Cell Membrane

Question 1

It…

Answer 1

Separates the cell from surroundings with a structure called the fluid mosaic model.

Question 2

Allows for movement in and out of the cell by…

Answer 2

Diffusion, facilitated diffusion and osmosis (Passive transport. No energy needed. Moves ALONG concentration gradient)
Protein pumps, vesicular (Active transport. Uses energy. Movies AGAINST concentration gradient)

Question 3

Diffusion…

Answer 3

Random movement of particles from area of high concentration to low concentration. Where SMALL molecules pass through the LIPID tails. eg. Oxygen, Co2

Question 4

Facilitated diffusion….

Answer 4

Where the CARRIER proteins and CHANNEL proteins transports the larger molecules eg. Water (channel) and glucose (carrier)

Question 5

Osmosis…

Answer 5

Diffuses water through membrane. Moves from high concentration of water to low conc. Water moves through channel proteins. Hypertonic= low water, cell shrivels. Hypotonic= high water, cell swells and bursts. Isotonic=equally moved water, healthy

Question 6

Protein pumps

Answer 6

Changes shape to move molecules into the cell. Transports proteins into the cell to do work.

Question 7

Endocytosis

Answer 7

TAKES bulky materials into the cell by forming a VESICLE. Cell membrane forms around food. “Cell eating”. Eg. Digesting foods.

Question 8

Exocytosis

Answer 8

REMOVES bulky materials out of the cell. Membrane around material FUSES with the cell membrane. Cell changes shape (needs energy) eg. Wastes or hormones released.

Question 9

Factors affecting movement through membrane…

Answer 9

Surface area to volume ratio: increased surface area=decreased volume, meaning more space for materials to move in + less volume to satisfy.
Concentration gradient: the difference in concentration of a substance between two areas. (Steeper the conc gradient+ faster the molecules will diffuse)
Physical/ chemical factors of the materials being exchanged