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Flashcards in Membranes Deck (40):
1

Phospholipids

Most abundant lipids found in biological membranes

2

Glycerophospholipids

Glycerol backbone, with a phosphate and two fatty acids esterified to backbone

3

Sphingolipids

Sphingosine backbone, with LCFA and phosphorylcholine

4

Glycolipids

Sphingosine backbone with carbohydrate (oligosaccharide) residues. Found in outer leaflet

5

Cholesterol

Embedded in lipid bilayer. Steroid nucleus with a hydroxyl group and hydrocarbon side-chain. Lipid Rafts

6

Which lipids make up the outer sheet of the membrane?

Phosphatidylcholine,
Sphingomyelin, Glycolipids

7

Which lipid is always present in the inner sheet of the membrane except during apoptosis?

Phosphatidylserine

8

Which lipid is a marker for apoptosis?

Phosphatidylserine goes to outer leaflet during apoptosis

9

Niemann-Pick Disease

Acid Sphingomyelinase deficiency. Results in enlarged liver, spleen and neuro damage, also cherry red spot in the eye

10

Integral Membrane proteins

embedded in the membrane and stabilized by hydrophobic reactions with lipids

11

Peripheral proteins

loosely bound to lipids and proteins in membrane through electrostatic interactions

12

Lipid-anchored proteins

attached via covalent bonds to a lipid

13

Glycocalix

carbohydrate shell located on the outer sheet of the membrane. always covalently bound to either lipids or proteins, never by itself

14

What are the three functions of Glycocalyx?

Protection, cell adhesion, cell identification

15

Which type of blood is the universal donor?

Type O because it has no surface antigens

16

Which type of blood is the universal acceptor

Type AB because it doesn't have any antibodies in the plasma

17

Explain Rh Factor and hemolytic disease

Erythroblastosis fetalis: when mom is Rh- and baby is Rh+, the mom produces antibodies during pregnancy and the second baby is at high risk if also Rh+

18

Explain Membrane fluidity

Proteins and lipids rotate and move laterally in membranes, this movement is crucial for function because it allows proteins and lipids to undergo conformational changes.

19

Factors that influence membrane Fluidity

Temperature
Lipid Composition
Cholesterol

20

How does Temp affect fluidity

If temp barely above melting temp(Tm) then optimal fluidity, if below Tm then rigid, if too high then too fluid

21

How does Lipid Composition affect fluidity?

Saturated FA: lower membrane fluidity
Unsaturated FA: increase fluidity

22

Cholesterol in rigid membrane

increase fluidity

23

Cholesterol in fluid membrane

decrease fluidity

24

Spur Cell Anemia

Elevated levels of Cholesterol result in increased rigidity of membrane leading to RBC's with broken membranes

25

What kind of molecules can cross membrane via simple diffusion?

Small nonpolar molecules High Concentration to low concentration: O2, N2, Ethanol, Diethylether, Benzene
Small, polar, uncharged molecules:
H2O, CO2, NH3, Urea

26

Ion Channels

high throughput (transport millions of molecules per second)

27

Ligand-gated ion channels

Ligands bind to transporter allowing for transporter to open and ions to enter.

28

How do anesthetic affect ion channels

They block the ion channels (pufferfish toxin)

29

Difference between Primary and Secondary active transport

Primary uses ATP directly, Secondary uses energy stored in concentration gradient

30

P type ATPases

ATP is hydrolysis gives energy, protein gets phosphorylated. Example: Na+/K+ ATPase and Ca2+ ATPase

31

ABC Transporters

ATP is hydrolyzed, but does not phosphorylate the transporter. Active transport goes against the gradient. ATP hydrolized but does not phosphorylate the proteins!

32

Secondary Active Transport

Moves things against concentration gradient but does not use ATP hydrolysis, Uses coupled reaction of unfavorable flow of one species against its gradient and flow of another with its gradient. Example: SGLT1

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Types of Secondary Transporters

Antiporter, symporter, uniporter

34

Sodium-glucose transporter 1 (SGLT1)

Line small intestine and renal tubes, Unidirectional movement of Na+ with its gradient and Glucose against its gradient.

35

Na+ - Ca2+ Exchanger (NCX)

Antiporter. Imports 3 Na+ down the gradient and exports 1 Ca2+ against the gradient.

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Apical side

Lumen of intestine

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Basolateral side

blood stream

38

Cystic Fibrosis

AR disorder. Mutation in CFTR gene which channel that mediates the active transport of Cl- from inside the cells to outside airways. Defective CFTR causes accumulation of Cl- inside the airway leads to thick mucous and leaves airways prone to bacterial infections.

39

Cystinuria

AR disoder caused by defect in transport that uptakes Cystine. Results in Cystine crystal formation.

40

Hartnup Disease

AR disorder caused by defect in transporter for all non-polar and neutral AA. Causes cerebella ataxia, photodermatitis and photo-sensitivity.