Lipids 1-3 Flashcards

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1
Q

Name 5 lipid classes

A
Phospholipid 
Steroids
Fatty Acids
Glycolipid
Triacylglycerol
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2
Q

What kind of fatty acid has a double bond and what does this do to its shape ?

A

Unsaturated fatty acid

Kinks the hydrocarbon chain

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3
Q

What kind of essential fatty acids do we get from plants ?

A

Linoleic fatty acids

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4
Q

Name three properties of Triacylglycerol lipids

A

1: Insoluble in water
2: Used as energy or storage
3: Esters of FA and Glycerol

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5
Q

Phospholipids are amphipathic, what does this mean ?

A

They have both a hydrophillic and a hydrophillic aspect

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6
Q

What is the main site of digestion within the body ?

A

The small intestine

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7
Q

What breaks down lipids in the small intestine ? and what is this emulsified by ?

A

Lipases

Bile salts

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8
Q

Name 3 properties of bile salts

A

1: Act as detergent
2: Saves lipids coalescing in an aqueous environment
3: Derivatives of cholesterol

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9
Q

TAG is degraded by ____ into ____ and ____

A

Lipases
FA
Glycerol

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10
Q

How are the products of lipid digestion taken up by the intestinal cells in the wall of the intestine ?

A

They form mixed micelles and diffuse across the lining of the intestine (This is not true for short and medium chain FA only long chain)

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11
Q

What is Steatorrhea ?

A

Excess fat in the feces due to lack of lipid absorption

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12
Q

What happens to the insoluble fats (TAG) ?

A

They are packaged up as chylomicrons and exocitosed into the lymph then the blood an then transported to the tissues

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13
Q

What breaks down TAG when it reaches the peripheral tissues ?

A

Lipoprotein lipase

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14
Q

What is TAG broke down into within the cell ?

A

Glycerol and free FA

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15
Q

How is TAG stored within the cells ?

A

Within adipose as droplets

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16
Q

Once TAG has been stored within the adipose how is it then extracted ?

A

Hormone sensitive lipase

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17
Q

How are free FA transported within the blood stream ?

A

Serum albumin

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18
Q

What is the structure of a lipoprotein ?

A

Hydrophobic center and hydrophillic outside

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19
Q

What are the classes of lipoprotein in order of Smallest to Largest ?

A

Chylomicrons
VLDL
LDL
HDL

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20
Q

What kind of lipoprotein is high in cholesterol and will cause atherosclerosis ?

A

LDL

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21
Q

What is Beta Oxidation ?

A

The breakdown of FA in mitochondria in order to generate Acetyl CoA which then enters the CAC

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22
Q

What has to happen in order to release the stored FA in TAG in the adipose tissue ?

A

Beta Oxidation

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23
Q

How many carbons does Beta oxidation degreade FA by ?

A

2 carbons at a time

24
Q

What are he 3 stages of Beta Oxidation ? and where do they occur ?

A

1: Activation (in cytosol)
2: Transport (Into the mitochondria)
3: Degradation (Has 4 steps and occurs in the mitochondrial matrix)

25
Q

How is the FA transported into the mitochondrial matrix ?

A

Carnitine shuttle

26
Q

What is added to Carnitine in order for it to be transported across the mitochondrial membrane ?

A

Malonyl CoA

Which gives us Aceyl carnitine

27
Q

What are the three steps of FA degredation (Beta Oxidation) ? what does this generate ? how much ?

A

1: Dehydrogenation
2: Hydration
3: Dehydrogentation
4: Thiolysis

Generates energy, 129 ATP !

28
Q

Why cant animals turn FA straight into Glucose ?

A

Due to thermodynamically irreversible pyruvate to acetyl CoA step

29
Q

How are ketone bodies generated ?

A

During starvation low glucose generates excess acetyl CoA from fatty acid metabolism is converted into ketone bodies.

30
Q

What are ketone bodies ?

A

Water soluble carriers of Acetyl CoA

31
Q

Where are ketone bodies made ?

A

The Liver

32
Q

What parts of the body use Ketone bodies as an energy source ?

A

Cardiac and skeletal muscle

33
Q

FA degradation and FA synthesis occur at the same time , true or false ?

A

False, they do not occur at the same time.

34
Q

Where does FA degradation occur ?

A

Mitochondrial matrix

35
Q

Where does FA synthesis occur ?

A

Cytosol

36
Q

Which, degradation or synthesis uses an enzyme complex ?

A

Synthesis

37
Q

What is the process of FA degradation ?

A

Oxidation
Hydration
Oxidation
Cleavage

38
Q

What is the process of FA synthesis ?

A

Reduction
Dehydration
Reduction
Condensation

39
Q

Which organ does FA synthesis occur in ?

A

The liver

40
Q

Where in the cell does FA synthesis occur ?

A

The cytosol

41
Q

What occurs when citrate is high within the mitochondria ?

A

The citrate shuttle

42
Q

What cannot cross the mitochondrial membrane ?

A

CoA

43
Q

What part of Acetyl-CoA can cross the mitochondrial membrane ?

A

Acetyl part

44
Q

What are the 2 enzymes required for FA synthesis ?

A

Acetyl-CoA Carboxylase

Fatty Acid Synthase

45
Q

What activates Acetyl-CoA Carboxylase ?

A

Insulin/Glucagon

Citrate

46
Q

What deactivates Acetyle-CoA Carboxylase ?

A

Epinephrine

Palmitoyl CoA

47
Q

How is Malonyl CoA formed ?

A

Acetyl CoA to Malonyl CoA is thermodynamically unfavorable therefore this reaction is coupled with the hydrolysis of ATP.
CO2 is added to Acetyl CoA to form Malonyl CoA

48
Q

Where is Malonyl CoA formed ?

A

In the Cytoplasm

49
Q

What enzyme regulates the formation of Malonyl CoA from Acetyl CoA ?

A

Acetyl CoA carboxylase

50
Q

What enzyme regulates the formation of Palmitic acid from Malonyl CoA ?

A

Fatty acid synthase

51
Q

How many sub-units does FAS have ? what attaches to these subunits ?

A

2

Malonyl and Acetyl groups

52
Q

What are steroid hormones ?

A

Chemical substances that serve as chemical messengers in the body

53
Q

Where is cholesterol made ?

A

The liver

54
Q

What is the starting material for the synthesis of steroid hormones ?

A

Cholesterol

55
Q

What are Eicasanoids ?

A

Derived from 20 carbon unsaturated FA

56
Q

Name 3 pre-cursors of Eicasanoids

A

Prostaglandins
Thromboxones
Leukotrienes