AP Cell Structure and Transport

When an action potential is generated, the inside of the membrane becomes

• positive relative to the outside
• negative relative to the outside
• polarised
• filled with potassium ions

Threshold stimulus means that

• the size of the action potential does not change
• only one impulse is conducted at a time
• a certain level of stimulus is required to generate an action potential
• the membrane becomes repolarised quickly after an action potential passes

The time following an action potential in which no new action potential can be generated is called

• the refractory period
• the nerve impulse
• the stationary phase
• the threshold period

What type of transport is shown in the picture?

• Osmosis
• Diffusion
• Endocytosis
• Exocytosis

If a molecule passes through a protein, but goes down a gradient, it is called

• active transport
• endocytosis
• facilitated diffusion
• exocytosis

The sodium-potassium pumps requires energy to move ions across the cell membrane against their concentration gradient so it is a type of

• active transport
• osmosis
• diffusion
• facilitated diffusion

The soil surrounding the roots of a plant has a water potential of -15 bars. The leaves of the plant have a water potential of -18 bars.
What will happen?

• Water will leave the plant and the plant will wilt.
• Water will move from the roots to the leaves of the plant.
• Nothing - these solutions are isotonic.
• IDK - What is a bar????

0.9% NaCl is isotonic to red blood cells.  Which of these describes what will happen if a technician misplaces a decimal point and makes 9.0% NaCl solution instead and administers it to a patient?

• The cells exposed to the solution will burst.
• The cells exposed to the solution will shrink.
• The cells will remain the same size.
• The cells exposed to the solution will expand but not burst.

What is something that prokaryotic and eukaryotic cells have in common?

• They have a nucleus. 
• They are multi-cellular. 
• They have DNA. 
• They have organelles that are membrane-bound.

Which of the following sequences describes the passage of a nerve impulse through a reflex arc in humans?

• receptor; interneuron; motor neuron; sensory neuron 
• interneuron; sensory neuron; receptor; motor neuron
• receptor; sensory neuron; interneuron; motor neuron