Lipids - Exam 1 Flashcards by Emillie Dodd

what are the building blocks of lipids

fatty acids

How well did you know this?

Not at all

Perfectly

what is a lipid, where is it found, what does it do

hydrophobic organic molecule; membranes or bound to plasma proteins; major source of energy for the body and help with compartmentalization, vitamins

How well did you know this?

Not at all

Perfectly

definition of hydrophobic

water insoluble

How well did you know this?

Not at all

Perfectly

examples of common lipids

fatty acids, triacylglycerol, phospholipid, steroid, glycolipid, prostaglandins, steroid hormones

How well did you know this?

Not at all

Perfectly

definition of amphipathic

hydrophilic (polar) head, hydrophobic tails

How well did you know this?

Not at all

Perfectly

where does lipid digestion start via what enzyme

in the stomach via lipases

How well did you know this?

Not at all

Perfectly

what is emulsification and where does it occur

makes fats more soluble so lipases can work by breaking down into smaller particles ; duodenum

How well did you know this?

Not at all

Perfectly

what emulsifies fat droplets and where are they found

bile acids ; synthesized in liver and stored in gall bladder

How well did you know this?

Not at all

Perfectly

how does lipid digestion occur

CCK is synthesized when lipids and proteins (food) enters the duodenum, it stimulates bile acid and pancreas enzyme secretion, which then stimulates bicarbonate from the pancreas

How well did you know this?

Not at all

Perfectly

significance of bicarbonate and where it’s found

helps neutralize stomach pH; lumen of the SI

How well did you know this?

Not at all

Perfectly

mixed micelles are formed post digestion by

FFA + cholesterol + MAG + lipid soluble vitamins + bile acids

How well did you know this?

Not at all

Perfectly

what do mixed micelles do

approach brush border of enterocytes and are absorbed into the jejunum

How well did you know this?

Not at all

Perfectly

what happens to bile acids post digestion

reabsorbed into the ileum (SI) and recycled multiple times

How well did you know this?

Not at all

Perfectly

only long chain FA form micelles because

small and medium chain so small they just diffuse right into the plasma membrane

How well did you know this?

Not at all

Perfectly

what is re-esterification and where does it occur

synthesis of more complex lipids (long chain fatty acids); endoplasmic reticulum

How well did you know this?

Not at all

Perfectly

chylomicron composition ; where is it found

phospholipids, TAG, fatty acids ; inside enterocyte or blood plasma

How well did you know this?

Not at all

Perfectly

what happens to short and medium chain fatty acids

directly released into portal circulation where they bind to albumin

How well did you know this?

Not at all

Perfectly

what happens to chylomicrons

released by exocytosis into the lymphatic vessels -> veins -> blood

How well did you know this?

Not at all

Perfectly

what is unique about chylomicrons

it is so large it can’t go straight into blood so the route it takes bypasses the liver

How well did you know this?

Not at all

Perfectly

main function of chylomicron

send lipids to the rest of the body without involving the liver

How well did you know this?

Not at all

Perfectly

types of plasma lipoproteins

chylomicron, LDL, VLDL, HDL

How well did you know this?

Not at all

Perfectly

composition of plasma lipoproteins

triacylglycerol, proteins, phospholipids, cholesterol

How well did you know this?

Not at all

Perfectly

what is the “good” cholesterol

HDL - 40% protein

How well did you know this?

Not at all

Perfectly

what is the “bad” cholesterol

LDL - 50% cholesterol

How well did you know this?

Not at all

Perfectly

lipoprotein lipase function

strip TAG of FFA & glycerol at the capillaries.

after stripped, FFA will

go into muscle cells or adipocytes or stay in the blood binding to plasma proteins

after stripped, glycerol will

go to the liver to synthesize glycerol 3 phosphate (gluconeogenesis)

chylomicron remnants will

be absorbed by the liver

relevance of fatty acids

during a fast, bound to albumin in plasma on the way to tissues -> oxidation to create energy

structural components of fatty acids

phospholipids & glycolipids in the plasma membrane

lipid hormone precursor

prostaglandins

lipid energy reserve

TAG in adipose tissue

saturated fatty acid structure

no double bonds

unsaturated fatty acid structure

double bonds (kinks), cis

alpha C

carboxyl group

beta C

gamma C

omega C

terminal methyl group

essential fatty acids can't

be synthesized in the body so we must ingest them

example of essential fatty acid and where it's found

arachidonic acid ; plasma membrane ; alpha linoleic acid

de novo synthesis of fatty acids occurs

cytosol of liver, mammary gland, adipose tissue cells

substrates of de novo synthesis

carbs & proteins from diet that were consumed in excess

1st step of de novo synthesis

Acetyl CoA from mitochondrial matrix broken down to citrate into the cytosol

2nd step of de novo synthesis (rate limiting)

ACoA -> malonyl CoA via ACC

all other fatty acid synthesis uses what enzyme

FAS (fatty acid synthase, or ACP)

when FAS/ACP is used what is generated

palmitate (fully saturated fatty acid)

newly synthesized fatty acids are stored

as 1, 2, or 3 molecules in lipid droplets in adipocytes | small portion stored in liver and released into blood as VLDL

mobilization of fat requires

release from TAG via enzyme stimulated by glucagon or epinephrine

Beta oxidation of fatty acids occurs

in the mitochondria

beta oxidation of fatty acids entails

the removal of 2 C and a transport carrier to get the long chain fatty acylcoa from the cytosol into the mitochondria; can do several times

beta oxidation net gain

1 palmitoyl -> 8 ACoA, 7 NADH, 7 FADH2 -> 129 ATP

how are ketone bodies made

converted from ACoA from fatty acid oxidation by liver (mitochondria)

examples of ketone bodies

acetoacetate, acetone, etc.

ketongenesis occurs when

there's a fast and fatty acids come from adipose tissue to the liver and it produces a lot of NADH which shifts OAA to malate

why do diabetic patients have a lot of ketone bodies

because they're hypoglycemic so not using glucose to use energy so will mobilize fat to make energy and ketone bodies form because of that

ketone bodies in peripheral tissues

converted to ACoA -> TCA cycle (used for energy)

when is a liposom made

if not building a lipid bilayer chain

phospholipid synthesis pathway

2 precursors + enzyme -> phosphatidic acid -> diacylglycerol -> phosphatidyl_______

all cells can make phospholipids except

RBC

synthesis of phospholipids occurs

in the sER -> Golgi -> membranous organelles

donation of phosphatidic acid makes

1 option

donation of DAG makes

2 options

glycerophospholipids composed of

phosphatidic acid + alcohol

cardiolipin

inner mitochondrial membrane; maintenance of ETC

PAF

platelet activating factor; activates inflammatory cells, hypersensitivity, anaphylactic rxn

sphingomyelin

myelin in nerve fibers

IP3 & DAG intracellular signaling

1st messenger: hormone, 2nd messenger: IP3 (released into cytosol) & DAG (stay in membrane) G protein coupled receptors activate enzymes, IP3 can send and retrieve Ca2+

glycosphingolipids

ABO blood group antigens, only difference is one phospholipid off the sugar molecule

prostaglandins

20C, made by arachidonic acid, aspirin blocks it; vasoconstriction, uterine contractions (induce labor)

thromboxanes

20C, made by arachidonic acid, aspirin blocks it; vasoconstriction, platelet aggregation, Ca, smooth muscle contraction

cis =

same side

trans =

opposite side

carnitine translocase

facilitates transport of fatty acid from cytosol -> mitochondrial matrix

how do NSAIDS work

block synthesis of inflammatory mediators

Lipids - Exam 1 Flashcards

(74 cards)