Bioenergetics and Regulation of Metabolism Flashcards
Liver:
The most metabolically diverse tissue. Hepatocytes are
responsible for the maintenance of blood glucose levels
by glycogenolysis and gluconeogenesis in response to
pancreatic hormone stimulation. The liver also processes
lipids and cholesterol, bile, urea, and toxins.
Adipose Tissue
Stores lipids under the influence of insulin and releases
them under the influence of epinephrine
Skeletal Muscle : also what is
Resting Muscle and Active Muscle
Skeletal muscle metabolism will differ depending on
current activity level and fiber type.
Resting muscle: Conserves carbohydrates in glycogen
stores and uses free fatty acids from the bloodstream.
Active muscle: May use anaerobic metabolism, oxidative
phosphorylation of glucose, direct phosphorylation from
creatine phosphate, or fatty acid oxidation, depending on
fiber type and exercise duration.
Cardiac Muscle:
Uses fatty acid oxidation in both the well-fed and fasting states.
Brain and
Nervous Tissue:
Consume only glucose in all metabolic states, except for
prolonged fasts, where up to 2/3 of the brain’s fuel may
come from ketone bodies.
Calorimetry:
Measures metabolic rates
Respiratory Quotient:
RQ. Estimates the composition of fuel that is actively consumed by the body. RQ = Co2 produced / O2 consumed
Regulatory Hormones:
function of Ghrelin
increase appetite. (sight, sound, taste, smell of food)
Regulatory Hormones:
function Orexin
increase appetite
Regulatory Hormones:
function Letin
decrease appetite by suppressing orexin production
Body Mass Index
BMI = mass/ Height^2
Equilibrium:
Equilibrium is an undesirable state for most biochemical reactions because organisms need to harness free energy to survive
Postprandial State:
Well-fed, absorptive. Increase Insulin. Anabolism prevails.
Postabsorptive State
Fasting decrease .Insulin. increase glucagon and catecholamine. Transition to catabolism
Prolonged Fasting:
Starvation increases glucagon and catecholamine. Most tissues rely on fatty acids. 2/3 of brain activity can be derived from ketone bodies.
High Energy
May be soluble or membrane-bound. Includes NADH
Electron Carriers
NADPH, FADH2, ubiquinone, cytochromes, and glutathione.
Flavoproteins
A subclass of electron carriers that are derived from riboflavin (vitamin B2). Examples: FAD and FMN
what is the role of ATP
ATP is a mid-level energy molecule. It contains high-energy phosphate bonds that are stabilized upon hydrolysis by resonance, ionization, and loss of charge repulsion
Energy Source:
ATP provides energy through hydrolysis and coupling to energetically unfavorable reactions. ATP = 30 kl/mol
Phosphoryl
ATP can donate a phosphate group to other molecules.
Group Transfers:
For example, in Glycolysis, it donates a Phosphate group to glucose to form glucose 6-phosphate
Open System:
Matter & energy can be exchanged with the environment
Closed System:
Only energy can be exchanged with the environment. No work is performed because pressure and volume remain constant. ∆enthalpy = ∆internal energy = heat exchange
Entropy
A measure of energy dispersion in a system
Change in Free Energy:
define Standard Free Energy
Standard Free Energy, DeltaG°: The energy change that occurs at 1 M concentration, 1 atm, and 25°C.
Change in free Energy define Modified Standard State
Modified Standard State, DeltaG°’: Indicates physiological conditions. [H=] = 10^-7, so pH is 7.
Define Insulin:
Secreted by pancreatic b-cells, regulated by glucose decrease¯blood glucose by increasing cellular uptake increase rate of anabolic metabolism
Glucagon:
Secreted by pancreatic a-cells, stimulated by low glucose and high amino acid levels increses blood glucose by promoting gluconeogenesis and glycogenolysis in the liver
Glucocorticoids:
Increase blood glucose in response to stress by mobilizing fat stores and inhibiting glucose uptake. They increase the impact of glucagon and catecholamines. Ex: cortisol
Catecholamines:
Promote glycogenolysis and increase basal metabolic rate through sympathetic nervous system activity. “Adrenaline rush”. Ex: epinephrine and norepinephrine
Thyroid Hormones
Increase basal metabolic rate, as evidenced by Increase O2 consumption and heat production when they are secreted. T3 is more potent than T4, but has a shorter half-life and is available in lower concentrations in the blood. T4 is converted to T3 at the tissues. Thyroid hormones are tyrosine-based
Liver definition
The most metabolically diverse tissue. Hepatocytes are responsible for the maintenance of blood glucose levels by glycogenolysis and gluconeogenesis in response to pancreatic hormone stimulation. The liver also processes lipids and cholesterol, bile, urea, and toxins
Adipose Tissue:
Stores lipids under the influence of insulin and releases them under the influence of epinephrine
Skeletal Muscle
define
Resting Muscle
Conserves carbohydrates in glycogen stores and uses free fatty acids from the bloodstream
Skeletal Muscle
define Active muscle
May use anaerobic metabolism, oxidative phosphorylation of glucose, direct phosphorylation from creatine phosphate, or fatty acid oxidation, depending on fiber type and exercise duration.
cardiac Muscle:
Uses fatty acid oxidation in both the well-fed and fasting states.
