Studied by 121 people
metabolism
the total of all cellular reactions that occur in cells and includes chemical pathways that result in the synthesis of molecules (anabolic reactions) as well as the breakdown of molecules (catabolic reactions)
bioenergetics
the chemical processes involved with the production of cellular ATP
oxygen, carbon, hydrogen, and nitrogen
what are the four main elements that compose 95% of the body?
cell membrane, nucleus, and cytoplasm
what are the 3 major structural parts of a cell?
sun
all energy on earth comes from the _____.
endergonic
what type of reactions require energy?
exergonic
what type of reactions give off energy?
coupled
______ reactions are reactions that are linked, with the liberation of free energy in one reaction being used to “drive” a second reaction.
true
true or false: energy-liberating reactions (exergonic) are “coupled” to energy-requiring reactions (endergonic).
true
true or false: oxidation-reduction reactions are an important type of coupled reaction.
oxidation
the process of removing an electron from an atom or molecule
reduction
the addition of an electron to an atom or molecule
coupled reactions
oxidation and reduction are _____ ______ because a molecule cannot be oxidized unless it donates electrons to another atom.
reducing agent
the molecule that donates the electron
oxidizing agent
the molecule that accepts the electron
false, they can use hydrogen atoms to donate
true or false: oxidation-reduction reactions in cells are not able to use hydrogen atoms in the process of donating electrons.
NADH and FADH
what are the two molecules that play important roles in the transfer of electrons through hydrogen atoms?
enzymes
the speed of cellular chemical reactions is regulated by catalysts called _____.
false
true or false: as well as regulating the rate or speed at which reactions occur, enzymes also cause reactions to occur.
activation energy
the energy required to initiate chemical reactions
lowering
enzymes work as catalysts by _______ the activation energy.
true
true or false: enzymes can be used to diagnose particular diseases.
risk of myocardial infarction
what does an elevated level of lactate dehydrogenase in the blood indicate?
temperature and ph
what two factors can alter enzyme activity?
increases
in general, a small rise in body temperature (1-2 degrees) above normal ________ the activity of most enzymes.
false, a slight increase is optimal
true or false: any increase of body temperature is harmful to enzymatic activity
true
true or false: any change in pH is harmful to enzymatic activity
glycogenolysis
the process of breaking down glycogen into glucose
the liver
where does glycogenolysis occur?
true
true or false: it is most optimal for the body to store glucose as glycogen as it keeps osmotic pressure stable and allows for lots of glucose to be stored
liver and muscle fibers
where is glycogen stored?
false, fat
true or false: stored glycogen and glucose is an ideal fuel for prolonged exercise.
fatty acids
what is the primary type of fat used by muscle cells for energy?
triglycerides
how are fatty acids stored in the body?
lipolysis
the process of breaking down triglycerides into fatty acids and glycerol
ATPase
what enzyme breaks the bond in ATP to release energy?
true
true or false: muscle cells store a small amount of ATP ready for use.
ATP-PC and glycolysis
what are the two anaerobic pathways of ATP production?
oxidative phosphorylation
what is the aerobic pathway of ATP production?
creatine kinase
which enzyme catalyzes the PC + ADP ——> ATP + C reaction?
5-10 seconds
how long is the ATP-PC system good for?
1 ATP
how much ATP does the ATP-PC system make?
glucose or glycogen
what is broken down during glycolysis?
sarcoplasm of the muscle cell
where does glycolysis occur?
2 ATP
what is the net gain of glycolysis?
2 pyruvate or lactate and 2 NADH or FADH
what are the other products of glycolysis besides ATP?
true
true or false: 2 ATP is required to start glycolysis if breaking down glucose. Only 1 ATP is needed to start glycolysis if breaking down glycogen.
false, glucose = 2 and glycogen = 3
true or false: glycolysis involving the breakdown of glucose has a higher net gain of ATP than glycolysis involving the breakdown of glycogen.
it does not require phosphorylation by ATP
why does glycogen produce more ATP during glycolysis than glucose?
true
true or false: if O2 is not available to accept the hydrogens in the mitochondria, pyruvate can accept the hydrogens to form lactate.
the citric acid cycle and the electron transport chain
what two cooperating pathways for the entirety of aerobic ATP production (or oxidative phosphorylation)?
to oxidate acetyl CoA using NAD+ and FAD
what is the primary function of the citric acid cycle?
true
true or false: acetyl-CoA can be formed from pyruvate or oxidation of fatty acids or amino acids
oxidation, electron transport chain
Acetyl-CoA enters the citric acid cycle where it undergoes _________, resulting in the release of electrons into the ___________________.
2
for every molecule of glucose entering glycolysis, _____ molecules of pyruvate are formed.
acetyl-CoA
in the presence of O2, the 2 pyruvate from glycolysis are converted to 2 molecules of _______.
3 NADH, 1 FADH
with each turn of the citric acid cycle, how many molecules of NADH and FADH are formed?
oxygen, 2.5
for every pair of electrons passed through the electron transport chain from NADH to the final electron acceptor ______, enough energy is available to form ____ molecules of ATP.
1.5, less
for every FADH molecule that is formed, sufficient energy is available to produce ___ molecules of ATP. Thus, FADH is _____ energy rich as NADH.
beta-oxidation
what are the series of reactions called that convert fatty acids into acetyl-CoA?
2-15%
what percent does protein contribute to exercise as a fuel source?
mitochondria
where does oxidative phosphorylation occur?
NADH, FADH, ADP, ATP
aerobic production of ATP uses the potential energy available in reduced hydrogen carries such as ___ and ____ to rephosphorylate ___ to ____.
false, if O2 is not present at the end, oxidative phosphorylation is mot possible
true or false: if oxygen is not available to accept the electrons at the end of the electron transport chain to thus make water with hydrogen, the electrons can be passed off to another molecule.
32, 33
the total ATP yield of aerobic degradation of glucose is ___ ATP and the aerobic ATP yield for glycogen breakdown is ___ ATP.
rate-limiting
the ______________ enzyme determines the speed of the particular metabolic pathway involved.
modulators, allosteric
the activity of rate-limiting enzymes is regulated by _______ which are substances that increase or decrease enzyme activity. Enzymes that are regulated by these are called ___________ enzymes.
creatine kinase
what is the rate-limiting enzyme of the ATP-PC system?
phosphofructokinase
what is the rate-limiting enzyme of glycolysis?
isocitrate dehydrogenase
what is the rate-limiting enzyme of the citric acid cycle?
cytochrome c oxidase
what is the rate-limiting enzyme of the electron transport chain?
50-75%
maximal heart rate of moderate intensity exercise: ______
76-85%
maximal heart rate of heavy intensity exercise: ______
86-100%
maximal heart rate of very heavy intensity exercise: ______
100%
maximal heart rate of severe intensity exercise: ______
less than 60%
% VO2 max of moderate intensity exercise: ______
60-75%
% VO2 max of heavy intensity exercise: ______
76-100%
% VO2 max of very heavy intensity exercise: ______
greater than 100%
% VO2 max of severe intensity exercise: ______
oxygen deficit
the lag in oxygen uptake at the beginning of exercise; the difference between oxygen uptake in the first few minutes of exercise and an equal time period after steady state has been obtained
EPOC
the elevated post-exercise oxygen consumption; related to replacement of creatine phosphate, lactate resynthesis to glucose, and elevated body temperature, catecholamines, heart rate, breathing, etc.
rapid and slow portion
what are the two portions of EPOC?
the steep decline in oxygen uptake following exercise
what does the rapid portion of EPOC represent?
the slow decrease in O2 consumption following exercise
what does the slow portion of EPOC represent?
true
true or false: heart rate and breathing remaining elevated after exercise, oxidative conversion of lactate to glucose in the liver, and elevated body temp and circulating hormones all contribute to EPOC
the heart and skeletal muscle (largely slow twitch fibers)
what structures in the body convert lactate to pyruvate to be used?
false, they rise
true or false: as the exercise intensity increases during an incremental exercise test, blood levels of lactate begin to drop in an exponential fashion
lactate threshold
a point during a graded exercise test when the blood lactate concentration increases abruptly
e. all of the above
which of these factors contribute to the sudden rise in blood lactate concentration during incremental exercise?
a. low muscle oxygen
b. recruitment of fast muscle fibers
c. a reduced rate of lactate removal
d. accelerated glycolysis due to epinephrine
e. all of the above
respiratory exchange ratio
a noninvasive technique that is commonly used to estimate the percent contribution of carbohydrate or fat to energy metabolism during exercise is the ratio of the volume of carbon dioxide produced to the volume of oxygen consumed
more
compared to fat, about 6% ____ energy per liter of oxygen is obtained when carbohydrate is used as the sole fuel for exercise.
carbohydrates contain more O2 than fat
why does fat oxidation require more O2 than carbohydrate oxidation?
5-10%
during prolonged exercise, the total contribution of protein to the fuel supply may reach _____ during the final minutes of work.
crossover point
what is the point at which exercise fuel switches from primarily fat to primarily carbohydrate?
a and d
which two factors cause the shift from fat to carb metabolism as exercise intensity increases?
a. recruitment of fast fibers
b. increasing blood lactate levels
c. recruitment of slow fibers
d. increasing blood levels of epinephrine
fast, glycolytic, carbs
as the exercise intensity increases, more and more, ____ muscle fibers are recruited. These fibers have an abundance of _________ enzymes but few mitochondrial and lipolytic enzymes. These means that these fibers are better equipped to metabolize ____ than fats.
false, muscle glucose
true or false: an increase in blood levels of epinephrine increase phosphorylase activity, which causes an increase in muscle fat breakdown.
lipases
what type of enzyme breaks down triglycerides into free fatty acids to be used for prolonged exercise?
after 10-20 minutes of exercise
when does fat metabolism typically occur?
white adipocytes as triglycerides
where is the large majority of fat stored and in what form is it stored?
Note 
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