General Questions in English

(B) Aspirin is a well-known drug that acts as an antipyretic,meaning it is used to reduce fever. It also possesses analgesic (pain-relieving) and anti-inflammatory properties.

(B) $VCRC$ stands for Vector Control Research Centre. It is a research institute under the Indian Council of Medical Research $(ICMR)$ and is situated in Puducherry (formerly Pondicherry).

(A) The skin on our body acts as the primary physical barrier that prevents the entry of microorganisms.
Additionally,the mucous coating of the epithelium lining the respiratory,gastrointestinal,and urogenital tracts also helps in trapping microbes that attempt to enter our body.

(A) An antibody molecule is a $Y$-shaped structure composed of $4$ polypeptide chains.
These include $2$ small chains known as light $(L)$ chains and $2$ longer chains known as heavy $(H)$ chains.
Due to the presence of $2$ heavy and $2$ light chains,the antibody is represented as $H_2L_2$.
Therefore,the correct mapping is $A-4, B-2, C-\text{light}, D-2, E-\text{heavy}, F-H_2L_2$.

(A) Diseases like whooping cough (pertussis),diphtheria,and tetanus (lockjaw) can be prevented by immunizing infants with the triple vaccine,known as $DTP$ (Diphtheria,Tetanus,and Pertussis vaccine).
Typhoid,which is caused by the bacterium $Salmonella \ typhi$,is not prevented by the $DTP$ triple vaccine. Instead,specific vaccines such as the typhoid vaccine are available for its prevention.

(C) Body Dysmorphic Disorder $(BDD)$ is a mental health disorder in which a person becomes obsessively concerned and hypersensitive about their physical appearance or perceived flaws.
$Hypochondria$ is a somatoform disorder characterized by an unfounded belief that one is suffering from a serious illness.
$Anxiety$ is a complex combination of feelings of fear,apprehension,and worry.
$Phobia$ is an uncontrollable,irrational fear of a specific object,situation,or activity.

(D) In the fomite borne method,pathogens are spread through contaminated inanimate objects (fomites) such as toys,door handles,handkerchiefs,towels,etc.

(D) The best $HLA$ match for organ or tissue transplants depends on genetic similarity.
Identical twins share the exact same genetic makeup, making them the best possible match.
Siblings are the next best choice as they share $50\%$ of their genes with the recipient.
Parents are the third choice, and unrelated donors are the least preferred due to the high risk of rejection.

(C) Opioids are a class of drugs that act on the central nervous system. They bind to specific opioid receptors located in both the central nervous system and the gastrointestinal tract to produce their effects.

(A) Statement $I$ is correct as vaccination provides immunity against infections.
Statement $II$ is correct as vaccines are available for these diseases.
Statement $III$ is correct because controlling vectors like mosquitoes is essential to prevent diseases like malaria and filariasis.
Statement $IV$ is incorrect because dengue and chikungunya are spread by $Aedes$ mosquitoes,not $Culex$ mosquitoes.
Therefore,statements $I, II,$ and $III$ are correct.

(D) Small pox was a deadly disease that has been completely eradicated worldwide through the use of vaccines. The first vaccine for smallpox was discovered by Edward Jenner in $1798$,which eventually led to the global eradication of the disease.

(B) Histamine is a chemical released by mast cells during an inflammatory response.
It causes vasodilation,which is the widening of blood vessels,leading to increased blood flow to the affected area.
Additionally,histamine increases vascular permeability,allowing white blood cells and proteins to move from the blood into the tissues to fight infection or injury.

(A) The oral polio vaccine $(OPV)$,also known as the Sabin vaccine,contains live attenuated (weakened) poliovirus.
When administered orally,it mimics the natural route of infection.
This stimulates the production of secretory $IgA$ antibodies in the intestinal mucosa,which provides local intestinal immunity.
This local immunity is crucial because it prevents the virus from multiplying in the gut and being shed in feces,thereby interrupting the transmission of the virus and preventing reinfection.
Therefore,both the Assertion and the Reason are correct,and the Reason is the correct explanation of the Assertion.

(D) The term "pro-life" in the context of human beings refers to antibiotics.
Antibiotics are chemical substances produced by some microbes and can kill or retard the growth of other disease-causing microbes.
They have significantly contributed to human welfare by treating various bacterial infections.

(A) An attenuated virus is a weakened form of a virus that has been modified in a laboratory setting to reduce its virulence (pathogenicity).
Because it is weakened,it does not cause the disease in a healthy individual but is still capable of replicating and stimulating the immune system.
This property makes attenuated viruses highly effective as vaccines,as they trigger a strong,long-lasting immune response without causing the actual infection.
Therefore,the correct description is that it is a virus that is non-pathogenic.

(C) $ELISA$ (Enzyme-Linked Immunosorbent Assay) is a diagnostic tool based on the principle of antigen-antibody interaction. It detects the presence of pathogens by identifying either antigens (proteins,glycoproteins,etc.) or antibodies produced in response to infection. It is not a nucleic acid-based technique; rather,techniques like $PCR$ (Polymerase Chain Reaction) are used for nucleic acid-based detection. Therefore,the Assertion is correct,but the Reason is incorrect.

(C) Early diagnosis is crucial for the effective treatment of diseases.
$ELISA$ (Enzyme-Linked Immunosorbent Assay) is a highly sensitive molecular diagnostic technique used for the early detection of pathogens or diseases.
It works on the principle of antigen-antibody interaction.
In $ELISA$,infection by a pathogen can be detected by the presence of antigens (proteins,glycoproteins,etc.) or by detecting the antibodies synthesized against the pathogen.
Therefore,$ELISA$ is widely used for early diagnosis.

(B) Louis Pasteur is widely recognized for his pioneering work in microbiology. He laid the foundation of Bacteriology by developing advanced culture techniques,which allowed scientists to isolate and study bacteria in a controlled environment. He also disproved the theory of spontaneous generation and developed the process of pasteurization.

(B) Lysozyme is an enzyme present in saliva and tears. It acts as an antibacterial agent that kills bacteria by breaking down their cell walls,thereby preventing infections.

(N/A) Health does not simply mean the absence of disease or physical fitness.
According to the World Health Organization $(1948)$, health is defined as a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.

(D) Good health can be maintained through the following practices:
$1$. Balanced diet: Consuming a diet that provides all essential nutrients in the correct proportions.
$2$. Personal hygiene: Maintaining cleanliness of the body to prevent infections.
$3$. Regular exercise: Engaging in physical activity to keep the body fit and improve physiological functions.

(A) Maintenance of personal and public hygiene is very important for the prevention and control of many infectious diseases.
- Measures for personal hygiene include keeping the body clean.
- Consumption of clean drinking water,food,vegetables,fruits,etc.
Public hygiene includes:
- Proper disposal of waste and excreta.
- Periodic cleaning and disinfection of water reservoirs,pools,cesspools,and tanks.
- Observing standard practices of hygiene in public catering.
The above measures are particularly essential where the infectious agents are transmitted through food and water,such as typhoid,amoebiasis,and ascariasis.

(D) Airborne diseases like pneumonia and the common cold spread through droplets released during coughing or sneezing.
To prevent their spread,the following precautions are necessary:
$1$. Avoid close contact with infected persons to prevent inhalation of contaminated droplets.
$2$. Avoid sharing personal belongings such as towels,handkerchiefs,or utensils with infected individuals.
$3$. Always cover the nose and mouth while sneezing or coughing to contain the spread of pathogens.
Therefore,all the mentioned measures are essential for prevention.

(N/A) Diseases like malaria and filariasis are transmitted through insect vectors.
The most important measure is to control or eliminate the vectors and their breeding places.
This can be achieved by avoiding the stagnation of water in and around residential areas.
Regular cleaning of household coolers,use of mosquito nets,introducing fishes like $Gambusia$ in ponds that feed on mosquito larvae,and spraying of insecticides in ditches,drainage areas,and swamps are effective methods.
In addition,doors and windows should be provided with wire mesh to prevent the entry of mosquitoes.
Such precautions have become all the more important,especially in light of the recent widespread incidences of vector-borne diseases (transmitted by $Aedes$ mosquitoes) like dengue and chikungunya in many parts of India.

(B) The advancements made in biological science have armed us to effectively deal with many infectious diseases.
The use of vaccines and immunization programs has enabled us to completely eradicate a deadly disease like smallpox.
$A$ large number of other infectious diseases like polio,diphtheria,pneumonia,and tetanus have been controlled to a large extent by the use of vaccines.
Biotechnology is on the verge of making available newer and safer vaccines.
Discovery of antibiotics and various other drugs has also enabled us to effectively treat infectious diseases.

(D) Both $Hepatitis-B$ and $HIV$ are blood-borne pathogens that can be transmitted through the following routes:
$1$. Sharing of contaminated surgical instruments or needles.
$2$. Blood transfusion involving infected blood.
$3$. Vertical transmission from an infected mother to her fetus during pregnancy or childbirth.
Therefore,all the listed options are correct modes of transmission.

(D) Human health is a state of complete physical,mental,and social well-being. It is influenced by several factors:
$1$. Genetic disorders: These are deficiencies with which a child is born and deficiencies/defects which the child inherits from parents from birth.
$2$. Infections: These include diseases caused by pathogens like bacteria,viruses,fungi,and parasites.
$3$. Lifestyle: This includes the food and water we take,rest and exercise we give to our bodies,and habits that we have or lack.
Therefore,all the given factors significantly affect human health.

(B) Good health is defined as a state of complete physical,mental,and social well-being.
Healthy people are more efficient at work,which increases productivity and brings economic prosperity.
Therefore,the statement that health leads to a decrease in economic prosperity is incorrect.
Health also increases longevity and reduces infant and maternal mortality rates.

(A) Cancer is a non-infectious disease because it is caused by the uncontrolled division of cells within the body and does not spread from one person to another through contact or vectors.
$AIDS$ (Acquired Immuno Deficiency Syndrome) is an infectious disease caused by the $HIV$ virus,which can be transmitted from an infected person to a healthy person through the exchange of body fluids.

(B) An antibody molecule is $Y$-shaped and consists of four polypeptide chains: two light chains and two heavy chains.
These chains are linked together by disulfide bonds ($S-S$ bonds) to form the functional antibody structure.
Therefore,the correct option is $B$.

(D) Adolescence is a period during which a child becomes mature in terms of his/her attitudes and beliefs for effective participation in society.
It is defined as the period of life between $12$ to $18$ years of age.
It is a bridge linking childhood and adulthood.
Adolescence is accompanied by several biological and behavioral changes.
It is a very vulnerable phase of mental and psychological development of an individual.
Therefore,all the given statements are correct.

(D) Antibiotics are chemical substances produced by some microbes that can kill or retard the growth of other disease-causing microbes.
They have greatly improved our capacity to treat deadly diseases such as plague $(Plague)$,whooping cough ($Kali$ $khansi$),diphtheria $(Diphtheria)$,and leprosy $(Kusthrog)$.
Therefore,all the diseases mentioned in the options are treated using antibiotics.

(B) For the effective treatment of any disease,it is essential to have an early diagnosis so that the disease can be managed before it progresses to a severe stage.
Furthermore,understanding the pathophysiology of the disease is crucial to target the specific biological mechanisms involved,thereby ensuring an effective therapeutic approach.
Therefore,both early diagnosis and understanding the pathophysiology are necessary for effective treatment.

(C) The correct matches are as follows:
$1$. Pneumonia is caused by the bacterium $Haemophilus influenzae$ $(a-q)$.
$2$. Common cold is caused by Rhino viruses $(b-p)$.
$3$. Filariasis is caused by the filarial worm $Wuchereria bancrofti$ $(c-s)$.
$4$. Ringworm is caused by fungi like $Microsporum$ $(d-r)$.
Therefore, the correct matching is $a-q, b-p, c-s, d-r$, which corresponds to option $C$.

(B) $(i)$ Diseases that are easily transmitted from one person to another are called infectious diseases.
$(ii)$ The malaria parasite $(Plasmodium)$ first enters the human body through the bite of an infected female $Anopheles$ mosquito and multiplies within the liver cells,then attacks the red blood cells $(\text{RBCs})$.
$(iii)$ Colostrum is the yellowish fluid secreted by the mother during the initial days of lactation,which is rich in antibodies (IgA) to provide immunity to the infant.
$(iv)$ Bone marrow and thymus are the primary lymphoid organs where lymphocytes mature and differentiate into antigen-specific lymphocytes.

(D) Rheumatoid arthritis is a chronic inflammatory disorder that occurs when the immune system mistakenly attacks the body's own tissues,specifically the synovium (the lining of the membranes that surround the joints). Therefore,it is classified as an auto-immune disease. Asthma is a respiratory condition,cancer is characterized by uncontrolled cell division,and osteoarthritis is a degenerative joint disease caused by wear and tear,not an auto-immune response.

(D) Vaccines and immunisation programmes have played a significant role in controlling and eradicating infectious diseases.
Small pox (Variola virus) is the only human disease that has been completely eradicated globally through intensive vaccination campaigns led by the World Health Organization $(WHO)$.
Other diseases like Tetanus and Diphtheria are controlled but not yet completely eradicated.

(C) The correct matches are as follows:
$1$. Malaria is caused by $Plasmodium \text{ } ovale$ $(ii)$ and leads to symptoms like arthralgia (joint pain) and anaemia $(r)$.
$2$. Elephantiasis (Filariasis) is caused by $Brugia \text{ } malayi$ $(iii)$ and leads to the enlargement of lymph vessels and nodes $(q)$.
$3$. Amoebiasis is caused by $Entamoeba \text{ } histolytica$ $(i)$ and leads to symptoms like diarrhoea and flatulence $(p)$.
Therefore, the correct sequence is $1-ii-r, 2-iii-q, 3-i-p$.

(C) Lysozyme is an enzyme found in secretions like saliva,tears,and mucus. It acts as a chemical barrier in innate immunity by hydrolyzing the peptidoglycan layer of bacterial cell walls. It is specifically active against certain pathogenic Gram-positive bacteria,making it an antibacterial agent.

(B) Diseases that are present in an individual from the time of birth are known as congenital diseases.
These are typically caused by genetic abnormalities or developmental issues during pregnancy.
In contrast,acquired diseases are those that develop after birth due to pathogens,lifestyle,or environmental factors.

(D) Edward Jenner is known as the father of immunology. In $1796$,he observed that milkmaids who had contracted cowpox were immune to smallpox. He tested this by inoculating a young boy with material from a cowpox lesion and later exposing him to smallpox. The boy did not develop the disease,thus proving the effectiveness of the first vaccine against smallpox.

(D) During an inflammatory response,damaged mast cells and basophils release chemical mediators that trigger the immune response.
These chemical mediators primarily include histamines and prostaglandins.
Histamines cause vasodilation and increased permeability of blood vessels,while prostaglandins contribute to pain and inflammation.
Therefore,the correct pair is $A$-histamines and $B$-prostaglandins.

(A) Pus is a thick,whitish-yellow or greenish-yellow fluid that forms at the site of an infection or inflammation.
It is primarily composed of:
$1$. Dead neutrophils: These are white blood cells that migrate to the site of infection to phagocytose pathogens and die in the process.
$2$. Dead microbes: The pathogens (bacteria,etc.) that have been killed by the immune response.
$3$. Damaged tissues: Cellular debris resulting from the inflammatory process and tissue destruction.
Therefore,the correct combination is $I, II,$ and $III$.

(B) $ELISA$ stands for Enzyme-Linked Immunosorbent Assay.
It is a diagnostic technique based on the principle of antigen-antibody interaction.
Infections can be detected by identifying the presence of antigens (proteins,glycoproteins,etc.) or by detecting the antibodies produced against the pathogen in the host's body.
Therefore,both statements are correct.

(D) $PCR$.
Polymerase Chain Reaction $(PCR)$ is a molecular biology technique that allows for the amplification and detection of very small amounts of $DNA$.
Because $PCR$ can amplify specific sequences of pathogen $DNA$ or $RNA$ (via reverse transcription),it enables the detection of disease-causing bacteria or viruses long before the symptoms of the disease appear in the patient.
This capability makes $PCR$ a powerful tool for early diagnosis and timely treatment.
Currently,$PCR$ is widely used to detect gene mutations in patients suspected of having cancer and to identify $HIV$ in patients suspected of having $AIDS$.