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describe the structure of prokaryotic cell (4 marks)

they don't have a nucleus, the DNA is present in cytoplasm. prokaryotic cell has a cell membrane that controls movement of molecules in and out of the cell. prokaryotic cells also have cell walls that provid...
JL
Answered by Julia L. • Biology tutor
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Could you describe the blood flow through the heart?

Blood flows through human bodies via a double circulatory system, the systematic system and the respiratory system, which are connected by the heart. Blood enters the right atrium of the heart from the vena ...
SJ
Answered by Steffan J. • Biology tutor
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Describe the structure of starch. How does this structure make starch well suited for energy storage?

Starch is a mix of 2 different polysaccharides:1) Amylose: a long chain of α-glucose monomers joined by 1,4-glycosidic bonds. The chain coils in a spiral shape, held together by hydrogen bonds. This shape ma...
MS
Answered by Molly S. • Biology tutor
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Describe the life cycle of HIV

A HIV molecule enters the blood stream and invades cells of the immune system (CD4 cells). To do this, proteins on the surface of the virus bind to receptors on the host cell. This then allows the envelope o...
LC
Answered by Lucy C. • Biology tutor
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Explain the structure of the DNA double helix, including its subunits and the way in which they are bonded together

DNA is made up of subunits called nucleotides. Each nucleotide is comprised of one nitrogenous base (either adenine, cytosine, guanine, or thymine), one phosphate, and one deoxyribose sugar. The nucleotides ...
BH
Answered by Bethan H. • Biology tutor
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