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Flashcards in Plasma membrane & structure Deck (11)
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1
Q

What is the Plasma Membrane?

A
  • The overcovering= a bilayer that ALL CELLS HAVE
  • Acts as a barrier & a very selective door for things that need to be let in (food) & let out (waste)= semipermeable
  • HOMEOSTASIS BEIBI
2
Q

What does the Plasma Membrane separate?

A

-Separates external from internal compartments (extracellular fluid from cytoplasm)

3
Q

What is the structure of the Plasma Membrane?

A
  • Thin, flexible covering over ENTIRE SURFACE of cell

- Thickness is less than 10nm (1 millionth of a cm)

4
Q

What makes the Plasma Membrane so flexible?

A

-phospholipids in the membrane are held together by noncovalent interactions (hydrophobic effect)= AREN’T HELD TOGETHER BY RIGID COVALENT CONNECTIONS

5
Q

What is the Plasma Membrane based on?

A
  • Phospholipid bilayer w/ nonpolar heads on the inside

- Also contains Cholesterol, Glycoproteins, Glycolipids

6
Q

How do we know that membranes have a bilayer?

A
  • Area of the phospholipid is twice the surface area of starting cells (P.L in cell formed a layer that’s 2 molecules thick= bilayer)
  • Monolayer area is twice the RBC surface area= membranes in cells is a bilayer
7
Q

What makes the Plasma Membrane complex?

A

-Multiple lipid & protein components

8
Q

What are the lipid components?

A
  • Cholesterol, steroid (4 carbon rings)
  • Sphingolipids (have 2 nonpolar tails but connected differently w/ a non-glycerol core
  • Glycolipids (have carbs attached)
9
Q

What are the Protein components?

A
  • Integral membrane proteins (span across the membrane & tightly attached to it)
  • Peripheral membrane proteins (sit only on the surface & loosely bound it membrane)
10
Q

What is the complete membrane described by?

A

-Fluid Mosaic Model

11
Q

What does the Fluid Membrane Model describe?

A
  • Membrane lipids & proteins that aren’t fixed can move laterally (in the plane of membrane)
  • Integral membrane proteins float freely even though they are partially submerged in sea of lipid
  • Peripheral membrane proteins can float freely on the surface (either extracellular or intracellular)