CBSE 2023 · Region 5 · Set 1 · Q29 · 4 marks
When a microorganism invades a host, a definite sequence of events usually occur leading to infection and disease, causing suffering to the host. This process is called pathogenesis. Once a microorganism overcomes the defense system of the host, development of the disease follows a certain sequence of events as shown in the graph. Study the graph given below for the sequence of events leading to appearance of a disease and answer the questions that follow :
(a)In which period, according to the graph there are maximum chances of a person transmitting a disease / infection and why ?Study the graph and write what is an incubation period. Name a sexually transmitted disease that can be easily transmitted during this period. Name the specific type of lymphocytes that are attacked by the pathogen of this disease.Draw a schematic labelled diagram of an antibody. $\displaystyle 2$(c)In which period, the number of immune cells forming antibodies will be the highest in a person suffering from pneumonia ? Name the immune cells that produce antibodies.
When a microorganism invades a host, a definite sequence of events usually occur leading to infection and disease, causing suffering to the host. This process is called pathogenesis. Once a microorganism overcomes the defense system of the host, development of the disease follows a certain sequence of events as shown in the graph. Study the graph given below for the sequence of events leading to appearance of a disease and answer the questions that follow :
(a)
In which period, according to the graph there are maximum chances of a person transmitting a disease / infection and why ?
Study the graph and write what is an incubation period. Name a sexually transmitted disease that can be easily transmitted during this period. Name the specific type of lymphocytes that are attacked by the pathogen of this disease.
Draw a schematic labelled diagram of an antibody. $\displaystyle 2$
(c)
In which period, the number of immune cells forming antibodies will be the highest in a person suffering from pneumonia ? Name the immune cells that produce antibodies.
Marking-scheme solution
(a)
Incubation period
Infected person may not take precautions during this period as there are no symptoms of the diseases.
//
Period of illness
Number of microorganisms is high and can be transmitted via droplet infection.
Time period between infection and appearance of its symptoms.
AIDS/any other correct example
T lymphocytes
(c)
Period of illness
B lymphocytes / B cells
Human Health and DiseaseImmunityUnderstandcase_studymedium
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CBSE Class 12 Biology past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.