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Why do cells first transcribe messenger RNA from DNA and then translate messenger RNA to protein? Why not directly translate DNA to protein?

Practically, the cell is unable to translate proteins from DNA as the translation machinery is in the cytoplasm and the DNA is in the nucleus and so the messenger RNA (mRNA) communicates the genetic code to ...
DG
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Describe the structure of the human heart and how the blood is pumped by the heart.

The heart can be described as a double pump system. It consists of 4 main chambers (sections) - 2 atria and 2 ventricles split into left and right. The atria have relatively thin walls whereas the ventricles...
WC
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Approximately how long is a double-stranded DNA molecule with a molecular weight of 3x10^9 g/mol? Assume the molecular weight of one nucleotide is 333 g/mol, and that there are 10 base pairs for each turn of the DNA helix equalling 3.4nm in length.

Let's begin by assessing the molecule. If we divide the molecular weight by two, that will give us the weight for one strand of the helix. Knowing that one nucleotide is 333 g/mol, then dividing the weight o...
AV
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When people have liver failure they may get swollen legs due to oedema. Explain the processes behind this.

The liver is responsible for making proteins found in the blood which help to maintain it's "oncotic pressure", the 'pull' factor that holds water inside the blood vessels. These proteins cannot pa...
JI
Answered by Joy I. • Human Biology tutor
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How are proteins made?

A protein is a long chain of amino acids, connected by a peptide bond. Amino acids are the essential building blocks, some of which the body can synthesise by itself and others which have to come from our di...
TD
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