LESSON 6 - bioenergetics of muscle metabolism : fat oxidation & substrate utilization Flashcards
what are the two ways we resynthesize ATP ?
non oxidative and oxidative
what are the two non oxidative energy sources ?
phosphocreatine and glycolysis/glycogenolysis
what are the two oxidative energy sources ?
citric acid cycle / electron transport and fatty acids from beta-oxidation
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ATP resynthesized through non-oxidative processes referred to as ___________________
substrate-level phosphorylation
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ATP resynthesized through oxidative processes referred to as ___________________
“oxidative” phosphorylation
what are the four types of fats ?
- fatty acids
- triglycerides
- phospholipids
- sterols
what are the two principal fats we talk about ?
fatty acids and triglycerides
which type of fat is known as the “oxidizable” form of fat ?
fatty acids
which type of fat is glycerol + 3 fatty acid groups ; stored in fat cells ?
triglycerides
how do we make a triglyceride ?
one glycerol and three fatty acids
what type of fat makes up membranes ?
phospholipids
what type of fat is cholesterol (in lipoprotein complexes) and transporters ?
sterols
what are the two forms of storage for fats ?
adipose tissue and muscle
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storage of adipose tissue is as ________
triglycerides
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storage of muscle about fat is as ___________
intramuscular triglycerides
what are the three ways fats transport ?
- in blood
- across sarcolemma
- into mitochondria
how soluble are fats through transportation ?
poorly soluble
how do fats transport in blood ?
as triglycerides, lipoproteins, free fatty acids
how do fats transport across sarcolemma ?
fatty acid translocase
how do fats transport into mitochondria ?
carmine transport system
per gram is one carb or one fat more efficient ?
one fat
what are the two ways we breakdown fats ?
- lipolysis
- oxidation
describe lipolysis :
breakdown (hydrolysis) of triglyceride into its components
describe oxidation in regard to breakdown of fats :
oxidation of fatty acids and glycerol
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before fatty acids can be oxidized in the mitochondria, they must first be _____________________ and then activated, forming _______________
- released from triglycerides
- fatty acyl CoA
how many steps are there of lipolysis in the cytosol ?
2
what are the two steps of lipolysis in the cytosol ?
STEP 1 = hydrolysis of triglycerides, reaction catalyzed by hormone sensitive lipase
STEP 2 = degradation of FA, reaction catalyzed by acyl-CoA synthetase as follows
what are free fatty acids attached to ?
albumin
when do we use fats / fatty acids ?
use in fast
what happens to your body when you use the fat in your adipose tissue ?
lose weight
what type of macro is glucose ?
carbs
how does transport of fatty acyl coach occur ?
carnitine transport chain
why must fatty acyl-CoA be transported across inner mitochondrial matrix ?
because it is impermeable to CoA and it derivates
how do fatty acyl-CoA transports occur ?
using proteins and the small molecule carnitine
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fatty acids attached to carnitine are able to cross the inner membrane through the protein transporter _____________________________
carnitine acylcarnitine translocase
what transport systems do we use to move fatty acids in and out ?
carnitine transport system
acyl CoA = fatty acyl coA
CoASH = CoA
what is beta-oxidation ?
the initial process of oxidation of fatty acids
what is known as a “four-step process that removes acetyl-CoA units, one at a time from fatty acyl CoA”
beta-oxidation
where does beta-oxidation occur ?
in the mitochondrial matrix
what process “removes two carbons from fatty acyl-CoA producing 1 acetyl CoA, 1 NADH and 1 FADH”
beta-oxidation
beta-oxidation process is repeated until when ?
until the original fatty acid is completely broken down to acetyl CoA
what does Acyl CoA help with ?
Krebs cycle
what does Acetyl CoA help with ?
another fatty acid breakdown
where does beta-oxidation happen ?
in the mitochondria
how many carbons in a fatty acid ?
18 carbons
why are fats so much more valuable ?
because it’s 3x120 instead of just 32
what is the net ATP of a fatty acid ?
120
what are two sources of acetyl-coA for TCA cycle with oxygen ?
glucose and fatty acid chain
once glucose goes through glycolysis what does it turn into ?
pyruvate
once fatty acid chain becomes fatty acyl - coA what does it go through ?
beta-oxidation
between both sources of acetyl-coA for TCA cycle which is the faster production of ATP but finite ATP formation ?
glucose
between both sources of acetyl-coA for TCA cycle which is the slower production of ATP but infinite ATP formation ?
fatty acid chain
what are other names for the TCA cycle ?
Krebs cycle
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required rate of ATP generation determines _________
intensity
when discussing substrate use during exercise (30 minute exercise bouts) which substrates do we see with a lower ATP resynthesis rate ?
- muscle triglycerides
- plasma FFA
- plasma glucose
when discussing substrate use during exercise (30 minute exercise bouts) which subtracted do we see with a higher ATP resynthesis rate ?
- muscle glycogen
- muscle triglycerides
- plasma FFA
- plasma glucose
if we are walking what type of macros are we using ?
carbs and glucose/glycogen
If we are doing a marathon what type of macros are we using ?
fats
in regards to the substrate utilization and exercise intensity what is the crossover point ?
when carbs and fats are being used to do the same thing ( they will meet )
what happens if you have lactate buildup ?
muscle cramps
how will majority of lactate produced in skeletal muscle cells enter ?
through the blood stream
what does lactate contain lots of ?
potential energy
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____________ can be transported and taken up by other tissues and converted back to pyruvate
fates of lactate
what are the two ways fates of lactate can be transported and taken up by other tissues and converted back to pyruvate ?
- used as substrate to resynthesize ATP (skeletal muscle and other tissues)
- converted back to glucose and stored as glycogen
what is the catalyst for the lactate reaction ?
lactate dehydrogenase
are fatty acids reversible ?
no
are carbs/glucose & glycogen reversible ?
yes
