Lipids Flashcards
The length of fatty acids (# of carbons)…
affects their solubility
Amphiathic
hydrophobic on the inside and hydrophilic on the outside, bile salts are amphipathic
Triglycerides
major dietary source of fat, consist of a glycerol backbone wit 3 fatty acids attached
Triglycerides are hydrolyzed into ____ in the small intestine
fatty acids and 2-monoacylglycerol
Triglycerides are
hydrophobic
not soluble
Triglycerides and other hydrophobic substances are _________ in the aq environment of the intestine
Bile salts
a derivative of cholesterol, made by the liver, act as emulsifies to surround the fat and allow them to be broken down and absorbed
bile salts and phospholipids are
secreted by the gall bladder where they are stored, amphipathic
Colipase
binds to the fat and bile salts around emulsion droplets, breaking triglycerides into fatty acids and monoglycerides
Micelles
from wen the bile salts reach a concentration greater than the “critical micelles concentration”, below which the bile salts are soluble
critical micelle concentration
the concentration of lipid required for micelle formation
What is packaged in micelles?
fat-soluble vitamins, cholesterol, triglycerides
Where will micelles be absorbed?
through the microvilli of the intestine
micelles formation
polar heads around the outside surrounding the hydrophobic materials within
the hormone CCK (cholecystokinin) causes what to happen when the chyme enters the duodenum?
bile salts are released from the gall bladder, enzymes from the pancreas, secretin signals bicarbonate to neutralize pH and allow enzymes to function
true or false little fat is lost in faces
true
Bile salts _______ be absorbed into the ______v
will not, mucosal cells
when will bile salts be reabsorbed?
further down the intestine bile salts will be absorbed to be used again in another digestive cycle
what chains of fatty acids do not require bile salts for absorption? Why?
medium and short. because water soluble, can enter blood and be transported to the liver bound to albumin
Chylomicrons
largest lipoproteins and contain the greatest proportion of trigylcerids. Within the blood that have come from the digestive tract
when lipids are reassembled into triglycerides they will be what?
packaged with protein to allow travel in water-based blood
how do chylomicrons travel?
first into the lymphatic system, enter the bloodstream through the thoracic duct
VLDL (very low density lipoprotein)
- fat delivery system from the liver
smaller tan chylomicrons, but still contain a high proportion of triglycerides
HDL
high cholesterol and are the densest lipoprotein due to their high protein content
Is insulin released in the fasted state
No
Is insulin released in fed state?
Yes
What is lipid mostly
Triglyceride
Triglycerides
- glycerol backbone with three fatty acids
- makeup of them is dependent on diet
- major source of dietary fat
When are lingual and gastric lipases most active?
In short and medium fatty acids which would be found in milk
What do bile salts do in fats?
Keep them separated and expand the surface a area of the fat to be broken down
Where are bile salts and enzymes released from?
Gallbladder
Where are enzymes released from?
Pancreas
Why is bicarbonate release?
Due to a signal from secretin to neutralize pH and allow enzymes to function
What is the absorption of fat soluble substances depending on?
Presence of dietary fats
LPL
- lines the capillaries in muscle and adipose tissue
- breaks down triglycerides into fatty acids and takes the fatty acids into the adipose tissue and muscle
Excess carbs and proteins
Make fat leading to LDL
What does LDL need?
Receptor mediated process to get taken from the blood
What is cholesterol’s polarity?
Extremely non polar
Is cholesterol soluble?
Is insoluble in water and needs to be transported with lipoproteins
Where are bike salts made and stored?
Made in liver, stored in gallbladder
Bile salts polarity
Lots of rings with C and H but have OH giving polarity
What are lipids mainly made up of?
triglycerides
What do lipases break down?
break down triglycerides (glycerol and 3 fatty acids)
When lipids break down triglycerides what do they break them down to?
take 2 fatty acids off and leave the middle 1 (monoglyceride)
When triglycerides are broken down what happens to them?
taken in enterocytes and made back into triglycerides and packaged in chylomicrons and delivered to the body
Because our bodies are a water based system what do we need to transport proteins and phospholipids?
lipoproteins that are soluble in water
Do chylomicrons circulate in the blood?
yes
Lipoproteins lipase
breaks down triglycerides in the chylomicrons and allow fatty acids to be taken up by muscle and adipose tissue
What does the makeup of triglycerides in our body depend on?
what we eat in our diet
What is the major dietary source of fat?
triglycerides
