MBOD block 4 Flashcards
What is metabolism?
The sum of all of the chemical reactions that can occur in a living organism.
What is the function of metabolism?
To supply all of the needs of every cell.
What are examples of anabolic pathways?
Biosynthetic pathways; Detoxification and waste disposal pathways.
What are examples of catabolic pathways?
Fuel storage pathways; Fuel oxidative pathways
What are some of the products of anabolic pathways?
Uric Acid, Urea, waste products
What are some of the products of catabolic pathways?
Energy, CO2, H20, ATP
What are some dietary fuels?
Carbohydrate, Fat, Protein
What are the categories of Metabolic pathways?
Anabolic (biosynthetic); Catabolic (degradative); ATP-synthesizing pathways.
What occurs in ATP-synthesizing pathways?
Energy released by oxidative catabolic reactions is used to synthesize ATP and other high energy compounds
What things occur during the transformation of ATP to ADP in the ATP-ADP cycle?
Motion, Active transport, biosyntheses, signal amplification
What things occur during the transformation of ADP to ATP in the ATP-ADP cycle?
Oxidation of fuel molecules, breakdown of sugars, photosynthesis
The breakdown of ATP to AMP produces what products?
Pyrophosphate -> 2Pi
What are carbohydrates, fats, and proteins oxidized to?
CO2, H2O, energy, (urea-proteins)
Which compound has the highest standard free energy?
Phosphate Enol pyruvate
What is an example of enol phosphate bond?
Phosphoenolpyruvate
What is an example of an anhydride bonded to carbon?
1,3-bisphosphoglycerate
What is creatine phosphate?
An activated carrier that stores energy in muscle.
What is an example of an anhydride bonded to phosphate?
ATP
Which compound has a phosphoester bond?
Glucose 6-phosphate
What are some of the uses of ATP?
Protein synthesis, Na/K ATPase, Ca ATPase, Gluconeogenesis, Urea synthesis, Myosin ATPase, RNA synthesis, substrate cycling.
What is a metabolic pathway?
A series of reactions leading from the transformation of one metabolite to another.
What is an enzyme catalyzed reaction?
The product of one enzyme becomes the substrate for the next enzyme.
T/F All pathways are linked and regulated.
TRUE
T/F Pathways are irreversible.
TRUE
How many irreversible steps are there in every pathway?
At least one
What is the slowest step in a pathway?
The rate limiting step
What is the committed step?
The first irreversible step unique to a pathway.
What are the tupes of metabolic pathways?
Linear, branched, cyclic, cascade/amplification
What are the characteristics of a linear pathway?
One substrate, one product
What is the characteristic of a branched pathway?
Multiple products
What are the characteristics of a cyclic pathway?
Pathway starts and ends with the same compound; molecules enter and leave the cycle.
What are some examples of a cascade or amplification pathway?
Signal transduction, blood clotting
How do you control the pathways?
By regulating the activity of enzymes or the amount of an enzyme.
What are types of regulation or control of enzymes and metabolic pathways?
Allosteric control; feedback inhibition; reversible covalent modification
What is required for metabolic pathways?
Cofactors (NADH, FADH2, THF, Vit.D,C,K,A
T/F Each tissue has its own unique metabolism.
TRUE
What is glucose 6-phosphate a precursor to?
Nucleotides
What is fructose 6-phosphate a precursor to?
Amino sugars, glycolipids, glycoproteins
What is dihydroxyacetone phosphate a precursor to?
Lipids
What is 3-phosphoglycerate a precursor to?
Serine
What is pyruvate a precursor to?
Alanine
What is citrate a precursor to?
Cholesterol, fatty acids
What is oxaloacetate a precursor to?
Aspartate, amino acids, purines, pyrimidines
What is a-ketoglutarate a precursor to?
Glutamate, amino acides, purines
What is succinyl CoA a precursor to?
Heme chlorophyll
What is the first stage of Metabolism?
Breakdown of macromolecules to monomers.
What is the 2nd stage of Metabolism?
Breakdown of simple subunits to Acetyl CoA accompanied by production of limited amounts of ATP and NADH
What is the 3rd stage of Metabolism?
Complete oxidation of Acetyl CoA to H2O and CO2 accompanied by production of large amounts of ATP in the mitochondrion
What are the functions of carbohydrates?
Nutritional roles; source of energy; energy storage; vitamins; non-nutritive dietary role; structural component; molecular recognition
What is the major dietary carbohydrate?
Starch; followed by disaccharides
What is the source of energy that can be used by all tissues?
Glucose
What do mammals stroe glucose as?
Glycogen
Which vitamin is a carbohydrate?
Vitamin C
What is a nondigestible carbohydrate and what is its role?
Fiber; important in normal digestion
What are carbohydrates a structural component of?
cofactors; DNA/RNA; glysoproteins; glycolipids; proteoglycans; bacterial cell wall; cellulose
How are carbohydrates involved in molecular recognition?
Receptors; adhesion molecules; cell surface markers; soluble and membrane glycoproteins; glycolipids
What is the blood glucose concentration a balance of?
Pathways that use blood glucose and those that add glucose back to the blood.
Which hormones play a major role in controlling blood glucose conc.?
Insulin and glucagon
What is the normal blood glucose concentration?
100mg/dL
What happens to the insulin/glucagon ratio after a high carbohydrate meal?
The ratio increases.
What does the balance of metaboiic homeostasis depend on?
Fuel availability and Tissue needs
What are the 3 signals used to maintain metabolic homeostasis?
Blood level of nutrient; hormone level; nerve impulse
What are the pathways and reactions that increase blood glucose?
Digestion of dietary carbs; conversion of other dietary sugars to glc; glycogenolysis; gluconeogenesis
What are the pathways that use blood glucose?
Glucose transporters and phosphorylation; glycolysis; glycogenesis; phosphogluconate pathway; sorbitol pathway (aldose reductase).
What is the key glucoregulatory hormone?
Insulin
What is insulin?
An anabolic hormone; synthesized by the pancreatic beta-cells of the Islets of Langerhans as a single chain- pre-proinsulin ->proinsulin -> insulin and C-peptide
What does insulin do?
Stimulates glucose storage and uptake my muscle and adipose tissue; increases hepatic glycogenesis and lipogenesis.
What are the counter-regulatory hormones?
Glucagon; epinephrine; cortisol; growth horm.
What does glucagon do?
Increases blood glucose by stimulating glycogenolysis and gluconeogenesis.
Where is glucagon synthesized?
By the alpha cells of the pancreas.