BIOCHEM Chp.12 Bioenergetics & Metabolism Regulation Flashcards
What is the diff b/w an open and closed biological system?
open - wherein matter and energy can be exchanged with the environment
closed - wherein only energy can be exchanged with the environment
What is enthalpy?
heat exchange
Why is work not done on a closed biological system?
because pressure and volume remain constant
What is entropy?
a measure of energy dispersion in a system
What are the conversions of 37 degrees Celsius to Freinheit and kelvins?
37 C = 98.6 F = 310 K
What is flavoprotein?
FAD is a subclass of electron carriers derived from riboflavin/vit. B2
What is released after eating in the postprandial/well-fed/absorptive state?
insulin, a hormone that is responsible for decreasing the concentration of glucose
What happens in the well-fed state?
insulin levels are increased. the skeletal muscles use glucose for gluconeogenesis and protein synthesis, the adipose tissues use glucose for triacylglycerol synthesis, and the liver releases Glycogen synthase so excess glucose can be converted to FA and triacylglycerols
What happens in the postabsorptive/fasting state?
insulin decreases and Epinephrine increases stimulate the release of AA from the skeletal muscle and fatty acids from the adipose tissue
the liver promotes glycogenolysis to convert glucagon into glucose.
When glucose reserves are used up, the muscle and brain begin to convert glucose to FA as their major energy source
What happens in a prolonged fasting/starvation state?
in the skeletal muscles, AA is released and carried into the liver for gluconeogenesis
in the adipose tissues, FA is broken down (lipolysis) to Acetyl-CoA, which can be used in the synthesis of ketone bodies that are released and carried into the liver for gluconeogenesis
in the liver, glycogenolysis occurs to break down glycogen into glucose
How are the negative feedback loops used for hormone regulation?
The hypothalamus releases Corticotropin Releasing Hormone. CRH induces the pituitary gland to secrete adrenocorticotropic hormones (ATCH) which stimulate the adrenal cortex to release glucocorticoids. Glucocorticoids are steroid hormones that can interact with the pituitary gland and the hypothalamus to inhibit their synthesis
What are the counterhormones of insulin?
Glucagon, cortisol, epinephrine, norepinephrine, and growth hormone
How does insulin facilitate glucose uptake?
Extracellular insulin is taken up by glucose transmembrane transporters (GLUT1/2) on the target cells, initiating a signal transduction pathway that opens the glucose transporters to get glucose inside the cell, crossing the plasma membrane, where it can be stored as glycogen via gluconeogenesis, cleave into pyruvate via glycolysis, or be used to fund FA synthesis in beta-oxidation
What is the diff b/w insulin and glucagon secretion?
insulin is a peptide hormone secreted by the beta-celLS and glucagon is secreted by the alpha-cells of the Pancreatic islet of Langerhans
What is the diff b/w diabetes type I and II?
Diabetes Typ1 I - insulin is not produced in the pancreatic cells, and as a result, glucose cannot be taken up at its target cells
Diabetes Type 2 - is caused by a malfunction of insulin receptors, and as a result, glucose cannot be taken up by its target cells
