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BC 2- > Lipids > Flashcards

Lipids Flashcards

1
Q

Define hormone

A

Hormone is any chemical that can elicit a cellular response

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2
Q

Define paracrine

A

Hormones that act on tissues that are nearby

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3
Q

Define autocrine

A

Chemical that act on the tissue that has produced the chemical itself

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4
Q

Define juxtacrine

A

Chemical and it’s receptor are cell membrane molecules. Ligands is expressed by one cell, the receptor is expressed by another cell. When the two interact, we call it Juxtacrine signaling

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5
Q

Define pheromone

A

Volatile substance that is made by one individual and act on another individual

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6
Q

Name biologically active lipids

A

Glycerophospholipids
Sphingolipids
Sterol lipids
Prenol lipids

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7
Q

What are biologically active lipids

A

Lipids, that are involved in bio signaling

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8
Q

What is the other name for membrane lipids

A

Structural lipids

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9
Q

What are precursors of inositol-phosphates

A

Glycerophospholipids

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10
Q

What type of lipid is PIP2?

A

Glycerophospholipid

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11
Q

How is PIP2 turned into inositol-phosphates

A

Phosphotylinositol 4,5-bisphosphate –Hydrolysis by Phospholypase C–> IP3 + DAG

Phosphotylinositol 4,5-bisphosphate –phosphorylation by PI3Kinase–> PIP3

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12
Q

IP3 and DAG which one stays in the membrane, which one enters the cytosol

A

IP3 enters the cytosol

DAG stays in the membrane

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13
Q

What does IP3 do?

A

Stimulates glycogen breakdown

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14
Q

How does IP3 stimulate glycogen breakdown?

A
  1. GPCR interacts with a ligand-> goes to activate its target
  2. Its target is PLC which cleaves PIP2 into IP3 and DAG
  3. IP3 cuases a release of Ca2+. Ca2+ activate calmodulin
  4. Calmodulin is an effector which leads to a signaling cascade that activates an enzyme phosphorylase kinase
  5. Phosphorylase kinase activates glycogen phosphorylase
  6. Glycogen phosphorylase cleaves off glucose molecules from glycogen polymers.
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15
Q

– is the simplest form of sphingolipids

A

Ceramide is the simplest form of sphingolipids

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16
Q

Can sphingolipids be involved in signaling?

A

Sphingolipids are mainly structural lipids

Assists in signaling process, but not a signaling molecule itself

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17
Q

How do sphingolipids assist in signaling?

A
  • Ceramide holds lipid rafts together
    These rafts are fully mobile. As they move in the plasma membrane, they carry with them any receptors or signaling molecules within that region
    That is how signal can be localized
  • Sphingomyelin insulate nerve axons
    Important for action potential propagation
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18
Q

What are glycosphingolipids?

A

Sphingolipids with sugars

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19
Q

Describe how genetics determine the blood groups

A

Blood group depends on the additional sugars added to a oligosaccharide head groups (H-antigen_ of glycosphingolipids
These sugars are added by specific glycosyltransferases
Depending on a gene for a specific glycosyltransferases oyu can either have:
O antigen: H antigen only
A- antigen: H antigen+ N-acetylgalactosamine
B antigen: H antigen + N-acetylglucosamine

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20
Q

What are eicosanoids?

A

Lipids with 2o carbons

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21
Q

What is the most basic eicosanoid?

A

Arachidonic acid

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22
Q

How is Arachidonic acid produced

A

It is released from glycerophospholipids by enzyme Phospholipase A2

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23
Q

What are the functions of prostaglandins?

A

Function in paracrine signals, smooth muscle contractions/ Also regulate reproductive cycles. Uterine contractions. Sometimes used in labors to induce uterine contractions

24
Q

What are the functions of thromboxanes? Where are they released from?

A

Form blood clots and reduce blood flow. Released from platelets - thrombocytes, hence the name

25
Q

What are NSAIDs?

A

Nonsteroidal anti-inflammatory drugs
Inhibit cyclooxygenase enzymes (COX1 and 2) that are involved in production of prostaglandins and thromboxanes from arachidonate
These drugs reduce inflammation as prostaglandins are pro-inhibitory lipids

26
Q

What are leukotrienes?

A

Cause airway smooth muscle contractions

They are produced by leukocytes- white blood cells.. In asthma and anaphylactic shock

27
Q

What can inhibit leukotrienes? Uses of it

A

Prednisone

Used to treat asthma

28
Q

Name eicosanoids (5)

A 
Arachidonate
Prostaglandins
Thromboxanes 
Leukotrienes
Lipoxin A
29
Q

Leukotrienes and lipoxins are called ___ eicosanoids- no ____

A

Leukotrienes and lipoxins are called linear eicosanoids- no ring structure

30
Q

Which enzyme should be targeted to inhibit production of all prostaglandins from arachidonate

A

Phospholipase A2

31
Q

Which type of receptors is used by eicosanoids?

A

All of their receptors are GPCRs

32
Q

Name the receptor of testosterone

A

Androgen receptor

33
Q

Name the receptor of estradiol

A

Estrogen receptor

34
Q

Name the receptor of cortisol

A

Glucocorticoidreceptor

35
Q

Name the receptor of aldosterone

A

Mineralocorticoid receptor

36
Q

Steroids- derived from __; carried in blood by ___

A

Steroids- derived from cholesterol; carried in blood by carrier protein

37
Q

What is the structure of steroids

A

three 6 carbon rings, one 5 carbon ring

38
Q

What do steroids mainly affect? How?

A

They mainly affect cellular transcription through their receptors- nuclear receptors

39
Q

Vit D is both a ___ and __

A

Vit D is both a hormone and vitamin

40
Q

What are the two form of Vit D3?

A
  • Cholecalciferol - inactive

- 1,25-Dihydroxycholecalciferol (Calcitriol)- active

41
Q

What does Calcitriol do?

A
  • Plays a major role in calcium metabolism- Ca absorption (intestine) and excretion (kidney)
  • Ca storage (bone)
42
Q

How does Vit D signal?

A

Signals through Vit D receptor (VDR), which is a nuclear receptor

43
Q

What are the consequences of Vit A deficiency?

A

Vit A deficiency leads to
growth retardation, night
blindness, etc

44
Q

Describe how does beta-carotene acts as a precursor

A

It’s a precursor for Vit A
b-carotene can be cleaved into all-tans-retinal which can either be converted to all trans-retinoic acid or all-trans-retinol (Vit A)

45
Q

What can be formed from all-trans-retinol (Vit A)? It importance?

A

Visual pigment rhodopsin which is converted to all-trans-retinal
This is the process by which our eyes sense light

46
Q

What are the receptors associated with carotenoids?

A

Nuclear receptors: Retinoic acid receptor (RAR) for hormone signaling (change in gene expression) and Retinoid X receptor (RXR) for neuronal signaling (vision)

47
Q

Name tocopherols and their general function

A

Tocopherols act as cofactors

  • Vitamin E
  • Vitamin K
  • Warfarin
48
Q

Function of ubiquinone

A

Mitochondrial electron carrier

49
Q

Function of warfarin

A

Blood anticoagulant- a synthetic compound- inhibits prothrombin

50
Q

Eicosanoids are __ hormones and ___ factors

A

Eicosanoids are paracrine hormones and paracrine factors

51
Q

What produces thromboxanes

A

They are produced by platelets

52
Q

Steps of Vit D3 formation

A

Active form is formed from 7-dehydrocholesterol to cholecalciferol (inactive D3)by UV light in skin. It is then converted in liver and kidney to 1α,25-dihydroxyvitamin D3
(calcitriol)

53
Q

Through which receptor does Vit A act?

A

Retinoid acid receptor (RAR), Retinoid X receptor (RXR)

54
Q

Name vitamins that are steroid hormones? Through which receptor do they act?

A

Vit A, D, K and E

Act through nuclear receptors

55
Q

What are tocopherols?

A

Vitamin E is the collective name for a group of closely related lipids called tocopherols

56
Q

What are the benefitial functions of Vit E, Vit K and Warfarin?

A

Vit E reacts with O2 radicals- antioxidant
Vit K is a co-factor for prothrombin- helps in blood clotting
Warfarin- Blood anticoagulant- a synthetic compound- inhibits prothrombin

BC 2- (19 decks)

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