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Once the contact is established between tail fibres of phase and bacterial cell, tail fibres bend to anchor the pins and base plate to the cell surface. This step is called pinning.

As soon as the phage injects its linear DNA into the host cell, it becomes circular and integrates into the bacterial chromosome by recombination. The integrated phage DNA is now called prophage.

Virion is an intact infective virus particle which is non – replicating outside a host cell.

On exposure to UV radiation and chemicals the excision of phage DNA may occur and results in lytic cycle.

(b) somatogamy

Chromista is a new kingdom in seven kingdom classification.

The unique feature of archaebacteria is the presence of lipids like glycerol and isopropyl ethers in their cell membrane. Due to the unique chemical composition the cell membrane show resistance against cell wall antibiotics and lytic agents. 

E.g. Methanobacterium.

In spermatization method a uninucleate pycniospore / microconidium is transferred to receptive hyphal cell (Example: PuccinialNeurospora).

Intracellular chains of 40 – 50 magnetite (Fe₃O₄) particles are found in bacterium Aquaspirillum magnetotacticum and it helps the bacterium to locate nutrient rich sediments.

Sexual reproduction in fungi includes three steps:

1. Fusion of two protoplasts (plasmogamy) 

2. Fusion of nuclei (karyogamy) and 

3. Production of haploid spores through meiosis

Actinomycetes comes under chromista kindgom.

Under favourable conditions the cell divides into two daughter cells. The nuclear material divides first and it is followed by the formation of a simple median constriction which finally results in the separation of two cells.

Three Components Of Gram Negative Cell Wall:

1. Lipoprotein 

2. outermembrane and 

3. lipopolysaccharide.

Majority of fungi are made up of thin, filamentous branched structures called hyphae. A number of hyphae get interwoven to form mycelium. The cell wall of fungi is made up of a polysaccharide called chitin (polymer of N – acetyl glucosamine).

The Gram positive bacteria retain crystal violet and appear dark violet, whereas Gram negative type loose the crystal violet and when counterstained by safranin appear red under a microscope.

Coenocytic mycelium is present. The cell wall is made up of glucan and cellulose. Zoospore with one whiplash and one tinsel flagellum is present. Sexual reproduction is Oogamous.

Example: Albugo.

Genetic recombination in bacteria occurs by conjugation, transduction and transformation.

Mesosomes are localized infoldings of plasma membrane produced into the cell in the form of vesicles, tubules and lamellae. They are clumped and folded together to maximize their surface area and helps in respiration and in binary fission.

Two Ammonifying Bacteria: 

1. Bacillus ramosus and 

2. Bacillus mycoides.

On the basis of their mode of nutrition bacteria are classified into two types namely autotrophs and heterotrophs.

I. Autotrophic bacteria: Bacteria which can synthesis their own food are called autotrophic bacteria. They may be further subdivided as

A. Photoautotrophic bacteria – Bacteria use sunlight as their source of energy to synthesize food. They may be:

1. Photolithotrophs: In Photolithotrophs the hydrogen donor is an inorganic substance.

Green sulphur bacteria: In this type of bacteria the hydrogen donor is H S and possess pigment called Bacterioviridin. 

Example: Chlorobium.

Purple sulphur bacteria: For bacteria belong to this group the hydrogen donor is thiosulphate, Bacteriochlorophyll is present. Chlorophyll containing chlorosomes are present. 

Example: Chromatium.

2. Photoorganotrophs: They utilize organic acid or alcohol ‘as hydrogen donor. 

Example: Purple non-sulphur bacteria – Rhodospirillum.

B. Chemoautotrophic bacteria – They do not have photosynthetic pigment hence they cannot use sunlight energy. These type of bacteria obtain energy from organic or inorganic substance.

1. Chemolithotrophs: This type of bacteria oxidize inorganic compound to release energy.

Examples:

• Sulphur bacteria – Thiobacillus thiooxidans
• Iron bacteria – Ferrobacillus ferrooxidans
• Hydrogen bacteria – Hydrogenomonas and
• Nitrifying bacteria – Nitrosomonas and Nitrobacter.

2. Chemoorganotrophs: This type of bacteria oxidize organic compounds to release energy. 

Examples:

• Methane bacteria – Methanococcus
• Acetic acid bacteria – Acetobacter and
• Lactic acid bacteria – Lactobacillus

II. Heterotrophic bacteria: They are parasites (Clostridium and Mycobacterium), Saprophytes (Bacillus mycoides) or symbiotic (Rhizobium in root nodules of leguminous crops).

Two types of respiration is found in bacteria. They are:

1. Aerobic respiration 

2. Anaerobic respiration

1. Aerobic respiration: These bacteria require oxygen as terminal acceptor and will not grow under anaerobic conditions (i.e. in the absence of O ) 

Example: Streptococcus.

(i) Obligate aerobes: Some Micrococcus species are obligate aerobes (i.e. they must have 1 oxygen to survive).

2. Anaerobic respiration: These bacteria do not use oxygen for growth and metabolism but obtain their energy from fermentation reactions. 

Example: Clostridium.

(i) Facultative anaerobes: There are bacteria that can grow either using oxygen as a terminal electron acceptor or anaerobically using fermentation reaction to obtain energy. When a facultative anaerobe such as E. coli is present at a site of infection like an abdominal abscess, it can rapidly consume all available O and change to anaerobic metabolism producing an anaerobic environment and thus allow the anaerobic bacteria that are present to grow and cause disease. 

Example: Escherichia coli and Salmonella.

(ii) Capnophilic bacteria: Bacteria which require CO₂ for their growth are called as capnophilic bacteria. 

Example: Campylobacter.

Bacteria’s: 

1. Green sulphur bacteria – Bacterioviridin 

2. Purple sulphur bacteria – Bacteriochlorophyll

Plasmids are classified into different types based on the function. Some of them are F (Fertility) factor, R (Resistance) plasmids, Col (Colicin) plasmids, Ri (Root inducing) plasmids and Ti (Tumor inducing) plasmids.

Acetobacter aceti bacteria oxidises ethanol obtained from molasses by fermentation to form vinegar.

Plasmids are extrachromosomal double stranded, circular, self-replicating, autonomous elements. They contain genes for fertility, antibiotic resistant and heavy metals. It also help in the production of bacteriocins and toxins which are not found in bacterial chromosome.

Glycogen, poly-β-hydroxybutyrate granules, sulphur granules and gas vesicles.

Two Groups of Aninmals: 

1. Enaima – animals with red blood.

2. Anaima – animals without red blood.

Acronyms: 

(a) SARS: Severe Acute Respiratory Syndrome 

(b) AIDS: Acquired Immuno Deficiency Syndrome

Correct Answer is : (c) 300 × 20 nm

Viruses infecting fungi are called mycophages or mycoviruses. Mycophages were first reported by Hollings in 1962.

The first visible symptom of TMV is discoloration of leaf colour along the veins and show typical yellow and green mottling which is the mosaic symptom. The downward curling and distortion of young apical leaves occurs, plant becomes stunted and yield is affected.

Two Disease: 

1. Bovine Spongiform Encephalopathy (BSE) (mad cow disease) 

2. Creutzfeldt – Jakob Disease (CJD)

Four Animal Disease: 

1. Anthrax 

2. Brucellosis 

3. Bovine tuberculosis and 

4. black leg.

RNA animal virus and DNA plant virus:

1. RNA animal virus is HIV. 

2. DNA plant virus is Cauliflower mosaic virus.

(a) 8.7 million

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.

Earth was formed around billion years ago 4.6.

In homoiomerous (algal cells evenly distributed in the thallus) and heteromerous (a distinct layer of algae and fungi present).

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.

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.

Homoiomerous and Heteromerous Lichens:

Living cells grow by the addition of new protoplasm within the cells. Therefore, growth in living thing is intrinsic.

The Beneficial Aspects of Lichens: 

1. Lichens secrete organic acids like oxalic acids which corrodes the rock surface and helps in weathering of rocks, thus acting as pioneers in Xerosere.

2. Usnic acid produced from lichens show antibiotic properties. 

3. Lichens are sensitive to air pollutants especially to sulphur-di-oxide. Therefore, they are considered as pollution indicators.

4. The dye present in litmus paper used as acid base indicator in the laboratories is obtained from Roccella montagnei. 

5. Cladonia rangiferina (Reindeer moss) is used as food for animals living in Tundra regions.

Metabolism: The sum total of all the chemical reactions taking place in a cell of living organism is called metabolism. It is broadly divided into anabolism and catabolism. 

The difference between anabolism and catabolism is given in table.

Fusion of motile gamete is called planogametic copulation. 

Types: 

1. Isogamy 

2. Anisogamy and 

3. Oogamy.

The sum total of all the chemical reactions taking place in a cell of living organism is called metabolism. It is broadly divided into anabolism and catabolism.

Reproduction is the tendency of a living organism to perpetuate its own species. There are two types of reproduction namely asexual and sexual.

In lower fungi the hypha is aseptate, multinucleate and is known as coenocytic mycelium (Example: Albugo)

The mycelium is organised into loosely or compactly interwoven fungal tissues called plectenchyma. It is further divided into two types: prosenchyma and pseudoparenchyma.

Number of nuclei in coenocytic mycelium many.