Flashcards in 16. Energy Balance and metabolism Deck (43):
how many calories per mole are released in the body by ATP-->ADP + Pi reaction?
-12,000 cal/mol released
Are glucose, galactose, fructose all interconvertable?
yes, all hexoses are
How is glucose transported into tissue cells?
active sodium-glucose co-transport
What does insulin do to glucose absorption?
increases absorption by 10x
Where can glucose phosphorylation be reversed, so glucose can leave the cells?
liver, intestinal cells, renal system
What are teh roles of glucokinase, phosphorylase, and phosphatase in the glycolysis pathway?
1. glucokinase: phosphorylates glucose to prevent leaving cells
2. phosphorylase: converts glycogen to usable form
3. phosphatase: removes P only present in renal, intestinal, and liver cells
What factors activate phosphorylase?
What are the end products of glycolysis?
1. pyruvic acid 2 molecules
2. 4 hydrogen ions
3. 2 ATP molecules (net)
What are the final products of converting pyruvic acid into acetyl-CoA?
1. acetyl-CoA (2)
2. hydrogen ion (4)
3. carbon dioxide (2)
What are the final products from pyruvic acid to lactic acid?
lactic acid and NAD+
-requires lactic dehydrogenase
Where does the citric acid cycle occur and what are the final products?
1. mitochondrial matrix
2. (16) hydrogen ion
3. (2) ATP
4. (4) carbon dioxide
Where do the hydrogen ions from TCA move?
to oxidative phosphorylation on the mitochondrial cristae
and others migrate to form NADH
What are major components of oxidative phosphorylation?
2. iron sulfide proteins
4. cytochrome A3 (donate electrons to oxygen)
What are the specific number of ATP from entire ox phosp process?
1. (2) glycolysis
2. (2) TCA
3. (34) ETC
The pentose phosphate pathway mostly is used for fat synthesis, but can provide immediate source of glucose. HOw?
1. five glucose can be resynthesized from 6 molecules
2. hydrogen ions are bound to NADP+ not NAD+
What role does NADPH have in biosynthesis?
1. converts acetyl-CoA into fatty acid chains
2. occurs when glucose store cells are saturated and glucose is then converted to fat
What ways can glucose be converted to triglycerides?
1. glycolytic pathway to form fatty acid to form trigs
2. pentose phosphate pathway to form fatty acid to form trigs
3. directly from alpha-glycerophosphate
How are triglycerides absorbed in the intestines?
1. converted to monoglycerides and fatty acids
2. can then be reformed in lymph as chylomicron
3. Apoprotein B added to chylomicron surface is important
Which tissues produce lipoprotein lipase in order to remove chylomicrons from blood?
What does lipoprotein lipase do to allow triglyceride absorption into tissue?
hydrolyzes trig to release fatty acid and glycerol
Can all the normal energy requirement of the body be provided by oxidation of fatty acids, without utilizing carbs or proteins as energy sources?
What will increase the utilization of fats for energy?
starvation mode, diabetes mellitus
What type of lipoproteins are synthesized by intestinal cells?
What lipoproteins are synthesized by the liver?
VLDL, IDL, LDL, HDL
What is the function of VLDL in blood?
1.transport from liver to adipose tissue
2. high [triglyceride], cholesterol and phospholipid
What is the function of LDL?
high [cholesterol] and phospholipids
What is the function of HDL?
1. high [protein] and low [cholesterol, fatty acid]
What are the principal functions of the liver in regard to lipid metabolism?
1. degrade fatty acids to energy
2. synthesis of triglycerides
3. synthesis of lipids from fatty acids, mainly cholesterol and phospholipids
Under what conditions are large quantities of triglycerides appearing in the liver?
1. starvation stage early
2. diabetes mellitus
3. any situation where fats, not carbs, are main energy source
Beta-oxidation occurs in the mitochondria to convert fatty acids to what?
acetyl-CoA where it binds with oxaloacetic acid
What are the products of one molecule of stearic acid undergoing beta-oxidation?
(9) acetyl-CoA molecules, (146) ATP molecules
Fatty acids that are degraded in the liver produce energy that is not used for metabolism. What is acetoacetic acid converted into?
beta-hydroxybutyric acid and acetone
What body conditions will favor ketosis?
2. diabete mellitus
3. fatty diet
What are the benefits of storing fat rather than carbohydrates?
1. more efficient. more storage than carbs
2. 2.5x amount of energy of same amount of carbs
Why are fats poorly synthesized during insulin deficiency?
1. decreased delivery of glucose to cells, reduces amount of NADPH and Acetyl-CoA required for fat synthesis
2. reduced glucose in cells reduces availability of alpha-glycerophosphate
Why are carbohydrates preferred over fats for energy?
1. triglycerides are in equilibrium with soluble fatty acids, but fatty acids will shift equilibrium to form more trigs.
2. fatty acid synthesis is faster than degradation when carbs in excess
What are the processes of athersclerotic plaque development?
1. vascular endothelium damage
2. monocytes and LDL accumulate at site of injury
3.Monocytes enter intima become macrophages
4. macrophages ingest lipoproteins
5. fatty streak develop and grow surrounding fibrous and smooth muscle tissue
How does damaged vascular endothelium contribute to athersclerotic plaques?
1. increase adhesion molecules
2. decrease NO, and anti-adhesive signaling molecules
How do monocytes contribute to athersclerotic plaque formation?
1. cross endothelium, form macrophages
2.enter the intima
What role do macrophages have in athersclerotic plaque formation?
1. ingest lipoproteins
2. become foam cells
3. form visible fatty streaks
What happens to fatty streaks to become athersclerotic plaque?
1. coalesce and increase in size
What is the threat of having large atherosclerotic plaques present in blood vessels?
2. become fibrotic or calcified