Unit 5: Disease causes & Prevention - Short Question Answers - General Science For Class IX (General Group)

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UNIT 5: DISEASE CAUSES & PREVENTION
Short Question Answers

Question 1: What are bacteria? Where are they found? Name three bacterial diseases and their causative agents?
Answer: BACTERIA:
Bacteria are the simple, true living form on the earth. They are unicellular microbes and occur in great numbers. They are present everywhere in water, air and soil. Their majority is harmless (and also beneficial in the soil) and only about 10% of them spread diseases.
They cannot prepare their food like plants. They are parasitic and get their food from dead bodies of plants and animals or from the digested food of their hosts. They have three basic shapes:

1. Rod like bacilli
2. Round like cocci
3. Spring like spirillia
   
   

BACTERIAL DISEASES AND THEIR CAUSATIVE AGENTS
Following are the names of bacterial diseases and their agents:

S.NO.	Name Of Bacterial Disease	Causing Agents
1.	Tuberculosis	Mycobacterium tuberculosis
2.	Typhoid	Salmonella Typhosa
3.	Cholera	Vibrio Cholerae

OR

(1) Tuberculosis:

• It is an infectious bacterial disease. It is a disease of the lungs.

Causative agents:

• This disease is cause by bacterium Mycobacterium tuberculosis.
• These T.B. bacteria reside in the lungs and form small swelling or spots, the tubercles in the lungs.

(2) Typhoid:

• It is an acute infectious disease of alimentary canal.

Causative agents:

• It is caused by a bacterium Salmonella Typhosa which is transmitted through food and water, contaminated by the faces of a carrier.
• The contamination is usually brought about by insect vectors like housefly.

(3) Cholera:

• It is very serious: infectious disease of the digestive tract.

Causative agents:

• It is caused by the toxins produced by a comma shaped bacterium, the Vibrio Cholerae, which is also transmitted by the vectors like flies, cockroaches, rats etc.

Question 2: Are all fungi parasites? Names two fungal diseases and the mode of their transmission? OR Are all fungi similar to germs? Write down the names of two diseases caused by fungi and their methods of infection or spreading?
Answer: FUNGI:
Fungi are not similar to microbes or germs. Fungi are simple unicellular as well as multicellular plants. They lack root, stem, leaf and chlorophyll and cannot manufacture their food. Some of the fungi like yeast are unicellular and microscopic. Other fungi are large in size and visible with naked eye e.g. Mucor, Penicillin and Mushrooms are common types of fungi.
Few fungi are parasites and pathogenic which infect human body, e.g. Ring worms, Athletes foot etc.

FUNGAL DISEASE:
Two fungal diseases are:

1. Athletes foot
2. Ring worm

1. Athletes' Foot:

• It is a skin infection caused by a fungus called Tinea.

Symptoms:

• It is an infection of skin, and nails. This disease is very cornmon.in athletes who put on sweaty shoes for a long time.
• There is itching between the toes due to infection. The skin starts peeling and cracking.
• The nails get infected and become yellow, thick 'and brittle.

Sources:
These infection are transmitted by:

• direct contact i.e. from man to man or animal to man.
• OR by indirect method when its spores are transmitted through air, clothes or common toilet articles.

Control:

• One must sprinkle powder, in shoes, and then wash the foot and pat dry with towel before wearing it.
• A person should wear flexy and comfortable shoes.
• Pedicure is also good and hygiene.
• Apply antifungal ointment.

2. Ring Worms:

• It is an infection of skin caused by a group of fungi. The fungi causing the disease are collectively known as Dermatophyte.

Symptoms:

• The fungi attacking the skin caused localized lesions in the skin
• Lesion appears in circular form as growth of the fungus in the skin is more or less equal in all directions.

Source:

• These infections are common in tropical areas where warm and moist climate helps in the propagation of the spores of fungi causing ring worm.

Control:

• Take bath regularly.
• Good sanitary conditions in local place.
• Can be caused by the external application of fungicide ointments.

Question 3(a): What is contamination? How is drinking water and food contaminated?
Answer: CONTAMINATION:
"Entry of Undesirable organisms into some material or objects."

OR

The state of being contaminated, polluted or, impure by contact or mixture, the state of having substance either foreign particles, chemicals or radio active substances which makes substance toxic.

CONTAMINATION OF FOOD & WATER:
When we either places the food outside instead of refrigerator or eat at dirty hands or when flies sit on it etc. Food gets poisonous because bacteria multiplies very quickly. If we will not preserves carefully or cover it carefully. In the Same manner water can be contaminated through pollution, through industries wastes like lead, or  human or animals urinate inside Water. Therefore we should boil Water carefully before drinking it.

OR

Question 3(b): What is Pollution or Contamination? How the food and drinking water become polluted?
Answer: POLLUTION:
When environmental changes occur in water, soil and other things in their physical and natural structures then some compounds are mixed with them and cause harmful effects in chemical and biological characteristics of environment adversely affecting man and other organisms then it is called Pollution. Difference kinds of pollutions are following:

1. Atmospheric or Air Pollution
2. Water Pollution
3. Noise Pollution

POLLUTIONS OF WATER AND FOOD:
Food and drinking water become polluted when the dust containing toxic matters and germs are mixed in them through air or when house flies and insects and animals carry them from sources to the food and water and pollute them. When such polluted food and water are consumed by healthy people they become infected.

Question 4: What are vectors? How do they transfer pathogens? Give example. OR What are Vectors? How they carry the germs of diseases? Explain with examples.
Answer: VECTORS
Vectors are carrier of germs.

OR

Any animal, which carries a disease causing germ.
Example:
Mosquito is a vector of malaria. Malaria is a disease caused by a very small animal, plasmodium, which gets into the blood as a result of a bite from a mosquito. It multiplies very quickly and causes a fever, which may end in death.

OR

Answer: VECTORS:
Such organisms which carry the germs of diseases by various methods and become a cause to spread the diseases are called Vectors.
Examples:
Following are examples of Vectors and their methods of transmission of germs.

1. The house flies sit on filth or rubbish and decaying and persisting organic matter they get the germs of diseases stuck to their body hairs and legs. When they next sit on the food and drinks of healthy people the germs of diseases are transferred to food and drinks and make them polluted.
2. When the female Anopheles mosquito having malarian parasites grows up in its stomach bites a healthy person then they transmit the plasmodium protozoans (Malarial parasite) into the blood of the said person and cause Malaria.
3. The rats bite food items. They transfer the germs of diseases present in their saliva to food and edibles of human .beings and make them polluted.

Question 5: "God has gifted human beings with many defense systems." Discuss. OR "God has bestowed many Immunity Systems of Man". Discuss. OR Which defence system to the human being has gifted by God? Write down .
Answer: IMMUNITY SYSTEM OF MAN:
God has provided many natural immunity systems to us which automatically protect human body from the infection of disease. There are many bacteria and viruses around us which can cause different diseases. These organisms have antigens. When these antigens enter our body, the body produces antibodies against them. Thus the body remains safe from the diseases in a natural way.

IMMUNE SYSTEM PROTECTS FROM GERMS:
Body defends against disease in many of the following ways as:
1. The skin serves as a resistance against the invasion of germs present in environment or air. It does not allow the germs to enter our body.
2. When cuts bleed  the germs are washed away by the running blood.
3. Tears wash away the germs entering our eyes. Tears and other body fluids also contain a germ killing enzyme called lysozyme.
4. Cilia (tiny hair) and mucous present in internal organs and inside our nose entangle the germs and coughing and sneezing expels them out.
5. Digestive juices, kill most of the germs which some how enter the alimentary canal are thrown out through the vomiting of the patient's.
6. White blood cells engulf and destroys the germs.
7. Specific antibodies are formed in the blood to kill every type of germs in the body.
8. If all the above defenses fail to stop or to kill the germs, a person falls sick and is given medicine and antibiotics to kill the germs and vaccine are given to develop immunity to avoid future infections.

Question 6: What is drug abuse?. Name the common narcotics and their effects. OR What is meant by Drug Addiction? Write down the names of common drugs and their effects.
Answer: DRUG ABUSE OR HABIT OF DRUGS:
People who abuse drugs for long time may become dependent on it. This is drug addiction or drug abuse. Drugs are cure but their abuse is always injurious:, It can make us drug addiction.

OR

Some medicines and drugs create excitement and emotional disorders and they affect the Nervous System and its efficiency becomes deteriorated and for a little while man feels relaxed. However, overdosing drugs becomes an abuse and the users of drugs become addicts.

COMMON NARCOTIC DRUGS AND THEIR EFFECTS:
The common narcotics and their effects are:

Type Of Drug	General Effects	Examples
Stimulant	Excitement, anxiety and sleeplessness.	Cocaine
Hallucinogen	Loss o f coordination, hallucination, abnormal behaviour and depression	LSD Marijuana
Depressant	Drowsiness, 1oss of co-ordination, slow reflexes and depression	Heroin, codeine, morphine and barbiturates.

Question 7: What is opium? Describe its origin and importance.
Answer: OPIUM:
Opium is a highly addictive narcotic drug acquired in the dried latex form from the poppy plant.

ORIGIN AND IMPORTANCE:

1. Morphine and codeine are both made from opium. Both are used as pain killers.
2. Heroin, a synthetic compound, made from morphine of opium, i5 now widely used as narcotic drug in the country and the world over.
3. Codeine and barbiturates are also depressing addition drugs.

.Question 8: What is neurosis and psychosis? Describe their causes.
Answer: NEUROSIS:
It is an illness resulting from some sort of psychological conflicts. It involves stimulation of autonomous system and affects a portion of mental functioning.

OR

It is a kind of Nervous System disease which develops as a result mental pressure. This pressure crops up as a result of lot of mental exertion and struggled by which involuntary or automatic Nervous system is motivated and some functions of the brain are adversely affected. It is a case of Mental disorder called Neurosis.

Causes:

• Neurosis may appear due to
• Anxiety
• Hysteria
• Phobia
• By depressions of any kind
• Hard mental struggle

PSYCHOSIS:
It is a major mental disorder in which a person's ability to think and respond emotionally is so seriously impaired that he is unable to meet the ordinary demands of life. It

OR

It is a disease of Nervous Fits causing mental disturbance in which the faculty of thinking and the functional emotional response are very adversely affected. The affected person tries to run away from the realities of life and falls prey to superstitions and Hallucinations.

Causes:
These mental disorders may appear due to:

1. Aging
2. Metabolic and nutritional disorders of infections
3. Fear
4. When an individual involves in excessive thinking, his Nervous System is hard pressed and mental disturbance is caused lead to Psychosis disease.
5. Due to depression in domestic and social condition the mental capacity of an individual is severely deteriorated and thoughts are shattered and dispersed which results into lack of coordination in the mental functions of an individual.
6. The adolescents generally indulge into love affairs with members of opposite sex causing fruitless efforts to have positive results which develop Psychosis.
7. When an individual fails to acquire social adjustment in the society then it develops into the Psychosis.

TYPES OF PSYCHOSIS:
There are following types of Mental Disease or Psychosis.

• Hallucination
• Delusions
• Schizophrenia
• Melancholia

Question 9: What is a disease?
Answer: DISEASE:
A disease is a condition that occurs, when our body goes out of balance, it is because normal functioning and internal environment has been altered, by tissue damage caused by the formation of toxic substances and thus the smooth running of body is not possible

OR

Anything which goes wrong with the body other than by an accident It may be due to germs or to some part of the body not working properly.

Question 10: What are viruses?
Answer: VIRUSES:
These are the smallest disease causing agents. They are extremely tiny and cannot be seen without the help of electron microscope. No organism is safe from them as they cause diseases in all organisms from bacteria to large animals.

Question 11: Name the diseases caused by the viruses?
Answer: DISEASES CAUSED BY VIRUS:
In man, they cause:

• Influenza
• Cold
• Poliomyelitis
• Flu
• HIV/AIDS
• Small pox
• Measles and
• Hepatitis (Jaundice) etc.

In Plants, they cause:

1. Damage to leaves of potato, tomato, tobacco and cauliflower.

Question 12: What are pathogens?
Answer: PATHOGENS:
Pathogens are disease causing organism. They are the disease agents or parasites. As most of them are microscopic so they are also called microbes. They may be viruses, bacteria, fungi, protozoans or parasitic worms. Or Pathogens are any plant or animal which causes disease. They have to depend on another organisms for their survival.

e.g. Malaria germs in the blood.

Question 13: Define germs?
Answer: GERMS:
Germs are the organisms, which cause disease may spread easily from one person to another, by entering his body through the nose, by breathing through mouth, by drinking or eating or directly through skin.

Question 14: How do germs enter a human body?
Answer: SPREADING OF GERMS:
The method or ways, these orgarusms enter in human body are:

1. By air
2. By food and water
3. By living organisms (animals)
4. Through faeces
5. Cut and scratches
6. By contact (touch)

Question 15: Define immunity?
Answer: IMMUNITY:
The ability of a plant or animal to resist to germs or attacks of disease , e.g. some men are immune to malaria.

Question 16: Define vaccine?
Answer: VACCINE:
Vaccines are actually antigens with low toxicity rate. They are the inoculation of certain antigens (virus and bacteria) to induce the production of Antibodies for increasing immunity against diseases.

Question 17: What is smoking?
Answer: SMOKING:
Smoking is inhaling the fumes of tobacco by lighting cigarettes, cigars, huqqa etc. Smoking is injurious to health. It causes many direct or indirect harmful disease.

Question 18: What are Narcotics?
Answer: NARCOTICS:
If drug like Heroin, Cocaine, and Marijuana are misused by people old or young for getting pleasure then they are called Narcotics.

Question 19: What is the effect of using drug in society?
Answer: EFFECTS OF DRUG ABUSE IN SOCIETY:
It should always be kept into consideration that misuse of drugs is very harmful. When such stage is reached, the addict feels that he can not live without the drug, then he feels bored and kills the desire by using more of it and more frequently.
These drugs are, very costly So he begs and borrows for purchasing these medicines. Ultimately his family life and social life are ruined. So he becomes useless for the society.

Question 20: What is nervous break down?
Answer: NERVOUS BREAK DOWN:
It is non-technical term applied to a wide range of mental disorders, usually marked by sharply decreased ability of the body to function properly and normally. These mental illnesses are of many types though two are common:

1. Neurosis
2. Psychosis

Question 21: Write down the names of six bacterial diseases?
Answer: BACTERIAL DISEASE:
Six bacterial diseases are as follows:

• Tuberculosis
• Whooping Cough
• Diphtheria
• Tetanus
• Typhoid
• Cholera

Question 22: Write down the names of two diseases spread by Fungi and names of two diseases spread by Protozoans?
Answer: FUNGAL DISEASE:
Following are the two diseases caused by fungi:

• Ring Worm Infection
• Athlete's Foot

DISEASE CAUSED BY PROTOZOANS:
Following are the two diseases caused by Protozoans:

• Malaria
• Amoebic Dysentery

Question 23: Write down giving examples of any four sources of diseases spread by germs?
Answer: SOURCES OF DISEASE SPREAD BY GERMS:
Following are four sources of diseases spread by germs:

• Whooping cough, influenza etc. are the diseases spread by air germs.
• Cholera, Typhoid and Dysentery etc. are diseases spread by food and water germs.
• Tetanus, Tuberculosis, itch etc. are the diseases caused by touching the victims or their stuff.
• AIDS, Hepatitis B and other fatal diseases are spread by the transfusion of non-tested blood to the healthy person.

Question 24: Write any fiveprecautionary measures to avoid infectious disease?
Answer: PECAUTIOnIARY MEASURES TO AVOID AN INFECTION :
1. Germs the causative organism of diseases are destroyed by sterilization. Sterilization is the process of killing the germs through , heating the articles at high temperature either directly in the flame or 4, I. we putting them in boiling water or soaking them in steam, Me-the-lated spirit and other antiseptics such as dottle etc are used to get rid of germs.
2. Vectors are carriers of germs and if they are eliminated diseases can be controlled. For example if environment is made mosquito free, malaria will not be spread.
3. Pet animals, another cause of some diseases, should be vaccinated and treated. Dogs and cats with disease called rabies should be destroyed at once.
4. Personel hygiene should be maintained and body be kept clean so the chances of entry of germ inside body be minimized.
5. Municipal hygiene should be stress upon to avoid any sort of contamination of air water, a food and hence chances of the spread of parasites or their carriers be reduced.
6. People suffering from contagious diseases or their carriers be isolated and properly treated.
7. Routine vaccination course be done and special vaccination drives be launched in case of epidemics.
(Note: As asked five measures so write down any five only from above points.)

Question 24: Smoking is dangerous for health. Explain? OR Smoking is injurious to health?
Answer: SMOKING IS DAGEROUS FOR HEALTH OR
SMOKING IS INJURIOUS TO HEALTH:
Smoking is inhaling the fumes of tobacco by lightning cigarettes, cigar huqqa etc. Smoking is dangerous (injurious) to health. It causes many direct or indirect diseases and a large number of people die of these diseases every year.
It involves inhaling harmful chemicals found in tobacco, which can lead to numerous diseases and a high mortality rate. Nicotine narrows arteries, increasing the risk of heart attacks, while tar accumulates in the lungs, causing cancer and reducing lung efficiency. Additionally, carbon monoxide impairs oxygen absorption, and other gases irritate the lungs, leading to conditions like bronchitis and emphysema. These health risks not only affect smokers but also pose a threat to non-smokers nearby.

Question 25: Write down two symptoms and three causes of AIDS?
Answer: SYMPTOMS OF AIDS:

• Fever
• Swollen lymph nodes
• Loss Of appetite and weight
• Red Rashes all over the body

CAUSES OF AIDS:
It is caused by HIV or Human immune deficiency virus.Three primary ways HIV can be transmitted, leading to AIDS:

1. Sexual Contact: HIV from the blood of carrier may be passed on by sexual contact.
2. Blood Transfusion: HIV can be transferred directly through blood during unscreened blood transfusion.
3. Sharing Used stuffs: Using contaminated needles or syringes, razors, tooth brushes or anything else which puncture skin and come in contact with the blood.