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A gene often has two alleles. One allele is dominant and the other allele is recessive. When is a recessive allele expressed as a characteristic?

A gene has two alleles, they can be either dominant (A) or recessive (a).So the possible combinations are:AAAaaaDominant alleles are expressed as they are 'stronger' . So in the Aa example the dominant al...

Answered by Thomas G. • Biology tutor

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What is active transport? Use an example to demonstrate when active transport is used.

Active transport is a process where particles move from an area of low concentration to an area of high concentration against a concentration gradient. In order for particles to move against a concentrati...

Answered by Nilofar S. • Biology tutor

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Briefly describe the steps of DNA replication and the enzymes involved.

DNA helicase breaks the hydrogen bonds that bind the two strands of the DNA double helix.Free nucleotide complementary base pairs are added to the newly exposed single strands of DNA.Binding of the free n...

Answered by • Biology tutor

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Use your knowledge of the humoral immune response to explain a vaccination programme

Interesting topic with regards to COVID-19A vaccine introduces a foreign pathogen into the body. This foreign body stimulates the innate immune response which occurs regardless. The process of phagocytosi...

Answered by Will A. • Biology tutor

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Cells need mRNA molecules to create proteins. How are they created?

Protein synthesis is a convoluted process but, essentially, all the cell is doing is 'reading' the instructions contained within the base sequence in the correct gene or 'section' of the DNA and then doin...

Answered by Matthew J. • Biology tutor

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