DLA1 Flashcards

1
Q

Membrane Components

A

Lipids

Proteins

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2
Q

3 major classes of lipids

A
  • Phospholipids

* Cholesterol • Glycolipids

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3
Q

2 major classes of proteins of membrane

A

Integral membrane

Peripheral membrane

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4
Q

Location of cholesterol in membrane and its effect on membrane fluidity

A

• Intercalates between phospholipids
• Affects membrane fluidity in temperature dependent manner
Reduce membrane fluidity.

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5
Q

What is glycolipid and where is it found?

A
  • Sugar-containing lipid molecules

* Found exclusively in outer monolayer

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6
Q

6 General Categories of Integral Membrane Proteins

A
  1. Pumps/Carriers/Transporters
  2. Channels
  3. Receptors
  4. Linkers
  5. Enzymes
  6. Structural proteins
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7
Q

What does pumps, carriers, transporters transport?

A

Transport specific ions across the membrane
• Sodium
• Potassium

Transport metabolic precursors
• Amino acids • Sugars

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8
Q

What are channels for?

A

Transport of ions, small molecules and water
• Passive diffusion

Aquaporins
• Water

Gap junctions
• Passage of ions, small molecules between adjacent cells

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9
Q

What is glycocalyx?

A

Cell coat where sugar residues are attached to cell surface (glycolipid, glycoprotein, proteoglycan)

  • carbohydrate rich zone on the cell surface
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10
Q

Function of glycocalyx

A

• Protection
• Cell recognition
• Cell to Cell Interaction
-Lectins: Carbohydrate binding proteins

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11
Q

4 features of Membrane Structure

A
  1. Lipid Bilayer
    2 . Asymmetry
    3.Lipid rafts
    4.Fluid mosaic model
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12
Q

Where is phosphatidyl located in membrane and what happens to it during cell death?

A

Phosphatidylserine localizes to the inner leaflet
• Enzymatically transferred to the outer leaflet during programmed cell death
• Triggers phagocytic removal of dying cells

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13
Q

What is lipid rafts?

A

• Specialized cholesterol enriched microdomains

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14
Q

2functions of lipid rafts

A
  • Signal transduction

* Endocytosis

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15
Q

Example of Regulated exocytosis

A

Secretory cells

  • ligand bind to receptor (stimulus)
  • then there is Ca2+ influx which allow Fusion of secretory vesicles with plasma membrane
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16
Q

Pathway of receptor-mediated endocytosis

A

Clathrin-dependent pathway

  1. Cargo protein binds to cargo receptor.
  2. Then Clathrin molecules interact with cargo receptors via Adaptin forming clathrin coated pit.
  3. Vesicle formation
  4. Dynamin mediates the vesicle pinching-off from the plasma membrane
  5. Clathrin and adaptins are recycled
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17
Q

Examples of Receptor recycled, ligand degraded (Receptor-Mediated Endocytosis)

A
  • Low-density lipoprotein (LDL) receptor
  • Insulin-glucose transporter receptor
  • Other peptide hormones & their receptors
18
Q

Examples of Receptor and, ligand recycled (Receptor-Mediated Endocytosis)

A
  • Iron, transferrin & transferrin receptor

* Major histocompatibility complex I & II

19
Q

Examples of Receptor and, ligand degraded (Receptor-Mediated Endocytosis)

A

• Epidermal growth factor (EGF) & receptor

20
Q

Examples of Receptor and, ligand transcytosis (Receptor-Mediated Endocytosis)

A
  • Secretion of immunoglobulins (secretory IgA) into saliva

* Secretion of maternal IgG into milk

21
Q

Pathway of vesicle targeting using Rab-GTPase

A

1.Rab-GRPase interact with vesicle.
2. RabGTPase interact with tethering proteins, immobilizing the vesicle near target membrane.
3. Rab-GTPase and receptor immobilize
the vesicle near target membrane, forming docking complex.
4. v-snare which is vesicle specific interact with t-snare which is target specific, forming cis-snare complex, opening up the vesicle.

22
Q

Difference between early and late endosome

A

Early endosome
• Functions to sort and recycle proteins

Late endosome
• Receives proteins for degradation
• Receives newly synthesized lysosomal enzymes from the Golgi
• Matures into a lysosome

23
Q

3 types of endocytosis

A
  1. Receptor-mediated
    • Cargo-specific
    • Clathrin-dependent
  2. Pinocytosis
    • Non-specific
    • Clathrin-independent
  3. Phagocytosis
    • Clathrin-independent
    • Actin-dependen
24
Q

“Cell Drinking”

A

Pinocytosis

25
Q

When is psudopods used?

A

Phagocytosis

26
Q

Extracellular conc Na

A

140

27
Q

Intracellular Na conc

A

14

28
Q

Extracellular Ca conc

A

2.5

29
Q

Intracellular Ca

A

1x10-4

30
Q

Extracellular Cl

A

105

31
Q

Intracellular Cl

A

10

32
Q

Extracellular HCO3

A

24

33
Q

Intracellular HCO3

A

10

34
Q

Extracellular Mg

A

0.8

35
Q

Intracellular Mg

A

20

36
Q

Extracellular pH

A

7.4

37
Q

Intracellular pH

A

7.1

38
Q

Potassium Ek

A

-84

39
Q

Sodium Ek

A

+66

40
Q

Cl Ek

A

-64