1
Q
Unsaturated FA
A
Double bonds present
- cause kinks
- three carbon intervals
- reduces melting temp, increases fluidity
2
Q
Why do membrane phospholipids often contain double bonds?
A
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
Q
What are 2 essential FA?
A
- a-linolenic acid
- linoleic acid
4
Q
Arachidonic acid
A
Becomes essential is linoleic acid is deficient in the diet
5
Q
Linoleic acid
A
- essential FA
- omega 6
- precursor for other omega 6 FA
- arachidonic acid becomes essential if this is deficient
6
Q
A-linoleic acid
A
- precursor for omega 3 FA
- important for growth and development
- essential FA
7
Q
Arachidonic acid
A
- substrate for prostaglandin
- becomes essential id linoleic acid is deficient in diet
8
Q
FA less than 12 carbons
A
-short and medium chain
9
Q
FA greater than 22 C
A
VLCFA
10
Q
Where are LCFA synthesized>
A
de novo synthesis
11
Q
Where are VLCFA synthesized ?
A
Brain tissue
12
Q
Dietary lipids
A
- TAG
- phospholipids
- free FA
- cholesterol
- cholesterol esters
13
Q
Acid lipase
A
- lingual lipase
- gastric lipase
- target TAG containing short and medium chain FA
- can get through to blood stream without micelle
14
Q
What are the two complimentary actions of emulsification in the small intestines?
A
- mechanical agitation
- bile salts secretion
- detergent
- don’t coalesce
- allows pancreatic enzymes more surface area
15
Q
What are the pancreatic enzymes responsible for TAG digestion
A
- pancreatic lipase
- colipase
16
Q
Phospholipase A2
A
- phospholipid digestion
- removes the fatty acid from position 2 from arachidonic acid
17
Q
What do gut endocrine cells sense?
A
CCK senses lipids and proteins, causes reduction of gut motility
Secretin senses low pH and secretes bicarbonate
18
Q
Micelles
A
- amphipathic lipids
- DEAK
19
Q
How do short and medium chain FA get into blood stream?
A
They don’t need a micelle
20
Q
Fatty acyl-CoA synthetase (thiokinase)
A
-loads fatty acyl-CoA for entry into chylomicron
21
Q
Chylomicron
A
- ER—lymph system—-blood
- contain B-48
- carries neutral lipids such as TAG and DEAK vitamins
22
Q
Lipoprotein lipase
A
- 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
Q
Lipid malabsorption
A
Poor digestion such as inability to secrete the proper amount of bile.
Shortened bowel disease
24
Q
Cystic fibrosis
A
- 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
Biochem BLOCK 2
flashcards
Decks in class (14)
# Cards
-
TCA (Krebs Cycle)57
-
Cholestero, Lipoprotein Metabolism And Steroids61
-
Deevska-Block 2166
-
YOUNGER BLOCK 262
-
ETC51
-
gluconeogensis (GNG)32
-
glycogen72
-
Pentose Phosphate pathway and NADPH40
-
Metabolism of other Mono-and Disaccharides34
-
Lipid classification34
-
Lipid Digestion and Absorption38
-
complex lipids112
-
Fatty acid synthesis50
-
Fatty Acid Metabolism100
