel open to the intermembrane space and the other into the matrix |
|
Definition
C ring
- a; c; Fo
- c; alpha helices; asp 61
- a |
|
|
Term
| __ must flow into the matrix for each atp formed |
|
Definition
|
|
Term
| the electron transport chain generates a __, which is used to __ |
|
Definition
| proton gradient; synthesize atp |
|
|
Term
- __ enter the mitochondria by shuttles
- __ also functions to regenerate nad+ for use in glycolysis
- __ cannot enter the mitochondria
- electrons from cytoplasmic nadh are carried across the mitochondrial membrane by two major mitochondrial shuttles: __ and __ |
|
Definition
- electrons from cytoplasmic NADH
- respiratory chains
- cytoplasmic NADH
- glycerol 3-phosphate shuttle (muscle); malate-aspartate shuttle (heart and liver) |
|
|
Term
-In muscle, electrons from cytoplasmic NADH enter the electron-transport chain via the __.
- Cytosolic NADH transported by the glycerol 3-phosphate shuttle, yields __ instead of __ |
|
Definition
- glycerol 3-phosphate shuttle
- 1.5 atp; 2.5 atp |
|
|
Term
- In heart and liver, electrons from cytoplasmic NADH are used to generate mitochondrial NADH in __
- Cytosolic NADH transported by malate-aspartate shuttle yields __. |
|
Definition
- malate-aspartate shuttle
- 2.5 atp |
|
|
Term
- the __ enables the exchange of cytoplasmic adp for mitochondrial atp
- __ must enter the mitochondria for __ to leave
- the translocase is powered by the __ |
|
Definition
- atp-adp translocase
- adp; atp
- proton motive force (requires the influx of one H+) |
|
|
Term
- p/o ratio =
- translocation of __ required by atp synthase for each atp produced
- __ needed for transport of Pi, ADP, and ATP
- net __ transported for each atp synthesized |
|
Definition
- molecules of adp phosphorylated / atoms of oxygen reduced
- 3 H+
- 1 H+
- 4 H+ |
|
|
Term
since 4 H+ are required for each atp synthesized:
- p/o ratio for nadh =
- p/o ratio for succinate (fadh2) substrate = |
|
Definition
- p/o = (10 H+ / 4H+) = 2.5ATP/O
- p/o = (6 H+ / 4H+) = 1.5ATP/O |
|
|
Term
-1 NADH = __ H+ = __ atp
-1 fadh2(succinate) = __ H+ = __ atp |
|
Definition
|
|
Term
| the complete oxidation of glucose yields about __ molecules of atp, __ is generated by oxidative phosphorylation |
|
Definition
|
|
Term
the rate of oxidative phosphorylation is determined by the need for __
-Electrons do not flow through the electron-transport chain to O2 unless __ is simultaneously phosphorylated to __.
-The level of __ is the most important factor in determining the rate of oxidative phosphorylation. This regulation is called __.
-ADP level increases when __, and so oxidative phosphorylation is coupled to the utilization of ATP. |
|
Definition
atp
- adp; atp
- adp; respiratory (acceptor) control
- atp is consumed |
|
|
Term
__ leads to the generation of heat
- If electron transport is uncoupled from ATP synthesis, __ is generated, a process called __.
- Such uncoupling is facilitated in a regulated fashion by __, also called thermogenin, an intergral protein of the inner mitochondrial membrane.
- Uncoupling occurs in mitochondria in __, called __. |
|
Definition
regulated uncoupling
- heat; nonshivering thermogenesis
- uncoupling protein 1
- brown fat; brown fat mitochondria |
|
|
Term
-Inhibition of the __ prevents oxidative phosphorylation by inhibiting the formation of the __
-Inhibition of __ by inhibiting proton flow prevents electron transport.
-__ carry protons across the inner mitochondrial membrane. The electron-transport chain functions, but ATP synthesis does not occur because the proton gradient can never form.
-Inhibition of the __ prevents oxidative phosphorylation. |
|
Definition
- etc; proton motive force
- atp synthase
- uncouplers
- atp-adp translocase |
|
|
Term
-Rotenone (fish/insect poison) and amytal (barbiturate sedative) block the electron transfer in __
-Antimycin A blocks the electron flow in __
-CN-, N3 and CO block the electron transfer in __ |
|
Definition
- nadh-q oxidoreductase
- q cytochrome c oxidoreductase
- cytrochrome c oxidase |
|
|
Term
-Oligomycin and dicyclohexylcarbodiimide (DCCD, antifungal agent) inhibits the ATP synthase by preventing the influx of __.
-2,4-Dinitrophenol (DNP) __ from phosphorylation in mitochondria by carrying the protons across the inner mitochondrial membrane. It stops ATP synthesis without affecting electron transport from NADH to O2. |
|
Definition
- protons
- uncouples electron transport |
|
|
