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Explain how the potential difference across the neuronal cell membrane changes during conduction of an action potential

Normal neuronal resting potential is around -70mV - this is maintained by sodium-potassium pumps. When the neuron is stimulated, sodium ion channels begin to open, allowing sodium ions to diffuse back into t...
MS
Answered by Melissa S. • Biology tutor
6543 Views

Solve the quadratic equation x^2 + 7x + 6 = 0

To solve a quadratic equation of the form Ax 2 + Bx + C = 0, where, in this example, A=1, B=7 and C=6, we need to factorise the left-hand side of the equation. To do this we first need to write the factors o...
CJ
Answered by Caitlin J. • Maths tutor
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A scientist discovers a diseased tomato plant where a disease has caused discolouration in the leaves due to a decrease in chlorophyll. Explain why this tomato plant produces far less tomatoes and is much smaller than a healthy tomato plant.

The decrease in chlorophyll in the diseased plant leaves means the light energy cannot be used to make glucose via photosynthesis in the chloroplasts. Tomatoes store a lot of glucose therefore with less gluc...
PS
Answered by Phoebe S. • Biology tutor
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A car travelling at 14 m/s has to make an emergency stop so applies the brakes and it takes 1.5s to become stationary. What distance has the van travelled in that time?

Assuming constant deceleration we can use the equation s = t(u+v)/2, where u=14m/s, v=0m/s and t=4s. Inputting these values we have that the distance travelled s = 1.5(14)/2 = 21/2 = 10.5m u = the starting v...
CJ
Answered by Caitlin J. • Physics tutor
2775 Views

Two fair six sided dice, called A and B, are rolled and the results are added together. The sum of the dice is 8, what is the probability that two fours were rolled?

We know that A+B = 8 so we should first count the number of ways that the two dice could total 8. (A = 2, B = 6), (A=3, B=5), (A=4, B=4), (A=5, B=3) , (A=6, B= 2) -- this gives 5 possible waysWe also know th...
JM
Answered by Jak M. • Maths tutor
4047 Views