lecture 14 fatty acid catabolism

About 1/3 of our energy needs comes from

dietary tracylglycerols

about 80% of energy needs of mammalian heart and liver are met by?

oxidation of fatty acids 

fats + hibernating animals

hibernating animals like grizzly bears rely exclusively on fats as their source of energy 

Glucose + Glycogen vs Fats 

Glucose & Glycogen= short term NRG needs— quick delivery

Fats= long term (months) energy needs, good storage— slow delivery

fatty acids carry more ____ per carbon because they are more reduced

energy

fatty acids carry less water because they are _______

non polar

Fatty acid absorption 

Fat is emulsified by?

by bile salts, which are made in the liver and stored in the gallbladder 

Lipids Transport

Lipids are transported in the blood in chylomicrons and brought to adipocytes

released fatty acids bind to albumin to be delivered to other tissues

Fat storage is stored in ______

adipocytes

White fat

Beige fat

Brown fat

White fat: in connective tissue beneath the skin (subcutaneous fat) and abdominal fat (visceral fat)

Beige fat: is derived from white fat from low temperatures (just above shivering) or exercise

Brown fat: is derived from muscle cells— it is found in the shoulder blades, neck, along the spinal cord, above the collarbone, and around vital organs

Adipocytes release…

adipokines

• proteins

• lipids

• metabolites

Non-coding RNAs

anddd

extracellular vesicles to relay information to other organs in the body

Fat release 

Fat release (lipolysis) - from adipocytes

• is inhibited by insulin

• activated by glucagon 

Lipases catalyze ________

triacylglycerol hydrolysis into free fatty acids and glycerol 

Triacyl Hydrolysis

• regulation by hormones

• Epinephrine (Adrenaline) : responds to stress — means “we need NRG now” —- increases gluconeogenesis

• Glucagon: responds to low blood sugar — means “ we are out of glucose” — increasing glycogenolysis

• BOTH activate triacylglycerol breakdown

Triacylglycerol hydrolysis occurs where?

Hydrolysis occurs in the cytoplasm of adipocytes