10200 A Level questions

How to answer short questions about the text from the reading insert?

First thing you have to remember, when answering these questions, is that it is absolutely crucial for you to understand what the question is actually asking you. Read the question several times and underline the key words. Then find the appropriate fragment in the text that talks about the issue mentioned in the question. Once you have done that there are two approaches you can use. They should both score you full marks on the actual exam:
Copy the exact answer from the text, without changing any words. Answer the question using your own words (more risky, but if done accurately will be alright).
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Natalia S.

Answered by Natalia, tutor with MyTutor


What is saltatory conduction?

·   Myelin sheath is an insulating layer of fatty material, composed of Schwann cells wrapped tightly around the neurone.·   Sodium and potassium ions cannot diffuse through this fatty layer.·   In between the Schwann cells are small gaps- the nodes of Ranvier.·  Therefore, the ionic movements that create an action potential cannot occur over much of the length of the neurone: they occur only at the nodes of Ranvier.·   In myelinated neurones the local currents are therefore elongated and sodium ions diffuse along the neurone from one node of Ranvier to the next.·  This means that the action potential appears to jump from one node to the next.·  This is called saltatory conduction.

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Natalia S.

Answered by Natalia, tutor with MyTutor


What are the advantages of saltatory conduction?

· The myelin sheath means that action potentials can occur only at the gaps between the Schwann cells that make up the myelin sheath.· Effectively the action potential jumps from one node of Ranvier to the next.· This speeds up the transmission of the action potential along the neurone.· Myelinated neurones conduct action potentials more quickly than non-myelinated neurones.· A myelinated neurone can conduct an action potential at up to 120 ms-1.
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Natalia S.

Answered by Natalia, tutor with MyTutor


How do I achieve the correct balance of assessment objectives in my essay?

The most important thing before trying to apply the AO's to your essay is to make sure you have an in-depth understanding of what each objective looks like in your writing. In your last essay, use highlighters to colour code the frequency of each AO (this will also allow you to identify what the examiner is looking for when they mark your work themselves). From here, compare your essay with the assigned assessment objectives, e.g. perhaps you don't have enough AO3 in your writing? Emphasise this aspect in your next essay. If the issue is that you don't feel confident in AO3 then WELL DONE you have now found a revision focus.
Tailoring your writing to a set of determined assessment objectives can be challenging but the best way to reach that balance is to keep a list of the objectives next to you and use it as a guide while you work. If you are pushing yourself to get a top band answer, the terminology of the objectives can also be highly technical so, again with your highlighter, pick out key words such as 'developed' and 'consistent' to remind yourself what the examiners are looking for.
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Skye F.

Answered by Skye, tutor with MyTutor


Find the equation of the normal to the curve at the point (1, -1 ): 10yx^2 + 6x - 2y + 3 = x^3

Firstly, an expression for dy/dx needs to be found to allow us to find the gradient of the normal. As a normal is a straight line, the equation y-y1=m(x-x1) can be used to find its equation. We are given x1 and y1 in the question and we want an equation in terms of x and y so we only need to find m, which is the gradient of the line. dy/dx gives the gradient of the tangent at a point, and the gradient of the normal at any point is the negative reciprocal of the gradient of the tangent, -dx/dy. Differentiating both sides of this equation with respect to x (using implicit differentiation) gives dy/dx = (3x^2 -20xy -6)/(10x^2 -2), leading to -dx/dy = (2-10x^2)/(3x^2-20xy-6). After substituting in the values of x and y given in the question, m=-dx/dy=-8/17. We can then plug this in the to equation we have for a straight line: y+1 = (-8/17)(x-1). It would be acceptable to leave the expression like this, however I would recommend rearranging to the form y=(-8/17)x-9/17.
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Joe M.

Answered by Joe, tutor with MyTutor


Express x^2-4x+9 in the form (x-p)^2+q where p and q are integers

The first step would be to expand the second equation:(x-p)^2+qx^2-px-px+p^2+q

this simplifies to x^2-2px+p^2+q

After this you examine the two equations and identify their similarities such as the x^2 term and the terms with have a single x in them.

From this you can equate the terms which have similar terms (see below)

-2px=-4x and p^2+q=9

Next determine which equation is solvable.

As -2px=-4x only has one variable is it solvable.

Solving this equations gives:


cancelling x


divide both sides by -2

p=2 (save this)

Next use this solution to solve the second equation:


substitute p=2


q=5 (save this)

Finally substitute the values for p and q into the original equation


 final answer: (x-2)^2+5

This can be checked by expanding it and ensuring that it does become x^2-4x+9.
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Mark N.

Answered by Mark, who has applied to tutor with MyTutor

1 view

Given that y = 2^x, express 4^x in terms of y.

4^x = (2*2)^x =2^x * 2^x = y^2
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Benjamin M.

Answered by Benjamin, tutor with MyTutor


What is the purpose of trying to achieve economic efficiency?

To ensure resources are not wasted.
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Alejandra T.

Answered by Alejandra, tutor with MyTutor


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