Metabolic Pathways Flashcards
What are the four major components of the respiratory system and how they are affected by nutritional status?
Digestive phase
Catabolism down to Acetyl-CoA
TCA cycle
Oxidative phosphorylation
What is catabolism?
A complex, slow, stepwise process with liberates small, usable amounts of energy.
What is anabolism?
Formation of proteins, fats and complex carbohydrates from energy-rich phosphate compounds.
What is Calorie (Kcal):?
Standard unit of heat energy is the calorie defined as the amount of heat energy necessary to raise the temperature of 1g of water 1 degree, from 15 to 16C. This unit is also called the gram calorie, small calorie, or standard calorie. Equals 1000 cals.
What is ATP?
АТР: the currency of energy: produced by oxidative phosphorylation “respiratory chain”
What is the number of Calories “burned” per liter of oxygen for carbohydrate, fat or protein?
CHO: 4.1 kcal/g
Fat: 9.3 kcal/g
Protein: 5.3 kcal/g (net 4.1 kcal/g)
What is/are NAD+, NADH + H*, FAD, and FADH,?
- Energy intermediates
- Acetyl CoA leads the molecular procession into the TCA cycle where the major amount of energy is transferred to these energy intermediates or energy shuttles.
Where does 2,3-DPG come from?
Glucose can be transferred, if sufficient ATP exists, into other molecules one of which is 2, 3-diphosphoglycerate (2,3-DPG).
Where is lactic acid generally metabolized?
Lactic acid produced in muscle cells is transported through the bloodstream to the liver, where it’s converted back to pyruvate and processed normally in the remaining reactions of cellular respiration.
What is aerobic and anaerobic metabolism?
Aerobic: Oxidative phosphorylation. Without O2, only highly limited anaerobic metabolism may occur.
Anaerobic: Occurs when the metabolic demand exceeds O2 delivery or tissue extraction capability. *Without sufficient O2, NADH+H → NAD+ →→→Pyruvate
*For each pyruvate, net gain of 2 ATPs
*The more lactate build up, the greater the O2 debt
*VE must be increased
What is the interrelationship between fat, protein and carbohydrate in terms of metabolism?
-Acetyl CoA
-In carbohydrate metabolism, during glycolysis, one molecule of hexose is broken down into two molecules of pyruvic acid.
-belong to the class of macronutrients
-all composed of carbon and hydrogen.
What is RQ and R and give the RQ for fat, protein or carbohydrate?
-The ratio of the volume of CO2 produced to the volume of O2 consumed per unit of time.
-RQ is a number used in calculations of basal metabolic rate when estimated from carbon dioxide production. It is calculated from the ratio of carbon dioxide produced by the body to oxygen consumed by the body.
Respiratory quotient and the RER are both calculated as the ratio of the volume of carbon dioxide (CO2) produced to the volume of oxygen (O2) used, orVCO2/VO2.
‘RQ = Vol CO2 released/Vol O2 absorbed'
RQ = respiratory quotient; AKA, R = respiratory exchange ratio
*RQ of carbohydrate = 1.0
*RQ of fat = 0.70
*RQ of protein = average of 0.82
*RQ = 0.8 considering a nutritional mixture of CHO and fats.
What is the significance of mitochondria?
-The “power house” of the cell; the organelle where all aerobic metabolism occurs
-The final destination of O2 that we breathe in
-In the respiratory chain, there is an electrical gradient
-The terminal cytochrome has a high affinity for O2 resulting in a transfer of electrons to O2
→ oxygen atom with -2 charge → attracts 2H+ = H2O
How is ATP produced?
process of cellular respiration in the mitochondria of a cell. can be through aerobic respiration, which requires oxygen, or anaerobic respiration, which does not.
3 ways ATP is generated:
the main energy source for cellular metabolism is glucose, which is catabolized in the three subsequent processes—glycolysis, tricarboxylic acid cycle (TCA or Krebs cycle), and finally oxidative phosphorylation—to produce ATP
How is oxygen utilized by the cell and what happens to it?
→ oxygen atom with -2 charge → attracts 2H+ = H2O
Oxygen’s primary function is to provide our body with energy. It all happens within the cells, in little organelles called mitochondria which are real energy generators: they use oxygento transform nutriments from the digestive process into energy that can be used directly by the cell (ATP).
