Top answers

How does the heart contraction and what controls Heart Rate (HR)?

Myogenic contraction mechanism of the heart: The heart is myogenic and so the heart beats due to electrical activity from inside the heart itself. This is compared to muscle that contracts due to signals fro...
BD
Answered by Bethany D. • Biology tutor
2765 Views

Explain why someone who has a high blood pressure is at a significantly higher risk of developing CVD

The endothelium lining the arteries will become damaged due to the high blood pressure. There will be an inflammatory response increasing the chance of an atheroma forming. This will increase the chance of t...
HS
Answered by Hannah S. • Biology tutor
5310 Views

How exactly can new species evolve from within a population, and how can we classify them as such?

There are two main mechanisms that contribute towards the process of speciation: natural selection, and genetic drift. The result of both of these mechanisms is phenotypic and genetic change as a population ...
Answered by • Biology tutor
2956 Views

Describe the lac operon, and it's transcriptional control when the concentration of glucose is low, and the concentration of lactose is high.

The lac operon is a section of DNA in E. Coli that consists of a promoter , operator and three genes encoding Beta-galactosidase , lactose permease and another gene. Beta galactosidase is an enzyme responsib...
AT
Answered by Albert T. • Biology tutor
3247 Views

Why does an action potential not flow backwards in a neuron? How does it always reach the pre-synaptic knob?

When an action potential occurs, the neuron reaches the maximum voltage of +40mV. It then begins to repolarise, with potassium ions diffusing back in to the neuron, down the concentration gradient. This make...
EM
Answered by Erin M. • Biology tutor
13671 Views