Unit 2 Quizes Flashcards
The rate limiting Enyzme in the Krebs cycle is:
Isocirtracte dehydrogenase
The primary purpose of the kerbs cycle is to:
Complete the oxidation of foodstuff using NAD and FAD as electrons carries
What is the primary purpose of the elctron trasport chain?
The pirpary purpose of the elctron transport chin is to harvet energy from electrons moving down this pathway to produce ATP and Water
For every acetyl-CoA molecule that enters the kerbs cycle ___ molecules of NADH and Molecules of FADH are created?
How many per pyruvate?
3 NADH
1 FADH
You have to double it
The Kerbs cycle is also known as the critic acid cycle because __ combiines with __ to produce citrate
oxaloacete; acetyl-CoA
In general, the higher the intensity of exercise, the greater the contribution of:
Anaerobic energy production
The majority of the energy liberated through oxidative metabolism is actually converted to heat. The calculated efficiency for oxidative phosphorylation is approximately:
34%
The total (net) ATP tally from the aerobic breakdown of glucose is:
32 ATP
The electrons passed through the electron transport chain from NADH to oxygen release energy to ultimately form ATP. Each NADH molecule is equivalent to:
2.5 ATP
Aerobic production of ATP occurs in the:
In the mitochondria called oxidative phosphorylation
The bioenergetic pathway that first provides ATP for skeletal muscle at the onset of exercise is:
(which system?)
The ATP-PC system
The term oxygen deficit refers to the:
Lag in oxygen consumption at the beginning of exercise
The lactate threshold is defined as the work rate or oxygen uptake at which there is an exponential:
Rise in blood levels of lactate.
During the “rapid” portion of the excess post-exercise oxygen consumption (EPOC), the excess VO2 is primarily due to:
Restoration of muscle PC and replacement of blood and muscle oxygen stores
In general, very heavy exercise lasting 60 seconds utilizes energy production that is:
70% anaerobic / 30% aerobic
(intense exercise = mostly anaerobic)
At rest, the VO2 consumption of a 70-kg young adult is approximately:
3.5 ml/kg/min.
0.25 L/min.
250 ml/min.
all correct
The exercise intensity that promotes the highest amount of total fat oxidation during exercise is approximately:
1) 30% of VO2 max.
2) 60% of VO2 max.
3) 75% of VO2 max.
4) 90% of VO2 max.
60% of VO2 max.
(Because it’s close to the lactate threshold)
A respiratory exchange ratio (R) of 0.95 during steady-state exercise is suggestive of a(n):
High rate of carbohydrate metabolism
(Closer to 0.7= fats. closer to 0.1 = Carbs)
0.95= closer to carbs
In a healthy individual consuming a nutritionally-balanced diet, most of the carbohydrate used as a substrate during very heavy exercise comes from:
1) muscle glycogen stores.
2) blood glucose.
3) liver glycogen stores.
4) glycogen stored in fat cells.
Muscle glycogen—
because you are using the muscle and that is where it is immediately available
The slow rise in oxygen consumption over time during prolonged exercise (at a constant sub-maximal load) in a hot environment is due, in part, to:
(Never see a steady state)
rising blood levels of epinephrine and norepinephrine.
Oxygen never plato’s, only climbs called: VO2 Drift
As exercise intensity increases, there is a progressive increase in the reliance of carbohydrate metabolism in the exercising skeletal muscles. This observation is described as the:
crossover concept.
The primary fuel source during high-intensity (85% VO2 max) exercise is:
muscle glycogen.
blood glucose.
muscle triglycerides.
plasma FFA.
muscle glycogen—
Higher intensity= pull from glycogen.
Doesn’t have time to grab it from anything else but the muscle
Which of the following is true concerning VO2 max?
It occurs at a lower intensity of exercise than the lactate threshold.
It is the maximal volume of oxygen that can be moved into the lungs in one minute.
It is a valid measure of cardiovascular fitness.
It is the highest VO2 achieved during prolonged steady-state exercise.
It is a valid measure of cardiovascular fitness.
Which of the following exercise intensities would rely primarily on carbohydrate as a fuel source?
carbs, higher intensity, closer to 1.0
90% of VO2 max.
Which physiological factors are potential mechanisms to explain the lactate threshold?
accelerated rate of glycolysis due to epinephrine
recruitment of fast-twitch muscle fibers
(makes more lactate)
reduced rate of lactate removal from the blood
(body can’t clear lactate fast enough)
Energy to run a maximal effort 400-meter race (i.e., duration 50 to 60 seconds) comes from:
a combination of aerobic/anaerobic metabolism, with most of the ATP coming from anaerobic sources.
The energy to perform long-term, submaximal exercise (i.e., >30 minutes) comes primarily from:
aerobic metabolism.
Energy to run a 40-yard dash comes:
(sprint)
almost exclusively from the ATP-PC system.
The excess post-exercise oxygen consumption (EPOC) is generally higher following intensive exercise when compared with moderate exercise because intensive exercise:
results in greater body heat gained,
greater PC depleted, higher blood levels of epinephrine and norepinephrine,
and higher blood lactate levels.
Which of the following statements is true about muscle ATP production during exercise?
During severe, short-duration exercise (e.g., 10 seconds), muscle ATP production is dominated by the ATP-PC system.
Severe exercise lasting 20-30 seconds relies primarily on aerobic (“slow”) glycolysis to produce the needed ATP for muscular contraction.
Very heavy exercise lasting 45-60 seconds uses a relatively equal combination of the ATP-PC system and protein catabolism to produce the needed ATP for exercise.
All of these statements are true.
During severe, short-duration exercise (e.g., 10 seconds), muscle ATP production is dominated by the ATP-PC system.
The measurement of VO2 max is commonly performed during a graded exercise test on a treadmill. However, some subjects will voluntarily terminate an incremental exercise test without reaching VO2 max. The primary (gold standard) criteria to determine if a subject reached their *“true” VO2 *max during an exercise test is:
a plateau in oxygen uptake with an increase in work rate.
During steady-state exercise, an R of 0.73 would indicate:
a relatively high level of fat metabolism.
When using the R to estimate fuel usage during exercise, the role that protein plays as a fuel source is often ignored. Why?
because protein generally plays a relatively small role as a fuel source during exercise
(Last resort)
Carbohydrate used as a fuel source during exercise comes from both blood glucose and muscle glycogen. The relative contribution of these two sources of carbohydrate varies as a function of:
Both “exercise intensity” and “exercise duration” are correct.
The process of breaking down triglycerides into free fatty acids and glycerol is called:
lipolysis.
(Lipase is the enzyme)
