20 Apr 2022

Samacheer Kalvi 9th Science Book Back Unit 8 Term 3

Samacheer Kalvi 9th Term III Science Book Back Question and Answers – Unit 8:

Samacheer Kalvi 9th Standard New Science Book Back 1 Mark and 2 Mark Question & Answers PDF uploaded and available below. Class 9 New Syllabus 2021 to 2022 Book Back Question & Answer solutions available for both English and Tamil Medium. Class 9 Science Book Term 3 Unit 8 – World of Microbes Answers/Solutions are provided on this page. 9th Std Science Book is of Term 1st, 2nd, 3rd, and consists of 9 Units in each Term. All 9 Units of Term 1st, 2nd, 3rd Science Book Back One, and Two Mark Solutions are given below.

Check Unit wise and  9th New Science Book Back Question and Answers Guide/Solutions PDF format for Free Download. English, Tamil, Maths, Science, and Social Science Book Back Questions and Answers available in PDF. Check Science – Physics, Chemistry, and Biology, Social Science – History, Geography, Civics, Economics below. See below for the Samacheer Kalvi 9th Science Book Back Unit 8 Term 3 PDF:



Samacheer Kalvi 9th Science Book Back Unit 8 Term 3 Solutions Guide PDF:

Science Subject 1 Mark and 2 Mark Solutions Guide PDF available below. Click the Download option to download the book back 1 Mark & 2 Mark questions and answers. Take the printout and use it for exam purposes.

Term – 3

Unit – 8

World of Microbes

I. Choose the correct answer:

1. Mycology is the branch of biology that deals with the study of
a) algae
b) virus
c) bacteria
d) fungi

2. The major constituent of vinegar is
a) citric acid
b) acetic acid
c) oxalic acid
d) hydrochloric acid

3. Bacterial involved in curd formation is
a) Lactobacillus acidophilus
b) Nitosomonas
c) Bacillus ramous
d) none of the above

4. Which of the following is transmitted through air?
a) Tuberculosis
b) Meningitis
c) Typhoid
d) Cholera

5. The most fatal form of Malaria is caused by
a) Plasmodium ovale
b) Plasmodium falciparum
c) Plasmodium malariae
d) Plasmodium vivax

6. One of the means of indirect transmission of a disease is
a) sneezing
b) coughing
c) vectors
d) droplet infection

7. Syphilis is caused by
a) Treponema polliadum
b) leptospira
c) Pasteurella
d) Vibrio cholera

8. Mosquito borne viral disease are
a) malaria and yellow fever
b) dengue and chikungunya
c) filariasis and typhus
d) kalaazar and diphtheria

9. Diptheria affects the
a) Lungs
b) throat
c) blood
d) liver

10. Which one of the following is a pair of viral disease?
a) Filariasis, AIDS
b) Common cold, AIDS
c) Dysentery, Common cold
d) Typhoid, Tuberculosis

11. Which of the following disease is spread by animal bite?
a) Pneumonia
b) Tuberculosis
c) Cholera
d) Rabies

12. The primary organ infected during tuberculosis is
a) bone marrow
b) intestine
c) spleen
d) lungs

13. Microbes that generally enter the body through nose are likely to affect
a) gut
b) lungs
c) liver
d) lymph nodes

14. The organ affected by Jaundice is
a) liver
b) lungs
c) kidney
d) brain

15. Severity of diseases symptom depends upon
a)number of microbes
b) target organ
c) both a and b
d) none of these

16. Poliomyelitis virus which causes infantile paralysis enters the body though
a) skin
b) mouth and nose
c) ears
d) eye

II. Fill in the blanks:

1. Putrefying bacteria and fungi break down organic matter and animal waste into ammonia.
2. The hyphae with branches form a complex network called mycelium.
3. First antibiotic Penicillin was developed by Alexander Fleming.
4. Baker’s yeast is saccharomyces.
5. The two non symbiotic nitrogen fixing bacteria are nitrosomonas and azotobacter.
6. Typhoid fever is caused by Salmonella typhi.
7. H1N1 virus causes Swineflue.
8. Aedes egypti is a vector of viral disease dengue.
9. B.C.G vaccine gives considerable protection against tuberculosis.
10. Cholera is caused by vibrio cholera and malaria is caused by plasmodium sp.





III. Expand the following:

1. ORS – Oral Rehydration Solution
2. HIV – Human Immunodeficiency Virus
3. DPT – Diphtheria, Pertussis and Tetanus.
4. WHO – World Health Organisation
5. BCG – Bacillus Calmette Guerin

IV. Pick out the odd one form the following:

i) AIDS, Retrovirus, Lymphocytes, BCG
Ans: Lymphocytes

ii) Bacterial disease, Rabies, Cholera, Common cold and influenza
Ans: Rabies

iii) Sporozoites, Merozoites, Trophozoites, Gametocytes (infective stages of plasmodium in human)
Ans: Sporozoites

V. State whether True or False, if false write the correct statement:

1. Glycogen and oil globules are stored form of food in fungi. – True
2. One of the differences between virus and viroid is the presence of protein coat in viroid and its absence in virus.
Ans: False – One of the differences between virus and viroid is the presence of a protein coat in virus and its absence in viroid.
3. Rhizobium, associated with root nodules of leguminous plants fixes atmospheric nitrogen. – True
4. Lophotrichous is a cluster of polar flagellae. – True
5. Non-infectious diseases remain confined to the person who develops the disease and do not spread to other.- True
6. The process of vaccination was developed by jenner in the year 1796. – True
7. Hepatitis B is more dangerous than Hepatitis A. – True

VI. Match the following:

1. Swine flu          a) Human Papilloma Virus
2. Genital warts  b) Human Immunodeficiency Virus
3. AIDS                 c) Mycobacterium
4. Tuberculosis   d) Influenza virus H1N1

Ans: 1- d; 2- a; 3- b; 4- c





VII. Short Questions & Answers:

1. Name the chronic diseases associated with respiratory system.
Whooping cough & Tuberculosis

2. Name the scientist who first discovered penicillin antibiotic . Can you name any other known antibiotic?
Alexander Flemming in 1929. Some other antibiotics : Streptomycin, Erythromycin, Bacitracin, Cephalosproin.

3. Name the organism causing diarrhoeal diseases and give one precaution against it.
Rota virus. Proper sanitation and hygiene.

4. Name the common mosquitoes and the diseases they transmit.
Aedesaegypti – Chikungunya
Female Anopheles – Malaria

5. Name one disease that is transmitted by houseflies. Mention their causative pathogen.
Cholera – Vibrio cholera

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