Tutor profile: Mena A.
Subject: Health and Medicine
A 4-year-old female was intentionally exposed to the varicella zoster virus (chicken pox) by her parents in order to better prevent infection in the future. Which of the following best explains the rationale for this idea?
Future exposures to varicella zoster virus will activate a larger population of B cells than initial exposure. When a primary immune response occurs after an antigen infects the body, plasma cells and memory cells are produced. If the antigen infects the body, a second time, it faces a larger amount of B cells (due to pre-made memory cells), which produces an even greater immune response compared to the primary immune response.
Subject: Biomedical Science
What occurs in the baroreceptor reflex when a person has elevated blood pressure?
The baroreceptor reflex is composed of afferent glossopharyngeal and vagus nerve endings that are wrapped around the carotid and aortic bodies, respectively. With elevated blood pressure, these bodies stretch causing increased neuronal action potential firing through the nerves. The elevated nerve signal is relayed to the medulla oblongata which increases the firing through parasympathetic nerve fibres and decreases the firing through sympathetic nerve fibres. Consequently, the arteries dilate and the heart rate decelerates resulting in decreased blood pressure. Thus, homeostasis is maintained.
What distinguishes between mitochondria and chloroplast?
Chloroplasts are only found in plants and unicellular organisms compared to mitochondria which are found in all cells. Chloroplast converts solar/light energy into chemical energy (sugar) while the mitochondria utilises chemical energy to generate ATP. Photosynthesis consists of a series of light reactions and the Calvin Benson cycle while cellular respiration in the mitochondria consists of glycolysis, electron transport chains, and oxidative phosphorylation.
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