Chapter 5: Cell Membrane Flashcards

1
Q

Fluid mosaic model

A

Is a model that describes a phospholipid bilayer in which proteins can move about (float in the lipid “lake”)

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2
Q

What are the 3 major functions of fluid mosaic model?

A
  1. Move materials through the membrane
  2. involved in intercellular recognition and adhesion
  3. receive chemical signals from the cell’s external environment
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3
Q

What does carbohydrate attach to in the fluid mosaic membrane?

A

They attach to either lipid or protein molecules

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4
Q

Lipid rafts

A

form from glycolipoprotein lipid microdomains and include more cholesterol (acts like a glue that holds it together and stiffens it)

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5
Q

cholesterol

A

Is a steroid and is found in the membranes of animals and some bacteria.

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6
Q

What is cholesterol made of?

A

It is made of multiple linked rings and a hydroxyl group that interacts with hydrophilic heads of phospholipids

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7
Q

Phospholipids may differ in what?

A
  1. Hydrocarbon chain length
  2. degree of saturation
  3. kinds of polar groups present
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8
Q

What are the 2 important factors in membrane fluidity?

A
  1. lipid composition and proteins
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9
Q

Lipid composition

A

Are types of hydrocarbon tails (Unsaturated or saturated) can increase or decrease fluidity

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10
Q

What are the 2 types of membrane proteins?

A
  1. peripheral membrane protein

2. Intergral membrane proteins

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11
Q

Peripheral Membrane Protein

A

They lack hydrophobic groups and are not embedded in the bilayer

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12
Q

Intergral Membrane Proteins

A

They are at least partly embedded in the phospholipid bilayer that contain both hydrophilic and hydrophobic groups. Hydrophobic groups anchor the protein in the membrane

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13
Q

Transmembrane Protein

A

An intergral membrane protein that extends all the way through the phospholipid bilayer and protrudes on both sides are always oriented the same way

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14
Q

glycolipid

A

They consists of a carbohydrate covalently bonded to a lipid

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15
Q

Glycoprotein

A

They consists of 1 or more short carbohydrate chains covalently bonded to a protein

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16
Q

Proteoglycan

A

A protein with even more carbohydrate molecules attached to it

17
Q

Passive transport

A

Does not require metabolic energy

18
Q

Active transport

A

Requires input of metabolic energy because they involve the movement of a substance against their concentration gradients

19
Q

Diffusion

A

is the process of random movement toward a state of equilibrium

20
Q

Simple diffusion

A

When molecules that are hydrophobic and soluble in lipids can pass through the membrane

21
Q

What does diffusion do?

A
  1. They have molecules from an area of higher concentration to one of lower concentration
  2. can occur in any medium (liquid, solid, gas)
  3. Doesn’t require a semipermeable membrane
22
Q

Osmosis

A

The net movement of a solvent across a selective permeable membrane into a region of higher solute concentration

23
Q

What does osmosis do?

A
  1. Can only occur in liquid
  2. requires a semipermeable membrane
  3. movement seeks to equalize solvent concentration (although it doesn’t achieve it)
24
Q

What are the 3 terms used to compare solute concentrations of 2 solutions separated by a membrane?

A
  1. Hypertonic
  2. Isotonic
  3. Hypotonic
25
Q

Hypertonic

A

The solution has a higher solute concentration than the other solution

26
Q

Isotonic

A

The solution has an equal solute concentration

27
Q

Hypotonic

A

The solution has lower solute concentration than other solution

28
Q

Channel proteins

A

Are integral membrane proteins that form channels across the membrane (speeds of diffusion)