Mix Example - WHY DO WE FALL ILL? Questions in English

(N/A)

Acute disease	Chronic disease
Lasts for a very short period of time.	Lasts for a long period of time,may be a lifetime.

Infectious disease	Non-infectious disease
Spreads from one person to another (communicable).	Does not spread from one person to another (non-communicable).

Symptom-based treatment	Microbe-based treatment
Medicines are given to reduce the effects (symptoms) of the disease.	Medicines are given to kill the specific disease-causing microorganism.

Antibiotics	Vaccines
Medicines given after the disease occurs to kill or inhibit microbes.	Biological preparations given before the disease to build immunity.

Congenital disease	Acquired disease
Disease present at the time of birth.	Disease developed after birth due to organ malfunction or pathogens.

(N/A) No, all students will not get infected and suffer from the disease because a large inoculum (number of pathogens) is required to transmit the disease.
$(b)$ Two major symptoms of cholera are:
$(i)$ Severe watery diarrhea (often described as rice-water stools).
$(ii)$ Dehydration, which can lead to low blood pressure and muscle cramps.
$(c)$ The different ways of spread of this disease are:
$(i)$ Consumption of contaminated water containing the bacterium $Vibrio$ $\text{cholerae}$.
$(ii)$ Consumption of food contaminated by soiled hands or flies carrying the pathogen.

(N/A) disease is a state of physical or mental discomfort caused by the malfunctioning of any tissue,organ,or organ system.
Diseases can be classified into various types:
$(i)$ Based on duration:
- Acute diseases: Last for a short period,e.g.,$Common \ cold$.
- Chronic diseases: Last for a long period,e.g.,$Diabetes$.
$(ii)$ Based on cause:
- Infectious (Communicable): Caused by pathogens like bacteria,viruses,etc.,e.g.,$Tuberculosis$.
- Non-infectious (Non-communicable): Caused by internal factors or lifestyle,e.g.,$Cancer$.
$(iii)$ Based on origin:
- Congenital diseases: Present from birth,e.g.,$Down \ syndrome$.
- Acquired diseases: Developed after birth,e.g.,$Malaria$.

(N/A) Prevention of diseases is more desirable than their successful treatment for the following reasons:
$(i)$ Having a disease can damage body organs, which may recover slowly or may never recover completely.
$(ii)$ Curing a disease takes time, and the patient may be bedridden for a long period, leading to a loss of productivity.
$(iii)$ An infected person can become a source of infection for others, causing the disease to spread in the community.
$(iv)$ Prevention is economically beneficial, as medical treatment often involves significant expenditure on medicines, hospital visits, and tests.
$(v)$ Prevention helps in controlling the population of pathogens, as they do not get the opportunity to multiply within a host.
$(vi)$ Prevention avoids the physical pain, mental stress, and discomfort associated with suffering from an illness.

(A-D) Immediate cause is the primary factor that leads to the onset of a disease. For Dengue fever,the immediate cause is the entry of the dengue virus into the human body.
$(b)$ Infectious diseases are those caused by biological agents (pathogens) that can spread from an infected person to a healthy person through mediums like air,water,food,or vectors. Examples include cholera and chickenpox.
$(c)$ The pathogen causing dengue fever is the dengue virus $(DENV)$,which belongs to the family Flaviviridae.
$(d)$ The vector responsible for transmitting the dengue virus is the female $Aedes$ $aegypti$ mosquito. The mosquito requires a blood meal to obtain proteins necessary for egg development. During the act of biting an infected person,the mosquito ingests the virus,which then replicates and is transmitted to a healthy person during subsequent bites.

(N/A) This is called symptom-based treatment.
$(b)$ We can reduce the effects of the disease by taking medicines like analgesics (for pain) and antipyretics (for fever).
$(c)$ The limitation of this treatment is that it only suppresses the symptoms and does not cure the underlying cause of the disease.
$(d)$ The possible remedies to prevent or overcome such diseases include:
$(i)$ Building a strong immune system.
$(ii)$ Providing a nutritious and balanced diet.
$(iii)$ Maintaining personal and public hygiene.

(C) This happens because when the immune system first encounters an infectious microbe,it responds against it and then remembers it specifically. So,the next time that particular microbe,or its close relatives,enters the body,the immune system responds with even greater vigour. This eliminates the infection even more quickly than the first time. This is the basis of the principle of immunisation.
$(b)$ We can 'fool' the immune system into developing a memory for a particular infection by introducing something into the body that mimics the microbe we want to vaccinate against. This does not actually cause the disease,but it prevents any subsequent exposure to the actual infecting microbe from turning into a disease.
$(c)$ This principle of disease prevention is called immunisation,which involves providing strong immunity to the body through vaccines. Many such vaccines are now available for preventing a wide range of infectious diseases and provide a disease-specific means of prevention. Examples include vaccines against tetanus,diphtheria,whooping cough,measles,and polio.

(N/A) Immune response is the reaction of the body's immune system to foreign substances,such as pathogens (bacteria,viruses,etc.),that are recognized as non-self or potentially harmful. This response involves the activation and production of specialized cells,such as $T$-lymphocytes and $B$-lymphocytes,and the secretion of proteins called antibodies. These components work together to identify,neutralize,and eliminate the invading pathogens to protect the body from disease.

(N/A) Active immunisation: It promotes the production of circulating antibodies against foreign antigens by injecting a small quantity of modified antigen into the bloodstream.
Passive immunisation: It is the application of antibodies from an immune individual to a non-immune patient. This treatment is used when an individual has been,or probably will be,exposed to an infectious disease and there is insufficient time for active immunisation.

(N/A) Infectious agents are biological pathogens that cause diseases in hosts. They can be classified into several categories as follows:

Infectious Agents	Diseases Caused
$I$. Viruses	Common cold,influenza,mumps,poliomyelitis,rabies,smallpox,measles,$AIDS$,etc.
$II$. Rickettsiae	Typhus fever,Trench fever.
$III$. Bacteria	Tuberculosis,cholera,tetanus,syphilis,pneumonia,etc.
$IV$. Fungi	Ringworm,athlete's foot.
$V$. Protozoa	Malaria,sleeping sickness,amoebic dysentery,etc.
$VI$. Helminths (Worms)	Filariasis,ascariasis,tapeworm infection,etc.
$VII$. Mites	Scabies.

(N/A)

Viruses	Bacteria
$(i)$ They are very small.	They are larger in size compared to viruses.
$(ii)$ Non-cellular.	Single-celled.
$(iii)$ Have no metabolism of their own.	Have metabolism of their own.
$(iv)$ Do not take food by any method.	Take food by absorption.
$(v)$ Do not grow and do not divide.	Grow in size and divide to produce more bacteria.
$(vi)$ Command the host cell to produce viruses.	They can reproduce on their own.
$(vii)$ Can be crystallised.	Cannot be crystallised.
$(viii)$ All produce diseases in humans,animals,or plants.	Some are harmless,some are useful,and some cause diseases.

(N/A) The different means by which infectious diseases spread are:
$(i)$ By direct contact between a healthy and an infected person.
$(ii)$ By indirect contact between a healthy and an infected person.
$(iii)$ Through air (droplets,aerosols).
$(iv)$ Through contaminated food and water.
$(v)$ By vectors such as mosquitoes,flies,and other insects.
$(vi)$ By the bite of a rabid animal (e.g.,dogs,bats).

(A) Pneumonia is a respiratory infection caused by bacteria (such as $Streptococcus$ $\text{pneumoniae}$), viruses, or fungi. It is transmitted through respiratory droplets when an infected person coughs or sneezes, not by mosquitoes.
Malaria is transmitted by the bite of an infected female $Anopheles$ mosquito.
Brain fever (encephalitis) can be transmitted by mosquitoes (e.g., Japanese encephalitis).
Dengue is transmitted by the bite of an infected $Aedes$ mosquito.

(B) Health is a state of physical,mental,and social well-being.
While a clean environment,social harmony,and good economic conditions are essential for maintaining overall health and preventing diseases,living in a large and well-furnished house is a matter of personal comfort or luxury.
It does not directly contribute to the biological or social requirements of health.
Therefore,living in a large and well-furnished house is not a fundamental requirement for individual health.

(D) Bacterial diseases are caused by pathogenic bacteria.
$1$. Typhoid fever is caused by the bacterium $Salmonella$ $typhi$.
$2$. Cholera is caused by the bacterium $Vibrio$ $cholerae$.
$3$. Tuberculosis $(TB)$ is caused by the bacterium $Mycobacterium$ $tuberculosis$.
$4$. Anthrax is caused by the bacterium $Bacillus$ $anthracis$.
Since all four diseases listed in options $(a)$ and $(b)$ are caused by bacteria, both options are correct. Therefore, the correct answer is $(d)$.

(D) Protozoans are single-celled eukaryotic organisms that can cause various diseases in humans.
$1$. Malaria is caused by protozoans of the genus $Plasmodium$.
$2$. Kala-azar (Leishmaniasis) is caused by the protozoan $Leishmania$ $\text{donovani}$.
Syphilis and Gonorrhoea are caused by bacteria. Allergy is an immune system response, and skin infections can be caused by bacteria or fungi. Cancer is a disease of uncontrolled cell growth, and $AIDS$ is caused by a virus $(HIV)$.
Therefore, the correct option is $D$.

(A) Typhoid is a bacterial disease caused by the bacterium $Salmonella \ Typhi$.
$AIDS$ is caused by the $Human \ Immunodeficiency \ Virus$ $(HIV)$.
Dengue is caused by the $Dengue \ virus$.
Influenza is caused by the $Influenza \ virus$.
Therefore,Typhoid is the only disease listed that is not viral.

(B) bacterial disease is caused by pathogenic bacteria.
$1$. Cholera is caused by the bacterium $Vibrio cholerae$.
$2$. Anthrax is caused by the bacterium $Bacillus anthracis$.
$3$. Tuberculosis is caused by the bacterium $Mycobacterium tuberculosis$.
$4$. Influenza (commonly known as the flu) is a viral disease caused by the influenza virus.
Therefore, Influenza is not a bacterial disease.

(C) $AIDS$ (Acquired Immuno Deficiency Syndrome) is caused by the $HIV$ virus.
It is transmitted through the exchange of infected body fluids,such as blood,semen,vaginal secretions,and breast milk.
$1$. Sexual contact involves the exchange of body fluids,which can transmit the virus.
$2$. Breast feeding can transmit the virus from an infected mother to her infant.
$3$. Blood transfusion using infected blood is a known mode of transmission.
$4$. Hugs,shaking hands,sharing food,or casual physical contact do not involve the exchange of infected body fluids,therefore $AIDS$ cannot be transmitted through hugs.

(D) The primary reason why developing anti-viral drugs is challenging is that viruses have very few biochemical mechanisms of their own.
Unlike bacteria,which have their own metabolic pathways and cellular machinery,viruses are obligate intracellular parasites.
They rely almost entirely on the host cell's machinery to replicate and synthesize their proteins.
Because they use the host's own metabolic processes,it is extremely difficult to design a drug that targets the virus without simultaneously damaging the host's cells.

(A) $Typhoid$ is a bacterial disease caused by the bacterium $Salmonella$ $typhi$. It is primarily transmitted through the ingestion of contaminated food or water (fecal-oral route),not by mosquitoes.
$Malaria$ is caused by $Plasmodium$ parasites and is transmitted by the bite of an infected female $Anopheles$ mosquito.
$Brain$ $fever$ (often referring to Japanese Encephalitis) is a viral disease transmitted by $Culex$ mosquitoes.
$Dengue$ is a viral disease transmitted by the bite of an infected $Aedes$ $aegypti$ mosquito.
Therefore,$Typhoid$ is the correct answer.

(D) The diseases caused by bacteria are as follows:
$1$. Typhoid is caused by the bacterium $Salmonella \text{ } typhi$.
$2$. Tuberculosis is caused by the bacterium $Mycobacterium \text{ } tuberculosis$.
$3$. Anthrax is caused by the bacterium $Bacillus \text{ } anthracis$.
Since options $A$, $C$, and $D$ are all caused by bacteria, the question implies identifying bacterial diseases. However, if this is a multiple-choice question where only one answer is expected, there is an error in the options provided. Assuming the question asks to identify a bacterial disease from a list where others are not, or if it is a multiple-correct type, all $A$, $C$, and $D$ are correct. Given the standard format, if we must choose one, all listed options except Malaria (which is caused by a protozoan) are bacterial. Therefore, the question is flawed as presented. If we assume the question intended to ask which is $NOT$ bacterial, the answer would be Malaria. If it asks which $IS$ bacterial, $A$, $C$, and $D$ are all correct.

(C) An active immune system is the body's defense mechanism against pathogens.
When a pathogen enters the body,the immune system recognizes it as foreign.
It responds by recruiting various immune cells (such as white blood cells) to the site of infection.
These cells work together to destroy or neutralize the disease-causing microbes,thereby protecting the body from infection.

(D) Microbes (microorganisms) are living organisms that are too small to be seen with the naked eye.
They include a wide variety of organisms such as viruses,bacteria,fungi,and protozoa.
Since both options $(a)$ (viruses and bacteria) and $(b)$ (fungi and protozoa) represent categories of microbes,option $(d)$ is the correct choice.

(A) Vaccination is a process of introducing a weakened or dead pathogen into the body to stimulate the immune system.
When a child is vaccinated against polio,the body recognizes the antigen and produces specific antibodies.
This process creates active immunity,which prepares the immune system to fight off the actual pathogen if exposed in the future.
Therefore,the primary purpose of vaccination is to create immunity in the body.

(B) Hepatitis is a viral infection that causes inflammation of the liver.
There are several types of hepatitis viruses,such as Hepatitis $A$,$B$,$C$,$D$,and $E$.
Hepatitis $A$ and $E$ are primarily transmitted through the fecal-oral route,which means they are spread through contaminated water or food.
Since the question asks for the transmission mode of hepatitis viruses in a general context (often referring to Hepatitis $A$ in school-level biology),water is the most appropriate answer among the given choices.

(C) Kala-azar,also known as visceral leishmaniasis,is a disease caused by protozoan parasites of the genus $Leishmania$.
These parasites are transmitted to humans through the bite of infected female phlebotomine sandflies.
$Ascaris$ is a genus of parasitic nematode worms (roundworms).
$Trypanosoma$ is a genus of kinetoplastids,a monophyletic group of unicellular parasitic flagellate protozoa,which causes diseases like sleeping sickness.
Bacteria are prokaryotic microorganisms that cause various diseases but are not the causative agents of kala-azar.

(D) Overcrowded and poorly ventilated living conditions facilitate the rapid spread of infectious pathogens through the air.
When many people share a small,enclosed space with limited air circulation,droplets containing pathogens released by an infected person (through coughing or sneezing) remain suspended in the air for longer periods.
This environment significantly increases the risk of contracting air-borne diseases such as tuberculosis,influenza,or the common cold.
Therefore,the correct option is $D$.

(A) Diseases caused by parasitic worms (helminths) are common in humans.
$1$. $Ascariasis$ is caused by the roundworm $Ascaris$ $lumbricoides$.
$2$. Many worms cause $Intestinal$ $infections$ by residing in the human gut.
$3$. $Elephantiasis$ (Filariasis) is caused by filarial worms such as $Wuchereria$ $bancrofti$.
Since all the listed options are diseases caused by different species of worms,the correct answer is $All$ $of$ $these$.

(B) The vaccine used to prevent tuberculosis $(TB)$ is $BCG$ (Bacillus Calmette-Guérin).
$DPT$ is a vaccine used to protect against Diphtheria,Pertussis,and Tetanus.
$MMR$ is a vaccine used to protect against Measles,Mumps,and Rubella.
$OPV$ stands for Oral Polio Vaccine,used to prevent Poliomyelitis.
Therefore,the correct option is $B$.

(C) Health is defined as a state of physical,mental,and social well-being.
Acute diseases like the common cold or chickenpox last for a short duration and do not cause major long-term damage to the body.
Chewing tobacco is a habit that leads to chronic conditions such as oral cancer,which has a severe,long-term,and often irreversible effect on an individual's health.
Stress can have long-term effects,but in the context of biological health hazards,the consumption of harmful substances like tobacco is a primary example of a long-term health risk factor.

(D) Vectors are living organisms that can transmit infectious pathogens between humans or from animals to humans.
They do not cause the disease themselves but act as carriers (intermediaries) for the pathogens.
For example,the female $Anopheles$ mosquito acts as a vector for the malaria parasite $(Plasmodium)$.
Therefore,option $D$ is the correct definition.

(D) disease is defined as a state of being uncomfortable or a condition that impairs normal functioning.
$1$. When a disease occurs,the body's systems (such as the digestive,respiratory,or nervous system) undergo changes in their functioning or physical appearance,which negatively affects the individual's health.
$2$. These physiological or structural changes manifest as specific signs (observable by a doctor) and symptoms (felt by the patient),which help in diagnosing the illness.
Therefore,both statements $(a)$ and $(b)$ correctly describe the nature of a disease.

(B) The statement 'Peptic ulcers are caused by eating acidic food' is incorrect.
Scientific research, notably by Barry Marshall and Robin Warren, proved that peptic ulcers are primarily caused by the bacterium $Helicobacter \text{ } pylori$, not by acidic food.
High blood pressure is indeed linked to lifestyle factors like obesity and inactivity.
Cancers are often associated with genetic mutations or abnormalities.
Acne is primarily caused by $Propionibacterium \text{ } acnes$, not by $Staphylococci$ (which are typically associated with skin infections like boils or impetigo).
Therefore, option $B$ is the wrong statement.

(C) Mosquitoes are considered vectors because they carry disease-causing pathogens from an infected person or animal to a healthy person.
They transmit serious diseases such as $Malaria$,$Dengue$,$Chikungunya$,and $Zika$ virus.
By preventing their breeding,we can significantly reduce the transmission of these infectious diseases in our surroundings.

(D) Infectious diseases are caused by pathogens such as bacteria,viruses,fungi,or parasites and can spread from one person to another.
$A$. Chickenpox is a viral infection.
$B$. Common cold is a viral infection.
$C$. Malaria is caused by a protozoan parasite.
$D$. Anaemia is a non-infectious condition,typically caused by a deficiency of iron,vitamins,or other nutrients,and it cannot be transmitted from one person to another.

(A) Infectious diseases are caused by pathogens (like bacteria,viruses,fungi,or parasites) that can spread from an infected person to a healthy person.
Sneezing is a common mode of transmission for respiratory infections,as it releases droplets containing pathogens into the air.
Genetic abnormalities,high blood pressure,and blood cancer are non-communicable diseases and cannot be transmitted through contact with an infected person.

(TRUE) The statement is True.
Health is defined as a state of complete physical,mental,and social well-being,not merely the absence of disease or infirmity.
Social equality and harmony are essential components of a healthy environment.
When individuals live in a society characterized by equality and harmony,it reduces stress,promotes mental peace,and fosters a supportive environment,all of which are crucial for maintaining good individual health.

(TRUE) The statement is True.
In biological organization,cells combine to form tissues,tissues organize into organs,and organs work together to form physiological systems or organ systems. These systems are responsible for performing specific life processes and body functions,such as digestion,respiration,and circulation,which are essential for maintaining homeostasis.

(B) The statement is False.
Diseases that last for only short periods of time are known as acute diseases.
Chronic diseases are those that last for a long time,sometimes even for a lifetime (e.g.,diabetes or tuberculosis).

(FALSE) False.
Health is defined as a state of complete physical,mental,and social well-being. When a disease causes poor functioning of any part of the body,it disrupts the body's normal physiological processes. This impairment inevitably impacts the overall health of an individual,as all organ systems are interconnected and rely on each other to maintain homeostasis.

(TRUE) The statement is True.
Chronic diseases are illnesses that persist for a long duration,often for months or years. Because they last for a long time,they can cause significant,lasting damage to various organ systems,leading to severe long-term health consequences.
In contrast,acute diseases are short-lived and usually do not cause major long-term health complications,as the body typically recovers quickly.

(TRUE) The statement is True.
Diseases are rarely caused by a single factor. They typically result from a complex interaction of factors.
$1$. Immediate cause: The primary organism or factor that directly causes the disease (e.g.,a virus or bacteria).
$2$. Contributory cause: Factors that make an individual more susceptible to the disease,such as poor nutrition,lack of public health facilities,or genetic predisposition.
Therefore,most diseases have multiple causes rather than one single cause.

(FALSE) The statement is $False$.
High blood pressure and cancer are classified as non-communicable or chronic diseases.
$1$. High blood pressure is often caused by genetic factors,lifestyle choices (such as diet,lack of exercise,and stress),and age,rather than by infectious agents like bacteria or viruses.
$2$. Cancer is primarily caused by genetic mutations,environmental factors (such as carcinogens or radiation),and lifestyle factors,not by infectious agents (though some viruses can increase the risk of specific cancers,they are not the primary cause for most cases).
Therefore,these diseases are not caused by infectious agents.

(FALSE) The statement is $False$.
Viruses are obligate intracellular parasites,meaning they can only replicate and survive inside the living cells of a host. They are metabolically inactive outside the host cell.
Conversely,many bacteria are free-living organisms that can survive and reproduce in various environments outside of a host,such as soil,water,or decaying organic matter.

(TRUE) True. Antibiotics are designed to target specific biochemical pathways,such as cell wall synthesis or protein synthesis,which are essential for bacterial survival. Since viruses do not possess these cellular structures or metabolic pathways and instead hijack the host cell's machinery to replicate,antibiotics are ineffective against them.

(FALSE) The statement is False.
Syphilis is a sexually transmitted infection $(STI)$ caused by the bacterium $Treponema \, pallidum$, and $AIDS$ is caused by the Human Immunodeficiency Virus $(HIV)$.
These diseases are not transmitted through casual physical contact such as shaking hands, hugging, or sharing food. They are primarily transmitted through sexual contact, exchange of infected blood, or from an infected mother to her child during pregnancy, childbirth, or breastfeeding.