Cell Membranes

Question 1

Intracellular

Answer 1

Inside the cell

Question 2

Extracellular

Answer 2

Everything outside the cell

Question 3

Intersitial

Answer 3

Is another term for outside the cell.

-Especially used when many cells are together

Question 4

What makes up the membrane of a cell?

Answer 4

Phospholipids are the basic structure of a membrane.

Question 5

Phospholipid Bylayer

Answer 5

Two layers of phospholipids with the lipid tails facing each other.

Question 6

Why is Cholesterol a necessary component of the Cell Membrane?

Answer 6

• It helps loosen the membrane

- Maintains membrane fluidity and strength

Question 7

How do proteins help the membrane?

Answer 7

They make the membrane functional.

Question 8

Transport Proteins

Answer 8

Transports stuff across the cell membrane

• Inside to outside and outside to inside
• very specific, they will only let one thing through

Question 9

Receptor Proteins

Answer 9

A signaling molecule binds to the receptor outside the cell membrane and on the other side the signal is taken and does something within the cell membrane.
-Very specific

Question 10

Membrane Bound Enzyme

Answer 10

Help carry out chemical reactions within or without the cell membrane.

Question 11

Recognition Proteins

Answer 11

It is often a Glycoprotein

• they tag on cells like a finger print saying I am this kind of cell.
• So cells know what kind of cell it is.

Question 12

Cell Adhesion Molecules

Answer 12

Hold cells together

Question 13

Tight Junctions

Answer 13

Holding the cell membranes together, so tight that no extracellular fluid can get through.

Question 14

Desmosomes (Spot or Adhering Junctions)

Answer 14

Proteins hold the cell together with rivets, so extracellular fluid can slip between the membranes.

Question 15

Gap Junctions

Answer 15

Form a channel between membranes.

• Specialized form of cell communication.
• The extracellular fluid passed through
• -All the cells of the heart are linked this way.

Question 16

Membrane Transport

Answer 16

Moving things across the membrane.

• Membranes are semi-permeable
• -Membranes will let somethings through easily, some with difficulty, and some not at all.

Question 17

Factors Effecting Membrane Permeability

Answer 17

Solubility- (fat solubility) if it is fat soluble it can slip across (oxygen)
Size- If it is to big it can’t go through. It needs to be smaller.
–If it is unsaturated phopholipids it can have more pass through them than saturated.

Question 18

Membrane transport based on passive forces mean

Answer 18

No energy needed to move it across the membrane.

• Diffusion
• Osmosis
• Electrical

Question 19

Diffusion

Answer 19

Random movement of particles

• Movement of a solute from an area of high concentration to an area of lower concentration
• Until they reach equilibrium
• The concentration difference/gradient is what drives diffusion.

Question 20

Simple Diffusion

Answer 20

Going through the membrane

Question 21

Facilitated Diffusion

Answer 21

Going through proteins, so they can slip through. No energy needed.

Question 22

What is the diffusion rate driven by?

Answer 22

The gradient

Question 23

Factors affecting net rate of diffusion

Answer 23

• Concentration Gradient
• Temperature
• Area
• Size
• Distance

Question 24

Concentration Gradient on diffusion rate

Answer 24

Bigger concentration gradient faster it goes through. Lower concentration gradient slower it goes through.

Question 25

Temperature on diffusion rate

Answer 25

Higher temperature, higher diffusion rate. Lower temperature lower diffusion rate.

Question 26

Area on diffusion rate

Answer 26

The space they have to diffuse. Bigger area faster rate of diffusion, smaller area slower rate of diffusion.

Question 27

Size on diffusion rate

Answer 27

The bigger something is the slower the diffusion rate will be.

Question 28

Distance on diffusion rate

Answer 28

How far something has to travel. The greater the distance the slower the rate of diffusion.

Question 29

Osmosis

Answer 29

The Movement of Water - Water molecules move from areas of low solute concentration to areas of high solute concentration. - The solute is to big to move, so the water moves through instead to equalize the solution.

Question 30

Osmotic Pressure/Potential

Answer 30

To move water molecules. | -The water is moving over to the high concentration to dilute the solution bringing them to equilibrium.

Question 31

Aquaporins

Answer 31

Protein channel to let water through.

Question 32

Tonicity

Answer 32

The concentration of a solution compares to what is inside your cell.

Question 33

Isotonic Solution

Answer 33

This solution is the same tonicity as your cells. | -No osmotic pressure created

Question 34

Hypertonic Solution

Answer 34

The solution has a higher concentration than the cell. - Through osmosis the water will move out of the cell to create equilibrium. - Causing the cell to crenate (shrink)

Question 35

Hypotonic Solution

Answer 35

The solution has a lower concentration than the cell. - Water will be drawn into the cell. Making the cell swell. - If the difference is big enough it will cause the cell to burst. (Lyse/Lysis)

Question 36

Electrical (membrane transport)

Answer 36

Passive movement requiring no energy. - the movement of ions. - difference in charges between 2 areas produces an electrical gradient that passively causes movement. - the forces of same charges trying to spread out will make it pass through the cell membrane. - -more powerful than something without a charge in diffusion.

Question 37

Electrochemical Gradient

Answer 37

- All cells have one - They all have different amounts of ions on the outside and inside. - Some cells use this to do what they do.

Question 38

Membrane Transport based on Active Processes

Answer 38

- Molecules which are impermeable because the are large, poorly lipid soluble. - Going against a concentration gradient - Active Transport--Pumps - Bulk Transport

Question 39

Active Transport-- Pumps

Answer 39

- Proteins that pump/push something through using energy to do it. - Moving something across/against the concentration gradient. - Very helpful in moving against the concentration gradient.

Question 40

What is a common protein pump?

Answer 40

Na+/K+ pump

Question 41

Na+/K+ Pump

Answer 41

Always pumps 3 Na+ out of the cell and pumps 2 K+ into the cell.

Question 42

What are the 3 Kinds of Bulk Transport?

Answer 42

Phagocytosis Pinocytosis Receptor-Mediated Endocytosis

Question 43

Phagocytosis

Answer 43

The Membrane reaches out and grabs what it needs and closes around it pulling the vesicle into the cell. -Big items normally

Question 44

Pinocytosis

Answer 44

The Membrane dimples in around what it needs and comes together and brings it into the cell.

Question 45

Receptor-Mediate Endocytosis

Answer 45

Receptors tell the cell to bring something in.

Question 46

Endocytosis

Answer 46

To bring into the cell.

Question 47

Exocytosis

Answer 47

Sending something out of the cell. | -Vesicles fuse to the membrane and the membrane opens and dumps what is in it outside the cell.