BIOLOGY 2 Marks Questions

1. Fresh water organisms found in stagnant water.
2. Instead of cell wall they have a protein rich layer called pellicle whick makes their body flexible.
3. They are autotrophs in the presence of sunlight and heterotrophs in the absence of sunlight.
4. A small light sensitive eye spot is present.

1. Methane gas is produced from the dung of ruminants by the methanogens.
2. Methanogens are also involved in the formation of biogas and sewage treatment.

These fungi grow around and into the roots. Both partners benefit so that neither would thrive without the other. This partnership is called mycorrhizal symbiosis.

1. Algae is autotrophic, while fungi is heterotrophic.
2. Algae cannot be a parasite, while fungi can be a parasite.

1. Phycomycetes: Mycelium is aseptate and branched.
   
2. Ascomycetes: Mycelium is septate and branched.
   
3. Basidiomycetes: Mycelium is septate and branched.
   
4. Deuteromycetes: Mycelium is septate and branched.
   

1. Crustose (crust-like).
2. Foliose (flat and lobed-like).
3. Fruticose (branched-like a bush).

1. They are used to make perfumes and soaps.
2. They are used to obtain alcohol after brewing and distillation.
3. Their absence in the environment indicates air pollution.
4. They are used to create medicines to various lung diseases and hydrophobia.

1. Monera. 
2. Protista.
3. Fungi.
4. Plantae.
5. Animalia.

1. Unicellular.
2. Well defined nucleus.
3. Membrane bound organelles.
4. The presence of Flagella.

Their mycelium is:

1. septate.
2. branched.

1. They discolour the walls and roofs of buildings.
2. Excessive growth in water bodies decreases oxygen levels, thereby killing aquatic animals.

1. Curdling of milk.
2. Lactobacillus is an important commensal in the gut flora of humans.
3. Penicillin antibiotics are prepared by bacteria.
4. Bacteria is a good decomposer, so it assists in completing the energy cycle.
5. Rhizobium bacteria helps in nitrogen fixation.

1. Lignocolous: Growing on wood.

2. Saxicolous: Growing on rock.

3. Certicolous: Growing on bark.

4. Terricolous: Growing on soil.

1. CoccusSpherical cell. 
2. Bacillus Rod-shaped cell.
3. Vibrio Comma-shaped cell. 
4. Spirillum Spiral-shaped cell.

1. They help in making curd from milk.
2. Some fix atmospheric nitrogen in the soil, as symbionts in legumes.
3. Some of them produce antibiotics.
4. Many are decomposers and help to get rid of organic wastes (garbage).

1. Female Anopheles mosquito: It is a primary host of malarial parasite. The sexual phase of parasite occurs in mosquito.

2. Human beings: These are intermediate or secondary host of Plasmodium. The asexual phase of parasite occurs in humans.

1. They lack a cell wall.
2. They are the smallest living cells.
3. They can survive without oxygen.
4. They are pathogenic, i.e. cause diseases in plants and animals.

1. Red rot: Colletotrichum falcatum.

2. Early blight: Alternaria solani.

3. Wilts: Fusarium oxysporum.

4. Brown leaf spot of rice: Helminthosporium oryzae.

1. Aplanospores, zoospores, conidia.
2. Oospores, zygospores, ascospores, basidiospores.

• The sex organs are absent and sexual reproduction is by somatogamy. Plasmogamy is effected by the fusion of two vegetative/ somatic cells of different strains or genotypes.
• It results in a dikaryon, which ultimately becomes the basidium.
• Karyogamy and meiosis occur in the basidium, l resulting in the production of four basidiospores, that are cut off exogenously on the basidium.
• The basidia become arranged into fruiting bodies,called basidiocarps.

1. Phycomycetes.
2. Rhizrpus.
3. Albugo, Plasmcpora.
4. Mita shows awareness, consciousness and alertness.

• Tuberculosis: Mycobacterium tuberculosis.

• Leprosy: Mycobacterium leprae.

• Diphtheria: Corynebacterium diphtheriae.

• Pneumonia: Diplococcus pneumoniae.

1. Nutrition: It is photosynthetic or autotrophic. Some forms are saprotrophic, parasitic and symbionts.

2. Locomotion: Dinoflagellates show rolling and spinning type of locomotion due to the presence of two flagella. Hence, they are also called whirling whips.

3. Reproduction: It occurs by asexual and sexual methods. Asexual reproduction occurs by cell division, spores and cysts. Sexual reproduction occurs by conjugation.

• Lichens are composite organisms showing symbiosis between an alga and a fungus.
• The algal component (phycobiont) is autotrophic and prepares food for the fungus too.
• The fungal component (mycobiont) is heterotropic and absorbs water and mineral nutrients for the alga and also provides protection to the alga.
• Thus, both the alga and fungus are mutually benefitted.

1. Euglenoids have no cell wall but a protein rich layer, called pellicle that makes their bodyflexible.
2. They have two flagella (one short and one long) at their anterior end. They are photosynthetic in the presence of light, but are heterotrophs (predators) in the absence of light.
3. The pigments of euglenoids are identical to the pigments of higher plants.

1. The morphology of the mycelium.
2. Mode of spore formation.
3. Mode of sexual reproduction, and
4. Nature of fruiting bodies.

• Plasmodium is the aggregation.
• During unfavourable conditions, it differentiates to form fruiting bodies that bear spores at their tips.
• The spores have a true wall and are extremely resistant and survive for many years under adverse conditions.
• The spores are dispersed by wind.

• It is because, when the sexual stage is identified, it is shifted to ascomycetes or basidiomycetes.
• It is also possible that the vegetative and asexual stages have been given a name and placed under Deuteromycetes and the sexual stage is given another name and placed under a different class.

1. Basidiomycetes.
2. Deuteromycetes.
3. Phycomycetes. 
4. Basidiomycetes.

1. Leaf mosaics
2. Leaf curling and rolling
3. Yellowing and vein clearing
4. Dwarfing and stunted growth.

1. Halophiles.
2. Thermoacidophiles.

2. They have a cell wall structure, which is responsible for this.

1. Photosynthetic Protists - Dinoflagellata, Euglenophyta, Chrysophyta
2. Chrysophyta

1. The intervening condition, is a dikaryon.
2. It is the dikaryophase.

1. Lichens.
2. Mycorrhizae.