11th Botany Assignment English Medium Tamilnadu 2021Answerkey:- Here is the full answerkey for the august assignment for 11th botany english medium.

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Assignment

Class:11 Subject: Botany

Unit 1. LIVING WORLD

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Part – A

I.One mark questions:

1.The correct statement about cyanobacteria ( blue green algae)

a. Absence of motile organs
b. Cell wall is made up of cellulose
c. Absence of mucilage around the thallus
d. Presence of floridean starch

Answer : a. Absence of motile organs

2.Identify the Archaebacteria is

a. Azotobacter
b. Erwinia
c. Treponema
d. Methanobacterium

Answer : d. Methanobacterium

3.Select the correctly matched pair

a. Actinomycetes – late blight disease
b. Mycoplasma – lumpy jaw disease
c. Agrobacterium – crown gall disease
d. Fungi – sandal spike disease

Answer : c. Agrobacterium – crown gall disease

4.EBOLA , ZIKA, SARS, H1N1 are……

a. Fungi
b. Viruses
c. Bacteria
d. Algae

Answer : b. Viruses

5.Red colour of the Red sea is due to the presence of……..

a. Archaebacterium
b. Cyanobacterium
c. Methanobacterium
d. Eubacterium

Answer : b. Cyanobacterium

6.Red rot of sugarcane disease is caused by

a. Colletotrichum falcatum
b. Albugo candida
c. Taphrina deformans
d. Puccinia graminis tritici

Answer : a. Colletotrichum falcatum

7.A prokaryote which grows on the fur of polar bear is……..

a. Trichodesmium
b. Nostoc
c. Aphanocapsa montana
d. Aanabaena

Answer : c. Aphanocapsa montana

8.The organic compound responsible for the the earthy odour to soil after rain is…..

a. Geosmin
b. Pruteen
c. Tetracycline
d. Polysaccharides

Answer : a. Geosmin

9.Who is the father of Indian mycology ?

a. A.M. Stalin
b. E.J. Butler
c. Alexander Fleming
d. Robert Koch

Answer : b. E.J. Butler

10 ……… Bacteria is called vinegar

a. Acetobacter aceti
b. Lactobacillus bulgaricus
c. Lactobacillus lactis
d. Clostridium tertium

Answer : a. Acetobacter aceti

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Part – B
II.Very Short Answer

1.Differentiate homoiomerous and heteromerous Lichens

The distribution of algal cells distinguishes lichens into two forms namely

• Homoiomerous (Alagal Cells evenly distributed in the thallus)
• Heteromerous (a distinct layer of alagae and fungi present)

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2.What is cyclosis?

The movement of cytoplasm is called cytoplasmic streaming or CYLOSIS

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3.Define Prions :

• Prions were discovered by stanley B.Prusiner in the year 1982 and are proteinaceous infectious particles
• They are the causative agents for about a dozen fatal degenerative disorders of the central nergous system of humans and other animals For Example Creutzfeldt – Jakob Disease (CJD) , Bovine Spongiform Encephalopathy (BSE) – Commonly known as mad cow disease and scrapie disease of sheep

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4.What is Plasmid? Give any two types.

5.Mention four types of Ascocarps?

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Part – C
III. Short Answer

1.Why do farmers plant leguminous crops in crop rotations/ mixed cropping

• Leguminous crops are known for their nitrogen-fixing ability
• Most of these crops bear symbiotic nitrogen-fixing bacteria in structures which are known as root nodules
• Due to this reason, leguminous crops play a vital role in crop rotation and the farmers plant this in crop rotations/mixed croping

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2.General account of on Lichens.

• The symbiotic association between algae and fungi is called lichens
• The legal partner is called phycobionet or photobiont., and the fungal partner is called mycobiont
• Algae provide nutrion for fungal partner in turn fungi provide protection and help to fix the thallus to the substratum through rhizinae
• Asexual reproduction takes place through fragmentation, soredia and isidia ,Phycobionts reproduced by akinetes,hormogonia, aplaneospore etc.,
• Mycobionts undergo sexual reproduction and produced ascocarps

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3.What is heterocyst?

• In some forms of cyanobacteria large colourless cells is found in the terminal or intercalary position called Heterocysts
• They are invoced innitrogen fixation

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4.What are Magnetosomes?

5.Write the living and non-living characteristic features of Viruses.

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Part – D

IV.Write in detail.

1.Write the steps involved in Gram staining.

2.Explain the Life cycle of Agaricus.

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• The symbiotic association between fungal myscelium and roots of plants is called as mycorrhizae
• In this relationship fungi absorb nutrition from the root and in turn the hyphal network of mycorrhizae forming fungi helps the plant to absorb water and mineral nutrients from the soil