(1) Bio SL B2.1 - quiz revision Q2

B2.1.1/ Plasma/Cell membrane contains:

Lipid bilayer (2 layers of lipids)

B2.1.1/ What do cell membranes do? (2)

Controls entry/exit of a cell (semipermeable) and protects organelles in a cell

B2.1.2/ Permeability is based on:

Size and charge

B2.1.2/ What type of molecules can pass through the membrane?

Small and non-polar molecules

B2.1.2/ Membrane is not permeable to:

Polar or charged particles

B2.1.2/ Hydrophobic tails will ___ anything that is ___ or has a ___

Repel, polar, charge

B2.1.3/ Definition of diffusion

Passive movement of particles from an area of high concentration to low concentration

B2.1.3/ Explain the process of simple diffusion

Small, non-polar particles diffuse across the membrane until they reach equilibrium

B2.1.3/ Functions of proteins in cell membrane are:

(JETRAT) Joining of cells, Enzymes, Transport that can act as protein channels or protein pumps, Recognition of cells, Attachment to other cells, Transduction of hormone signals

B2.1.4/ Protein channels and protein pumps are:

Integral proteins

B2.1.4/ What are integral proteins?

Transmembrane proteins. They go across the membrane from outside to inside the cell

B2.1.4/ Integral proteins will come into contact with:

Polar heads and non-polar tails / will need both hydrophilic and hydrophobic parts

B2.1.4/ Peripheral proteins are:

Only attached to the surface of cell membrane. Hydrophilic

B2.1.5/ Aquaporins are:

Pores that assist water when moving in/out the cell / special channels that make it easier for water to move via osmosis

B2.1.5/ Osmosis is:

Movement of water molecules across a semipermeable membrane. The movement continues till equilibrium is reached

B2.1.5/ Is osmosis active or passive?

Passive