1.11 - Cell Membrane & Transport within Cell Membrane

Question 1

What are cell membranes made of?

Answer 1

phospholipids

Question 2

What is the fluid mosaic model?

Answer 2

• imbeded amongst phospholipids, are specialized proteins.
• they are always in motion
• and made of many different pieces

Question 3

What are integral proteins?

Answer 3

Proteins imbeded directly inbetween the phosoplipids.
(act as channels)

Question 4

What are peripheral proteins?

Answer 4

Proteins that are tied down to the surface/ hydrophilic portion of the phospolipids

Question 5

What are membrane proteins?

Answer 5

• act as traposrters that help materials move back and forth
• anchors that can be used to attach items to the surface of the cell
• receptors of messages of hormone and enzymes
• plays role in cell regonition-> allpws immmune system to identify which cells are friendly and which are not

Question 6

What does cholesterol do in a cell membrane?

Answer 6

• helps keep membrane fluid
• prevents membrane from getting too cold and solidifying
• prevents membrane from getting too warm which causes it to be liquidy and drifting/tearing apart

Question 7

What are the 2 catagories of transport through the cell membrane?

Answer 7

Passive and active transport

Question 8

What is passive transport?

Answer 8

Materials moving through the membrane without excerting any energy.
Moves through with foces of osmosis and difussion

Question 9

What is Active transport?

Answer 9

Materials that move throughthe membrane while excerting energy.
(“pumps” materials through)

Question 10

What is diffusion?

Answer 10

• natural tendency for materials to move from a high concentrated area to a low concentration
• diffusion only occurs if the membrane/barrier is permeable
• water, small particles and molecules with small/low charges can pass through a cell membrane

Question 11

Can glucose pass through a cell membrane?
Why or why not?

Answer 11

No.
It is too large and has partial charges

Question 12

What is a concentration gradient?

Answer 12

This is the difference on concentration

Question 13

What is a concentration gradient?

Answer 13

This is the difference on concentration

Question 14

What is osmosis?

Answer 14

• specific type of diffusion
• movement of water down its concentration gradient
• water moves from high (less solute) to low (more solute) concentration

Question 15

What does isotonic mean?

Answer 15

• a cell with equal water concentration on both sides
• no net movement

Question 16

What does hypotonic mean?

Answer 16

• cell with a low concentration of water due to more solute present
• water moves into the cell
• cell could burst

Question 17

What does hypertonic mean?

Answer 17

• cell with high water concentration due to less solute present
• water moves out of the cell
• cell could shrivel and die

Question 18

What is Turgor Preassure?

Hint: in plant cells

Answer 18

Plant cell walls can hold the preassure created by the movement of water and are allowed to swell a bit

Question 19

What are the 2 types of active transport?

Answer 19

Endocytosis and exocytosis

Question 20

What is endocytosis?

Answer 20

involves taking large amounts of materials outside/ on the surface of the membrane, engulfing it, and bringing it into the cell using a vesicle.

Question 21

What is a vesicle?

Answer 21

a “bubble” of cell membrane that brings materials on the surface of the cell inside the cell or vise versa (removing excess materials)

Question 22

What is exocytosis?

Answer 22

involves ejecting large amounts of material using membrane as a vesicle and bring it back up to the surface of the membrane

Question 23

What is Phagocytosis?

[fag-o-sigh-toe-cis]

Answer 23

• When a cell completely engulfs another cell
• “cell eating”
• Ex) immune system destroying bacteria

Question 24

What is receptor mediated endocytosis?

Answer 24

when receptor proteins bind to the desired molecule to make sure it is brought into the cell