Kerala Board Class 12 Biology — Flashcards for Quick Revision

A: Living organisms exhibit three main characteristics: 1. Irritability (ability to respond to stimuli), 2. Growth (increase in size and complexity), and 3. Reproduction (ability to produce offspring). N

A: The early atmosphere contained ammonia (NH₃), water vapour (H₂O), hydrogen (H₂), and methane (CH₄). There was no free oxygen because oxygen-producing organisms (like plants with chlorophyll) had not y

A: Stanley Miller and Harold Urey (1953) created an air-tight apparatus with four gases (NH₃, CH₄, H₂, H₂O) and subjected them to electric discharge for one week. They found organic substances like amino

A: Reproduction is the ability of living organisms to produce offspring of their own kind. Asexual reproduction involves production of offspring from a single organism without formation of gametes (commo

A: Males attain sexual maturity at 13-14 years, females at 11-13 years. During puberty: Males - voice deepening, shoulder widening, beard/mustache growth, axillary hair, genital enlargement. Females - br

A: Male reproductive system consists of: Pair of testes (in scrotum), pair of epididymis, pair of vas deferens, urethra, penis, and accessory glands (seminal vesicles, prostate gland, Cowper's glands). S

A: Kingdom Monera is the only prokaryotic kingdom, meaning its organisms lack a membrane-bound nucleus and other membrane-bound organelles. The genetic material (DNA) is present in a region called the nu

A: 1. Spherical (Coccus) - round-shaped bacteria 2. Rod-shaped (Bacillus) - cylindrical bacteria 3. Spiral-shaped (Spirillum) - twisted, cork-screw like bacteria 4. Comma-shaped (Vibrio) - curved, comma-

A: 1. Cell Wall: Rigid structure made of peptidoglycan for protection 2. Pili: Short thread-like structures for attachment to surfaces 3. Flagella: Long whip-like structures for locomotion 4. Plasma Memb