General Questions in English

(B) An autoimmune disease occurs when the body's immune system mistakenly attacks its own healthy cells and tissues.
Rheumatoid arthritis is a classic example of an autoimmune disease where the immune system attacks the joints,causing inflammation and pain.
Fever is a symptom,not a disease.
Malaria is an infectious disease caused by the $Plasmodium$ parasite.
Cold is a viral infection of the upper respiratory tract.

(B) The $Spleen$ is a large, bean-shaped organ that primarily contains lymphocytes and phagocytes.
It acts as a filter of the blood by trapping blood-borne microorganisms.
It also provides the sites for the interaction of lymphocytes with antigens, which then proliferate to become effector cells.
Therefore, the $Spleen$ is the correct site for this interaction.

(D) $1$. Physiological barriers include secretions like acid in the stomach,saliva in the mouth,and tears from the eyes,which prevent microbial growth.
$2$. Physical barriers are anatomical structures like the skin and the mucus coating of the epithelium lining the respiratory,gastrointestinal,and urogenital tracts.
$3$. Therefore,statement $A$ is correct as acid and saliva are physiological barriers.
$4$. Statement $R$ is incorrect because tears are also physiological barriers,not physical barriers.

(B) The correct matches are as follows:
- Typhoid is caused by the bacterium $Salmonella \ typhi$ $(1-w)$.
- Malaria is caused by the protozoan $Plasmodium$ $(2-x)$.
- Pneumonia is caused by $Haemophilus \ influenzae$ or $Streptococcus \ pneumoniae$. In the given options,$3-z$ $(Haemophilus \ influenzae)$ is provided.
- Common cold is caused by $Rhino \ virus$ $(4-y)$.
Therefore,the correct sequence is $1-w, 2-x, 3-z, 4-y$.

(A) In the human immune system,innate immunity consists of four types of barriers:
$1$. Physical barriers: These prevent the entry of microorganisms into the body. The skin on our body is the main barrier which prevents entry of the micro-organisms. Mucus coating of the epithelium lining the respiratory,gastrointestinal,and urogenital tracts also help in trapping microbes entering our body.
$2$. Physiological barriers: These prevent microbial growth in the body. Examples include acid in the stomach,saliva in the mouth,and tears from eyes.
Therefore,the correct pair is Physical barrier = Skin and Physiological barrier = Saliva in the mouth.

(D) Plants are susceptible to a wide variety of pathogens that can cause diseases and significantly reduce crop yields.
Bacteria, such as $Xanthomonas$ $oryzae$, cause bacterial blight in rice.
Fungi, such as $Fusarium$ $oxysporum$, cause wilting in various crops.
Viruses, such as Tobacco Mosaic Virus $(TMV)$, cause mosaic diseases in plants.
Since all three categories of pathogens are known to cause significant damage to plants, the correct answer is $All$ $correct$.

(A) $ELISA$ 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 can be detected by identifying either the antigens (proteins,glycoproteins,etc.) produced by the pathogen or by detecting the antibodies synthesized by the host against the pathogen.
Therefore,both statements $A$ and $B$ are correct.

(C) Interferons $(IFNs)$ are a group of signaling proteins made and released by host cells in response to the presence of several pathogens,such as viruses,bacteria,parasites,or tumor cells.
However,they are most characteristically known for being synthesized in response to a $Virus$ infection.
When a cell is infected by a virus,it secretes interferons,which signal neighboring cells to heighten their antiviral defenses,thereby preventing the spread of the viral infection.

(C) Phytoalexins are antimicrobial substances synthesized de novo by plants that accumulate rapidly at areas of pathogen infection. They act as a chemical defense mechanism against various pathogens,including fungi,bacteria,and viruses. Therefore,the correct answer is Phytoalexins.

(C) The housefly,belonging to the genus $Musca$ (specifically $Musca$ $domestica$),is considered the greatest mechanical carrier of diseases.
It carries pathogens on its hairy legs and body parts from contaminated surfaces like garbage and excreta to human food and water.
It is responsible for transmitting diseases such as cholera,typhoid,dysentery,and tuberculosis.

(B) Adult mosquitoes of the genera $Culex$ and $Anopheles$ can be distinguished primarily by their resting position on a surface.
$Anopheles$ mosquitoes rest at an angle,with their body held at an acute angle to the surface,often appearing as if they are standing on their head.
In contrast,$Culex$ mosquitoes rest with their body parallel to the surface,appearing hunched or horizontal.

(B) Analgesics are a class of drugs specifically designed to provide relief from pain. They act by blocking pain signals to the brain or by modifying the body's perception of pain. Therefore,the primary function of analgesic drugs is to relieve pain.

(C) Poliomyelitis (Polio) is a viral disease that has been the target of global eradication programs. Due to widespread vaccination campaigns (such as the Pulse Polio Programme),the incidence of polio has decreased significantly worldwide. It is considered one of the diseases that can be completely eradicated in the near future.

(A) Smallpox (Variola virus) was officially declared eradicated from India in $1977$ by the World Health Organization $(WHO)$. While India has been declared polio-free,smallpox is the only disease that has been completely eradicated globally and from India.

(B) In vertebrates,cells infected with a virus produce special proteins called $Interferons$ $(IFNs)$.
These proteins are released into the surrounding cells and protect non-infected cells from further viral infection.
$Interferons$ act as a part of the innate immune system,specifically as a cytokine barrier,by inhibiting the replication of the virus within the host cells.

(D) Polio drops administered orally contain the attenuated (weakened) form of the polio virus. This is an example of active immunization,where the body's immune system is stimulated to produce its own antibodies against the pathogen. Passive immunization,on the other hand,involves the direct administration of pre-formed antibodies (e.g.,tetanus antitoxin). Therefore,the correct answer is $D$.

(B) The Bordeaux mixture is a fungicide made from copper sulfate $(CuSO_4)$ and slaked lime $(Ca(OH)_2)$.
It was discovered by Pierre-Marie-Alexis Millardet in the late $19^{th}$ century.
He observed that grapevines treated with this mixture were protected from the downy mildew disease caused by the oomycete pathogen $Plasmopara \ viticola$.
Therefore,the Bordeaux mixture is historically associated with the control of downy mildew of grapes.

(C) An autoimmune disease occurs when the immune system mistakenly attacks healthy cells in the body.
$A$. Vitiligo is an autoimmune condition where the immune system destroys melanocytes.
$B$. Psoriasis is an autoimmune disease that causes skin cells to multiply up to $10$ times faster than normal.
$C$. Alzheimer's disease is a progressive neurodegenerative disorder characterized by the accumulation of amyloid plaques and tau tangles in the brain; it is not classified as an autoimmune disease.
$D$. Rheumatoid arthritis is an autoimmune disorder in which the immune system attacks the joints,causing inflammation.
Therefore,the correct answer is $C$.

(C) Aflatoxins are toxic secondary metabolites produced primarily by the fungus $Aspergillus$ $flavus$.
These toxins are highly carcinogenic and harmful to humans and animals,causing liver damage and other health issues.
Therefore,the Assertion is correct,but the Reason is incorrect because these toxins are harmful,not useful to mankind.

(A) Plant cuticles are protective waxy coverings produced by the epidermal cells of leaves,young shoots,and other aerial plant organs.
Beyond acting as a permeability barrier for water and other molecules,the micro- and nanostructure of the cuticle provides specialized surface properties that prevent the contamination of plant tissues by external water,dirt,and microorganisms.
The waxy layer of the cuticle also functions in defense by forming a physical barrier that resists penetration by virus particles,bacterial cells,and the spores or growing filaments of fungi.
Therefore,a thicker cuticle provides enhanced resistance against pathogens,making the Assertion and Reason both correct,and the Reason serves as the correct explanation for the Assertion.

(A) Leptospirosis is a bacterial disease transmitted through contact with water contaminated by the urine of infected animals. Bilharzia (schistosomiasis) is caused by parasitic flatworms (flukes) whose larvae,known as cercariae,penetrate the human skin when a person wades or swims in contaminated freshwater. Both diseases are commonly associated with exposure to dirty or flood water.

(B) An insect bite causes tissue damage,which triggers an inflammatory response at the site of the injury.
This response is mediated by the release of chemical mediators known as alarm chemicals.
$Histamine$ is released by mast cells and basophils,which causes vasodilation and increased capillary permeability,leading to redness and swelling.
$Kinins$ (such as bradykinin) are polypeptides that also promote vasodilation,increase vascular permeability,and stimulate pain receptors.
Therefore,the correct combination of alarm chemicals involved in this process is $histamine$ and $kinins$.

(A) Many plants have evolved structural defenses to protect themselves against pathogens. $A$ thick cuticle acts as a physical barrier on the surface of leaves and stems. Because the cuticle is a waxy,non-living layer,disease-causing agents (pathogens) cannot easily grow on it or penetrate through it to reach the living tissues underneath. Therefore,a thick cuticle is a significant trait in disease-resistant plants,and the reason provided correctly explains this biological adaptation.

(A) Myasthenia gravis is an autoimmune disorder that affects the neuromuscular junction,leading to fatigue,weakening,and paralysis of skeletal muscles. It occurs when the immune system produces antibodies that block or destroy acetylcholine receptors at the neuromuscular junction. Arthritis,osteoporosis,and gout are skeletal or joint-related disorders but are not primarily classified as autoimmune disorders in the context of the neuromuscular junction.

(D) For a long time,health was considered a state of body and mind where there was a balance of certain 'humors' like $Vata$,$Pitta$,and $Kapha$. Ancient Greek thinkers like Hippocrates and the Indian Ayurveda system shared this view.
It was believed that persons with 'black bile' were hot-tempered and suffered from fever. This was based purely on reflective thought.
William Harvey,through experimental methods,discovered blood circulation and used a thermometer to demonstrate that individuals with black bile did not have elevated body temperatures.
This disproved the 'good humor' hypothesis of health. Later,biology showed that the nervous system and endocrine system influence our immune system,which in turn maintains our health.

(D) Our health is affected by the following factors:
$(i)$ Genetic disorders: These are the deficiencies or defects that a child inherits from parents from birth.
$(ii)$ Infections: These are caused by pathogens like bacteria,viruses,fungi,etc.
$(iii)$ Lifestyle: This includes the food and water we consume,the amount of rest and exercise we provide to our bodies,and the habits that we possess or lack.

(D) Achieving good health requires a combination of several factors:
$1$. Awareness about diseases and their effects on different body functions.
$2$. Proper disposal of waste and maintenance of environmental sanitation.
$3$. Vaccination or immunization against infectious diseases.
$4$. Controlling vectors that transmit harmful microorganisms.
$5$. Maintenance and consumption of hygienic food and clean water resources.
$6$. Regular physical exercise and a balanced diet.

(N/A) disease is defined as a condition where the normal functioning of one or more organs or systems of the body is adversely affected,characterized by various signs and symptoms.
Any change from the normal state that causes discomfort or disability is called a disease.
Diseases can be broadly classified into two categories: infectious and non-infectious diseases.
$1$. Infectious diseases: These are diseases that can be easily transmitted from one person to another. They are very common,and everyone suffers from them at some point. Some infectious diseases,like $AIDS$,are fatal.
$2$. Non-infectious diseases: These are diseases that cannot be transmitted from an affected person to a normal,healthy person. Cancer is a major example of a non-infectious disease and is a leading cause of death. Additionally,drug and alcohol abuse also adversely affect our health.

(D) Pathogens are disease-causing organisms such as bacteria,viruses,fungi,protozoa,and helminths that infect the human body.
$1$. Upon entering the host,pathogens multiply rapidly,which interferes with the normal vital activities of the host.
$2$. They cause morphological and functional damage to the host's tissues and organs.
$3$. They often release toxic substances that disrupt physiological processes.
Therefore,pathogens cause harm to humans through all of the mentioned processes.

(N/A) The prevention and control of many infectious diseases are essential through both personal and public hygiene.
$1$. Personal hygiene includes keeping the body clean,consuming clean drinking water,food,vegetables,etc.
$2$. Public hygiene includes proper disposal of waste and excreta,periodic cleaning and disinfection of water reservoirs,pools,cesspools,and tanks. It is also necessary to observe standard hygiene practices in public catering.
$3$. These measures are particularly essential where infectious agents are transmitted through food and water,such as typhoid,amoebiasis,and ascariasis. In air-borne diseases like pneumonia and the common cold,in addition to the above measures,one should avoid close contact with infected persons or their belongings.
$4$. For vector-borne diseases like malaria and filariasis,the most important aspect is the control and elimination of vectors and their breeding sites. This includes not allowing water to stagnate in and around residential areas,regular cleaning of household coolers,using mosquito nets,introducing fish like Gambusia in ponds to feed on mosquito larvae,and spraying insecticides in ditches,drainage areas,and swamps.
$5$. Additionally,doors and windows should be fitted with wire mesh to prevent the entry of mosquitoes. These measures are crucial in the context of widespread diseases like dengue and chikungunya,which are transmitted by Aedes mosquitoes.
$6$. Advances in biotechnology and medicine have provided effective tools to combat infectious diseases. Vaccination and immunization programs have enabled the complete eradication of diseases like smallpox. We have also controlled many infectious diseases like polio,diphtheria,pneumonia,and tetanus through vaccines. Biotechnology has allowed for the development of newer and safer vaccines,while research into antibiotics and other drugs has enabled the effective treatment of infectious diseases.

(N/A) $1$. Infectious diseases: These are diseases that are easily transmitted from one person to another. They are very common,and everyone suffers from them at some point. Some infectious diseases,like $AIDS$,are fatal.
$2$. Non-infectious diseases: These diseases are not transmitted from one person to another. Cancer is a major cause of death among non-infectious diseases. Additionally,the use of drugs and alcohol also adversely affects our health.

(B) The discovery of antibiotics has revolutionized medicine by providing effective treatments for previously incurable bacterial and fungal infections.
Antibiotics have significantly improved our ability to treat life-threatening diseases such as Plague,Whooping cough (Kali khansi),Diphtheria (Galgotu),and Leprosy (Kusht rog).
These diseases were responsible for millions of deaths worldwide before the advent of antibiotics.
Today,antibiotics are essential tools in modern medicine,and it is impossible to imagine a world without them.

(C) Infectious diseases are caused by external pathogens such as bacteria,viruses,or fungi. Treatment involves using antibiotics,antivirals,or antifungals to eliminate the pathogen and strengthening the immune system.
Genetic diseases,however,are caused by mutations in the $DNA$,leading to the production of faulty proteins or defective enzymes. Since the defect is present in the genetic code itself,standard medication cannot 'cure' the disease,often requiring gene therapy or symptomatic management.

(N/A) Pathogens often exhibit tissue or organ specificity,meaning they target particular sites within the host body to survive and multiply.
$1$. $Salmonella \ typhi$ is a pathogen that specifically infects the small intestine,leading to typhoid fever.
$2$. In contrast,the intestinal endoparasite $Entamoeba \ histolytica$ specifically targets the large intestine,causing amoebic dysentery.
These examples demonstrate that different pathogens have evolved to thrive in specific physiological environments within the human body.

(B) During changing weather,one is advised to avoid closed,crowded,and air-conditioned places like cinema halls because:
$1$. Infectious agents are more prevalent during this period as moist conditions are favourable for the growth of microbes.
$2$. People are more vulnerable during this time as their body systems are busy adapting to changing environmental conditions such as temperature and humidity,making them more susceptible to infections.

(N/A) Yes,passive smoking is considered highly dangerous.
In passive smoking,the smoke released from the burning end of a cigarette (sidestream smoke) and the smoke exhaled by the active smoker is inhaled by a non-smoker.
It is often considered more dangerous because the active smoker inhales smoke through a filter,whereas the passive smoker inhales the unfiltered,toxic smoke directly from the environment. Furthermore,the concentration of certain harmful chemicals like carbon monoxide and carcinogens is often higher in the sidestream smoke than in the mainstream smoke inhaled by the active smoker.

(N/A) Maintenance of personal and public hygiene is very important for the prevention and control of many infectious diseases.
$1$. Personal Hygiene: This includes keeping the body clean,and the consumption of clean drinking water,food,vegetables,and fruits.
$2$. Public Hygiene: This includes the proper disposal of waste and excreta,periodic cleaning and disinfection of water reservoirs,pools,household coolers,and tanks,and observing standard practices of hygiene in public catering.
$3$. Vector Control: For diseases like malaria and filariasis transmitted by insect vectors,it is crucial to eliminate breeding grounds. This is achieved by avoiding water stagnation,using mosquito nets,introducing larvivorous fish like $Gambusia$ in ponds,and spraying insecticides in drainage areas.

(N/A) Personal hygiene measures include keeping the body clean, and the consumption of clean drinking water, food, vegetables, and fruits.
Public hygiene includes the proper disposal of waste and excreta, periodic cleaning and disinfection of water reservoirs, pools, cesspools, and tanks, and observing standard practices of hygiene in public catering.
These measures are particularly essential where infectious agents are transmitted through food and water, such as in cases of $Typhoid$, $Amoebiasis$, and $Ascariasis$.
Additionally, maintaining healthy habits such as regular exercise and adequate sleep strengthens the immune system, further aiding in disease prevention.

(N/A) Diseases like dysentery,cholera,and typhoid are more common in overcrowded human settlements due to the following reasons:
$1$. Poor Sanitation: Overcrowded areas often lack proper waste disposal systems,leading to the accumulation of garbage and human/animal excreta in the open.
$2$. Contamination: These conditions facilitate the contamination of drinking water and food sources with pathogens.
$3$. Infectious Nature: These diseases are infectious and spread easily from one person to another through contaminated water,food,or direct contact.
$4$. High Population Density: In overcrowded settlements,the close proximity of individuals increases the rate of transmission of pathogens,leading to rapid outbreaks of diseases like cholera,typhoid,and $TB$.

(N/A) broad-spectrum antibiotic is an antimicrobial agent that is effective against a wide range of both Gram-positive and Gram-negative bacteria.
Examples include tetracyclines,chloramphenicol,and fluoroquinolones.

(N/A) The Pulse Polio Programme is an immunisation campaign established by the Government of India to eliminate poliomyelitis (polio) by vaccinating all children under the age of five years against the polio virus.
The project fights poliomyelitis through a large-scale pulse vaccination programme and active surveillance for polio cases.
In $1995$,following the Global Polio Eradication Initiative of the World Health Organization $(1988)$,India launched the Pulse Polio Immunisation Programme alongside the Universal Immunisation Programme,which aimed at $100\%$ coverage.
The last reported cases of wild polio in India were in West Bengal and Gujarat on $13$ January $2011$. On $27$ March $2014$,the World Health Organization $(WHO)$ declared India a polio-free country,as no cases of wild polio had been reported for three years.
$OPV$ stands for Oral Polio Vaccine. It uses a weakened (attenuated) poliovirus and is administered orally.
Regarding the eradication status: India was officially declared polio-free by the $WHO$ in $2014$. While wild poliovirus has been eradicated,the country maintains strict surveillance to prevent the re-importation of the virus and to manage vaccine-derived poliovirus cases.

(D) To achieve this,it is necessary to prevent the stagnation of water in and around residential areas,regularly clean household coolers,use mosquito nets,introduce fish like $Gambusia$ in ponds to feed on mosquito larvae,and spray insecticides in ditches,drainage areas,and swamps. Additionally,installing wire mesh on doors and windows is essential to prevent the entry of mosquitoes. These measures are crucial in the context of widespread diseases like $Dengue$ and $Chikungunya$ transmitted by vectors such as the $Aedes$ mosquito in India.

(C) The correct matches are as follows:
$(a)$ Typhoid is caused by the bacterium $Salmonella$ $typhi$ $(iii)$.
$(b)$ Pneumonia is caused by bacteria like $Streptococcus$ $pneumoniae$ or $Haemophilus$ $influenzae$ $(iv)$.
$(c)$ Filariasis (Elephantiasis) is caused by filarial worms like $Wuchereria$ $bancrofti$ or $Wuchereria$ $malayi$ $(i)$.
$(d)$ Malaria is caused by protozoan parasites of the genus $Plasmodium$ $(ii)$.
Therefore,the correct sequence is $(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)$.

(N/A) According to Hippocrates and the Indian Ayurveda system of medicine,health is considered a state of balance among the body's humors or fluids.
$1$. Hippocrates proposed that the human body contains four basic humors: $black \ bile$,$yellow \ bile$,$blood$,and $phlegm$.
$2$. These humors were associated with natural elements: $black \ bile$ (earth),$yellow \ bile$ (fire),$blood$ (air),and $phlegm$ (water).
$3$. It was believed that a person is in good health when these four humors are in a state of equilibrium.
$4$. An imbalance in these humors,such as an excess of one,was thought to lead to physical or mental illness,manifesting as poor health.
$5$. For instance,individuals with an excess of $black \ bile$ were historically associated with a 'hot' personality and a tendency toward fevers.

(A) The "good humor" hypothesis of health, which suggested that health is a state of body and mind where there is a balance of certain humors, was disapproved by William Harvey.
$1$. William Harvey, an English physician, discovered blood circulation using experimental methods.
$2$. He demonstrated that people with "black bile" (associated with hot personality in the hypothesis) did not necessarily have a higher body temperature, which he proved using a thermometer.
These findings showed that health is not merely a balance of humors, but is influenced by the neural and endocrine systems, which in turn regulate our immune system.

(N/A) $1$. $A$ healthy person is more efficient at work.
$2$. $A$ healthy person increases productivity,which brings economic prosperity to their life.
$3$. $A$ healthy person increases the longevity of people.
$4$. Maternal mortality and infant mortality rates are reduced.

(N/A) The factors affecting health are as follows:
$1$. Genetic disorders: These are deficiencies with which a child is born and defects which the child inherits from parents from birth.
$2$. Infections: These are diseases caused by microorganisms such as bacteria,viruses,fungi,and parasites.
$3$. Lifestyle: This includes the food and water we consume,the amount of rest and exercise we get,and our daily habits or the lack thereof.

(N/A) Infectious diseases are disorders caused by organisms such as bacteria,viruses,fungi,or parasites. Some examples include:
$1$. Viral diseases: $AIDS$,influenza,chickenpox,measles,hepatitis.
$2$. Bacterial diseases: Typhoid,cholera,plague,leprosy,diphtheria.
$3$. Fungal diseases: Ringworm.
$4$. Protozoan diseases: Dysentery (amoebiasis).

(N/A) wide range of organisms belonging to bacteria,viruses,fungi,protozoans,helminths,etc.,can cause disease in humans.
These disease-causing organisms are called pathogens.
Most parasites are therefore pathogens as they cause harm to the host by living in or on them.
Pathogens can enter the body through various means,multiply,and interfere with normal vital activities,which results in morphological and functional damage.
Pathogens must have the ability to adapt to life within the environment of the host.
For example,pathogens entering the gut must know how to survive in the stomach at low $pH$ and resist various digestive enzymes.