TG POLYCET Biology: Life Processes, Heredity and Environment
TG POLYCET Biology tests Telangana SSC life-science concepts: nutrition, respiration, transportation, excretion, coordination, reproduction, heredity and environment. Most questions ask for the correct process, organ or ratio, so precise terminology and direction of flow are more important than long descriptions.
Core rules
- Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ in chloroplasts, using chlorophyll and sunlight. Stomata allow gas exchange and transpiration.
- Respiration: aerobic respiration uses oxygen and releases more ATP; anaerobic respiration in muscle produces lactic acid, and in yeast produces ethanol and CO₂.
- Transportation: xylem carries water and minerals upward; phloem carries food. The human heart has four chambers; arteries carry blood away from the heart, veins toward it.
- Excretion: the nephron is the functional unit of the kidney; urine formation includes filtration, reabsorption and secretion. Dialysis removes nitrogenous wastes when kidneys fail.
- Coordination: a reflex arc is a rapid involuntary response; the neuron is the structural and functional unit of the nervous system. Insulin lowers blood glucose; thyroxine regulates metabolism.
- Reproduction: pollination transfers pollen to the stigma; fertilisation is fusion of male and female gametes. Asexual modes include budding, fragmentation and regeneration.
- Heredity: Mendel's monohybrid cross gives a 3:1 phenotypic ratio and a 1:2:1 genotypic ratio in F₂. Human males are XY and females XX.
Worked example
Cross a pure tall pea plant (TT) with a pure dwarf plant (tt). All F₁ offspring receive T from one parent and t from the other, so all are Tt and tall because tall is dominant. Selfing Tt × Tt gives gametes T and t from each parent. The Punnett square yields TT, Tt, Tt and tt: genotypic ratio 1 TT : 2 Tt : 1 tt; phenotypic ratio 3 tall : 1 dwarf. The dwarf trait reappears because both parents carry the recessive allele.
Traps
Reversing xylem and phloem; confusing pollination with fertilisation; writing 1:2:1 for phenotypes instead of genotypes; mixing up insulin and thyroxine; forgetting that anaerobic respiration still produces some ATP.