Membranes, membrane transport and a bit of mitosis

Membrane structure is a (a)   mosaic

Ions pass through membranes by simple diffusion

• True

• False

Answer explanation

it's facilitated diffusion, because they are charged

Which part of the membrane does the water pass through?

• carrier proteins

• channel proteins

• phospholipids

• cholesterol

Answer explanation

even though it isn't llipid-soluble, water is small enough to pass through

Draw a small section of a phospholipid bilayer

(a)   is molecule which stabilises the membrane structure

Carrier and channel proteins are both examples of extrinisic proteins

• True

• False

Answer explanation

they are both intrinsic proteins

Carrier proteins can be used for active transport and facilitated diffusion

• True

• False

Answer explanation

they are both examples of carrier proteins

Which is the correct definition of osmosis?

• Movement of molecules across a partially permeable membrane, from high to low concentration

• Movement of water from a less to a more negative water potential

• Movement of water through a partially permeable membrane, from a less to a more negative water potential

• Diffusion of ions across a partially permeable membrane, from a low to a high concentration

This describes a solution which has a less negative water potential than a cell

• isotonic

• hypertonic

• hypotonic

Draw what a red blood cell will look like after it's been placed in a hypertonic solution

Answer explanation

it will shrink because it loses water by osmosis