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Explain the role of T-cells in immune response to viral infection

When T cells bind to viral antigens presented by macrophages they undergo mitosis to form 4 distinct cell variants: Memory T cells- remain in the blood stream to initiate a faster immune response upon re-exp...
WS
Answered by Will S. • Biology tutor
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Explain how FHS and oestrogen illustrate the principle of negative feedback during the menstrual cycle, and explain therefore why oestrogen may be used as a contraceptive.

FHS is released from the anterior pituitary gland in the brain and causes the follicle to develop in the ovary. the developing follicle produces and secretes oestrogen. This release of oestrogen stimulates t...
CP
Answered by Catrin P. • Biology tutor
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Describe the hormone changes that occur during a womens menstrual cycle

A womens menstrual cycle is on average 28 days long. Hormone release occurs due to signals from the brain. Days 1-5 is when a period occurs and levels of all hormones are low. After this, LH (luteinizing hor...
BP
Answered by Bhavina P. • Biology tutor
3301 Views

Explain how a synapse between two neurons functions

When impulse arrives at pre-synaptic terminal, the depolarisation opens the voltage-gated Ca2+ ion channels. This causes Ca2+ to enter synapse due to differences in concentration. This causes the vesicles to...
GB
Answered by George B. • Biology tutor
2968 Views

Describe the process of phagocytosis of a pathogen.

The membrane of the phagocyte surrounds the pathogen and engulfs the pathogen. Enzymes inside the phagocyte break down the pathogen and destroy it. Pathogen proteins can then be presented on the surface of t...
HB
Answered by Harriet B. • Biology tutor
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