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Describe semi-conservative DNA replication

The double helix structure unzips which is catalysed by the DNA Helicase enzyme. DNA Helicase overcomes hydrogen bonding between nitrogenous bases. Two strands are produced, each one acts a template. Free DN...
PA
Answered by Prashant A. • Biology tutor
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Explain how pressure differences in the heart ensure sufficient pumping of blood into the arteries. (3)

increased pressure in the ventricles the pressure in the ventricles is higher than the pressure in the atria causing the atrioventricular valves to closecausing the semilunar valves to open and the blood flo...
KW
Answered by Kelly W. • Biology tutor
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Define antibodies and antigens, and describe the different ways in which the body develops immunity.

Immunity is the capacity of the body to recognise the intrusion of disease-causing microorganisms (pathogens) and develop a response to fight infection. Antigens and antibodies are crucial to the process of ...
CB
Answered by Charlotte B. • Biology tutor
3499 Views

Explain the ways in which the structure of alveoli is related to its function

The alveolar epithelium is a site of rapid diffusion, consequently it is very thin, only one cell thick, providing a short diffusion pathway.Alveoli have constant blood flow and ventilation, maintaining a st...
JM
Answered by Joanne M. • Biology tutor
5837 Views

Explain Cohesion-Tension Theory

Transpiration of water through stomata creates low potential at the top of the xylem. Water molecules stick together via hydrogen bonds in a process known as COHESION . This occurs because water molecules ar...
JM
Answered by Joanne M. • Biology tutor
11805 Views