Top answers

Biology
A Level

How does a vaccine lead to the production of antibodies and why does this provide immunity?

Vaccines are designed so that they contain antigens - for example viral antigens from the virus we wish to protect against. When these are injected they are recognised as foreign by white blood cells call...

EJ
Answered by Emily J. Biology tutor
13119 Views

What is crossing over?

Crossing over is a process that happens during meiosis and results in genetic variation in gametes. It happens between prophase and metaphase. Pairs of homologous chromosomes lined up next to each other t...

EB
Answered by Erin B. Biology tutor
28122 Views

Explain the process of semi-conservative DNA replication.

  • The enzyme DNA helicase breaks the hydrogen bonds between the two polynucloetide DNA strands causing the double helix to unzip, forming two single strands.

  • Each original single...

BJ
Answered by Bardwell J. Biology tutor
54647 Views

What is a condensation reaction?

A condensation reaction is the formation of a chemical bond between two molecules with the elimination of a water molecule. You can tell this reaction has occurred when you see an equation written down as...

RN
Answered by Rebecca N. Biology tutor
4908 Views

What are the four stages of aerobic respiration in humans?

Glycolysis which is where glucose is broken down into 2 molecules of pyruvate releasing 2ATP and 2NADH. Second is the link reaction. This links glycolysis to the Krebs Cycle. Pyruvate molecules are decarb...

TK
Answered by Taqua K. Biology tutor
7339 Views

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