C4 Transport Cell Membranes

Question 1

Fluid-mosaic model

Answer 1

Fluid - properties and lipids are free to move around. Mosaic - an assortment of components of different sizes and shapes embedded in the phospholipid bilayer

Question 2

Phospholipid bilayer

Answer 2

Phospholipids arrange themselves into a bilayer so that the hydrophilic heads are facing out (towards water) and the hydrophobic tails are facing in

Question 3

Cholesterol

Answer 3

Membrane Stability: 1. Prevents membrane from becoming too FLUID by reducing phospholipid movement; hydrophobic regions bind to phospholipid fatty acid tails, causing them to pack more closely together 2. Prevents membrane from becoming too RIGID - reduces cell frigidity @ low temperatures

Question 4

Extrinsic proteins

Answer 4

Present on only one side of the phospholipid bilayer - provide support to the membrane or may be involved in cell signalling.

Question 5

Intrinsic proteins

Answer 5

Embedded through both sides of the phospholipid bilayer - channel and carrier proteins which transport large molecules and ions across the membrane

Question 6

Glycoproteins

Answer 6

Attached to Intrinsic proteins: Cell adhesion - This is the attachment of cells to one another.
Cell recognition - This allows cells to recognise one another.
Cell signalling - This is communication between cells.

Question 7

Glycolipids

Answer 7

Attached to lipids Cell adhesion - This is the attachment of cells to one another.
Cell recognition - This allows cells to recognise one another.
Cell signalling - This is communication between cells.

Question 8

Diffusion of NON-POLAR (attracted to lipids/ lipid soluble) molecules through phospholipids

Answer 8

RAPIDLY diffuse

Question 9

Diffusion of POLAR molecules (water soluble) through phospholipids

Answer 9

SLOW diffuse

Question 10

Diffusion of CHARGED particles (ions/polar molecules)

Answer 10

UNLIKELY to diffuse

Question 11

Osmosis

Answer 11

The net movement of water from a high water potential (dilute solution) to a lower water potential (more concentrated solution) through a partially permeable membrane. This will happen until equilibrium is reached

Question 12

HYPERtonic

Answer 12

Solution with a HIGHER solute (sugar,salt,etc.) concentration outside of the cell

Question 13

HYPOtonic

Answer 13

Solution with a LOWER concentration outside the cell

Question 14

Turgid

Answer 14

Enlarged and swollen with water (plant cells stay like this due to strength from CELL WALL)

Question 15

Cell Lysis

Answer 15

When animal cells BURST after they become TURGID due to them not having a cell wall

Question 16

Pasmolysis

Answer 16

When the cell membrane becomes INTACT from the cell wall (detached)

Question 17

Flaccid

Answer 17

Cell shrinking due to loss of water after being in a hypertonic solution for long periods