ELM 11.2

Question 1

paramecium is an ______. it has a resting membrane potential of around -40mV, and can fire _____ based action potentials in response to chemical, heat, touch, and light stimuli

Answer 1

excitable cell
Ca2+

Question 2

pawn mutation in paramecium

Answer 2

cannot reverse direction - little or no calcium current and therefore cannot generate action potentials

Question 3

dancer mutation in paramecium

Answer 3

enhanced calcium current - reverse direction in response to much weaker stimuli than normal cells

Question 4

pantophobiac mutation in paramecium

Answer 4

reduced voltage gated potassium channel current and show prolonged depolarization - swim backwards for much longer than wild type

Question 5

Which is thought to be the order (earliest to latest) in which voltage gated ion channels evolved?

a.	 Sodium, calcium, potassium

b.	 Potassium, calcium, sodium

c.	 Calcium, sodium, potassium

d.	 Calcium, potassium, calcium

Answer 5

b

Question 6

The depolarisation phase of action potentials in Paramecium is based around which ion?

a.	 Ca2+

b.	 Cl_

c.	 K+

d.	 Na+

Answer 6

a