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When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the presynaptic knob. Describe how.

The arrival of a nerve impulse at a synapse causes Ca2+ channels to open (1 mark). Ca2+ ions enter the presynaptic knob by facilitated diffusion (1 mark). The presence of Ca2+ ions causes synaptic vesicle...

Answered by Andrew B. • Biology tutor

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Raya buys a van for £8500 plus VAT at 20%.Raya pays a deposit for the van. She then pays the rest of the cost in 12 equal payments of £531.25 each month. Find the ratio (in simplest form) of the deposit Raya pays to the total of the 12 equal payments.

Raya buys a van for £8,500 x 1.2 = £10,200. Total of 12 equal payments = 12 x £531.25 = £6375. Raya's deposit = £10,200 - £6375 = £3825. Ratio of the dep...

Answered by Andrew B. • Maths tutor

27815 Views

How are London forces (Van Der Waals) formed?

This is the weakest intermolecular force. It is formed by the uneven distribution of electrons in a molecule which induces a dipole in the molecule (meaning a delta positive and delta negative charge form...

Answered by Sonia H. • Chemistry tutor

2918 Views

A ladder of length 4.5m is leaning against a wall. The foot of the ladder is 2.3m from the base of the wall. What is the angle the ladder makes with the wall?

This is an application of trigonometry. The right angle in this case is between the wall and the floor and the hypotenuse is the ladder. The angle between the wall and the ladder can using the sine of the...

Answered by Nicci F. • Maths tutor

5185 Views

How can I evaluate the extent to which increased competition leads to higher levels of economic efficiency?

Keeping all other factors fixed, increased competition will make the demand curve that firms face flatter due to increased elasticity of the demand. By drawing a diagram depicting a firm's costs and reven...

Answered by Rebecca S. • Economics tutor

1881 Views