Lipids Flashcards

1
Q

What are some properties of lipids

A

Heterogenous
Insoluble in water
Exist in cell membranes

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2
Q

What are the different lipid classes

A

F.A
Triacylglycerol
Phospholipid
Glycolipid
Steroids

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3
Q

What are the essential FA and where do we get them from?

A

Linoleic
Linolenic
We get from plants

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4
Q

What are triacylglycerols

A

Esters of FAs and glycerol
TAG major lipid in adipose tissue
Used for fuel and insulation

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5
Q

What are the properties of phospholipids

A

Amphipathic:
Glycerol + 2FA+ phosphate group
Contain a Hydrophilic head and hydrophobic tail

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6
Q

What are the Main Steroids

A

Cholesterol
Steroid hormones
Bile salts

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7
Q

Properties of cholesterol

A

-Precursor to Sterol hormones and bile salts
-Made in liver
-Found in animal food

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8
Q

How is cholesterol synthesis regulated

A

Via statins
Inhibit HMG-CoA reductase

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9
Q

What are eicosanoids and what do they regulate?

A

Lipid class derived from 20C unsaturated FA
Regulate:
inflam response
B.p
clotting
Pain & fever

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10
Q

What is the main dietary lipid

A

Triacylglycerol

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11
Q

What is the main site of lipid digestion

A

small intestine

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12
Q

What are lipids digested by

A

Lipases via emulsification by bile salts and mixing

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13
Q

What are bile salts

A

Biological detergents
Derivative of cholesterol

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14
Q

How is TAG digested

A

In small intestine via pancreatic lipase->monoacylgycerol + 2FA

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15
Q

What is cholesterol esters digested to

A

Cholesterol and free FA

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16
Q

How are phospolipids digested

A

Hydrolysed to FA and lysophospholipid

17
Q

How are digested lipids uptaken

A

Form mixed miscelles with bile salts
Enter cells via diffusion

18
Q

How are absorbed FA transported

A

Packaged into chylomicrons
Released by exocytosis into lymph then blood

19
Q

Summary of lipid digestion

A

Bile salts emulsify dietary fats in the small intestine
Intestinal lipases degrade triglycerol
Fatty acids and other breakdown products are absorbed by the intestinal mucosa and converted to triaglyceroids.
Triaglycerols are incorporated with cholesterol
Lipoprotein lipase converts triaglycerols into fatty acids
Fatty acids enter cells
Fatty acids are oxidized as fuel

20
Q

How are FA transported in blood

A

Serum albumin
Esterified FA carried in lipoproteins

21
Q

What do lipoproteins carry

A

TAG, cholesterol

22
Q

What are the lipoprotein classes

A

Chylomicrons
VLDL
LDL
HDL

23
Q

What are the fates of FA after metabolism in plasma

A

Oxidation - energy
TAG formation
FA->Fatty acetyl CoA->Triglyceride

24
Q

What does B-oxidation of FAs involve

A

Degrades FA 2 carbons at a time
Produces acetyl CoA +NADH + FADH2
Occurs in mitochondrial matrix

25
What happens on B-oxidation
1. Activation of FA in cytosol 2. Transport into mitochondria 3. Degredation to 2C in mitchondrial matrix
26
What does transport of FA involve
Carnitine shuttle
27
What are the 4 degredation steps of B-oxidation
1. Dehyrdrogenation FAD->FADH2 2. Hydration 3. Dehydrogenation NAD+->NADH 4. Thiolysis- produces acetyl CoA for CAC
28
What happens during starvation
Excess acetyl CoA from fat metabolism converted to ketone bodies
29
What are ketone bodies used for
Cardiac and skeletal muscles use it as energy source Fuels brain cells during starvation
30
Where does FA synthesis occur
Liver Mammary gland Adipose tissue
31
FA synthesis and degredation