Classification of Plants

Bread mould respires aerobically and needs oxygen; it is a saprophyte that digests food outside its body using enzymes secreted by hyphae.

Step 1: Bread mould grows on the TOP of bread because respiration in bread mould is mainly AEROBIC – it needs oxygen from the air. The inner layers of bread have less oxygen. Step 2: This explains the observation that mould is seen only on the surface. Step 3: For nutrition, bread mould is a saprophyte – it lives on dead organic matter (stale bread). Step 4: The hyphae of bread mould secrete digestive enzymes (digestive juices) INTO the bread. These enzymes break down starch into glucose outside the mould's body. Step 5: The glucose is then absorbed through the hyphae and stored as glycogen. T

Pseudopodia are temporary finger-like extensions formed by the outward flow of cytoplasm along with the cell membrane.

Step 1: The word 'pseudopodium' comes from Greek – 'pseudo' means false and 'podium' means foot. So pseudopodia are false feet. Step 2: They are NOT permanent structures. They form temporarily when needed and disappear afterward. Step 3: Structurally, pseudopodia form when the cytoplasm flows outward in a particular direction, pushing the cell membrane with it, creating a finger-like projection. Step 4: Amoeba extends one pseudopodium longer than the others in the direction of movement, and the rest of the body flows into it. Step 5: Option A is wrong because Amoeba has no cell wall and pseudo

Excess water and ammonia are expelled through the contractile vacuole, which expands when full and shrinks to release the contents.

Step 1: Amoeba produces ammonia as its main nitrogenous waste product from metabolic activities. Step 2: Most of the ammonia diffuses out directly through the cell membrane (general body surface) by the process of diffusion. Step 3: However, EXCESS WATER is collected in a special structure called the contractile vacuole. Step 4: Since ammonia is soluble in water, some ammonia is also expelled along with water through the contractile vacuole. Step 5: The contractile vacuole works rhythmically – it expands as water accumulates and then contracts (shrinks) to push the water out of the cell. Optio

Vibrio shape – Vibrio cholerae – causes cholera.

Step 1: Bacteria are classified into four shapes – coccus (spherical), bacillus (rod-shaped), spirillum (spiral), and vibrio (comma-shaped). Step 2: Vibrio cholerae is a comma-shaped bacterium – it belongs to the vibrio form. Step 3: It is responsible for causing cholera, a dangerous water-borne disease. Step 4: Option A is wrong because Vibrio cholerae is NOT spiral (spirillum); it is comma-shaped (vibrio). This is a common confusion. Step 5: Option C is wrong because Streptococcus pneumoniae is a coccus (spherical) shaped bacterium, not bacillus. Option D is wrong because Salmonella typhi is