Ketone Bodies (mini-test 1 AND 2) Flashcards
Once glycogen is gone, proteins in skeletal muscle gets broken down to AAs to make glucose and in this process, malate will be shuttled out of the mitochondria and converted to OAA. So after a week of fasting and protein breakdown….
there will be low malate and OAA in TCA cycle and it needs to be replaced!
Are ketone bodies made in fed state or fasting state?
fasting state
What are ketones used for?
brain fuel (the brain only likes glucose or ketone bodies)
During fasting state what gets used up to help fuel the brain and for how long?
1) liver glycogen is used within 12 hours
2) muscles break down to AAs (muscles provide 50% of energy to the brain)
3) lipids will provide very little energy, but will still be used
4) after 1 week, fat is broken down to ketone bodies
If insulin is high, then will ketone bodies be generated?
NO
During fasting state what gets used up to help fuel the muscles in order?
1) ATP
2) creatinine-P
3) glucose
4) muscle glycogen
5) FAs
6) ketone bodies
3 molecules are ketone bodies. What are the 3?
1) acetoacetate (2 acetones)
2) beta hydroxybutyrate (4C, beta carbon has OH)
3) acetone
You can convert one ketone body to another. Acetoacetate to beta hydoxybutyrate is what type of reaction?
reduction reaction
You can convert one ketone body to another. Beta hydroxybutyrate to acetoacetate is what type of reaction?
oxidation reaction
You can convert one ketone body to another. acetoacetate to acetone is what type of reaction?
spontaneous decarboxylation
Ketone bodies are ________ soluble fuels, so they can enter the brain
water
Ketone bodies are typically exported by the liver and produced naturally at ____ levels
low
Ketone bodies are acidic, so if theres a buildup then it can cause….
ketoacidosis (or less severe version is ketosis)
When are ketone bodies overproduced?
when theres a depletion of OAA
-so starvation mode or untreated DM (body thinks its starving)
What diet is dangerous for diabetics?
keto/atkins diet
What organ generates/produces ketone bodies but CANNOT use them?
liver
How is ketosis diagnosed?
sweet smell of acetone through a person’s breath
What tissues cannot use ketone bodies?
1) liver bc TCA is not working due to ketone bodies built up
2) RBCs bc theres no mitochondria
Ketone bodies are formed from what molecule?
acetyl CoA
Ketone bodies are exported out of liver as energy source to the….
-heart
-skeletal muscles
-kidneys
-brain
During starvation or keto/atkins diet, OAA is mainly used for….
gluconeogenesis in the liver
T/F: a lack of OAA will slow the TCA cycle down so acetyl CoA begins to accumulate and uses the CoA pool in the liver
TRUE
CoA is needed for continuous FA beta oxidation, creating energy for the liver. With a depleted CoA pool. FAs are….
incompletely oxidized in the liver
(ketone body formation removes excess acetyl CoA and frees up CoA pools for continuous oxidation in the liver)
Ketone bodies replace ___________ as the primary energy source for many tissues
glucose
The formation of ketone bodies in the liver (ketogenesis) begins with acetyl CoA + acetyl CoA which combines to form acetoacetyl CoA and this releases 1 CoA. The acetoacetyl CoA will then undergo a reaction with acetyl Coa to make hydoxyl-methyl glutary CoA (HMG CoA) and release another CoA. HMG-CoA then undergoes a reaction to make acetoacetate and releases acetyl CoA. At this point, 2 reactions can be done. What are they?
reduction reaction to make beta hydroxyburyrate or remove carbon dioxide to make acetone
What 2 ketone bodies can be used in peripheral tissue for acetyl CoA and in TCA cycle?
acetoacetate and 3 hydroxybuterate (acetone DOES NOT enter energy metabolism)
Where is beta ketoacyl CoA transferase located?
in muscle tissues
Which enzyme converts acetoacetate to acetoacetyl CoA in muscle tissues?
beta ketoacyl CoA transferase
T/F: ketogenesis and ketolysis work at the same time
true (apparently)
What is the keto diet?
-low carb intake
-moderate protein
-high fats
-not meant for long term
-good for focusing on plant based proteins
-people usually like eating red meat with this diet because its high in fats compared to white meat
note: it is different from a low carb diet- low carb diet doesn’t care about anything besides carbs. Can eat anything as long as its low carbs
What are the concerns for keto diet?
-keto flu (flu like symptoms that last about a week after starting new diet)
-bad breath bc of acetone
-GI symptoms like diarrhea and constipation
-kidney stones because of lots of calcium excretion from bones to kidney
-can cause osteoporosis
-increase of red meat intake can increase risk for cardiovascular disease and cancer
-can cause fatty liver because the liver is working so hard
-causes numerous vitamin deficiencies
What are the pros of keto diet?
-limits bad carbs
-fast weight loss
-treatment for epilepsy, tumors, and neurodegenerative diseases
-increases insulin sensitivity for pre-diabetics
Who shouldn’t do the keto diet?
-pregnant women
-women who plan on getting pregnant/trying bc it limits vitamins needed for fetus
-DM patients
-HTN patients
-patients with kidney, liver, or heart disease
-people with a low BMI
-kids bc kids need all the vitamins and nutrients possible while growing
-patients with gallstones (can increase pain)
-osteoporosis patients
-athletes bc they want to build muscle and glucose impacts performance
What are the 6 big food groups?
1) grains, starchy veggies (high in carbs)
2) veggies
3) fruit (high in carbs)
4) legume proteins (plant based) or meat proteins (no carbs)
5) dairy (high in carbs)
6) oil (no carbs)
What is good protein?
plant based protein
Lots of meat and oil leads to….
constipation because most of the nutrients is absorbed so there not much to poop
What are phospholipids?
glycerol backbone with 2 FAs and a phosphohead
What does phospholipase A1 (PLA1) do?
removes 1st FA and it will be used for energy
What does phospholipase A2 (PLA2) do?
removes 2nd FA which will create eicosanoids
What does phospholipase C (PLC) do?
removes phosphohead
What does phospholipase D (PLD) do?
removes X group
How are sphingolipids broken down?
within lysosomes/ lysosomal enzymes
What is lecithin?
phospholipid with choline as the X group
Several congenital lysosomal diseases are associated with an inability to degrade specific sphingolipids. Massive accumulations of sphingolipid metabolites causes cell impairment and cell death. What are the 2 diseases involved with sphingolipid accumulation?
1) tay sachs disease
2) niemann-pick
What enzyme is defective in tay sachs disease?
hexoaminidase A
What enzyme is defective in niemann pick?
sphingomyelinase
What sphingolipid accumulates in tay sachs disease?
neuro gangliosides
What sphingolipid accumulates in niemann pick?
sphingomyelin
What are the 4 lipid classes?
1) TG, DG, MG
2) phospholipids
3) sphingolipids
3) cholesterol
can cholesterol be broken down?
no
in order to decrease cholesterol, you have to increase cholesterol excretion or eat less cholesterol
-cholesterol can also change to steroid hormones but this is a minor way to use cholesterol
-for excretion, cholesterol will be converted to bile, but 95% of bile gets recycled/reabsorbed
-cholesterol can be converted to vitamin D
-cholesterol can be used to stabilize cell membranes
Lipases ONLY break down…..
triglycerides, diglycerides, or monoglycerides
What is the most abundant FA?
palmitate 16:0
Taurocholate is a part of…..
bile
Leukotrienes are synthesized from…..
FAs/ eicosanoids
