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Biology
GCSE

Explain the concept of recessive and dominant alleles

Firstly it is always good to relate such a concept with an example that is easily remembered and therefore easily applied. Alleles refer to alternate forms of the same gene, which code for a particular tr...

JC
Answered by Juliette C. Biology tutor
5241 Views

Bob and Brenda are both heterozygous for a genetically inherited recessive trait. (a) Calculate the probability that they would have a healthy child. Use a genetic diagram to help. (b) Suggest an example of a recessive inherited disorder

Heterozygous means that the parents both carry a dominant allele (A) and a recessive allele (a).

Dominant alleles are always expressed in the phenotype. Recessive alleles are expressed in the pheno...

CM
Answered by Charlotte M. Biology tutor
2819 Views

Neurons do not make direct contact but are separated by synapses. Impulses cross a synapse by means of a neurotransmitter. Describe the process of neurotransmitter release at a synapse. You may use a labelled diagram.

  1. Action potential arrives at axon terminal of presynaptic neuron

  2. Voltage-gated Ca2+ channel opens

  3. ...
CM
Answered by Charlotte M. Biology tutor
2705 Views

How does the circulatory system work?

This system is made up of two main components: the heart and the vasculature.  The heart is an organ with two sides, each of which is dedicated to carry out a different job.  The right side receives deoxy...

NW
Answered by Nicholas W. Biology tutor
4037 Views

explain diffusion and give an example

diffusion is the movement of particles from a high concentration to a low concentration through a semi permeable membrane. an example would be the movement of food molecules through the gut wall as they p...

CH
Answered by Charlie H. Biology tutor
2373 Views

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