Week 1 Flashcards
What is the difference between your basal metabolic rate and your MET?
MET: is the objective measure of the ratio at which a person expends energy expressed as unit of volume per mass per min. When sitting quietly the convention for MET is 3.5 mL x kg X min.
Basal Metabolic Rate: is the rate of energy expenditure per unit of time at rest.
Name and describe the different methods of cell signaling.
o Intracrine: when a chemical messenger is produced inside a cell that triggers a pathway within the cell leading to a specific response.
o Juxtacrine: communication between cells that share junctions to their cytoplasm’s
o Autocrine: a cell produces a chemical messenger that is released into the ECF and then acts upon the cell from where it was released.
o Paracrine: a cell produces a signal that acts on a set of local cells to produce a coordinated response, such is the case with some hormones
o Endocrine: chemicals released into the bloodstream which are carried throughout the body to a distant target.
How do enzymes specifically aid in the conversion of ATP to ADP?
Generally, enzymes are proteins which have specific binding sites for their preferred substrates. In the case of ATP, the respective enzyme is ATPase which catalyzes the reaction of ATP to ADP and Pi which releases energy used to do work. ATP binds to ATPase’s binding site to form an enzyme-substrate complex which produces the intended products, leaving the enzyme unaltered.
Name and describe the different classifications of enzymes.
Kinases: enzymes that catalyze the transfer of a phosphate group to a specific substrate.
Dehydrogenases: an enzyme that belongs to a group of oxidoreductases that oxidizes (removes electrons) by reducing an electron acceptor.
Oxidases: enzymes that promote the transfer of hydrogen to an oxygen molecule to form water.
Isomerases: an enzyme that catalyzes the conversion of a specified compound to an isomer
How do elevated levels of lactate dehydrogenase and creatine kinase in the blood indicate a myocardial infarction?
A myocardial infarction would likely result in myocardial necrosis. During this process myocardial cells release the enzymes lactate dehydrogenase and creatine kinases into the blood stream which allows for doctors to conclude on their diagnosis.
What are the three ATP synthesis pathways and how do they differ in their ATP yields?
o ATP-PCr System (anaerobic metabolism): yields one mol of ATP per one mol of phosphocreatine. This pathway is used for action lasting 3 to 15 seconds. In this system PCr releases a free inorganic phosphate which is then used to synthesize ATP from an existing ADP molecule. Creatine kinase catalyzes this reaction and is modulated by concentrations of ATP, like any organic equilibrium equation.
o Glycolytic System (anaerobic metabolism): yields 2 to 3 mol ATP per one mol of substrate. This pathway is used for exercise lasting from 15 seconds to 2 minutes. In this system glucose or glycogen is used as a substrate to produce ATP, specifically glucose-6-phosphate. After about 10 to 12 enzymatic reactions 2 ATP are produced for glucose and 3 for the metabolism of glycogen and pyruvate which is converted into lactic acid. This is a precursor to oxidative glycolysis which is an aerobic pathway.
o Oxidative phosphorylation System (aerobic): yields 32 to 33 mol of ATP per glucose molecule and 100+ ATP/ 1 mol of FFA. This process occurs in the mitochondria compared to the cytoplasm for the previous two. (1) glycolysis occurs such as the previous pathway then pyruvate enters the krebs cycle in the presence of oxygen as acetyl-CoA. The krebs cycle produces some ATP along with proton carriers such as NADH and FADH. These carriers move across mitochondrial membranes to create an electrical gradient along the membrane which powers the formation of ATP.
Is indirect calorimetry the same as a respiratory quotient?
RQ: is the ratio of CO2 being produced by the body over the amount of O2 being consumed.
Indirect Calorimetry: measures total body energy expenditure based on the amount of O2 used and the amount of CO2 produced.
In a way they are the same thing.
What is VO2 and VO2max?
VO2 is the amount of oxygen being consumed per unit of time. VO2max is the maximum capacity that a person can use oxygen per minute. In other words, VO2 max is the value of oxygen consumption where there is no increase with increased intensity, this is affected by genetics and training since it is the physiological ceiling for delivery of O2 to muscle tissue. It is the best way to measure aerobic fitness.
Describe the oxygen deficit experienced pre- exercise and the excess postexercise O2 consumption (EPOC).
During the start of exercise there is a lag between the quantity of O2 being consumed and the amount that the body requires, this explains the increases in rate of ventilation and heart rate. The body cannot immediately. Supply oxygen as the body is demanding; this is oxygen deficit. As exercise ends the body uses more O2 than the muscles need, and this is the definition of EPOC. Eventually the body returns to resting state oxygen consumption.
Where does the body prefer CHO fuel from during high intensity and during low intensity exercise?
During high intensity exercise muscle glycogen is the preferred source of CHO fuel. During low intensity exercise the body prefers blood glucose released from the liver through glycogenolysis.
Generally, during high intensity exercised muscles will use what is most bioavailable.
What is the Cori Cycle?
The Cori Cycle demonstrates the conversion of lactate into a usable fuel source primarily. The muscle produces lactate which is transported to the liver to become pyruvate and then glucose which is released back into the blood stream to be used by skeletal muscle.
