Control and coordination in mammals — Biology 9700 AS & A Level Question & Worked Solution

(a(i))[1]

Using the letter(s) A to F from Fig. 6.1, state which letter(s) shows depolarisation.

(a(ii))[1]

Using the letter(s) A to F from Fig. 6.1, state which letter(s) shows hyperpolarisation.

(a(iii))[1]

Using the letter(s) A to F from Fig. 6.1, state which letter(s) shows the point where the membrane is most permeable to potassium ions.

(a(iv))[1]

Using the letter(s) A to F from Fig. 6.1, state which letter(s) shows resting potential.

(b(i))[1]

Saxitoxin is a potent poison made naturally by single-celled, eukaryotic, photosynthetic, marine organisms. Shellfish can feed on organisms containing saxitoxin but are not harmed. If humans eat shellfish containing saxitoxin they become very ill and may die. State the kingdom to which the organisms that produce saxitoxin belong.

(b(ii))[3]

Saxitoxin prevents sodium ion channels in the cell surface membranes of neurones from working. Describe the role of sodium ion channels in the transmission of a nerve impulse.

(b(iii))[2]

Suggest why saxitoxin could be fatal to humans.

Control and coordination in mammals — practice question

Worked solution & mark scheme