cell membrane Flashcards

1
Q

true or false?

cell membrane is fluid

A

true

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2
Q

true or false?

a membrane is made of lipids

A

true

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3
Q

true or false?

lipid heads are hydrophilic

A

false

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4
Q

true or false?

lipid heads are hydrophobic

A

true

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5
Q

true or false?

lipid tails are hydrophilic

A

true

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6
Q

true or false?

lipid tails are hydrophobic

A

false

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7
Q

true or false?

Cholestrol molecules are both polar and nonpolar

A

true

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8
Q

what does polar mean?

A

A structure having an uneven distribution of electron density

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9
Q

what is nonpolar?

A

A structure in which electron density is more or less evenly distributed

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10
Q

what are hormones madde of?

A

cholesterol

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11
Q

What do cholesterol molecules do?

A
  • anchor phospholipids in the bilayer
  • keeps it from becoming too fluid at a higher temp
  • gives cell membrane a more defined structure
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12
Q

a cell membrane contains…

A

carbohydrates, lipids, and proteins

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13
Q

what do proteins do?

A

form chanells and pumps to help move materials

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14
Q

what do carbohydrates do?

A
  • they’re attatched to the outside of the cell membrane
  • they act like chemical indentification, allowing cells to recognize each other
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15
Q

the cell membrane is selectively permeable

A

toxins (waste material) are pumped out

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16
Q

the cell membrane is self sealing

A
  • a small tear in the bilayer creates a free edge with water
  • allows for the formation of vesticles to release proteins and to create new cells during cell division
17
Q

the cell membrane in flexible

A
  • at high temps: cholesterol molecules interfere with phopholipid movement and reduce fluidity
  • at low temps: keeps the saturated fatty acid tails from packing and mantains adequate fluidity
18
Q

what is the phospholipid bilayer?

A

the cell membrane is arranged in two layers
- extracellular
- intracellular
- hydrophilic tails facing each other
- two rows of lipids
- hydrophobic heads facing out