Text Book Back Questions and Answers - Chapter 1 Living World 11th Biology Botany Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

Updated By SaraNextGen

On April 24, 2024, 11:35 AM

Living World
Text Book Back Questions and Answers
Choose the correct answer
Question 1.
Which one of the following statement about virus is correct?
(a) Possess their own metabolic system
(b) They are facultative parasites
(c) They contain DNA or RNA
(d) Enzymes are present
Answer:
(c) They contain DNA or RNA
Question 2.
Identify the incorrect statement about the Gram positive bacteria.
(a) Teichoic acid absent
(b) High percentage of peptidoglycan is found in cell wall
(c) Cell wall is single layered
(d) Lipopolysaccharide is present in cell wall
Answer:
(a) Teichoic acid absent
Question 3.
Identify the Archaebacterium.
(a) Acetobacter
(b) Erwinia
(c) Treponema
(d) Methanobacterium
Answer:
(d) Methanobacterium
Question 4.
The correct statement regarding Blue green algae is

(a) lack of motile structures
(b) presence of cellulose in cell wall
(c) absence of mucilage around the thallus
(d) presence of floridean starch
Answer:
(a) lack of motile structures
Question 5.
Identify the correctly matched pair
(a) Actinomycete - 1 . Late blight
(b) Mycoplasma - 2. Lumpy jaw
(c) Bacteria - 3. Crown gall
(d) Fungi-4. Sandal spike
Answer:
(c) Bacteria - 3. Crown gall
Question 6.
Differentiate Homoiomerous and Heteromerous lichens.
Answer:
Homoiomerous and Heteromerous Lichens:

Question 7.
Write the distinguishing features of Monera.
Answer:
Distinguishing Features of Monera:
1. This kingdom includes all prokaryotic organisms. Example: Mycoplasma, bacteria, actinomycetes and cyanobacteria.
2. These are microscopic. They do not have a true nucleus and membrane bound organelles.
3. Many other bacteria like Rhizobium, Azotobacter and Clostridium can fix atmospheric nitrogen into ammonia.
4. Some bacteria are parasites and others live as symbionts.
Question 8.
Why do farmers plant leguminous crops in crop rotations/mixed cropping?
Answer:
Rotations / Mixed Cropping:
1. Legumes have bacteria on nodules which are on the roots of the plants. The bacteria on the nodules takes nitrogen from the air and fixes it into the soil, so that other plants that require nitrogen can use it as well.
2. Rotation of crops improves the fertility of the soil and hence brings about an increase in the production of food grains.
3. Rotation of crops helps in saving on nitrogenous fertilizers, because  leguminous plants grown during the rotation of crops can fix atmospheric nitrogen in the soil with the help of nitrogen fixing bacteria.
4. Crop rotation adds diversity to an operation.
Question 9.
Briefly discuss on five kingdom classification. Add a note on merits and demerits.
Answer:
R.H. Whittaker, an American taxonomist proposed five kingdom classification in the year 1969. The kingdoms include Monera, Protista, Fungi, Plantae and Animalia. The criteria adopted for the classification include cell structure, thallus organization, mode of nutrition, reproduction and phylogenetic relationship. A comparative account of the salient features of each kingdom is given in table.

Merits:
- The classification is based on the complexity of cell structure and organization of thallus.
- It is based on the mode of nutrition.
- Separation of fungi from plants.
- It shows the phylogeny of the organisms
Demerits:
- The kingdom monera and protista accommodate both autotrophic and heterotrophic organisms, cell wall lacking and cell wall bearing organisms thus making these two groups more heterogeneous.
- Viruses were not included in the system.
Question 10.
Give a general account on lichens.
Answer:
The symbiotic association between algae and fungi is called lichens. The algal partner is called Phycobiont and the fungal partner is called Mycobiont. Algae provide nutrition for fungal partner and also help in fixing the thallus to the substratum through rhizinae. Asexual reproduction takes place through fragmentation, Soredia and Isidia. Phycobionst reproduce by akinetes, hormogonia, aplanospore, etc. Mycobionts undergo sexual reproduction and produce ascocarps.
Classification:

1. Based on the habitat lichens are classified into following types: Corticolous (on bark) Lignicolous (on wood) Saxicolous (on rocks) Terricolous (on ground) Marine (on siliceous rocks of sea) and Fresh water (on siliceous rock of fresh water).
2. On the basis of morphology of the thallus they are divided into Leprose (a distinct fungal layer is absent) Crustose - crust like; Foliose - leaf like; Fruticose - branched pendulous shrub like.
3. The distribution of algal cells distinguishes lichens into two forms namely Homoiomerous (Algal cells evenly distributed in the thallus) and Fleteromerous (a distinct layer of algae and fungi present).
4. If the fungal partner of lichen belongs to ascomycetes, it is called Ascolichen and if it is basidiomycetes it is called Basidiolichen.
Textbook Activity Solved
Get a button mushroom. Draw diagram of the fruit body. Take a thin longitudinal section passing through the gill and observe the section under a
microscope. Record your observations.