Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
A Sexually Transmitted Infection () is an infection that is transmitted via body fluids through sexual contact.
The Human Immunodeficiency Virus () is a pathogen that causes .
specifically targets and destroys -lymphocytes (helper -cells), which are crucial for the immune response.
As the number of -lymphocytes decreases, the body becomes unable to defend itself against opportunistic infections, leading to Acquired Immunodeficiency Syndrome ().
Transmission of occurs through the exchange of body fluids: unprotected sexual intercourse, sharing of hypodermic needles, blood transfusions with contaminated blood, and from mother to child across the placenta or through breast milk.
Methods of limiting the spread of include the use of mechanical barriers like condoms (femidoms and male condoms), regular testing, and education regarding safe sexual practices.
Bacterial , such as Gonorrhea and Syphilis, can often be treated with antibiotics, whereas viral like are currently managed with antiretroviral therapy but cannot be cured.
📐Formulae
💡Examples
Problem 1:
A patient tests positive for . Over several years, their T-lymphocyte count drops from to . Explain the biological consequence of this change.
Solution:
The patient has progressed from being -positive to having .
Explanation:
The reduction in -lymphocytes means the immune system can no longer produce enough antibodies or coordinate an effective immune response. When the count falls below the threshold, the individual is susceptible to life-threatening infections like pneumonia or rare cancers.
Problem 2:
Explain why cannot be treated with antibiotics like Penicillin.
Solution:
is a virus, and antibiotics only target bacterial structures.
Explanation:
Antibiotics work by disrupting bacterial cell wall synthesis (e.g., peptidoglycan) or ribosomes. Since is a virus, it lacks a cell wall and uses the host cell's machinery to replicate; therefore, antibiotics have no effect on it.