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How many chromosomes dies each cell of the human body have ?

All human body cells have 23 pairs of chromosomes (46 total), 22 pair of autosomes and 1 pair of sex chromosomes. However, sperm and egg cells only have one set of chromosomes (23 total).
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Answered by Helen K. • Biology tutor
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What are three differences between DNA and RNA? ( 3 marks)

RNA is single stranded whereas DNA is double stranded - RNA has the bases A,G,C and U whereas DNA has the bases A,G,C and T - An RNA nucleotide has ribose as its sugar component whereas a DNA nucleotide has ...
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Answered by Prahalad N. • Biology tutor
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It has been suggested that smoking, an epigenetic factor can lead to tumour growth and cancer. Use your knowledge of the epigenome and its structure to explain how this could occur. [5 marks]

Marking Scheme: MP1: Define epigenome- layers of chemical tags covering the DNA and histone protein complex MP2: Increased Methylation of DNA molecule MP3: enzymes attracted to complex/ acetyl groups removed...
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Answered by Hannah H. • Biology tutor
2983 Views

The Polar Bear is the largest species of bear in the world. With regards to adaptation, suggest a reason for this.

The habitat of the Polar Bears is the arctic. This is a much colder climate than the other species of bear found in the wild. Therefore the Polar Bear has adapted to live in this colder climate. One adaptati...
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Answered by Zia F. • Biology tutor
6521 Views

How are impulses propagated along an axon?

The axon is polarised at rest. This means that there is a negative charge within the axon and a positive charge outside. This resting polarisation is caused by a Na/K pump that uses active transport to trans...
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Answered by Zia F. • Biology tutor
6656 Views