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Biochemistry 2 > Lipids as signals > Flashcards

Lipids as signals Flashcards

1
Q

Hormone is

A

any biochemical that can act as a signal

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2
Q

Three types of hormones

A

Paracrine - any hormone or signal that acts on the same tissue or nearby cells

Autocrine- influcnes itself, targets the cell that produces the signal

Juxtacrine- that requires close contact to produce an effect

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3
Q

Three types of lipids

A

Structural( membrane ) and bioactive lipids

Storage

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4
Q

Eight major categories of biological lipids

A 
Fatty acids
Glycerolipids
Glycerophospholipids( membrane lipids+ bioactive)
Sphingolipids ( bioactive +membrane)
Sterol lipids
Prenol lipids( vitamin A, K,E, -> bioactive)
Saccharolipids ( bioactive)
Polyketidies
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5
Q

Glycerophospholipids are precursors of

A

Inositol phosphate (phosphotylinositol 4,5-biphosphate ->PIP2)

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6
Q

Types of phospholipases

A

Phospholipase A1- hydrolyses of first ester bond
A2- second ester bond
C- detaches the sugar and phosphate group from glycerol
D- detaches sugar

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7
Q

How do you get IP3 and PIP23

A

PIP2 with phospholipase C->IP3(second messenger) +DAG

PIP2 with PI3Kinase->PIP3( nucleation center )

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8
Q

What stimulates glycogen breakdown

A

IP3 opens Ca channels
Binding of Ca to calmodulin activates phosphorylase kinase
Glycogen ->(glycogen phosphorylase)->glucose

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9
Q

How do sphingolipids participate in signal regulators?

A

Ceramides stabalize “Lipid drafts”

Sphingomyelins insulate nerve axons-> they allow the signal propagate faster

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10
Q

What is a Lipid raft?

A

Raft - is like a boat in the ocean ( phospholipid), rafts move freely along the cytoplasm membrane, they can carry any signaling mechanism with them , localizing the signal

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11
Q

What is the marker of blood groups

A

Glycosphingolipids

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12
Q

What is the basic sequence of sugars attached to sphingolipids?

A

glucose+galactose+GLcNAc+galactose+fructose-> N-antigen

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13
Q

Why do we have different blood types?

A

regulated by glycosyltransferases, enzymes that are coded in your gene that attaches a sugar
According to what glycosyltransferase you have, you have a specific sugar attached. In O people, we can have any glycosyltransferase, but because One nucleotide deletion in O group, no sugar attached

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14
Q

How do you get blood type A and B

A

A: basic+GalNAc
B:galactose

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15
Q

How do we get arachidonate?

A

It is released from glycerophospholipids by phospholipase A2

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16
Q

Arachidonic acid is

A

An eicosanoid

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17
Q

What can you get from eicosanoid

A

Prostaglandins
Thromboxane
Leukotriens
Lipoxin

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18
Q

The function of prostaglandins

A

Smooth muscle contraction, regulate blood flow, regulate body temperature

When you have fever , you have high concentration of them , prostaglandins are involved in the reproductive cycle ( involved in ovalution), uterine contraction in labering( can be used as drug ) or mence

19
Q

Function of thromboxanes

A

form platelets
form blood clot
reduce blood flow

20
Q

What are NSAIDs ad what do they do

A

nonsteroidal anti-inflammatory drugs (aspirin, iboprufen)

that blocks early steps in arachidonic acids, that prevent formation ofthromboxanes and prostaglandins by inhibiting cycloxigenase enzymes -> reduce inflammation,

21
Q

what do leukotriens do

A

Airway smooth muscle contraction,

22
Q

What is done in Asthma, Arthritis, organ transportation ,etc.

A

Prednisone is given, it inhibits phospholipase A2

23
Q

Eicosanoids function through which signaling pathway

A

GPCR

24
Q

Molecules derived from cholesterol

A 
Testosteron (AR)
Estradiol (ER)
Cortisol (GR)
Aldosterone (MR)
Vitamin D
25
Q

How are steroids transported in the blood

A

By carrier proteins, because they are lipids in the aqueous solution

26
Q

What do steroids do

A

Affect cellular transcription through nuclear receptors

27
Q

How do we sunthesize vitamin D in the skin and how it gets activated

A

formed in the skin from 7-
dehydrocholesterol in a photochemical reaction driven by the UV component of sunlight

Vitamin D3(cholecalciferol) is not itself biologically active, but it is converted by enzymes in the liver and
kidney to 1α,25-dihydroxyvitamin D3 (calcitriol),.
28
Q

What are linear and ring eicosanoids

A

Ring->prostaglandinds,thromboxanes

Linear->Lipoxin, leukotriens

29
Q

Functions of calcitriol

A

a hormone that regulates calcium uptake in the

intestine and calcium levels in kidney and bone

30
Q

Vitamin D3 deficiency results in

A

Rickets

31
Q

Vitamin D sugnals through

A

VDR- nuclear receptor

32
Q

Prenol lipids examples

A

Carotenoids, vitamin A

33
Q

Vitamin A deficiency leads to

A

Growth retardation, night blindness

34
Q

Tretinoin ised to treat

A

Retin -A is used to treat acne and wrinkled skin

35
Q

What receptors are involved with vitamin A

A

Retinoic acid receptor (RAR)

Retinoid X receptor (RXR)

36
Q

How do we get viramin A and use it

A

Vitamin A1 or β-

carotene in the diet can be converted enzymatically to all-trans-retinal and then to all-trans-retinoic acid

37
Q

Vitamin A functions

A

regulate gene expression

central to embryonic development, stem cell differentiation, and cell proliferation

38
Q

Function of vitamin A in vision

A

From all trans-retinal-> all-trans-retinol or obtained directly through the diet, can
be converted to the cis-retinal . This product combines with the protein opsin to form rhodopsin. When a rhodopsin
molecule is excited by visible light, the 11-cis-retinal undergoes a series of photochemical reactions that convert it to alltrans-
retinal .This transformation in the rod cell of the
vertebrate retina sends an electrical signal to the brain that is the basis of visual transduction

39
Q

Tocopherols acting as cofactors examples

A

Vitamin E and vitamin K
Ubiquinone
Plastoquinone

40
Q

Vitamin E and vitamin K functions

A

Vitamin E->an antioxidant. reacts with O2 radicals

Vitamin K- a blood clotting cofactor to prothrombin

41
Q

What medicine is prescribed to patients with strokes

A

Warfarin : a blood coagulant . It inhibits prothrombin

42
Q

Tocopherol is the same as

A

Prenol lipids

43
Q

Functions of ubiquinone and platoquinone

A

Electron transporters in mitochondria
Ubiquinone -> coenzyme A in electric transport chain

Plastoquinone: chloroplast electron carrier

44
Q

How does tretinoin reduce acne acne and skin wrinkle?

A

Tretinoin is all-trans retinoic acid

Acne occurs due to increased cell-cycle and increased inflammation

Tretinoin normalizes cell cycle and reduces expression of enzymes that increases proinflammatory response
Tretinoin increases Type 1 collagen expression and reduces matrix metalloproteinase expression->reduced skin wrinkle

Biochemistry 2 (17 decks)

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