KIN 362--Exam 1 (copy) (copy)

Bioenergetics, metabolism, and hormones

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)

metabolism

the chemical processes involved with the production of cellular ATP

bioenergetics

what are the four main elements that compose 95% of the body?

oxygen, carbon, hydrogen, and nitrogen

what are the 3 major structural parts of a cell?

cell membrane, nucleus, and cytoplasm

all energy on earth comes from the _____.

sun

what type of reactions require energy?

endergonic

what type of reactions give off energy?

exergonic

______ reactions are reactions that are linked, with the liberation of free energy in one reaction being used to “drive” a second reaction.

coupled

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.

true

the process of removing an electron from an atom or molecule

oxidation

the addition of an electron to an atom or molecule

reduction

oxidation and reduction are _____ ______ because a molecule cannot be oxidized unless it donates electrons to another atom.

coupled reactions

the molecule that donates the electron

reducing agent

the molecule that accepts the electron

oxidizing agent

true or false: oxidation-reduction reactions in cells are not able to use hydrogen atoms in the process of donating electrons.

false, they can use hydrogen atoms to donate

what are the two molecules that play important roles in the transfer of electrons through hydrogen atoms?

NADH and FADH

the speed of cellular chemical reactions is regulated by catalysts called _____.

enzymes

true or false: as well as regulating the rate or speed at which reactions occur, enzymes also cause reactions to occur.

false

the energy required to initiate chemical reactions

activation energy

enzymes work as catalysts by _______ the activation energy.

lowering

true or false: enzymes can be used to diagnose particular diseases.

true

what does an elevated level of lactate dehydrogenase in the blood indicate?

risk of myocardial infarction

what two factors can alter enzyme activity?

temperature and ph

in general, a small rise in body temperature (1-2 degrees) above normal ________ the activity of most enzymes.

increases

true or false: any increase of body temperature is harmful to enzymatic activity

false, a slight increase is optimal

true or false: any change in pH is harmful to enzymatic activity

true

the process of breaking down glycogen into glucose

glycogenolysis

where does glycogenolysis occur?

the liver

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

true

where is glycogen stored?

liver and muscle fibers

true or false: stored glycogen and glucose is an ideal fuel for prolonged exercise.

false, fat

what is the primary type of fat used by muscle cells for energy?

fatty acids

how are fatty acids stored in the body?

triglycerides

the process of breaking down triglycerides into fatty acids and glycerol

lipolysis

what enzyme breaks the bond in ATP to release energy?

ATPase

true or false: muscle cells store a small amount of ATP ready for use.

true

what are the two anaerobic pathways of ATP production?

ATP-PC and glycolysis

what is the aerobic pathway of ATP production?

oxidative phosphorylation

which enzyme catalyzes the PC + ADP ——> ATP + C reaction?

creatine kinase

how long is the ATP-PC system good for?

5-10 seconds

how much ATP does the ATP-PC system make?

1 ATP

what is broken down during glycolysis?

glucose or glycogen

where does glycolysis occur?

sarcoplasm of the muscle cell

what is the net gain of glycolysis?

2 ATP

what are the other products of glycolysis besides ATP?

2 pyruvate or lactate and 2 NADH or FADH

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.

true

true or false: glycolysis involving the breakdown of glucose has a higher net gain of ATP than glycolysis involving the breakdown of glycogen.

false, glucose = 2 and glycogen = 3

why does glycogen produce more ATP during glycolysis than glucose?

it does not require phosphorylation by ATP

true or false: if O2 is not available to accept the hydrogens in the mitochondria, pyruvate can accept the hydrogens to form lactate.

true

what two cooperating pathways for the entirety of aerobic ATP production (or oxidative phosphorylation)?

the citric acid cycle and the electron transport chain

what is the primary function of the citric acid cycle?

to oxidate acetyl CoA using NAD+ and FAD

true or false: acetyl-CoA can be formed from pyruvate or oxidation of fatty acids or amino acids

true

Acetyl-CoA enters the citric acid cycle where it undergoes _________, resulting in the release of electrons into the ___________________.

oxidation, electron transport chain

for every molecule of glucose entering glycolysis, _____ molecules of pyruvate are formed.

2

in the presence of O2, the 2 pyruvate from glycolysis are converted to 2 molecules of _______.

acetyl-CoA

with each turn of the citric acid cycle, how many molecules of NADH and FADH are formed?

3 NADH, 1 FADH

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.

oxygen, 2.5

for every FADH molecule that is formed, sufficient energy is available to produce ___ molecules of ATP. Thus, FADH is _____ energy rich as NADH.

1.5, less

what are the series of reactions called that convert fatty acids into acetyl-CoA?

beta-oxidation

what percent does protein contribute to exercise as a fuel source?

2-15%

where does oxidative phosphorylation occur?

mitochondria

aerobic production of ATP uses the potential energy available in reduced hydrogen carries such as ___ and ____ to rephosphorylate ___ to ____.

NADH, FADH, ADP, ATP

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.

false, if O2 is not present at the end, oxidative phosphorylation is mot possible

the total ATP yield of aerobic degradation of glucose is ___ ATP and the aerobic ATP yield for glycogen breakdown is ___ ATP.

32, 33

the ______________ enzyme determines the speed of the particular metabolic pathway involved.

rate-limiting

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.

modulators, allosteric

what is the rate-limiting enzyme of the ATP-PC system?

creatine kinase

what is the rate-limiting enzyme of glycolysis?

phosphofructokinase

what is the rate-limiting enzyme of the citric acid cycle?

isocitrate dehydrogenase

what is the rate-limiting enzyme of the electron transport chain?

cytochrome c oxidase

maximal heart rate of moderate intensity exercise: ______

50-75%

maximal heart rate of heavy intensity exercise: ______

76-85%

maximal heart rate of very heavy intensity exercise: ______

86-100%

maximal heart rate of severe intensity exercise: ______

100%

% VO2 max of moderate intensity exercise: ______

less than 60%

% VO2 max of heavy intensity exercise: ______

60-75%

% VO2 max of very heavy intensity exercise: ______

76-100%

% VO2 max of severe intensity exercise: ______

greater than 100%

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

oxygen deficit

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.

EPOC

what are the two portions of EPOC?

rapid and slow portion

what does the rapid portion of EPOC represent?

the steep decline in oxygen uptake following exercise

what does the slow portion of EPOC represent?

the slow decrease in O2 consumption following exercise

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

true

what structures in the body convert lactate to pyruvate to be used?

the heart and skeletal muscle (largely slow twitch fibers)

true or false: as the exercise intensity increases during an incremental exercise test, blood levels of lactate begin to drop in an exponential fashion

false, they rise

a point during a graded exercise test when the blood lactate concentration increases abruptly

lactate threshold

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

e. all of the above

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

respiratory exchange ratio

compared to fat, about 6% ____ energy per liter of oxygen is obtained when carbohydrate is used as the sole fuel for exercise.

more

why does fat oxidation require more O2 than carbohydrate oxidation?

carbohydrates contain more O2 than fat

during prolonged exercise, the total contribution of protein to the fuel supply may reach _____ during the final minutes of work.

5-10%

what is the point at which exercise fuel switches from primarily fat to primarily carbohydrate?

crossover point

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

a and d

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.

fast, glycolytic, carbs

true or false: an increase in blood levels of epinephrine increase phosphorylase activity, which causes an increase in muscle fat breakdown.

false, muscle glucose

what type of enzyme breaks down triglycerides into free fatty acids to be used for prolonged exercise?

lipases

when does fat metabolism typically occur?

after 10-20 minutes of exercise

where is the large majority of fat stored and in what form is it stored?

white adipocytes as triglycerides