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Explain the structure of a DNA polynucleotide strand

Think of DNA like 2 long shoelaces coiled around each other to form a spiral - or a double helix as it's called. Each of the 2 shoelaces is called a 'strand' and is made up of something called 'polynucleotid...
DF
Answered by Darius F. • Biology tutor
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How does a nerve transmit impulses?

At rest a nerve cell or fiber has more sodium (NA+) ions in the extracellular fluid and more potassium (K+) ions in the intracellular fluid. There are both NA+ and K+ ion channels in the membrane of the nerv...
KW
Answered by Kay W. • Biology tutor
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Please can we go over the process of spermatogenesis?

Of course. Spermatogenesis takes place in the seminiferous tubules of the testis. The germinal epithelium cells, which are in the wall of the seminiferous tubule, first differentiate into diploid spermatogon...
MH
Answered by Molly H. • Biology tutor
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What are the important similarities and differences between RNA and DNA?

Similarities Nucleotides consist of pentose sugar, phosphate and base Differences RNA: ribose (sugar) single stranded Made in the nucleus but can move outside it U, A, G, C bases DNA: deoxyribose (sugar) Dou...
RL
Answered by Rosie L. • Biology tutor
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What is the difference between allopatric and sympatric speciation?

Allopatric speciation occurs when populations of a species are separated by a physical barrier - this could be a river for animals that cannot swim, for example. Separation of the populations means that ther...
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Answered by Tom M. • Biology tutor
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