A Unity and Diversity

A1.1 Water

A1.2 Nucleic acids

A2.1 Origins of cells

A2.2 Cell structure

A2.3 Viruses [HL only]

A3.1 Diversity of organisms

A3.2 Classification and cladistics [HL only]

A4.1 Evolution and speciation

A4.2 Conservation of biodiversity

B Form and Function

B1.1 Carbohydrates and lipids

B1.2 Proteins

B2.1 Membranes and membrane transport

B2.2 Organelles and compartmentalization

B2.3 Cell specialization

B3.1 Gas exchange

B3.2 Transport

B3.3 Muscle and motility [HL only]

B4.1 Adaptation to environment

B4.2 Ecological niches

C Interaction and Interdependence

C1.1 Enzymes and metabolism

C1.2 Cell respiration

C1.3 Photosynthesis

C2.1 Chemical signalling [HL only]

C2.2 Neural signalling

C3.1 Integration of body systems

C3.2 Defence against disease

C4.1 Populations and communities

C4.2 Transfers of energy and matter

D Continuity and Change

D1.1 DNA replication

D1.2 Protein synthesis

D1.3 Mutation and gene editing

D2.1 Cell and nuclear division

D2.2 Gene expression [HL only]

D2.3 Water potential

D3.1 Reproduction

D3.2 Inheritance

D3.3 Homeostasis

D4.1 Natural selection

D4.2 Stability and change

D4.3 Climate change

IB Biology HL C2.2 Neural signalling Question Bank

[Maximum number: 1]

Common pesticides used by gardeners contain neonicotinoids.

What is the effect of a neonicotinoid pesticide on the transmission of a nerve impulse between neurons in an insect?

It prevents the release of acetylcholine from the presynaptic membrane.

It widens the synaptic cleft so diffusion of acetylcholine across the gap is slower.

It irreversibly binds with acetylcholine receptors on the postsynaptic membrane.

It interferes with the enzymatic breakdown of acetylcholine by acetylcholinesterase.

[Maximum number: 1]

How does potassium move across the membrane of a neuron during repolarization?

Simple diffusion

Facilitated diffusion

Endocytosis

Active transport

[Maximum number: 5]

Cholinergic synapses use acetylcholine as their neurotransmitter. They are widespread in the body, passing on signals to muscle cells. These synapses are affected by neonicotinoid pesticides.

The diagrams, which are not drawn to scale, show the synapse between two neurons and a detail of the synaptic cleft.

(a)

On the diagrams, label:

[ 1 ]

(i)

On the diagrams, label with a letter P a location where a neonicotinoid pesticide could bind.

[ 1 ]

(b)

Outline how depolarization of the membrane of an axon occurs.

[ 2 ]

(c)

Explain how acetylcholine initiates an action potential in a postsynaptic membrane.

[ 2 ]

(a)

The diagram shows part of two neurons.

[ 4 ]

(i)

State the name of the structure shown.

[ 1 ]

(ii)

X indicates the movement of a structure in the neuron. Explain what events trigger this movement and what happens next.

[ 3 ]

[Maximum number: 5]

The diagram shows a cell from the nervous system.

(a)

Outline how the myelin sheath and nodes of Ranvier increase the speed of an action potential along a neuron.

[ 2 ]

(b)

Describe the effect of neonicotinoid pesticides on synaptic transmission in insects.

[ 3 ]

[Maximum number: 1]

Defects in the formation of synapses could be the cause of neurological disorders such as Alzheimer's disease that affects the ability to think and remember clearly. It is more frequent in people older than 65 years of age. The graph shows the changes in synapse number over time. The diagram shows activity-related neural development.

(a)

State what happens to unused neurons.

[ 1 ]

[Maximum number: 6]

Earthworms (Lumbricus terrestris) have a nerve cord on the ventral (underside) side of their body. It contains three nerve fibres (axons), each with a very large diameter, which extend along the whole length of the nerve cord. There is one medial giant fibre (MGF) and two lateral giant fibres (LGFs). The diameter of the MGF is 1.4 times larger than the LGF.

Scientists developed a non-invasive method to record giant nerve fibre activity. The response from the MGF was measured by the electrical activity produced when touching the front segments of the earthworm while the LGF was measured when touching the back segments.

The table shows the mean conduction rates, standard deviation (SD) and number of individual measurements of MGF and LGF action potentials in each earthworm. At the end of the table, the mean and standard error (SE) for 9 of the earthworms are shown.

(a)

State the apparatus used to show the resting and action potentials.

[ 1 ]

(b)

(i)

Calculate how many times faster the mean MGF is compared to the mean LGF.

[ 1 ]

(ii)

Suggest one possible reason that the conduction rate in the MGF is much faster than in the LGF.

[ 1 ]

(c)

Explain saltatory conduction.

[ 3 ]

(a)

The diagram below shows a synapse where the neurotransmitter is dopamine and some of the processes that take place during nerve transmission.

Explain the effect of cocaine on neurotransmission at a synapse.

[ 3 ]

[Maximum number: 1]

What is the action of neonicotinoids on the synapse of an insect?

They prevent the release of acetylcholine from the presynaptic membrane.

They increase the permeability of the presynaptic neuron to sodium ions.

They bind to the acetylcholine receptor on the postsynaptic neuron.

They block the uptake of acetylcholine in vesicles in the presynaptic neuron.

[Maximum number: 7]

The graph shows the change in the membrane potential of an axon during an action potential.

(a)

State the approximate value of the membrane potential at X .

[ 1 ]

(b)

Y is the threshold potential. State what happens when the threshold potential is reached.

[ 1 ]

(c)

Describe the movements in ions that occur during time t.

[ 2 ]

(d)

Explain how a nerve impulse is passed on to other neurons.

[ 3 ]

0 selected

Question 1

Question 2

Question 2

Question 2(a)

Question 2(a)(iii)

Question 2(b)

Question 2(c)

Question 2

Question 2(c)

Question 2(c)(i)

Question 2(c)(ii)

Question 3

Question 3(a)

Question 3(c)

Question 4

Question 4(a)

Question 3

Question 3(a)

Question 3(c)

Question 3(c)(i)

Question 3(c)(ii)

Question 3(d)

Question E2

Question E2(c)

Question 17

Question 3

Question 3(a)

Question 3(b)

Question 3(c)

Question 3(d)