Samacheer Class 11 Bio Botany - Living World

Distinguishing Features of Monera:
* This kingdom includes all prokaryotic organisms. Example: Mycoplasma, bacteria, actinomycetes, and cyanobacteria.
* These are microscopic. They do not have a true nucleus and membrane-bound organelles.
* Many other bacteria like Rhizobium, Azotobacter, and Clostridium can fix atmospheric nitrogen into ammonia.
* Some bacteria are parasites and others live as symbionts.

Rhizobium- Nitrogen-fixing bacteria,
Living in the root modules of leguminous plants has a symbiotic association with it, fix atmospheric nitrogen, and convert it into nitrates, thereby increases the fertility of the soil. Growing legumes alternatively with paddy can help paddy to give high yield- This method of growing paddy, alternatively with leguminous plants is known as crop rotation.
Mixed cropping:
Amidst, other crops. The leguminous crop is also raised as a mixed crop – so that it enriches the soil and increases the yield by fixing atmospheric nitrogen.

a. Proposed by R.H. Whittaker (American taxonomist)
b. Criteria considered – cell structure, Thallus Organization, Mode of Nutrition, Reproduction, and Phytogenitic Relations.
5 kingdom classifications include: –
a. Monera b. Protista c. Fungi d. Plantae e. Animalia
S. No
Merits:
Demerits:
1.
Based on the complexity of cell structure & organization of thallus
Monera & Protista – Include both autotrophic & heterotrophic organisms
2.
Based on mode of nutrition.
Include cell wall lacking & cell wall
3.
Fungi-kept in a separate category from plants
Bearing organisms.
4.
It shows the phylogeny of the organisms
So the group is more heterogeneous

a. Definition: A symbolic association of algae and Fungi helping each other & living together known as lichens.
b. Partners: Algal partner known as Phycobiont & Fungal partner known as Mycobiont
c. Role of Algal partner – Autotrophic prepare food – give nutrition to fungal partner also
d. Role of fungal partner – gives protection- helps in fixing to the substratum by rhizines.
Classification:
Character
Phycobiont
Mycobiont
1
Asexual reproduction
Akinetes, hormogonia, Aplanospore, etc.
fragmentation soredia, and isidia
2
Sexual reproduction
absent
sexual reproduction by ascocarp & ascospores
Character
Classification of lichens
1.
Habitat
Corticolous – growing on the bark
Lichnicolous – growing on wood
Saxicolous – growing on rock
Terricolous – growing on the ground
Marine – siliceous rock sea
Freshwater – siliceous rocks (freshwater habitat).
2.
Morphology of thallus
Leprose – distinct fungal layer absent Crustose – crust like Foliose – Leaf-like Fruticose-branched pendulous shrub-like
3.
On the basis of the distribution of algae cells
Homoiomerous – Algae cells evenly distributed Heteromerous – A distinct layer of Algae and Fungi present
4.
On the basis of the fungal partner
If it is Ascomycetes – Ascolichen If it is basidiomycetes-Basidiolichen
Economic importance:
Secretion of acids of lichens
Uses
1
Oxalic acid
Weathering of rocks Pioneers in xerosere
2
Usnic acid
Antibacterial
II. a. Pollution Indicators – Lichens sensitive to air pollutants- (pollution indicators)
b. Rocella Montagne – Produces a dye used in litmus paper (acid-base indicator)
c. Cladonia rangiferina – Food for animals in tundra regions
Part – II.
11th Bio Botany Guide Living World Additional Important Questions and Answers
Choose The Right Answer:

Year
Name of the Scientist
Achievement
1796
Edward Jenner
Vaccination for smallpox
1886
Adolf Mayer
Proved infectious nature of- TMV- from mosaic leaves sap
1892
Dimitry Ivanowsky
Viruses are smaller than bacteria

Even though Bacteria cause many diseases to plants animals and human beings they are beneficial to day-to-day life also. Ex: Milk (lactobacillus acidophobus)/(lactobaci llus lacti)
a. Curd b. Butter c. Cheese d. Yogurt These are a few of the beneficial activities.

a. In the lysogenic cycle, the injected phage DNA become circular and integrates into bacterial chromosome by recombination.
b. The integrated DNA of phage and bacteria is known as Prophase.

Cyanophage
Mycophage
1
Vims infecting blue green Algae are known as
Cyanophage
Vims allacking fungi are called Mycovimses or
Mycophage
2
1st reported by Safferman and Mores(1963)
1st reported by Holling(1962)
3
Eg. Lyngbuya, Plectonema
Eg. Myc ovims attacking Mushrooms

1
Size
20-30mm in diameter 15 pm in length
Bigger in size
2
Structure
Simple made up of single fibril
In C.S flagella contain 9+2 microtubules
3
No of position
Many types
few types
4
Function
Locomotion
Locomotion

Photolithotrophs
Photo organotrophs
1.Hydrogen donor is an in organic substance 2 types – Green sulphur bacteria Hydrogen donor H 2 S Posses bacterioviridin.
E.g chlorobium Purple sulphur bacteria
Here hydrogen donor is thiosulphate
pigment bacterial chlorophyll in chlorosomes
E.g chromatium
2. The hydrogen donor is an organic acid or alcohol
e.g purple non sulphur bacteria Rhodospirillum
E.g
* Purple non sulphur bacteria
* Rhodospirillum

Sexual reproduction is so simple formation and fusion of gametes is absent. However by Three different methods gene recombination can occur
* Conjugation
* Transduction
* Transformation
2 Marks

• The type of bacteria oxidise in organic compound to release energy
• Eg Sulphur bacteria – Thiobacillus thio oxidants
• Iron bacteria – Ferrobacillus ferro oxidants
• Hydrogen bacteria – Hydrogenomonas

• Microorganism such as lactobacillus bifidobacterium when consume as a dietary supplement help to maintain or restores beneficial bacteria to the digestive tract. They are called friendly or good bacteria. They keep our gut healthy
• They help to increase the immunity of the body
• Eg: Probiotic Yoghurt
• Probiotie tooth paste.

• Actinomycetes are called as ray fungi due to their mycelia like growth
• They are anaerobic or facultative anaerobic
• They are gram + ve
• Don’t produce aerial mycelium
• DNA contain high guanine and cytosine content Eg strepotmyces

Property of self-regulation and tendency to maintain a steady-state within an external environment which is liable to change is called homeostasis. It is essential for the living organism to maintain internal conditions to survive in the environment.

b. The number of ribosomes per cell varies from 1000 to 1500.
IV. Find out the True and False statements from the following and on that basis find the correct answer: