Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem 2 Exam 2 > Eicosanoids > Flashcards

Eicosanoids Flashcards

0
Q

What is the purpose of the eicosanoids?

A

They are a 20 carbon structure that control/modulate several body functions by acting on extracellular surface receptors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Essential fatty acids are ________ fatty acids and are the precursor for what?

A

polyunsaturated (PUFA); EFAs are the precursors of hormone-like molecules - the eicosanoids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the parents of the omega 3 and omega 6 fatty acid families?

A

a-Linolenic (w3) and linoleic (w6)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 types of eicosanoids?

A

Prostaglandins (PG), Leukotrienes (LT), Prostacyclins, and Thromboxanes (TX)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which two eicosanoids have opposing actions?

A

Prostacyclins and Thromboxanes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the opposing actions of prostacyclins and thromboxanes?

A

Prostacyclins (endothelium): anti-aggregation of cells, vaso-dilation, lowers BP
Thromboxanes (platelets): aggregation of cells, vaso-constriction, raises BP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do eicosanoids act as local signaling molecules?

A

They connect to G-proteins and act locally to produce local effects.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which cells do the leukotrienes act upon?

A

WBCs - specifically the phagocytes: macrophages, neutrophils, and monocytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the parent molecule of prostaglandins?

A

Prostanoic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Bonds projecting from the ring at position 8 and 12 of prostanoic acid is in which configuration?

A

Trans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

All natural prostaglandins have a hydroxyl at which carbon?

A

C-15

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the additional letter on PG designate? (i.e. PGA)

A

Variation in ring structure and substiuents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the designation of the numerical subscript of PG?

A

Number of double bonds in the hydrocarbon chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In PG what are the configurations for the following double bond locations? (13,14), (5,6), and (17, 18)

A

(13,14): Trans
(5,6): Cis
(17,18): Trans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

True/False: Acetyl CoA can be converted to glucose…

A

FALSE!!! Acetyl CoA CANNOT be converted to glucose!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How are TX similar to PG?

A

TX ring structure is a 6 carbon oxy-heterocycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are LT derived from and what is their structure?

A

They are derived from HPETEs and they are an open-chain structure containing 3-5 double bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the additional letter for the LT?

A

It is the specific modification of the parent chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where is arachidonic acid (AA) found?

A

It is inserted into the C-2 position of membrane phospholipids and influences membrane properties.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is AA released from membrane phospholipids?

A

The major releasor of AA is phospholipase A2, which is also used to remodel the membrane. The amount of AA released is in direct proportion to how much is available.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which part of the cell membrane phospholipids is inhibited by steroids?

A

Steroids inhibit the phospholipases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are inhibitors of cyclooxygenase? (COX1 or COX2 inhibitors)

A

Pharm.: Aspirin, indomethacin

Natural: Ginger & Omega 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the natural inhibitor of 5- (LOX)?

A

Ginger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are natural inhibitors of Prostacyclin (PGI2)?

A

Selenium, curcumin, and zinc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a natural inhibitor of the production of both prostacyclins and TXs?

A

Zinc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is a natural inhibitor of TXs?

A

Garlic and curcumin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the direct parent materials of prostacyclins and TXs?

A

Prostaglandin H2 (which derived from PGG2, from COX)

27
Q

Which material creates HPETE?

A

5-Lipoxygenase (LOX)

28
Q

HPETE creates 12-Lipoxygenase which in turn creates which two materials and what do those materials do?

A

Lipoxin A (LXA4) and Lipoxin B (LXB4): Inhibit neutrophil adhesion and chemotaxis

29
Q

HPETE creates Leukotriene A4, C4, D4, and E4. Which are the most powerful vasoconstrictors known and what do they do?

A

Leukotriene C4, D4, and E4. They are responsible for slow reacting vasoconstriction, brochospasm, and increased vascular permeability. (anaphylaxis)

30
Q

5-HPETE creates 5-HETE which is responsible for the creation of which reaction and which leukotriene?

A

Chemotaxis; leukotriene B4

31
Q

Aside from prostacyclins and TX, what does PGG (followed by PGH2) create and what are their functions?

A

PGD2 and PGE2; vasodilation and increased vascular permeability

32
Q

Cyclooxygenases (COX) initiates conversion of arachidonate and other precursors into ______ and ______.

A

PGs and TXs

33
Q

COX 1 and COX 2 are considered the ________ of all cells.

A

Housekeeper

34
Q

Lipoxygenases (LOX) converts arachidonate into _________ which is the precursor for which eicosanoids?

A

HPETEs; leukotrienes or into lipoxins

35
Q

What are the system types of COX versus LOX?

A

COX - cyclic pathway

LOX - linear pathway

36
Q

Eiscosanoids have a short half-life. How are they inactivated?

A

It is inactivated when the hydroxyl at C15 is oxidized to a ketone

37
Q

What is the anti-inflammatory action of steroids on arachidonic acid?

A

It is mediated by inducing synthesis of a protein (lipocortin) which INHIBITS Phospholipase A2.

38
Q

NSAIDS are __________ of COX. What are 2 NSAIDS and which one is reversible and which one is irreversible?

A

inhibitory; Aspirin (irreversible) and Ibuprofen (reversible)

39
Q

What is special about acetaminophen?

A

It is not an NSAID, so therefore it is not anti-inflammatory; it is a pain reliever.

40
Q

COX1 is a constitutive enzyme of what?

A

gastric mucosa, platelets, vascular endothelium and kidney; (they produce “housekeeping” prostaglandins)

41
Q

How is COX2 derived and what does it produce?

A

It is inducible; produced in response to inflammation (produces inflammatory prostaglandins)

42
Q

What are 3 stimulus for the production of arachidonic acid?

A
  1. ) Thrombin (platelet aggregation)
  2. ) Histimine
  3. ) Cytokines: IL-1, IL-6, and TNFg
43
Q

What does the number after LOX (i.e. LOX 5, LOX 12, LOX 15) designate?

A

It designates where oxygen is introduced.

44
Q

Where do we get our main sources of arachidonic acid? Why?

A

Diet; it is inefficiently synthesized from linoleic acid because delta 5 and delta 6 desaturases are slow enzymes

45
Q

The capacity for arachidonic acid synthesis is _________ with gamma-linolenic acid (GLA) in the diet.

A

greater

46
Q

Which parental eicosanoids compete for placement in membrane phospholipids?

A

Linoleic and a-linolenic compete with arachidonic acid

47
Q

What product formed from GLA is also inserted into the C2 position of membrane phospholipids?

A

Most of the DGLA

48
Q

Ultimately, which 7 products compete for placement into the membrane?

A

Oleic, linolenic, a-linoleic, GLA, DGLA, w6, and w3

49
Q

What are the 3 major types of omega-3 fatty acids in the diet?

A

a-linolenic (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)

50
Q

What is ALA converted to? What is the capacity for this pathway?

A

EPA and DHA; this pathway has a limited capacity (1-5% is actually converted)

51
Q

True/False: Omega 3 and Omega 6 fatty acids compete for placement in membrane phospholipids.

A

True

52
Q

What percent of arachidonic acid is synthesized in the body?

A

Only 5%, it is a highly inefficient system

53
Q

True/False: GLA’s are omega 3 fatty acids.

A

FALSE! They are NOT omega 3

54
Q

What are the products of DGLA?

A

Series 1 prostaglandins (PGE1) and thromboxanes (TXA1, LT3)

55
Q

Arachidonic acid is the precursor for which series eicosanoids? What processes are promoted by these?

A

Series 2 (TX2 & LT4); promotes inflammatory responses and resolution of inflammation

56
Q

What is the precursor of the series-3 eicosanoids? What are the consequences?

A

EPAs; they are less inflammatory

57
Q

What are specialized lipid pro-resolving mediators and what are they important for?

A

Lipoxins; important control elements of inflammation (repair process - recruits cells & chemical mediators)

58
Q

What is the function of lipoxins?

A

They mediate reduction in inflammation.

59
Q

Lipoxins are a product of what? Which makes them which type of omega fatty acid?

A

arachidonic acid; omega 6

60
Q

Synthesis of lipoxin epimers which physiological activity can be induced by what?

A

Aspirin

61
Q

EPA and DHA serve as precursors for what potent anti-inflammatory lipids and what are they made from?

A

Resolvins (RVs - resolves inflammation) and Protectins (PDs)
D series resolvins are made from DHA
E series resolvins are made from EPA

62
Q

Low dose aspirin induces synthesis of what?

A

Resolvins

63
Q

What tissue does protectin operate and what does it protect?

A

They operate within brain tissue and protect retinal epithelial cells

64
Q

How can specialized lipid pro-resolving mediators arise from transcellular synthesis?

A

Cell to cell interactions involving the transfer of biosynthetic intermediates.

Biochem 2 Exam 2 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions