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Flashcards in YOUNGER BLOCK 2 Deck (62):
1

Unsaturated FA

Double bonds present
-cause kinks
-three carbon intervals
-reduces melting temp, increases fluidity

2

Why do membrane phospholipids often contain double bonds?

Because they are LCFA (the longer the chain, the higher the melting temp) and needs the double bonds there to lower the melting temp and increase fluidity

3

What are 2 essential FA?

-a-linolenic acid
-linoleic acid

4

Arachidonic acid

Becomes essential is linoleic acid is deficient in the diet

5

Linoleic acid

-essential FA
-omega 6
-precursor for other omega 6 FA
-arachidonic acid becomes essential if this is deficient

6

A-linoleic acid

-precursor for omega 3 FA
-important for growth and development
-essential FA

7

Arachidonic acid

-substrate for prostaglandin
-becomes essential id linoleic acid is deficient in diet

8

FA less than 12 carbons

-short and medium chain

9

FA greater than 22 C

VLCFA

10

Where are LCFA synthesized>

de novo synthesis

11

Where are VLCFA synthesized ?

Brain tissue

12

Dietary lipids

-TAG
-phospholipids
-free FA
-cholesterol
-cholesterol esters

13

Acid lipase

-lingual lipase
-gastric lipase
-target TAG containing short and medium chain FA
-can get through to blood stream without micelle

14

What are the two complimentary actions of emulsification in the small intestines?

-mechanical agitation
-bile salts secretion
-detergent
- don't coalesce
- allows pancreatic enzymes more surface area

15

What are the pancreatic enzymes responsible for TAG digestion

-pancreatic lipase
-colipase

16

Phospholipase A2

-phospholipid digestion
-removes the fatty acid from position 2 from arachidonic acid

17

What do gut endocrine cells sense?

CCK senses lipids and proteins, causes reduction of gut motility

Secretin senses low pH and secretes bicarbonate

18

Micelles

-amphipathic lipids
-DEAK

19

How do short and medium chain FA get into blood stream?

They don't need a micelle

20

Fatty acyl-CoA synthetase (thiokinase)

-loads fatty acyl-CoA for entry into chylomicron

21

Chylomicron

-ER---lymph system----blood
-contain B-48
-carries neutral lipids such as TAG and DEAK vitamins

22

Lipoprotein lipase

-clip FA from chylomicron
-synthesized and secreted by muscle and adipose


Remnants interact with liver cells and are endocytosed, this is where the vitamins get absorbed into the body

23

Lipid malabsorption

Poor digestion such as inability to secrete the proper amount of bile.
Shortened bowel disease

24

Cystic fibrosis

-cant take up fat soluble vitamins
-pancreatic insufficiency, significant reduction in dietary calories, decrease fat soluble vitamin up take
-treatment includes: enzyme replacement, and fat soluble vit supplements

25

De novo synthesis

-well fed
-cytosol of liver and mammary glands of lactating mammals
-cytosolic acetyl CoA is carbon source for growing FA chain (originate in mitochondria)
-energy source: ATP and NADPH

26

Which membrane of the mitochondria is hard to get across?

The inner mitochondrial membrane

27

ACC

-dimers in cytosol
-coalesce to larger molecule which is active
-takes CO2/energy and carboxylase acetyl CoA to malonyl CoA
-RATE LIMITING STEP

28

Presence of citrate

Signals ACC

29

Short term regulation of ACC

-AMPK reversibly phosphorylates and inhibits ACC
-LCFA presence also inhibits it (substrate)

30

Long term regulation of ACC

-prolonged high calorie, high carb increases ACC synthesis
-low calorie or high fat diet reduces ACC synthesis

31

FAS

-multifunctional dimeric enzyme
-7 different enzymatic activities
-acyl carrier protein (ACP)
-holding site for cysteine


2 C from malonyl CoA
ATP
NADPH

32

Predominant source of the NADPH required for FA synthesis

HMP shunt

33

Palmitate

Elongated at the smooth ER
Reduction of NADPH
2 C from malonyl CoA

34

Desaturation of FA chains

Add double bonds to maintain fluidity at body temp

35

Carbon 2 on TAG

Unsaturated FA of varied length

36

Where is TAG generated ?

In liver and adipose

37

TAG generation in liver

Glycerol kinase converts free glycerol to glycerol phosphate simply by adding a phosphate group

38

What do chylomicrons deliver?

Exogenous dietary lipids

39

What do VLDLS deliver?

De novo synthesized lipids

40

Adipose lipase

-constitutive, low level release of FA

41

Hormone sensitive lipase

-major role in regulated TAY lipolysis and release
-much more than adipose lipase
-heavily influenced by insulin

42

What is the major pathway for obtaining energy from FA

B-oxidation in the mitochondria
FA must be in the fatty acyl CoA

43

Products of B oxidation

Acetyl CoA, NADH, FADH2q

44

Carnitine shuttle

-imports LCFAs into the mitochondria
-CATI on outer mitochondrial membrane acyl groups transferred from CoA to carnitine. Regulated by malonyl CoA
-CATII on matrix side acyl group transfer from carnitine to CoA

45

CAT I inhibition

Malonyl CoA
-preventing LCFA transfer from CoA to carnitine

46

Source of carnitine

Diet
Synthesized in liver/ kidney

47

Where is most of the carnitine

Skeletal muscle

48

Secondary carnitine deficiency

-liver disease
-malnutrition
-dialysis
-pregnancy

49

Primary carnitine deficiency

congenital deficiencies
CAT I and CAT II defect

50

Energy molecules for B oX

NADH
FADH2
Acetyl CoA--produce ketone bodies in liver to be used by peripheral tissue

51

What vitamin is required for odd number of carbon degeneration?

Vitamin B12

52

Saturated or unasturated FA release less energy?

Unsaturated
-require additional enzymes

53

MCAD deficiency

Decreased oxidation of 6 to 10 carbon FA
-hypoglycemia

54

Ketone bodies

-produced in liver from B-oxidation derived acetyl CoA
-acetoacetate and 3-hydroxybutarate transported in the blood to peripheral tissues
-peripheral cells convert ketone bodies back into acetyl CoA, a substrate for the TCA cycle
-decrease the demand on blood glucose

55

Hypoketosis

-fatty acid oxidation disorder due to decreased acetyl CoA availability

56

Hypoglycemia

-fatty acid disorder due to increased reliance on glucose for energy

57

HMG CoA synthase=

-rate limiting step in ketone body synthesis and is present only in the liver to significant amounts
-makes 6-C chain to make ketone

58

Can liver uses ketone bodies as fuel?

No because it lacks thiophorase
-extrahepatic cells having mitochondria can conduct this process

59

Imbalances in use and production of ketone bodies

Cause ketone ketone bodies to rise
-blood (ketonemia)
-urine (Ketonuria)

60

How can ketoacidosis be caused?

Fasting
-decreases blood volume increases H+ concentration causing severe acidosis

61

Why is thromboxane synthesis more severely affected by NSAIDs and how does it affect coagulation?

Inhibits the COX step in the formation of both prostacyclin and thromboxanes
-platelets cannot synthesize new COX because no nucleus and significantly limits the thermogensis potential

62

Glucocorticoids and inhibited phospholipase A2

-inhalers
-steroidal anti-inflammatory drug
-promotes gene level up-regulating of phsopholipase A2 inhibitor