Final exam Flashcards
(62 cards)
what four macronutrients are in the diet and what are their monomers?
proteins- amino acids
carbohydrates- monosaccarides
fats/lipids- fatty acids
nucleic acids- nucleotides
what are three key properties of co-enzymes in metabolic pathways?
low concentration in cells
act as carries
have two forms
what 2 types of reaction happens to fuel molecules in the pathway?
those involving ADP and ATP
oxidising fuel molecules= releasing lots of energy
what does reducing equivalent mean?
moving hydrogen moves an electron, but a proton also moves as well
therefore H+ is referred to as a reducing equivalent= dehydrogenase
carb digestion involves the hydrolysis of _____ bonds catalysed by the enzyme _____ which digests starch into _________
glycosidic
amalayse
disaccarides
why are monosaccarides unable to cross the cell membrane unaided?
because they’re highly polar and need specific transporter proteins.
what is meant by ‘symport’ transport of glucose by the SGLT1 transporter?
glucose and Na+ move into the epithelial cell together
Na+ goes down its concentration gradient passively
glucose goes up its concentration gradient but moves with Na+
which cells of the human body is glucose favoured as a fuel? Why?
brain- high energy requirement. glucose easily crosses blood brain barrier. also provides a quick source of ATP without risk of damage
red blood cells- they dont have any mitochondria
the eye- low levels of blood vessels and mitochondria
white muscle cells- fast response with glucose as a fuel
what are the two phases of glyocolysis?
energy investment- activation of glucose
energy payoff- making ATP profit
why is ATP hydrolysed in glucose activation?
it is coupled with adding a phosphate to glucose to make the reaction energetically favourable
why is the oxidation of glyceraldehyde-3-phosphate essential for glycolysis to make ATP profit
the NAD+ is reduced- giving oxidising power
so phosphate from solution can be added to the substrate
and no ATP has been spent
the ATP produced in glycolysis is produced through what type of reaction? what is the key aspect of this type of reaction?
a substrate level phosphorylation, phosphate cleaved releases energy. That energy is then used for a substrate level phosphorylation
the coupling of these two reactions results in a energetically favourable reaction
why does arsenate prevent an ATP profit being made in glycolysis?
arsenate hydrolyses but energy isnt captured so ATP isnt synthesised by phosphoglycerate kinase= no net gain of ATP.
what is the overall reaction for glycolysis?
glucose+ 2NAD+ + 2ADP + 2Pi —-> 2 pyruvate +2NADH + 2ATP + 2H+
delta G= -73kj/mol
therefore pathway is energetically favourable
name two diatary lipids obtained in our diet? Which of them makes up 90% of our dietary fat?
sterols
triacylglyerols- 90% of diatary fat \
lipids are made soluble for digestion by ____ acids which act as detergents. They are made from ____, synthesised in the _____ stored in the ____ and secreted into the ____
bile
cholestrol
liver
gall bladder as bile
small intestine=
what is a lipoprotein and what is its function?
delivery system for transporting lipids around the body. solubilise lipids for transportation in the blood from digestion
what are the four classed of lipoprotein and how are they classed?
chylomicrons- TAG transport low protein to lipid ratio
very low density lipoprotein (VLDL)- TAG, medium protein to lipid ratio
Low density lipoprotein (LDL)- cholesterol transport
High density lipoprotien (HDL)-cholesterol regulation
what are two major lipid transport pathways and which lipoprotein is used in each?
exogenous- from diet, lipoprotein lipase in endothelial cells on capillary surface
endogenous- recycling in the body, (VDL) very low density lipoprotein
what is the function of the lipoprotein lipase enzyme?
to hydrolyse TAG in lipoproteins to monoacylglycerol and fatty acids that enter the tissue
ApoCll activates lipoprotein lipase. Chylomicron reminant remains in the blood
why does the body store fats rather than carbs?
because storage of carbs takes up more space as they hold more water.
in terms of ATP hydrolysis what is the cost of activating fatty acids?
energy to add Coa from hydrolysis of ATP–> AMP = the energy equivalent of 2 ATP.
how is fatty-acyl Coa transported into the mitochondria?
has to pass 2 membranes
outer= fatty acyl-coa carrier
inner= conversion to fatty acid carnitine
what 4 reactions occur in beta oxidation
1) oxidation
2) hydration
3) oxidation
4) cleavage
