7.4 Flashcards
(50 cards)
intermediary metabolism
-metabolic steps within the cells in in which the nutrient molecules are metabolised and converted into cellular components and provide energy
what does intermediary metabolism provide
-appropriate energy supply for cells and tissues
energy donors
carbs, lipids, AA
difference between uptake of energy and energy demand
-uptake of energy is intermittent
-energy demand is continuous
where do cells get their nutrition
-nutrients circulating around in the bloodstream for immediate use
whats the issue with cells getting their nutrition from circulating nutrients and why and effect
-the amount of available nutrients in the plasma is small
-because many nutrients are stored in tissues
effect- can only fulfil demand for very limited time
why cant the conc. of transport nutrients be raised 1-
1-have low molecular weight so only a small mass contributes to high molar concentration in plasm
-if plasma conc. increased significantly then osmotic activity would also rise so water moves out of cells and intracellular dehydration
why cant the conc. of transport nutrients be raised 2-
2-they are filtered in the kidney and excreted in urine
-an increased plasma conc. leads to osmotic diuresis (urination)
why cant the conc. of transport nutrients be raised 3-
3-lipids are poorly soluble in water
-increase In lipids contributes to increase in athersclerosis
why cant the conc. of transport nutrients be raised 4-
-increased glucose leads to protein glycation (non-enzymatic binding of glucose to proteins)
-this alters protein function and contributes to diabetes
storage of nutrients (intracellular)
carbs - glycogen
AA - proteins
fats - triglycerides as lipid droplets
storage form of glycogen
small amount
liver - 50g (sufficient for 1-2 hours)
muscle - 200g, doesnt contribute to blood glucose because lacks G6P enzyme
advantage and disadvantage of carbs
advantage - appropriate for every tissue
disadvantage - bad storage properties
storage form of protein
more than glycogen
-found in all tissues
-large amount found in muscle
storage form of lipids
largest amount
-primarly in adipose tissue
-storage without water binding
-cannot be converted to glucose, only glycerol from TG can contribute to glucose production
advantage and disadvantage of lipids
advantage - ideal storage properties
disadvantage - only oxidative break down, not suitable for every tissue
advantage and disadvantage of amino acids
advantage - can be glucogenic
disadvantage - too valuable to be used up due to their other
-urea formed during their breakdown
major components of the intermediary metabolism
