13. Why Do We Fall ill Class 9 science Solutions English Medium-Additional -Questions 3

Why do we fall ill ?

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Ques:- Define health according to WHO?

Ans:– According to WHO, “Health is therefore a state of being well enough  to function well physically, mentally and socially”.

Ques: - What is antibiotic? How does it work?

Ans. – Antibiotic is a medicine which kills various Species of bacterias. It breaks the sule of bacteria formed by them for protection. However its blocks the formation of capsule. Thus the bacteria die easily.

Ques: – Write the different between Acute and chronic disease.

Ans. -

Acute disease

It has short incubation period.
It effects minimum organs of the body.
it does not effect the general health.
Examples: - common cold, fever etc.

Chronic disease

It has long incubation period.
It effects about the whole body.

It effect the general health.

Examples:- Tuberculosis, diabetes, etc.

Ques:– How is antibiotic penicillin effective on bacteria?

Ans:– The penicillin is the most effective antibiotic on various species of bacteria those who are capsulated. It breaks the capsule of bacteria formed by them for protection.

Ques:– State any two conditions essential for good health.

Ans:– There are two conditions essential for good health.

(i) Good and balance diet.
(ii) Good economic conditions and physical environment.

Ques:- What are antibodies?

Ans:- Antibodies are specialized proteins that defend against foreign substances in the body. They are produced by white blood cells known as B cells that develop from bone marrow stem cells.

Ques:– Define infectious diseases.

Ans:- Diseases where microbes are the immediate causes are called infectious diseases. Ex. – typhoid, tuberculosis, cholera etc.

Ques:– Define non- infectious diseases.

Ans:- There are also diseases that are not caused by infectious agents. Ex – diabetes, cancer, arthritis etc.

Ques:– Name the bacterium which is responsible for peptic ulcer.

Ans:- Helicobacter pylori.

Ques:- Name the some infectious agents.

A – Virus, bacteria, fungus, protozoa, worms.

Q – Name the diseases caused by virus.

A - Diseases caused by viruses are the common cold, influenza, dengue fever and AIDS.

Q – Name the diseases caused by bacteria.

A - Diseases like typhoid fever, cholera, tuberculosis and anthrax are caused by bacteria.

Q – Name the diseases caused by fungi?

A – Most of the skin diseases are caused by fungi.

Q – Name the causative organism of acne?

A - Staphylococci

Q – Name the causative organism responsible for sleeping

Sickness.

A – Trypanosome.

Q – Name the causative organism responsible for Kala-ajar.

A – Leis mania.

Q – Define communicable diseases.

A – The diseases those spread very fast to each others. They communicate and so are also called communicable diseases. Ex – cholera, plague, swine flu etc.

 

Q – Define non-communicable diseases.

A – The diseases those do not spread to each others. It means they do not communicate so such diseases are called non-communicable diseases. Ex. – typhoid, malaria, cancer etc.

Q – Write the modes to spread the infections.

A – The diseases spread directly and indirectly from infected body to healthy body by air, soil, water.

Direct mode;
  Droplet: sneezing, coughing, talking.
  Contact: sexual transmission.
 Blood transmission: injection, blood transfusion.
  Indirect mode;
  By the vector: Mosquitoes, flies, and other animals.
  By infected air, water and food.
Q – What is inflammation?

A - An active immune system recruits many cells to the affected tissue to kill off the disease-causing microbes. This recruitment process is called inflammation.  As a part of this process, there are local effects such as swelling and pain, and general effects such as fever.

Q – On what factor does the severity of disease manifestations depend on?

A – The severity of disease manifestations depend on the number of microbes in the body.

Q – What is immunization?

A – Immunization is a preventive system by various diseases, in which antigens are transmitted into body through injection in the form of vaccine to form antibodies against the micro-organisms of diseases.

Q – Define sexual transmitted disease?

A – The diseases which occur due to sexual contact are known as sexual transmitted diseases. Ex – syphilis, AIDS, Gonorrhea.

Q – On which types of microbes’ penicillin are effective?

A – The microbes having cell wall.

Q – Why do antibiotics not effective on virus infection?

A – The life of viruses is different than bacteria. Many bacteria build cell wall, but all have not so, antibiotic blocks biochemical pathways of bacteria. But viruses do not use these pathways at all, and that is the reason why antibiotics do not work against viral infections.

Q – In which disease do the symptoms of water phobia appear?

A – Rabies.

Q – Write the mode of spreading AIDS.

A –

         By infected needle or syringe.
Pregnant mother to her baby.
Sexual contact.
Blood transfusion
Q – What disease may occur if any person is exposed by animal?

A – Rabies.

Q – Write the name of vector of malaria.

A – Anopheles Female Mosquito.

Q – Write the name of vector of cholera.

A – Home flies.

Q – On what Factor do the signs and symptoms of a disease depend ?

A - The signs and symptoms of a disease will thus depend on the tissue or organ which the microbe targets.   

Que. - What is antibiotic? How does it work?

Ans. – Antibiotic is a medicine which kills various Species of bacterias. It breaks the capsule of bacteria formed by them for protection. However its blocks the formation of capsule. Thus the bacteria die easily.

Que. – Write the different between Acute and chronic disease.

Ans. -

Acute disease.

(i) It has short incubation period.
(ii) It affects minimum organs of the body.
(iii) it does not affect the general health.
(iv) Examples: - common cold, fever etc.
Chronic disease.
(i) It has long incubation period.
(ii) It affects about the whole body.
(iii) It affects the general health.
(iv) Examples:- Tuberculosis, diabetes, etc.

Que. – How is antibiotic penicillin effective on bacteria?

Ans. – The penicillin is the most effective antibiotic on various species of bacteria those who are capsulated. It breaks the capsule of bacteria formed by them for protection.

Que. - Define health according to WHO?

Ans. – According to WHO, “Health is therefore a state of being well enough  to function well physically, mentally and socially”.

Que. – State any two conditions essential for good health.

Ans. – There are two conditions essential for good health.

(i) Good and balance diet.
(ii) Good economic conditions and physical environment.

QUES: Define infectious diseases.

ANS: Diseases where microbes are the immediate causes are called infectious diseases. Ex. – typhoid, tuberculosis, cholera etc.

QUES: Define non- infectious diseases.

ANS: There are also diseases that are not caused by infectious agents. Ex – diabetes, cancer, arthritis etc.

QUES: Name the bacterium which is responsible for peptic ulcer.

ANS: Helicobacter pylori.

Q- Name the some infectious agents.

ANS: Virus, bacteria, fungus, protozoa, worms.

QUES: Name the diseases caused by virus.

ANS: Diseases caused by viruses are the common cold, influenza, dengue fever and AIDS.

QUES: Name the diseases caused by bacteria.

ANS: Diseases like typhoid fever, cholera, tuberculosis and anthrax are caused by bacteria.

QUES: Name the diseases caused by fungi?

ANS: Most of the skin diseases are caused by fungi.

QUES: Name the causative organism of acne?

ANS: Staphylococci

QUES: Name the causative organism responsible for sleeping

Sickness.

ANS: Trypanosome.

QUES: Name the causative organism responsible for Kala-ajar.

ANS: Leis mania.

QUES: Define communicable diseases.

ANS: The diseases those spread very fast to each others. They communicate and so are also called communicable diseases. Ex – cholera, plague, swine flu etc.

QUES: Define non-communicable diseases.

ANS:The diseases those do not spread to each others. It means they do not communicate so such diseases are called non-communicable diseases. Ex. – typhoid, malaria, cancer etc.

QUES: Write the modes to spread the infections.

ANS:The diseases spread directly and indirectly from infected body to healthy body by air, soil, water.

Direct mode:
(i) Droplet: sneezing, coughing, talking.
(ii) Contact: sexual transmission.
(iii) Blood transmission: injection, blood transfusion.
Indirect mode:
(i) By the vector: Mosquitoes, flies, and other animals.
(ii) By infected air, water and food.
QUES: What is inflammation?

ANS: An active immune system recruits many cells to the affected tissue to kill off the disease-causing microbes. This recruitment process is called inflammation.  As a part of this process, there are local effects such as swelling and pain, and general effects such as fever.

QUES: On what factor does the severity of disease manifestations depend on?

ANS:The severity of disease manifestations depend on the number of microbes in the body.

QUES: What is immunization?

ANS:Immunization is a preventive system by various diseases, in which antigens are transmitted into body through injection in the form of vaccine to form antibodies against the micro-organisms of diseases.

QUES: Define sexual transmitted disease?

ANS:The diseases which occur due to sexual contact are known as sexual transmitted diseases. Ex – syphilis, AIDS, Gonorrhea.

QUES: On which types of microbes’ penicillin are effective?

ANS:The microbes having cell wall.

QUES: Why do antibiotics not effective on virus infection?

ANS:The life of viruses is different than bacteria. Many bacteria build cell wall, but all have not so, antibiotic blocks biochemical pathways of bacteria. But viruses do not use these pathways at all, and that is the reason why antibiotics do not work against viral infections.

QUES: In which disease do the symptoms of water phobia appear?

ANS:Rabies.

QUES: Write the mode of spreading AIDS.

A –

(i) By infected needle or syringe.
(ii) Pregnant mother to her baby.
(iii) By Sexual contact.
(iv) Blood transfusion
QUES: What disease may occur if any person is exposed by animal?

ANS:Rabies.

QUES: Write the name of vector of malaria.

ANS:Anopheles Female Mosquito.

QUES: Write the name of vector of cholera.

ANS:Doemstic flies.

QUES: On what Factor do the signs and symptoms of a disease depend ?

ANS: The signs and symptoms of a disease will thus depend on the tissue or organ which the microbe targets. 

Q1. What does the word health mean?

Ans: For our grandmothers, being able to go out to the market or to visit neighbours is .being well., and not being able to do such things is .poor health.. Being interested in following the teaching in the classroom so that we can understand the world is called a healthy attitude. While not being interested is called the opposite. .Health  is therefore a state of being  well enough to function well physically, mentally and socially.

Q2. How does the health of an organism depend upon the surroundings?

Ans: Human beings live in societies. Our social environment, therefore, is an important factor in our individual health.  We live in villages, towns or cities. In such places, even our physical environment is decided by our social environment. Consider what would happen if no agency is ensuring that garbage is collected and disposed. What would  happen if no one takes responsibility for clearing the drains and ensuring that water does not collect in the streets or open  spaces? So, if there is a great deal of garbage thrown in our streets, or if there is open drain water lying stagnant around  where we live, the possibility of poor health increases. Therefore , public cleanliness is important for individual health.

Q3. What do we mean by “disease”?

Ans: Disease (disturbed ease) in other words, literally means being uncomfortable. However, the word is used in a more limited meaning. We talk of disease when we can find a specific and particular cause for discomfort. This does not mean that we have to know the absolute final cause; we can say that someone is suffering from diarrhoea without knowing exactly what has caused the loose motion When there is a disease, either the functioning or the appearance of one or more systems of the body will change for the worse. These changes give rise to symptoms and signs of disease.

Q4. What are symptoms?

Ans: Symptoms of disease are the things we feel as being .wrong.. So we have a headache, we have cough, we have loose motions, we have a wound with pus; these  are all symptoms. These indicate that there may be a disease.

Q5. How do you distinguish between acute and chronic diseases?

Ans: Some diseases last for only very short periods of time, and these are called acute diseases. We all know from experience  that the common cold lasts only a few days. Other ailments can last for a long time, even as much as a lifetime, and are called chronic diseases. An example is the infection causing elephantiasis. Acute and chronic diseases have different effects on our health. Any disease that causes poor functioning of some part of the body will affect our general health as well. This is because all functions of the body are necessary for general health. But an acute disease, which is over very soon, will not have time to cause major effects on general health, while a chronic disease will do so. As an example, think about a cough and cold, which all of us have from time to time. Most of us get better and become well within a week or so. And there are no bad effects.

Q6. What are the various causes of diseases?

Ans: It is useful to think of the immediate causes of disease as belonging to two distinct types. One group of causes is the infectious agents, mostly microbes or micro-organisms. Diseases where microbes are the immediate causes are called infectious diseases. This is because the microbes can spread in the community, and the diseases they cause will spread with them. On the other hand, there are also diseases that are not caused by infectious agents. Their causes vary, but they are not external  causes  like microbes that can spread in the community. Instead, these are mostly internal, non infectious causes.

Q7. Name some common infectious diseases

Ans: Common examples of diseases caused by viruses are the common cold, influenza, dengue fever and AIDS. Diseases like typhoid fever, cholera, tuberculosis and anthrax are caused by bacteria. Many common skin infections are caused by different kinds of fungi. Protozoan microbes cause many familiar diseases, such as malaria and kalaazar. All of us have also come across intestinal worm infections, as well as diseases like elephantiasis caused by different species of worms.

Q8. Explain the effect of antibiotic penicillin on bacterial cells.

Ans: Taxonomically, all bacteria are closely related to each other than to viruses and vice versa. This means that many important life processes are similar in the bacteria group but are not shared with the virus group.  As a result, drugs that block one of these life processes in one member of the group is likely to be effective against many  other members of the group. But the same drug will not work against a microbe belonging to a different group. As an example, let us take antibiotics. They commonly block biochemical pathways important for bacteria. Many bacteria, for example, make a cell-wall to protect them. The antibiotic penicillin blocks the bacterial processes that build the  cell wall. As a result, the growing bacteria become unable to make cell-walls, and die easily.

Q9. Why are human cells not affected by penicillin?

Ans: Human cells don’t make a cell-wall anyway, so penicillin cannot have such an effect on us. Penicillin will have this effect  on any bacteria that use such processes for making cell-walls.

Q10.. Why are antibiotics ineffective against viruses?

Ans: Viruses have very few biochemical pathways of their own, and that is the reason why antibiotics do not work against viral infections. If we have a common cold, taking antibiotics does not reduce the severity or the duration of the disease. However, if we also get a bacterial infection along with the viral cold, taking antibiotics will help. Even then, the antibiotic

 will work only against the bacterial part of the infection, not the viral infection.

Q 11. How do communicable or infectious diseases spread?

Ans: Many microbial agents can commonly move from an affected person to someone else in a variety of ways. In other words, they can be communicated, and so are also called communicable diseases. Such disease-causing microbes can spread through the air. This occurs through the little droplets thrown out by an infected person who sneezes or coughs.  Someone standing close by can breathe in these Diseases can also be spread through water. This occurs if the excreta from someone suffering from an infectious gut disease, such as cholera, get mixed with the drinking water used by people living nearby. The cholera causing microbes will enter new  hosts through the water they drink and cause disease in them. Such diseases are much more likely to spread in the  absence of safe supplies of drinking water. The sexual act is one of the closest physical contact two  people can have with each other. Not surprisingly, there are microbial diseases such as syphilis or AIDS that are transmitted by sexual contact  from one partner to the other. However, such sexually transmitted diseases are not spread by casual physical contact.  Casual physical contacts include handshakes or hugs .sports, like wrestling, or by any of the other ways in which we  touch each other socially.

Q 12.How does AIDS spread?

An: Other than the sexual contact, the AIDS virus can also spread through blood-to-blood contact with infected people or from an infected mother to her baby, by sharing of same syringe and having unprotected sex.

Q13. What are vectors? Name some vector transmitted diseases.

Ans:  Many diseases will be transmitted by other animals. These animals carry the infecting agents from a sick person to another potential host. These animals are thus the intermediaries and are called vectors. The commonest vectors we all know are mosquitoes. In many species of mosquitoes, the females need highly nutritious food in the form of blood in order to be able to lay mature eggs. Mosquitoes feed on many warm-blooded animals, including us. In this way, they can transfer diseases from person to person. Eg. Malaria, rabies.

Q14. The disease-causing microbes enter the body through different means. Where do they go then?. Do all microbes go  to the same tissue or organ, or do they go to different ones?

Ans: Different species of microbes seem to have evolved to home in on different parts of the body. In part, this selection is connected to their point of entry. If they enter from the air via the nose, they are likely to go to the lungs. This is seen in the bacteria causing tuberculosis. If they enter through the mouth, they can stay in the gut lining like typhoid causing bacteria Or they can go to the liver,like the viruses that cause jaundice. But this needn.t always be the case. An infection like HIV,  that comes into the body thru the sexual organs, will spread to lymph nodes all over the body. Malaria-causing microbes, entering through a mosquito bite, will go to the liver, and then to the red blood cells. The virus causing Japanese encephalitis, or brain fever, will similarly enter through a mosquito bite. But it goes on to infect the brain.

Q15. The signs and symptoms of a disease depend upon the tissue or organ targeted.  Explain.

Ans: The signs and symptoms of a disease will thus depend on the tissue or organ which the microbe targets. If the lungs are the targets, then symptoms will be cough and breathlessness. If the liver is targeted, there will be jaundice. If the brain is the target, we will observe headaches, vomiting, fits or unconsciousness.