Top answers


Explain how a vaccination prevents infection [3 marks]

The main way in which vaccinations prevent infection is by causing white blood cells to produce antibodies . These antibodies are produced rapidly upon re-infection and kill the pathogens.
OF
Answered by Odette F. Biology tutor
12473 Views

What is diffusion? (GSCE: OCR, Edexcel, AQA)

Definition : diffusion is the spreading out of particles from an area of high concentration to an area of low concentration The theory: Diffusion, is the scientific description for the gradual movement of pa...
NF
Answered by Ned F. Biology tutor
14057 Views

What are pathogens and how do they cause disease?

Pathogens are microorganisms that can cause disease. Pathogenic bacteria make us ill in 2 way: 1) by damaging body cells 2) releasing toxins. Pathogenic viruses invade body cells where they use the cellular ...
GG
Answered by Golnoush G. Biology tutor
14712 Views

What is a reflex arc and how does it work?

A reflex is an unconcious response to a potentially harmful stimulus, such as pulling a tray out of the oven without oven gloves on! Reflexes bypass the brain and instead have a circuit that only passes thro...
PC
Answered by Polly C. Biology tutor
8442 Views

Explain the process of allopatric speciation

A population of one species is separated by a physical barrier, e.g a geographical barrier such as the movement of tectonic plates. There will then be 2 isolated groups of the same species unable to interbre...
MS
Answered by Matthew S. Biology tutor
9019 Views