Chapter 3 bioenergetics Flashcards
hydrolysis of atp for cross bridge recycling is catalyzed by what enzyme?
Myosin ATPase
_ catalyzes pumping Ca to SR, and _ maintains sarcolemmal concentration gradient after deploarization
calcium ATPase, sodium-potassium ATPase
AKA flow of energy in a biological system and concerns mainly the conversion of macronutrients to biologically usable forms of energy
bioenergetics
energy releasing reactions that are generally catabolic
exergonic reactions
what are the 3 basic energy systems used to replenish ATP in mammalian muscle cells?
phosphagen system, glycolysis, oxidative system
what is the chemical structure of ATP?
adenosine and a triphosphate (3 phosphate) group
adenosine is the combination of adenine (nitrogen containing base) and ribose (5 carbon sugar)
phosphagen and glycolytic systems are anaerobic mechanisms that occur in the _
sarcoplasm (of a muscle cell)
what are the aerobic mechanisms that occur in the mitochondria?
krebs cycle, oxidative system, electron transport chain
which of the macronutrients can be metabolixed for energy without direct involvement of oxygen?
carbs
_ is the enzyme that catalyzes the synthesis of ATP from CP and ADP
creatine kinase
give the equation that depicts the reactants, the enzyme, and the products during ATP hydrolysis
ATP + H2O <-ATPase-> ADP + Pi + H+ + Energy
give the equation that depicts the enzyme creatine kinase, its reactants, and its products
ADP + CP <-creatine kinase-> ATP + PC
give the equation that depicts the adenylate kinase (myokinase) enzyme, its reactants, and its products
2ADP <-Adenylate kinase-> ATP + AMP
T or F: phosphagen system relies on ATP hydrolysis
T
_ supplies a phosphate group that combines with ADP to form ATP
creatine phosphate (CP) AKA phosphocreatine (PCr)
CP is stored in _ amounts
small
body stores approximately _ g of ATP at any given time, which is _ for exercise
80-100 , not enough
what single enzyme reaction uses 2ADP to make ATP + AMP?
Adenylate kinase (also called myokinase) reaction
T or F: AMP is not a powerful stimulator of glycolysis
F
up to how much % can ATP decrease during exercise?
50-60%
why do those with type 2 fibers replenish ATP faster than type 1 via phosphagen system?
type 2 has more CP
what allows the transfer of energy from exergonic to endergonic reactions?
ATP
the breakdown of 1 ATP molecule to yield energy is known as hydrolysis because?
it requires one molecule of water
ATP hydrolyisis is catalyzed by what during
a) cross bridge recycling
b) pumping calcium to sarcoplasmic reticulum
c) maintaining sarcolemmal concentratipn gradient after depolarization
a) myosin ATPase
b) calcium ATPase
c)sodium-potassium ATPase
further hydrolysis of ADP cleaves _ and yields _
2nd phosphate grp, AMP
ATP is classified as a _ energy molecule since it stores _ amounts of energy in the chemical bonds of 2 phosphate groups
high; large
ATP is classified as a _ energy molecule since it stores _ amounts of energy in the chemical bonds of 2 phosphate groups
high; large
describe the law of mass action or the mass action effect
concentrations of reactants or products (or both) in the solution will drive the direction of the reactions
T or F: ATPase, adenylate kinase, and creatine kinase are near equilibrium reactions that proceed in the direction dictated by the reactants’ concentrations due to the law of mass action
T
glycolysis is the breakdown of carbohydrate either
_ stored in the muscle or _ delivered in the blood to resynthesize ATP
glycogen, glucose
end product of glycolysis
pyruvate
pyruvate may proceed where?
shuttled to _ in krebs
converted to _ in _ during anaerobic glycolyis
- converted to lactate in sarcoplasm (anaerobic or fast glycolysis)
- shuttled into mitochondria (krebs cycle)
when pyruvate is converted to lactate, ATP resynthesis occurs at a faster rate via rid regeneration of _ but is limited in duration due to subsequent _ production resulting decrease in cytostolic _
NAD+, H+, pH
when pyruvate undergoes krebs cycle, ATP resynthesis is slower or faster?
slower - due to numerous reactions
krebs cycle is also referred to as?
aerobic or slow glycolysis
at higher intensities, pyruvate and NADH will rise above what can be handled by the _ and will then be converted to _ and _
pyruvate dehydrogenase
lactate, NAD+
pyruvate goes to where when energy demand is
- high
- not as high and enuf O2 is present
high: converted to lactate for further support at the anaerobic glycolysis
not as high and enuf O2 is present: further oxidized in the mitochondria
formation of lactate from pyruvate is catalyed by the enzyme called
a) pyruvate dehydrogenase
b) lactate dehydrogenase
c) myosin dehydrogenase
lactate dehydrogenase
T or F: lactic acid is the product of lactate dehydrogenase
F, because Lactate is
process of exercise induced decreases in pH is called
metabolic acidosis
often used as an energy substrate especially in type 1 and cardiac muscle fibers
a) lactic acid b) pyruvate
c) lactate d) glycerol
lactate
accumulation of what causes reduced intracellular pH, inhibits glycolytic reactions, and directly interferes with muscle’s excitation contraction coupling?
Proton (H+ )
lactate is used in the ff
a)glycogenolysis
b)gluconeogenesis
c)glycolysis
b and c
_ is the formation of glucose from non carb sources during extended exercise and rcovery
gluconeogenesis
at rest, normal reported lactate concentration in blood is
0.5 to 2.2 mmol/kg of wet muscle
total energy yield from oxidation of 1 glucose molecule for SLOW glycolysis
-substrate level phosphorylation
-oxidative phosphorylation 2NADH (3 ATP each)
total for SLOW glycolysis: 10
-substrate level phosphorylation: 4
-oxidative phosphorylation 2NADH (3 ATP each): 6
total energy yield from oxidation of 1 glucose molecule for KREBS cycle (2 rotations through the krebs cycle per glucose)
-substrate level phosphorylation:
-oxidative phosphorylation - 8NADH (3 ATP each)
-via GTP - 2 FADH2 (2ATP each)
KREBS cycle (2 rotations through the krebs cycle per glucose): 40 (but net is 38 since glycolysis consumes 2ATP if starting with blood glucose)
-substrate level phosphorylation: 2
-oxidative phosphorylation: 24
-via GTP: 4
severe fatigue may occur at blood lactate concentrations of?
20 to 25 mmol/L and even greater than 30 following multiple bouts of dynamic exercise
blood lactate concentrations reflect the net balance of lactate prod and clearance as a result of _ buffering
bicarbonate (HCO3-)
T or F: bicarbonate (HCO3-) minimizes the disrtipn of the influence of the H+ on pH by accepting the proton (HCOO2)
F because it’s by accepting the proton H2CO3
give 3 ways lactate can be cleared or used
1) by oxidation within the muscle fiber it was made
2) transported in the blood to other muscle fibers
3) cori cycle: transported in the blood to the liver where it is converted to glucose
T or F: heavy activity post exercise period has been shown to increase lactate clearance ratez
F, it should be light activity or active recovery
where is blood lactate accumulation greater?
a) high intensity intermittent exercise
b) low intensity continuous exercise
a)
T or F phosphoglycerate kinase reaction of glycolysis causes no proton dissociation from lactate which is why lactic acid does not cause metabolic acidosis
T
total energy yield from oxidation of 1 glucose molecule for KREBS cycle (2 rotations through the krebs cycle per glucose) at oxidative phosphorylation
24 via 8NADH that yields 3ATP each
total energy yield from oxidation of 1 glucose molecule for KREBS cycle (2 rotations through the krebs cycle per glucose) at GTP
4 via 2 FADH2 (2ATP each)
total energy yield from oxidation of 1 glucose molecule for KREBS cycle (2 rotations through the krebs cycle per glucose) at GTP
4 via 2 FADH2 (2ATP each)
if enough oxygen is present in the mitochondria, the end product of glycolysis (pyruvate) is transported there together with
a) 2 NADH
b) 2 FADH
c) 3 NADH
d) 3 FADH
2 NADH
when pyruvate enters the mitochondria, it is converted to
a) pyruvate dehydrogenase
b) lactate
c) fructokinase
d) acetyl CoA
converted to acetyl CoA via pyruvate dehydrogenase
net reaction for glycolysis when puruvate is shuttled to the mitochondria may be summarized as
a) pyruvate + 2Pi + 2ADP + 2NAD+ -> + 2ATP + 2NADH + 2H2O
b) glucose + 1Pi + 1ADP + 2NAD+ -> 2Pyruvate + 2ATP + 1NADH + 2H2O
c) glucose + 2Pi + 2ADP + 2NAD+ -> 2Pyruvate + 2ATP + 2NADH + 2H2O
d) glucose + 2H2O+ 2ADP + 2NAD+ -> 2Pyruvate + 2ATP + 2NADH + 2Pi
glucose + 2Pi + 2ADP + 2NAD+ -> 2Pyruvate + 2ATP + 2NADH + 2H2O
energy yield glycolysis: what are the 2 main mechanisms for ATP resynthesis during metabolism?
substrate level phosphorylation
oxidative level phosphorylation
this refers to the resynthesis of ATP in the ETC
oxidative phosphorylation
this refers to the direct resynthesis of ATP from ADP during a single reaction in the metabolic pathways
substrate level phosphorylation
acetyl CoA combines with a 4 carbon molecule called _ to form a 6 carbon molecule called _
4 carbon molecule called oxaloacetate
6 carbon molecule called citrate
what is the gross number of ATP made by substrate level phosphorylation? why is its net ATP less?
gross number is 4
net ATP is less because the reaction that converts fructose-6-phosphate to fructose 1,6-bisphosphate catalyzed by PFK (phosphofructokinase) in glycolysis needs the hydrolysis of 1 ATP
there are 2 possible sources of glucose which are? *
blood glucose and muscle glycogen
T OR F when blood glycose enters the muscle cell, it does not need to be phosphorylated
F , it must be phosphorylated to remain in the cell and to maintain the glucose concentration gradient
phosphorylation of 1 blood glucose is catalyzed by
a) glycogen phosphorylase
b) phosphofructokinase
c) hexokinase
d) pyurvate kinase
hexokinase
T OR F when muscle glycogen is broken down, it does not need the hydrolysis of ATP
T because its already phosphorylated
muscle glycogen is broken down with the help of the enzyme
a) glycogen phosphorylase
b) phosphofructokinase
c) hexokinase
d) pyurvate kinase
glycogen phosphorylase
what is the net ATP for
a) 1 blood glucose
b) 1 muscle glycogen
a) 2 net ATP (since 4 is made and 2 is used)
b) 3 net ATP (since 4 is made and 1 is used)
rate of glycolysis is stimulated to increase during intense muscle actions by high concentrations of _ , _ and _ and by a slight decrease in _ and _ .
high concentrations of ADP, P , ammonia
slight decrease in pH and AMP
T OR F rate of glycolysis is stimulated to increase when there are signs of increased ATP hydrolysis and need for energy
T
glycolysis regulation is influenced by the concentrations and turnover rates of what 3 glycolytic enzymes?
hexokinase
PFK
pyruvate kinase
T OR F: hexokinase, PFK, pyruvate kinase are regulatory enzymes in glycolysis because each has allosteric binding sites
T
refers to when end product of reaction (or series of reactions) FEEDS BACK to REGULATE the turnover rate of key enzymes in the metabolic pathways
allosteric regulation, AKA end product regulation or feedback regulation
refers to when end product binds to the regulatory enzyme and DECREASES its turnover rate and SLOWS product formation
allosteric inhibition
when an “ACTIVATOR” binds with the enzyme and INCREASES its turnover rate
allosteric activation
what is the difference between allosteric inhibition and allosteric activation in terms of turnover rate?
allosteric inhibition decreases turnover rate
allosteric activation increases turnover rate
what catalyzes the phosphorylation of glucose to glucose-6-phospphate
a) pyruvate kinase
b) pyruvate dehydrogenase
c) hexokinase
d) PFK
hexokinase