week 2- lipids Flashcards

1
Q

what is fat important for?

A

Insulation
Protection
Storage
Energy Production
Synthesis of hormones and lipoproteins

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2
Q

What are the most commonly ingested lipids?

A

triacylglycerols (TAGs)

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3
Q

What happens to TAGs in the mouth during digestion?

A

there is little effect on lipids as the enzymes in the mouth are aqueous

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4
Q

what happens to TAGs in the stomach during digestion?

A

TAGs are churned into droplets called CHYME

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5
Q

which enzyme begins actual lipid digestion

A

lipase

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6
Q

approximately how many TAGs are hydrolysed In the stomach

A

10%

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7
Q

which enzyme hydrolyses insoluble triglycerides

A

pancreatic lipase

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8
Q

how do pancreatic lipase hydrolyse insoluble triglyceride

A

by binding to the bile-salt micelles

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9
Q

how are TAGs partially hydrolysed and reformed again

A

they are partially hydrolysed ;having a monoacylglyceril and 2 fatty acid chains

they’re then formed into micelles with the help of bile salts

they are taken up the intestine and reformed into triacylglycerols

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10
Q

What is bile?

A

An emulsifier

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11
Q

how do bile salts aid in the formation of spherical micelle shapes formed by oil droplets

A

by clumping fatty acids and monacylglycerols

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12
Q

what is the structure of a fatty acid micelle?

A

Bile salts on the exterior

Hydrophobic fatty acids and monoacylglycerols in the interior

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13
Q

what are free fatty acids and monoglycerols reformed into

A

triacylglycerols

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14
Q

what is a chylomicron?

A

It is a lipoprotein.

It consists of TAGs, membranes and protein

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15
Q

What do chylomicrons do?

A

They transport TAGs from the intestinal cells to the bloodstream via the lymph system

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16
Q

Why do chylomicrons travel through the lymph system?

A

Because they are too large to fit in blood capillaries and may clog up blood vessels.

17
Q

What are the uses of triacylglycerols after being transported by chylomicrons?

A
  1. absorbed by cells and processed for energy by forming Acetyl CoA
  2. Stored in adipose tissue/adipocytes (fat cells) as lipids
18
Q

How are fats released from adipocytes when needed?

A

They are hydrolysed (broken down) in the adipocyte and released as fatty acids when needed

19
Q

what are adipocytes?

A

They are fat cells in the adipose tissue found mostly in the abdominal cavity and subcutaneous tissue

20
Q

what do adipocytes do?

A

They store energy
Used as insulation
Used as a shock absorber for organs

They are metabolically very active meaning they break down and synthesise TAGs constantly

21
Q

What is lipolysis?

A

The breakdown of triglycerides by lipases.

Lipolysis is under hormonal control.

22
Q

What are the hormones involved in lipolysis and what do they do?

A

Epinephrine and glucagon - promote lipolysis

Insulin - inhibit lipolysis

23
Q

What is the structure of TAGs and what is their structure when they get hydrolysed (broken down)?

A

TAGs consist of 1 glycerol and 3 fatty acid chains

When they are hydrolysed , 1 fatty acid chain is released.

TAGs can keep getting hydrolysed (broken down) until there is just the glycerol molecule left

24
Q

what happens to the glycerol molecule after the 3 fatty acid chains have been hydrolysed?

A

The glycerol molecule gets metabolised:

  1. It enters into the blood stream
  2. Travels to the liver OR kidney for processing
  3. It then gets converted to dihydroxyacetone phosphate
25
Q

how does glycerol get converted into dihydroxyacetone phosphate?

A

MAKE A DIAGRAM

26
Q

What are the 2 processes in which dihydroxyacetone phosphate is used as an intermediate

A

Glycolysis - It is converted to pyruvate, then Acetyl CoA, then CO2, it releases its energy

Gluconeogenesis - It creates glucose from a non carb source

27
Q

What kind of reaction is needed for fatty acids to be broken down?

A

Oxidation

learn more of this

28
Q

name 2 lipid disorders

A

familial combined dyslipidaemia

remnant particle disease