Exam #2: Metabolism Flashcards
The term metabolism is best defined as:
the sum of energy produced by all the chemical reactions the mechanical work of the body
The food sources from which we derive energy are composed mainly of:
carbon, hydrogen, nitrogen, and oxygen
Carbohydrates are stored in the body as
glycogen
Lipid storage is at least 50 times as much (in kcal of energy) as glycogen storage in the body even in a lean adult
true
The Tricarboxylic cycle, the citric acid cycle, the Kreb’s cycle are three differing metabolic functions important for producing energy from foodstuffs
False
Sucrose —> Glucose + Fructose
The sucrase above is called a(n) _______, and the activity shown in the figure is called _________.
enzyme
hydrolysis
Which compound is necessary to transport fatty acids (as acetyl CoA) into the mitochondrial matric, making the use of fatty acids possible as cellular energy sources?
carnitine
The electron transport chain resulting from the oxidative system results in _____ ATP from one mole of glycogen, and the resultant total ATP from a mole of glycogen from glycolysis + Kerb’s cycle + the ETC is _____ ATP
34;39
Within the mitochondrion, theATP formed along the electron transport chain a created by the process called oxidative phosphorylation
True
Which of the following statements is most obviously true regarding the relative roles of fat, carbohydrate, and protein as energy sources for cellular metabolism?
Fat cannot provide all of the energy required for high-intensity muscular activity because the rate of energy release from fat is too slow
During maximal, very short-duration exercise, ATP is generated almost exclusively from:
ADP and CrP
Fat provides more kilocalories per gram than carbohydrate, but oxidation requirements for fat are greater than oxidation requirements for carbohydrate, making fats less efficient as an energy source per unit of oxygen
True
Phosphocreatine is a high-energy phosphate compound that is used in the cell
to resynthesize ATP
Before fat can metabolized by the muscle cells, it must be first be broken down into
free fatty acids and glycerol
The synthesis of glycogen from glucose is called:
glycogenesis
Each human enzyme has an optimal _____ and ______ for it to work most efficiently
temperature and pH
Most of the energy for a 2-hour bout of exercise is provided by
the oxidative system
Which of the following statements is NOT an accurate description of anaerobic glycolysis
It takes place in the mitochondria of the cell
For each liter of oxygen consumed by the body, which substrate provides the greatest number of kcal of energy?
carbohydrate
The major metabolic waster product that causes the muscles and blood to have a lower pH during exercise of increasing intensity is:
hydrogen ions
Glycolysis takes place in:
the muscle cell cytoplasm
Which of the following measurements is necessary when assessing the rate of protein metabolism in the body?
urine nitrogen excretion
An important enzyme is involved in one of the simplest and earliest form of the energy systems, called:
creatine kinase
NAD and FAD are
coenzymes that transfer hydrogen to the electron transport chain
The process of which triglycerides are broken down into glycerol and free fatty acids is called:
lipolysis
The process of converting liver or muscle glycogen into glucose-1-phosphate is referred to as glycogenesis
False
Beta oxidation is the name for
the process by which free fatty acids are broken down to yield multiple molecules of acetyl CoA
The two enzymes most commonly measured in order to assess the oxidative capacity of muscle tissues are:
succinate dehydrogenase and citrate synthase
Fast-twitch muscle fibers are best suited for glycolytic energy production
True
During near-maximal exercise, significant amounts of lactic acid are generated by the ATP-PCr energy system
False
The respiratory exchange ratio (RER) is defined as the ratio between the:
amount of CO2 released to the amount of O2 consumed during metabolism
The catabolism of lipids for energy during metabolism will result in a RER of:
> 1.0
An aerobically trained athlete will have a higher RER during exercise of low to medium intensity than a lesser trained, untrained, or an anaerobically trained athlete
False
Accumulation of lactate in the blood is determined by the balance between lactate production and lactate clearance
True
Which organ would suffer the most if blood glucose levels during exercise were to drop drastically?
brain
Which of NOT true of beta oxidation?
It involves the anabolism of fats
Why is beta oxidation called “beta”?
Because oxidation of the fatty acyl chain is on the beta carbon and the chain is broken at each beta carbon atom
Protein is not used at all for energy production
False
Fatty acids are soluble in blood
False
In order to increase lipid metabolism during exercise, aerobic training causes:
improved transport of FFAs through the sarcolemma
Free Fatty Acids with a 18-carbon chain entering beta oxidation will yield:
9 molecules of acetic acid for Kreb’s cycle
Increased carnitine and carnitine acyl tranferase increases the speed of carbohydrate transport in sacroplasm.
False
The Cori cycle
recycles lactate via the blood back through the liver to reform glucose
After exercise, metabolism returns to resting state
within hours after the end of exercise
Metabolic regulation during rest and exercise is controlled by two systems
neural and endocrine
At the beginning of exercise, endogenous local ATP loses a phosphate to produce ADP. The ADP stimulates
enhanced secretions of catecholamines
blood flow shifts
gluconeogenesis
increased enzyme activation
Lipids released by lipolysis into the blood stream during exercise are carried by:
albumin
The first form of ATP buffering during activity is:
ADP+ADP=ATP+AMP
Creatine kinase is needed to resynthesize ATP from ADP by phosphorylation, and is boundto the M line proteins on myosin filaments
True
Which two hormones stimulate the enzymes necessary for gluconeogenesis
epinephrine and glucagon
Exercise stimulates a glucose transporter to get glucose into the sarcoplasm called:
GLUT4
As exercise commences, the release of ____ triggers acceleration of pyruvate oxidation
Ca++
Overproduction of ____ in intensely contracting muscles is the largest factor stimulating the shutdown of the Krebs cycle
NADH
Extremely high levels of lactate in the blood during exercise indicates:
extreme anaerobic exercise
increasing lactate levels beyond threshold
that the athlete is “in great anaerobic shape”
Anaerobic threshold is defined as:
when blood lactate levels rise noticeable above resting levels
Pyruvate’s dilemma is:
the fact that pyruvate can follow either an aerobic or anaerobic metabolic rate
Prolonged exercise causes greater need for lipid energy, which can result in increased
ketone bodies
Hard aerobic training does NOT result in increase of ___ in resting muscle
muscle fibers
The end product(s) of Beta oxidation that are funneled into the Kreb’s cycle and ETC is (are):
acetyl CoA, FADH, and NADH
During exercise, gluconeogenesis in the liver oxaloacetate since dependence of fats (i.e. lack of carbohydrate) and depleted oxaloacetate causes the results of fat metabolism to produce ketone bodies
True
“Alactic” ATP Production
Production of ATP through anaerobic pathways WITHOUT the lactate as the product
“Lactic” ATP Production
Production of ATP through anaerobic pathways WITH the lactate as the product
Glycotic ATP Production
Production of ATP through glycolysis.
Oxidative ATP Production
Produces ATP through Kreb’s cycle and Electron Transport Chain.
Explain why is the function of Cori Cycle so important during exercise?
- Lactate is recycled via blood to the liver to supply additional energy to the muscle
- It also gets rid of waste products
Explain the implications of the illustrated part of the figure concerning #3 (phosphofructokinase)
Exercise increases glycolytic enzymes as ATP and CP levels decrease and AMP levels increase causing stimulation of phosphofructokinase
Explain the implications of the illustrated part of the figure concerning #10 (pyruvate kinase)
Exercise increases glycolytic enzymes as ATP and CP levels decrease and ADP levels increase causing stimulation of Pyruvate kinase
