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Describe how differential gene causes the production of specialized cells from stem cells. (A-Level)

All stem cells contain the same genes, but not all of these genes are expressed. Signalling causes certain genes to become activated within a stem cell. Only these activated genes are transcribed into mRNA. ...
ME
Answered by Maymoona E. • Biology tutor
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Explain why: a) Fluorine is more electronegative than chlorine b)∆H hydration fluoride is more negative than ∆H hydration chloride

a) The fluorine atom is smaller than the chlorine atom, and there is less shielding from other shells of electrons. Thus the bonding pair of electrons are more attracted to the positive nucleus. b) The fluor...
OS
Answered by Osama S. • Chemistry tutor
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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
6796 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
12170 Views

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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