Glucose Metabolism Flashcards
What is catabolism and anabolism?
catabolism is the process of complex molecules like carbohydrates, fats, and proteins being degraded into simpler molecules, releasing ATP in the process. anabolism is the opposite process of creating more complex molecules from precursor molecules, which requires energy.
How are catabolism and anabolism regulated?
by each other - they are constantly in flux and if a complex molecule is being made it is not also being degraded.
Which organ primarily regulates blood glucose level?
liver
Which organs use glucose to generate energy (ATP)
brain and muscles
How are disaccharides broken down into single glucose units?
alpha-amylase performs hydrolysis on glycosidic bonds
What is fiber made up of and why is it not digestible? Who breaks these down?
cellulose, which is not digestible because we don’t have the enzymes needed to break down the beta-1,4 bond. Gut bacteria can hydrolyze these fibers, causing gas/bloating.
What is the basis of lactose intolerance?
Lactase enzyme is not available to breakdown lactose into galactose and glucose in the small intestine, so it goes into the large intestine as an unbroken disaccharide, where it is fermented by gut bacteria causing bloating, diarrhea, and dehydration.
How is glucose taken up by the cells of the intestine? How is this maintained?
Glucose is coupled with energetically favorable movement of sodium into the epithelial cells. The sodium gradient is maintained by a Na/K ATPase - pumps K in and Na out using ATP (active transport).
What are the possible fates of glucose-6-phosphate? how does it choose?
Glycogen - for storage if cell has excess glucose/energy
Glycolysis - for ATP synthesis if the cell does not have enough energy
Pentose-phosphate cycle - if needing to breakdown into NADP+ for biosynthesis (making complex molecules) or ribose for nucleic acid metabolism (DNA/RNA)
When is the Krebs/TCA cycle used to create more ATP?
When oxygen is available.
Which tissue rely on TCA?
skeletal muscle, heart, and brain.
Where does TCA take place?
In the mitochondria.
What is the importance of vitamin B1 in the TCA?
required for TPP, which is a cofactor for the enzymes responsible for the TCA.
What regulates the glycolysis and TCA in non-muscle cells?
energy level of the cell:
high energy cell = high levels of products - ATP and NADH, inhibits TCA
low energy cell = high levels of substrates ADP and AMP, activates TCA cycle.
What molecule activates skeletal muscle TCA?
Ca2+
