Explanation

• Denitrification → conversion of NO₃⁻ and NO₂⁻ to N₂ or N₂O by anaerobic bacteria.

Additional information:

• Immobilization → nitrogen taken up by microbes, temporarily unavailable to plants.
• Mineralization → conversion of organic nitrogen to inorganic forms (NH₄⁺).

Last verified on 11-02-2026

Explanation

• Some plants can reproduce asexually, producing offspring genetically identical to the parent.
• Such a group of plants with the same genetic makeup is called a clone.
• Cloning helps in preserving desirable traits in agriculture and horticulture.

Last verified on 11-02-2026

Explanation

• Dioecious plants → individual plants produce either male or female flowers, e.g., Date palm, Papaya, Spinach.

Additional information:

• Monoecious plants → both male and female flowers on same plant, e.g., Maize, Cucumber.

Last verified on 11-02-2026

Explanation

• Arthropods are divided into different classes based on body structure, legs, and antennae.
• Spiders, ticks, and mites have eight legs and no antennae, which classifies them differently from insects.
• These belong to the class Arachnida.

Last verified on 11-02-2026

Explanation

• Abscission is the natural detachment of plant parts like leaves, flowers, or fruits.
• It occurs at the abscission zone, a specialized layer at the base of the plant part.

Additional information:

• Hormones involved → ethylene promotes abscission, auxin delays it

Last verified on 11-02-2026

Explanation

• Manipulation of genes is part of genetic engineering, a branch of biotechnology.
• Cheese making uses microbes to ferment milk, which is an example of traditional biotechnology.
• Manipulation of biological systems refers to modern biotechnology applications in medicine, agriculture, and industry.

Last verified on 11-02-2026

Explanation

• Cell membrane (plasma membrane) surrounds the cytoplasm of animal cells.
• It is selectively permeable, allowing some substances to pass while blocking others.

Additional information:

• Made of lipid bilayer with proteins.
• Plays a role in cell signaling and communication.

Last verified on 11-02-2026

Explanation

• Genes are units of heredity found on chromosomes that carry instructions for traits.
• They control physical characteristics, biochemical processes, and even sex determination.
• Genes are made of DNA.
• They are passed from parents to offspring.

Last verified on 11-02-2026

Explanation

• Crown gall is a bacterial disease caused by Agrobacterium tumefaciens.
• It produces tumor-like growths (galls) on roots, stems, and crowns of plants.
• Commonly affects fruit trees, grapes, and ornamental plants.

Last verified on 11-02-2026

Explanation

• Photosynthesis is the process by which green plants make their own food using sunlight, water, and carbon dioxide.
• It occurs in chloroplasts of plant cells.
• The process starts with light-dependent reactions, which capture solar energy to produce energy-rich molecules.

Last verified on 11-02-2026