Chapter 7 - Cell Membrane

Question 1

What is ur Fluid Mosaic Model?

Answer 1

A model of what we think a cell membrane looks like.

Question 2

What is the cell membrane made up of?

Answer 2

Phospholipid bilayer

Question 3

What does amphipathic mean?

Hint: phospholipids

Answer 3

Has hydrophobic and hydrophilic properties.

Question 4

How is a cell membrane held together?

Answer 4

They are held together by hydrophobic and hydrophilic reactions.

Question 5

What are integral proteins?

Answer 5

It is a membrane protein that penetrate the hydrophobic interior if the lipid bilayer.

Question 6

What is a peripheral protein?

Answer 6

They are proteins that aren’t embedded in the lipid bilayer at all; they are appendages loosely Bond to the surface of the membrane, often to expose parts of integral proteins.

Question 7

What are glycolipids?

Answer 7

They are membrane carbohydrates that are usually short; some are covalently bonded to lipids.

Question 8

What are glycoproteins?

Answer 8

They are membrane carbohydrates that are usually short; most of these carbohydrates are covalently bonded to proteins.

Question 9

Do cell membranes move? How fast?

Answer 9

Yes they move, they have a lateral movement and they move 10 to the 7th power times per second.

Question 10

Lipids on a cell membrane have…

Answer 10

Hydrophilic heads - stays on the outside of the membrane

Hydrophobic - tails will stay on the inside of the membrane

Question 11

What happens to a membrane when there are unsaturated fats?

Answer 11

It makes the membrane more fluid by linking the tails so that the tails can’t pack like they should.

Question 12

When are cell membranes more fluid? What about in lower temperature?

Answer 12

At high temperatures

It will remain fluid at lower temperatures if there is a lot of phospholipids with unsaturated hydrocarbon tails.

Question 13

What function does cholesterol have for the membrane?

Answer 13

It is like a fluid buffer.
At higher temperature labor makes the membrane less fluid to help the cell from getting destroyed.
At lower temperatures it hinders solidification by disrupting the packing of the tails within the membrane.

Question 14

What is an integral protein?

Answer 14

Proteins that penetrate the hydrophobic interior of the membrane.

They have hydrophilic and hydrophobic portions

Question 15

What are peripheral proteins?

Answer 15

They are proteins that are not embedded in the lipid bilayer at all; they are appendages loosely bound to the surface of the membrane. Hey

Question 16

What are the functions of proteins?

Answer 16

Transport
Enzymatic activity
Signal transduction
Cell-cell recognition
Intercellular joining
Attachment  to the cytoskeleton and extra cellular matrix (ECM)

Question 17

What are glycoproteins?

Answer 17

Short branch chained carbohydrates of <15 sugar Monomers

They are covalently bonded to proteins.

Question 18

What are glycolipids?

Answer 18

Short branch chained carbohydrates of <15 sugar Monomers

Glycolipids are covalently bonded to lipids

Question 19

How is blood types distinguished?

Answer 19

Variations of the carbohydrate part of glycoproteins on the surface of red blood cells.

Question 20

What is a fluid mosaic model?

Answer 20

A model of what we think a cell membrane looks like.

Question 21

What are the 5 different types of membrane transport?

Answer 21

Diffusion
Osmosis
Facilitated diffusion
Active transport
Bulk transport

Question 22

What is diffusion?

Answer 22

When something moves from high concentration to low concentration.

Equilibrium can be reached (where there is the same number of molecules on one side and the other side)

Question 23

What is osmosis?

Answer 23

Diffusion of water through a semipermeable membrane

Isotonic - solutes in a solution; the outside is the same as the concentration on the inside.
Hypertonic - solutes in a solution greater outside (will pull water out)
Hypotonic - solutes in a solution less outside (will pull water in)

Question 24

What is facilitated diffusion?

Answer 24

Going towards equilibrium

Will work through membranes to get to equilibrium

Question 25

What is active transport?

Answer 25

To pump a solute across a membrane against its gradient

This pump also requires ATP

Question 26

What is the sodium-potassium pump?

Answer 26

Pump sodium and potassium through to help make energy.

Potassium will be on one side of the membrane while sodium will be on the other side.

Question 27

What is the proton pump?

Answer 27

Actively transports protons out of the cell.

The pumping of H+ transfers positive charge from the cytoplasm to the extracellular solution.

By generating voltage across membranes, electromagnetic pumps help store energy that can be tapped for cellular work.

Question 28

What is the cotransport?

Answer 28

When hydrogen pumps out of proton pump it will pump hydrogen back through the cotransport bringing sucrose with it.

Question 29

What is the bulk transport?

Answer 29

When a molecule hits a membrane it will wrap around molecule until it closes off into the cell

Question 30

What is endocytosis?

Answer 30

Part of the bulk transport where a molecule goes from the outside to the inside.

Question 31

What is exocytosis?

Answer 31

Part of bulk transport where a molecule goes from the inside to the outside.