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What is an allele?

In the nucleus of the cell, there are pairs of chromosomes which carry the same genes in the same places. 2) Alleles are different versions of these genes.3) For example, a person may have an allele for brow...
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Answered by Ella S. • Biology tutor
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Why do we vaccinate people - how does it work?

Vaccination is an important method used in healthcare to prevent people from getting certain diseases. Vaccines contain a dead or weakened ( attenuated) form of a pathogen, and the immune system responds to ...
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Answered by Ella S. • Biology tutor
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Explain the principles of PCR

The Polymerase Chain Reaction (PCR) is a method of DNA amplification in vitro. It consists of 3 stages - denaturation, annealing and extending. PCR relies on the use of a thermophilic Taq polymerase enzyme.
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Answered by David B. • Biology tutor
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State the differences between introns and exons.

Introns and exons are parts of genes - exons code for proteins, whereas introns do not, ie: exons are converted into messenger RNA to allow these parts of the gene to then be transcribed into protein. Intron...
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Answered by David B. • Biology tutor
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Name the major organs of the Gastrointestinal tract

Oral cavity, Oesophagus, Stomach, duodenum, jejunum, ileum, colon, rectum, anus.
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Answered by David B. • Biology tutor
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