Advertisement

MAHARASHTRA

XII (12) HSC

XI (11) FYJC
X (10) SSC
9TH 5TH 6TH 7TH 8TH
BOARD SOLUTIONS: 2019 2020 New Time table
ESSAYS DIALOGUE EXPANSION SPEECH LETTERS GRAMMAR WRITING SKILLS INFORMATION-TRANSFER LEAFLET REPORT APPEAL INTERVIEW VIEW AND COUNTERVIEW DATA INPUT SHEET OTHER BOARDS LATEST NEWS  PRIVACY DISCLAIMER
TAMIL-NADU: 8TH 9TH 10TH 11TH 12TH சமையல் மற்றும் சினிமா அ முதல் ஃ வரை 

Microorganisms Class 8th Science Term 1 Tamilnadu Board Solution

Class 8th Science Term 1 Tamilnadu Board Solution

Evaluation
Question 1.

Choose the best answer:

a) Algal bloom leads to loss of species diversity which is known as _______. (Eutrophication, Pasteurisation)

b) Which one of the following cause amoebic dysentery? (Entamoeba histolytica, Plasmodium vivax, Plasmodium falciparum)

c) Milk is heated to 72o C for 30 minutes and then suddenly cooled to12o C. Microbes are killed without causing damage to the taste and quality of milk. Name this process (dehydration, pasteurisation)

d) Nodules are responsible for nitrogen fixation. Name the bacteria present inside the root nodules. (Acetobactor, Rhizobium, Clostridium)


Answer:

a) Eutrophication

In some conditions, the algae produce thick material masses, called 'bloom' which covers the upper surface of a water body (usually standing water like pond, lake) like a carpet. This cuts off the oxygen supply to water under the bloom and thus decreasing oxygen content, leading to the death of aquatic species. This is called Eutrophication.


b) Entamoeba histolytica


Entamoeba histolytica is a protozoan, which contaminated food and water easily, if proper hygienic conditions are not maintained. Thus, the microorganisms can enter our alimentary canal and damage it, causing amoebic dysentery. In this, one experiences pain in abdomen and blood in stools.


c) Pasteurisation


Louis Pasteur developed the method of preservation of food (mainly milk) by process of heating at specified temperature for a given duration of time. The technique was thus named Pasteurisation.


d) Rhizobium


Nitrogen plays an important role in life processes, specially for plants. As plants cannot take in nitrogen directly, they are helped by some bacteria for this purpose. Rhizobium are present inside the root nodules and help in fixing the atmospheric nitrogen for the plant.



Question 2.

Living organisms show a great degree of diversity in their size. A considerable number of species are not visible to naked eye. They can only be seen with the help of a microscope. How will you measure the size of micro organisms?


Answer:

Due to very small size, some organisms are not visible to naked eye and can only be seen under a microscope. Such organisms are thus called microorganisms. To measure them, units such as micron (10^-6 m, or tenth lac fraction of one metre), or millimicron (10^-9) are used.



Question 3.

Fungi do not possess chlorophyll. Hence, they are incapable of photosynthesis. So, they depend on either living organisms or non-living things. Name the two types of modes of nutrition in fungi.


Answer:

Because of inability to synthesise their own food, fungi have adopted two modes of nutrition:-

i) When they depend on living organisms, it is called parasitic mode and fungi are called parasites. They use a living organism as host and eat the living tissues using their enzymes. This is harmful for the host and causes disease or illness.


ii) When they depend on non-living plants and animals, they act as saprophytes. The feed on organic substance which is soluble. By this mode they are helpful in decomposing the dead and decaying organisms and maintaining the flow of energy in ecosystem.



Question 4.

Communicable diseases are pathogenic diseases which are spread from person to person either directly or indirectly. Write the mode of transmission of the following diseases.

i) Cholera, typhoid

ii) Malaria


Answer:

i) Cholera and typhoid are diseases caused by bacteria and spread through contaminated water, specially when there is absence of proper hygiene, or the water with standing water and it’s surroundings are not kept clean.

ii) Malaria is a disease caused by protozoan called Plasmodium, but spreads through vectors. Vectors are organisms , e.g. mosquitoes, that spread the disease from an infected person to a healthy individual (by , say mosquito bites) .



Question 5.

The conversion of sugar solution into alcohol and liberation of carbon dioxide is known as fermentation. Which microorganism is responsible for this process?


Answer:

Fungi are responsible for fermentation. The sugar solution is converted to alcohol and carbon dioxide is released. The sugar solution is said to be fermented and gives out a typical odour. The process of fermentation is used for the production of wine and other alcoholic drinks.



Question 6.

i) Identify the following bacteria based on its shape.

ii) Draw and label the following parts of the bacteria.

a) Flagella b) pili c) cell wall cytoplasm cell membrane



Answer:

i) Spherical or circle shaped – cocci

Rod shaped – bacilli


Spiral shaped – spirillium


Comma shaped - vibrio




Question 7.

In the world today many industries totally depend upon the microbial activities.

For example, oxalic acid is the fermented product of fungi Aspergillus niger.

Name any two bacteria used in industry with their product.


Answer:

The role of microorganisms in industries is increasing day by day. Some industrially useful microorganisms are:-

• Bacillus megaterium- This bacterium is used for curing. Curing is the process where tea - tobacco leaves and coffee beans are fermented to give out the flavour.


• Acetobacter acetic - this fungi is used for the fermentation of sugar solution for the manufacturing of vinegar, which acts as a good preservative.



Question 8.

Farmers consider microorganisms such as bacteria, fungi and virus a menace on their fields and gardens because they cause disease to their crops. Name any one of the bacterial disease, viral disease and fungal disease.


Answer:


PDF FILE TO YOUR EMAIL IMMEDIATELY PURCHASE NOTES & PAPER SOLUTION. @ Rs. 50/- each (GST extra)

SUBJECTS

HINDI ENTIRE PAPER SOLUTION

MARATHI PAPER SOLUTION
SSC MATHS I PAPER SOLUTION
SSC MATHS II PAPER SOLUTION
SSC SCIENCE I PAPER SOLUTION
SSC SCIENCE II PAPER SOLUTION
SSC ENGLISH PAPER SOLUTION
SSC & HSC ENGLISH WRITING SKILL
HSC ACCOUNTS NOTES
HSC OCM NOTES
HSC ECONOMICS NOTES
HSC SECRETARIAL PRACTICE NOTES

2019 Board Paper Solution

HSC ENGLISH SET A 2019 21st February, 2019

HSC ENGLISH SET B 2019 21st February, 2019

HSC ENGLISH SET C 2019 21st February, 2019

HSC ENGLISH SET D 2019 21st February, 2019

SECRETARIAL PRACTICE (S.P) 2019 25th February, 2019

HSC XII PHYSICS 2019 25th February, 2019

CHEMISTRY XII HSC SOLUTION 27th, February, 2019

OCM PAPER SOLUTION 2019 27th, February, 2019

HSC MATHS PAPER SOLUTION COMMERCE, 2nd March, 2019

HSC MATHS PAPER SOLUTION SCIENCE 2nd, March, 2019

SSC ENGLISH STD 10 5TH MARCH, 2019.

HSC XII ACCOUNTS 2019 6th March, 2019

HSC XII BIOLOGY 2019 6TH March, 2019

HSC XII ECONOMICS 9Th March 2019

SSC Maths I March 2019 Solution 10th Standard11th, March, 2019

SSC MATHS II MARCH 2019 SOLUTION 10TH STD.13th March, 2019

SSC SCIENCE I MARCH 2019 SOLUTION 10TH STD. 15th March, 2019.

SSC SCIENCE II MARCH 2019 SOLUTION 10TH STD. 18th March, 2019.

SSC SOCIAL SCIENCE I MARCH 2019 SOLUTION20th March, 2019

SSC SOCIAL SCIENCE II MARCH 2019 SOLUTION, 22nd March, 2019

XII CBSE - BOARD - MARCH - 2019 ENGLISH - QP + SOLUTIONS, 2nd March, 2019

HSC Maharashtra Board Papers 2020

(Std 12th English Medium)

HSC ECONOMICS MARCH 2020

HSC OCM MARCH 2020

HSC ACCOUNTS MARCH 2020

HSC S.P. MARCH 2020

HSC ENGLISH MARCH 2020

HSC HINDI MARCH 2020

HSC MARATHI MARCH 2020

HSC MATHS MARCH 2020


SSC Maharashtra Board Papers 2020

(Std 10th English Medium)

English MARCH 2020

HindI MARCH 2020

Hindi (Composite) MARCH 2020

Marathi MARCH 2020

Mathematics (Paper 1) MARCH 2020

Mathematics (Paper 2) MARCH 2020

Sanskrit MARCH 2020

Sanskrit (Composite) MARCH 2020

Science (Paper 1) MARCH 2020

Science (Paper 2)

Geography Model Set 1 2020-2021


MUST REMEMBER THINGS on the day of Exam

Are you prepared? for English Grammar in Board Exam.

Paper Presentation In Board Exam

How to Score Good Marks in SSC Board Exams

Tips To Score More Than 90% Marks In 12th Board Exam

How to write English exams?

How to prepare for board exam when less time is left

How to memorise what you learn for board exam

No. 1 Simple Hack, you can try out, in preparing for Board Exam

How to Study for CBSE Class 10 Board Exams Subject Wise Tips?

JEE Main 2020 Registration Process – Exam Pattern & Important Dates


NEET UG 2020 Registration Process Exam Pattern & Important Dates

How can One Prepare for two Competitive Exams at the same time?

8 Proven Tips to Handle Anxiety before Exams!

BUY FROM PLAY STORE

DOWNLOAD OUR APP

HOW TO PURCHASE OUR NOTES?

S.P. Important Questions For Board Exam 2022

O.C.M. Important Questions for Board Exam. 2022

Economics Important Questions for Board Exam 2022

Chemistry Important Question Bank for board exam 2022

Physics – Section I- Important Question Bank for Maharashtra Board HSC Examination

Physics – Section II – Science- Important Question Bank for Maharashtra Board HSC 2022 Examination

Important-formula


THANKS