Cell Membrane

Question 1

Define plasma membrane

Answer 1

Membrane that encloses the cell. Regulates inbound and outbound traffic, provides support, assists signalling, and supports metabolic activities.

Question 2

Define Fluid Mosaic Model

Answer 2

Membrane that is fluid with a ‘mosaic’ of protein embedded in it.

Question 3

Define Amphipathic

Answer 3

Having both a hydrophobic and hydrophilic end, able to interact with polar and non-polar substances.

Question 4

Define phospholipid

Answer 4

One is charged end and polar (hydrophilic) and the other is uncharged and non-polar (hydrophobic). Are mobile in lateral phase, but flip flop infrequently

Question 5

Define Phospholipid Bilayer

Answer 5

Cell membranes are lipid bilayers, and are impermeable to most essential molecules/ions. Some permeability to water and small, uncharged molecules.

Question 6

How does Cell Membrane protect the cell

Answer 6

The membrane forms a barrier between the inside and outside of the cell. Different chemical environments can exist on each side of the cell membrane. Selectively permeable, allows certain molecules through and blocks the movements of others.

Question 7

Define Cytoskeleton

Answer 7

Proteins in the cell membrane attach to cytoskeleton fibres and help define and maintain the shape of the cell.

Question 8

What’s the function of Extracellular Matrix

Answer 8

In plant and animal tissues the cell membrane interacts with the cell membrane of adjacent cells.

Question 9

Define Passive Transport

Answer 9

Molecules diffuse across a membrane with a concentration gradient, high to low concentration. No energy is needed.

Question 10

Define Bulk Transport

Answer 10

Exocytosis and endocytosis move items in and out of the cell via secretory vesicles.

Question 11

Define Active Transport

Answer 11

Molecules are pumped across the membrane against a concentration gradient, lower to higher concentration. Requires energy.

Question 12

Define Transport Proteins

Answer 12

They span the membrane, specific for what it transports.

Question 13

What are markers and signalling

Answer 13

Surface protein markers embedded in the cell membrane identify cells, enabling nearby cells to communicate. The cell membrane includes receptor proteins for specific chemicals to recognise.

Question 14

Where do Metabolic Activities occur

Answer 14

Enzymes perform metabolic activities in the membrane.

Question 15

Define Hydrophobic Molecules

Answer 15

They pass through the membrane and the largest part is hydrophobic.

Question 16

Define Hydrophilic Molecules

Answer 16

Has difficulty passing the membrane. The larger or more charged they are, the harder it is to pass unassisted.

Question 17

Define Diffusion

Answer 17

Molecules move through one of the pores in the synthetic membrane and end up on the side that contains water. Diffusion ends when the concentration is the same on both sides.