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30% of a population lacks the ability to taste the chemical PTC. Non-tasters are homozygouse recessive for this tasting gene. What percentage of the population are tasters and what percentage of the population are NOT heterozygous for this trait?

This question requires the knowledge of two equations from the Hardy-Weinberg Principle. p + q = 1 and p 2 + 2pq + q 2 = 1 where p = dominant allele, and q = recessive allele. Firstly we know from the questi...
FH
Answered by Fergal H. • Biology tutor
6166 Views

What is natural selection and how is it different from evolution?

Natural selection can be defined as: The gradual process in which inherited characteristics become more or less common in a population, in response to the environment determining the breeding success of indi...
HC
Answered by Harry C. • Biology tutor
2901 Views

How is blood glucose regulated?

High blood glucose levels - such as following a large, carbohydrate rich meal. The increase is detected by Beta cells of the pancreas, which release insulin (a hormone) into the blood. Insulin acts on cells ...
LK
Answered by Lois K. • Biology tutor
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TMV (tobacco mosaic virus) can cause plants to produce less chlorophyll. This causes leaf discoloration. Explain why plants with TMV have stunted growth.

The virus is causing less chlorophyll to be produced. This is a problem as chlorophyll is an essential component in photosynthesis. Photosynthesis is a process by which plants are able to use sunlight in the...
RS
Answered by Reece S. • Biology tutor
14346 Views

Messenger RNA (mRNA) is used during translation to form polypeptides. Describe how mRNA is produced in the nucleus of a cell.

This question, from an AQA past paper, is worth 6 marks and it is asking for you to describe the process of transcription - you do not have to explain or say why things happen. You should make 6 clear points...
TM
Answered by Tessa M. • Biology tutor
3146 Views