General Questions in English

(N/A) Non-infectious disease: These diseases remain limited to the individual in whom they have developed and are not transmitted from one person to another. Examples include cancer and genetic disorders.
Infectious disease: These diseases are caused by pathogenic organisms such as viruses,bacteria,fungi,protozoa,and helminths. They are easily transmitted from one person to another,such as the common cold,$AIDS$,and malaria.

(A) The full form of $WHO$ is $World$ $Health$ $Organization$. It is a specialized agency of the $United$ $Nations$ responsible for international public health.

(D) According to the World Health Organization $(WHO)$,health is defined as a state of complete physical,mental,and social well-being and not merely the absence of disease or infirmity.
Therefore,a healthy person must be physically fit,mentally stable,and socially well-adjusted.
Thus,all the given options are correct.

(D) Maintaining good health is a multifaceted process that requires a combination of several lifestyle factors.
$1$. $A$ balanced diet provides the essential nutrients,vitamins,and minerals required for the proper functioning of the body.
$2$. Daily exercise helps in maintaining physical fitness,improving cardiovascular health,and strengthening the immune system.
$3$. Proper sleep is crucial for the body to repair tissues,consolidate memory,and regulate hormonal balance.
Therefore,all these factors are essential for overall well-being.

(B) Pathogens are disease-causing organisms such as bacteria,viruses,fungi,protozoa,and helminths.
Mosquitoes are not pathogens themselves; rather,they act as vectors that transmit pathogens (e.g.,Plasmodium for malaria) from one host to another.
Therefore,mosquitoes are not classified as pathogens.

(C) The body has physical barriers that prevent the entry of microorganisms. The epithelial lining of the respiratory,gastrointestinal,and urogenital tracts is a type of physical barrier that traps microorganisms entering our body. $HCl$ acid in the stomach,saliva in the mouth,and tears from the eyes are physiological barriers. $PMNL$,monocytes,and $NK$ cells are cellular barriers,while interferons are cytokine barriers.

(C) $PMNL$ stands for Polymorphonuclear Leucocytes.
These are a type of white blood cell (leucocyte) characterized by a multi-lobed nucleus.
They are a key component of the innate immune system,acting as phagocytes to engulf and destroy pathogens.

(D) $ELISA$ stands for Enzyme-Linked Immunosorbent Assay.
It is a diagnostic technique based on the principle of antigen-antibody interaction.
In this technique,the presence of a pathogen (like a virus or bacteria) is detected either by the presence of antigens (proteins,glycoproteins,etc.) or by detecting the antibodies synthesized against the pathogen.
Therefore,it can identify both the pathogen and the immune response (antibodies) generated by the host.

(B) The $BCG$ (Bacillus Calmette-Guérin) vaccine is the specific vaccine used to prevent tuberculosis $(TB)$.
$TAB$ vaccine is used for typhoid,paratyphoid $A$,and paratyphoid $B$.
$DPT$ vaccine is used for diphtheria,pertussis (whooping cough),and tetanus.
Therefore,the correct option is $B$.

(C) Diseases that are present in an individual from birth are known as $Congenital$ $diseases$. These are typically caused by genetic abnormalities or metabolic disorders present at the time of conception or during embryonic development. In contrast, $Infectious$ $diseases$ are caused by pathogens, and $Non-infectious$ $diseases$ are acquired during an individual's lifetime.

(A) Serology is a branch of immunology that deals with the scientific study of serum and other bodily fluids.
In practice,the term usually refers to the diagnostic identification of antibodies in the serum.
These antibodies are typically formed in response to an infection (against specific antigens) or other foreign substances.
Therefore,serology is primarily defined as the study of antigen-antibody reactions.

(C) Vasodilation is the widening of blood vessels,which is a key part of the inflammatory response.
Mast cells and Basophils are the primary cells that release histamine.
Histamine is a potent vasodilator that increases blood flow to the site of injury or infection,allowing immune cells to reach the area more effectively.
Therefore,both Mast cells and Basophils contribute to this process.

(A) Interferons are a group of signaling proteins released by host cells in response to the presence of pathogens such as viruses.
Specifically,human interferon-alpha $(IFN-\alpha)$ is a well-studied type of interferon.
The primary structure of the mature human leukocyte interferon ($IFN$-alpha) consists of $166$ amino acids.
Therefore,the correct number of amino acids in the mature human $IFN-\alpha$ protein is $166$.

(B) During the process of $Inflammation$,damaged cells and immune cells release various chemical mediators.
$Prostaglandins$ are lipid compounds that sensitize nerve endings (nociceptors),which significantly contributes to the sensation of pain.
$Histamine$ is primarily involved in vasodilation and increasing vascular permeability,leading to redness and swelling.
$IFN$ (Interferons) are antiviral proteins,and $Interleukins$ are signaling molecules involved in immune cell regulation.
Therefore,$Prostaglandins$ are the primary mediators responsible for inducing pain.

(B) An antibody molecule is represented as $H_2L_2$.
It consists of four polypeptide chains: two light chains $(L)$ and two heavy chains $(H)$.
These chains are held together by disulphide bonds ($S-S$ bonds) to form a $Y$-shaped structure.

(D) vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease.
It typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe,its toxins,or one of its surface proteins.
$1$. Inactivated (killed) pathogens are used in vaccines like the polio vaccine.
$2$. Weakened (attenuated) pathogens are used in vaccines like the $BCG$ vaccine.
$3$. Protein antigens (subunits) are used in vaccines like the Hepatitis-$B$ vaccine.
Therefore,all the given options are correct components used in the preparation of vaccines.

(D) Louis Pasteur is known as the father of microbiology and immunology. He developed the vaccines for anthrax,chicken cholera,and rabies. Edward Jenner is known for the smallpox vaccine,while Von Behring is known for diphtheria antitoxin.

(B) Hashimoto's disease,also known as chronic lymphocytic thyroiditis,is an autoimmune disorder in which the immune system attacks the thyroid gland.
This leads to the destruction of thyroid cells,resulting in hypothyroidism (underactive thyroid).
It is characterized by the presence of autoantibodies against thyroid peroxidase and/or thyroglobulin.
Therefore,it is an autoimmune disease of the thyroid gland.

(C) Smallpox ($Variola$ virus) is the only human infectious disease that has been completely eradicated globally through intensive vaccination and immunization programs. The World Health Organization $(WHO)$ declared the world free of smallpox in $1980$.

(C) $ELISA$ (Enzyme-Linked Immunosorbent Assay) is a highly sensitive diagnostic technique used to detect the presence and quantify the concentration of specific antigens or antibodies in a sample.
It is capable of detecting substances at very low concentrations,such as the nanogram level,by utilizing enzyme-labeled antibodies that produce a measurable color change upon reaction with a substrate.
$Widal$ test is used for typhoid diagnosis,while $W. B.$ (Western Blot) is used for protein detection (e.g.,$HIV$ confirmation).

(D) The correct matching is as follows:
$(P)$ Pertussis is caused by the bacterium $Bordetella \, pertussis$ $(iv)$.
$(Q)$ Dengue is a viral disease caused by the Dengue virus $(i)$.
$(R)$ Amoebiasis is caused by the protozoan parasite $Entamoeba \, histolytica$ $(ii)$.
$(S)$ Filariasis (Elephantiasis) is caused by filarial worms like $Wuchereria \, bancrofti$ $(iii)$.
Therefore, the correct sequence is $P-iv, Q-i, R-ii, S-iii$.

(A) $1$. Fever is treated with antipyretics,which reduce body temperature. This is a correct association.
$2$. Typhoid is a bacterial infection caused by Salmonella typhi,which is treated with antibiotics like chloramphenicol,not penicillin.
$3$. Cancer is treated with chemotherapy agents like Taxol,not Stavudine (which is an antiretroviral drug).
$4$. $AIDS$ is treated with antiretroviral drugs like Stavudine,not Taxol (which is an anti-cancer drug).
Therefore,the correct pair is Fever - Antipyretic medicine.

(B) $1$. Analgesics are drugs used to provide relief from pain, which is a correct statement.
$2$. Streptomycin is an antibiotic obtained from the bacterium $Streptomyces \text{ griseus}$, not from a virus. Therefore, this statement is incorrect.
$3$. Aspirin is a common antipyretic and analgesic, widely used for fever and pain.
$4$. Cetirizine is an antihistamine used to treat allergy symptoms, not to increase them. Therefore, this statement is also incorrect.
Given the options provided, the question asks to identify the incorrect statement. Since both $B$ and $D$ are factually incorrect, in the context of standard biology multiple-choice questions where Streptomycin is a classic example of an antibiotic (not a virus-derived product), option $B$ is the most fundamentally incorrect statement regarding biological origin.

(C) Fever,also known as pyrexia,is a systemic response to infection or inflammation.
It is primarily triggered by the release of substances known as pyrogens.
Endogenous pyrogens are cytokines,such as $Interleukin-1$ $(IL-1)$,$Interleukin-6$ $(IL-6)$,and $Tumor$ $Necrosis$ $Factor$ $(TNF)$,which are released by activated immune cells like macrophages.
These substances travel to the hypothalamus in the brain and reset the body's thermostat to a higher temperature,resulting in fever.
Therefore,the production of endogenous pyrogens is the direct cause of a fever-like condition.

(B) Alexander Fleming discovered penicillin,while Howard Florey and Ernst Chain were instrumental in establishing its potential as an effective antibiotic. For their pioneering work in the discovery and development of penicillin,they were jointly awarded the Nobel Prize in Physiology or Medicine in $1945$.

(D) Effective treatment of any disease requires a deep understanding of its nature.
$1$. $Early \ diagnosis$ is crucial because it allows for timely intervention,which significantly increases the chances of recovery.
$2$. $Pathophysiology$ (the study of the disordered physiological processes associated with disease or injury) is essential to understand how the disease affects the body's functions,which helps in selecting the appropriate therapeutic approach.
Therefore,both early diagnosis and understanding the pathophysiology are fundamental for effective treatment.

(A) The Polymerase Chain Reaction $(PCR)$ is a molecular biology technique used to amplify specific segments of $DNA$.
In the context of diagnostics,$PCR$ is highly sensitive and can detect pathogens (like bacteria or viruses) even when their concentration in the sample is very low,by amplifying their nucleic acid sequences.
Therefore,$PCR$ is the standard method for identifying pathogens through nucleic acid amplification.

(D) $ELISA$ stands for Enzyme-Linked Immunosorbent Assay.
It is a diagnostic technique that relies on the principle of antigen-antibody interactions.
In this method,the presence of pathogens (like bacteria or viruses) is detected by the presence of antigens or by detecting antibodies synthesized against the pathogen.
$PCR$ (Polymerase Chain Reaction) is used for amplifying $DNA$,and $r-DNA$ technology is used for genetic engineering,not primarily for antigen-antibody detection.

(D) parasite is an organism that lives on or inside another organism (the host) and derives nutrients at the expense of the host.
$Plasmodium$ is an endoparasite that causes malaria.
$Ascaris$ is an endoparasite that lives in the human intestine.
The female $Anopheles$ mosquito is considered a parasite because it feeds on human blood to obtain nutrients for egg development,acting as a temporary ectoparasite.
$A$ cockroach is a scavenger or a detritivore that feeds on decaying organic matter,waste,and food scraps. It does not depend on a living host for its survival or nutrition in the manner of a parasite. Therefore,it is not a parasite.

(C) The organisms listed are parasites. $A$ parasite lives on or inside another organism (the host) and derives nutrients at the host's expense.
$A$. Tapeworm is an endoparasite living in the intestine of the host.
$B$. Entamoeba is an endoparasite living in the intestine of the host.
$C$. Leech is an ectoparasite that attaches to the external surface of the host.
$D$. Plasmodium is an endoparasite living inside the red blood cells or liver cells of the host.
Among these,the Leech $(C)$ is an ectoparasite,while the others are endoparasites. Therefore,the Leech is the inconsistent organism based on the habitat (internal vs. external).

(C) Dicumarol is a natural anticoagulant found in spoilt sweet clover hay.
When cattle consume this hay,it interferes with the synthesis of clotting factors in the liver,effectively acting as a vitamin-$K$ antagonist.
This leads to a functional vitamin-$K$ deficiency,which prevents proper blood clotting.
Consequently,the cattle suffer from prolonged bleeding or even fatal haemorrhage.

(B) Triazenes are a class of chemical compounds containing a functional group consisting of three nitrogen atoms. They are structurally related to urea derivatives,where the oxygen atom is replaced by a nitrogen-based group,and are synthesized from urea or its derivatives.

(C) Alzheimer's disease is a progressive neurodegenerative disorder. It is characterized by the accumulation of misfolded proteins in the brain,specifically amyloid $\beta$-peptide plaques and tau protein tangles. These accumulations lead to the death of nerve cells,resulting in memory loss and cognitive decline.

(A) According to the National Immunization Schedule $(NIS)$,the primary vaccination series for infants begins at $6$ weeks of age.
At $6$ weeks,the following vaccines are administered:
$1$. Oral Polio Vaccine $(OPV)$ - $1^{st}$ dose
$2$. Hepatitis-$B$ vaccine - $1^{st}$ dose
$3$. Pentavalent vaccine (which includes $DPT$,Hepatitis-$B$,and Hib) - $1^{st}$ dose
$4$. Rotavirus vaccine - $1^{st}$ dose
$5$. Fractional Inactivated Polio Vaccine (fIPV) - $1^{st}$ dose
Therefore,the first dose of both the Oral Polio Vaccine and the Hepatitis-$B$ vaccine is given at $6$ weeks after birth.

(A) $NSEP$ stands for National Smallpox Eradication Programme.
This was a major public health initiative launched by the Government of India to eliminate smallpox from the country.
Other significant national health programmes include:
$(a)$ National Malaria Eradication Programme $(NMEP)$
$(b)$ National Cholera Control Programme $(NCCP)$
$(c)$ National Leprosy Control Programme $(NLCP)$
$(d)$ National Filaria Control Programme $(NFCP)$
$(e)$ Family Planning Programme $(FPP)$

(B) The correct full form of $NLCP$ is National Leprosy Control Programme.
The Government of India initiated several national health programmes to eradicate major communicable diseases. Some of these include:
$(a)$ National Malaria Eradication Programme $(NMEP)$
$(b)$ National Cholera Control Programme $(NCCP)$
$(c)$ National Leprosy Control Programme $(NLCP)$
$(d)$ National Smallpox Eradication Programme $(NSEP)$
$(e)$ National Filaria Control Programme $(NFCP)$
$(f)$ Family Planning Programme $(FPP)$

(A) $NFCP$ stands for National Filaria Control Programme.
This programme was initiated by the Government of India to control the spread of filariasis,a parasitic disease caused by filarial worms.
Other major national health programmes include:
$(a)$ National Malaria Eradication Programme $(NMEP)$
$(b)$ National Cholera Control Programme $(NCCP)$
$(c)$ National Leprosy Control Programme $(NLCP)$
$(d)$ National Smallpox Eradication Programme $(NSEP)$
$(e)$ Family Planning Programme $(FPP)$

(C) $NMEP$ stands for National Malaria Eradication Programme.
The Government of India initiated several national health programmes to control or eradicate major communicable diseases.
Some of the key national programmes include:
$(a)$ National Malaria Eradication Programme $(NMEP)$
$(b)$ National Cholera Control Programme $(NCCP)$
$(c)$ National Leprosy Control Programme $(NLCP)$
$(d)$ National Smallpox Eradication Programme $(NSEP)$
$(e)$ National Filaria Control Programme $(NFCP)$
$(f)$ Family Planning Programme $(FPP)$

(A) $NCCP$ stands for National Cholera Control Programme.
The Government of India initiated several national health programmes to eradicate or control major communicable diseases.
Some of the major national programmes include:
$(a)$ National Malaria Eradication Programme $(NMEP)$
$(b)$ National Cholera Control Programme $(NCCP)$
$(c)$ National Leprosy Control Programme $(NLCP)$
$(d)$ National Smallpox Eradication Programme $(NSEP)$
$(e)$ National Filaria Control Programme $(NFCP)$
$(f)$ Family Planning Programme $(FPP)$

(A) According to the standard National Immunization Schedule, the first dose of the Oral Polio Vaccine $(OPV)$ and the Hepatitis-$B$ vaccine is administered to an infant at $6 \; \text{weeks}$ of age.
These vaccines are crucial for building immunity against polio and hepatitis-$B$, which are serious viral infections. The immunization schedule ensures that children receive protection at the appropriate developmental stages to prevent these communicable diseases.

(A) According to the National Immunization Schedule,the $BCG$ (Bacillus Calmette-Guérin) vaccine is administered to infants to provide protection against tuberculosis. The first dose of the $BCG$ vaccine is recommended to be given at birth or as early as possible. Therefore,the correct option is birth.

(A) The $DPT$ vaccine is a combination vaccine that protects against Diphtheria,Pertussis (whooping cough),and Tetanus. According to the standard National Immunization Schedule $(NIS)$,the primary series of $DPT$ vaccination is administered as follows:
$1$. $1^{st}$ dose: $6$ weeks
$2$. $2^{nd}$ dose: $10$ weeks
$3$. $3^{rd}$ dose: $14$ weeks
Therefore,the $2^{nd}$ dose is given at $10$ weeks and the $3^{rd}$ dose is given at $14$ weeks.

(C) The $DPT$ (Diphtheria, Pertussis, and Tetanus) vaccine is a primary immunization series given to infants.
According to the National Immunization Schedule, the primary doses are administered at $6$, $10$, and $14$ weeks of age.
- $1^{st}$ dose: $6 \; \text{weeks}$ after birth $(I)$
- $2^{nd}$ dose: $10 \; \text{weeks}$ after birth $(II)$
- $3^{rd}$ dose: $14 \; \text{weeks}$ after birth $(III)$
Therefore, the correct sequence is $I$, $II$, and $III$.

(C) Louis Pasteur proposed the germ theory of disease,which states that microorganisms are the cause of many diseases.
Robert Koch provided the definitive experimental proof for the germ theory of disease by establishing Koch's postulates.
Robert Koch is also considered one of the founders of modern microbiology and received the Nobel Prize in $1905$ for his work on tuberculosis.

(A) The use of antibiotics in cattle feed is a common practice to promote growth and prevent infections.
However,this practice leads to the development of antibiotic-resistant bacteria in the gut of the cattle.
These resistant bacteria can be transferred to humans through the food chain or direct contact,making human infections harder to treat.
Due to this public health risk,many countries have banned the use of antibiotics as growth promoters in cattle feed.
Therefore,both the Assertion and the Reason are correct,and the Reason provides the correct explanation for the Assertion.

(C) Malaria is a well-known human disease caused by infection with a pathogenic protozoan,the $Plasmodium$. Female $Anopheles$ mosquitoes act as vectors and transmit $Plasmodium$ from an infected person to a healthy person.

(C) Edward Jenner $(1796)$,an English physician,prepared the first vaccine when he injected the fluid from the sore of a milkmaid suffering from cowpox into the body of a healthy boy. When this boy was later exposed to smallpox,he exhibited resistance to the disease.
Louis Pasteur $(1879)$ discovered that ageing cultures of cholera bacteria were too weak to cause disease when injected into chickens. However,chickens injected with these weakened cultures became immune to fowl cholera.
By using this method,Pasteur developed a vaccine against rabies in $1885$,thereby establishing the scientific basis of vaccination.

(C) Smallpox is caused by the Variola virus,which exclusively infects humans. There is no animal reservoir for this virus. Therefore,the eradication of smallpox was not achieved through the elimination of an animal reservoir,but rather through global vaccination efforts and international cooperation.

(A) An autoimmune disease occurs when the immune system mistakenly attacks the body's own healthy cells.
Rheumatoid arthritis $(RA)$ is a classic example of an autoimmune disease where the immune system attacks the synovial membranes of the joints,leading to inflammation and pain.
$AIDS$ is caused by the $HIV$ virus (immunodeficiency),$Hepatitis-B$ is a viral infection of the liver,and $Swine$ $flu$ is a respiratory infection caused by the $H1N1$ virus.