Tamil Nadu HSE First Year Biology flashcards
Tamil Nadu HSE First Year Biology · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Binomial nomenclature
- A two-part naming system where each species receives a genus name (capitalized) and a species epithet (lowercase), both italicized, established by Linnaeus.
- Five-kingdom classification
- Whittaker's system dividing life into Monera, Protista, Fungi, Plantae, and Animalia, based on cell type, body organization, and mode of nutrition.
- Herbarium
- A storehouse of pressed, dried, and preserved plant specimens mounted on sheets, labeled with scientific names and collection data, used for taxonomic study.
- Bryophytes
- Non-vascular plants with a dominant gametophyte generation that require water for sperm to reach the egg; examples include mosses and liverworts.
- Pteridophytes
- Seedless vascular plants with a dominant sporophyte and independent gametophyte; they need water for fertilization and include ferns and horsetails.
- Double fertilization
- A unique angiosperm process where one sperm fuses with the egg to form a zygote and another fuses with two polar nuclei to form triploid endosperm.
- Coelom
- A body cavity lined by mesoderm; animals are acoelomate (no cavity), pseudocoelomate (false cavity), or coelomate (true cavity) based on its presence.
- Notochord
- A flexible rod of cells that provides skeletal support and defines the chordate phylum; in vertebrates it is replaced by the vertebral column during development.
- Arthropoda
- The largest animal phylum, characterized by jointed appendages, a chitinous exoskeleton, segmented body, and open circulatory system; includes insects and crustaceans.
- Fluid mosaic model
- The description of the plasma membrane as a fluid phospholipid bilayer with embedded proteins that can move laterally, explaining selective permeability and membrane dynamics.
- Mitochondria
- Double-membraned organelles that generate ATP through oxidative phosphorylation and contain their own DNA and 70S ribosomes, supporting the endosymbiotic theory.
- Meiosis
- A reductional cell division producing four haploid daughter cells from one diploid cell, involving two divisions and crossing over, essential for genetic variation.
- Water potential
- The potential energy of water per unit volume relative to pure water, equal to solute potential plus pressure potential; water moves from higher to lower water potential.
- Calvin cycle
- The light-independent reactions of photosynthesis occurring in the stroma, where RuBisCO fixes CO2 into organic molecules using ATP and NADPH.
- Kranz anatomy
- A leaf structure in C4 plants with a wreath-like arrangement of bundle sheath cells around vascular bundles, enabling efficient CO2 concentration before Calvin cycle.
- Glycolysis
- The first stage of cellular respiration occurring in the cytoplasm, breaking one glucose into two pyruvate molecules and yielding a net of two ATP and two NADH.
- SA node
- The sinoatrial node in the right atrium that generates electrical impulses setting the heart's rhythm; it acts as the natural pacemaker of the heart.
- Nephron
- The functional unit of the kidney consisting of a glomerulus and renal tubule, responsible for filtering blood, reabsorbing useful substances, and forming urine.
- Sliding filament theory
- The mechanism of muscle contraction where actin filaments slide over myosin filaments, shortening the sarcomere and generating force through ATP-dependent cross-bridge cycling.
- Insulin
- A hormone secreted by pancreatic beta cells that lowers blood glucose by promoting cellular uptake and glycogen synthesis; deficiency causes diabetes mellitus.
- Spermatogenesis
- The process in testes where diploid spermatogonia undergo meiosis to produce four haploid sperm cells, regulated by testosterone and follicle-stimulating hormone.
- Menstrual cycle
- A roughly 28-day hormonal cycle in human females involving follicular development, ovulation around day 14, and endometrial shedding if fertilization does not occur.
- Apomixis
- A form of asexual reproduction in plants where seeds are formed without fertilization, producing genetically identical offspring; useful for preserving hybrid vigor.
- Mendel's law of segregation
- The principle that two alleles of a gene separate during gamete formation so each gamete carries only one allele, rediscovered as the basis of monohybrid inheritance.
- Central dogma
- The flow of genetic information from DNA to RNA to protein, describing transcription and translation as the processes by which genes determine traits.
- Hardy-Weinberg principle
- A principle stating that allele and genotype frequencies in a population remain constant in the absence of evolutionary forces, expressed as p² + 2pq + q² = 1.
- Recombinant DNA technology
- A technique that joins DNA fragments from different sources, often using plasmids and restriction enzymes, to create recombinant DNA for cloning or protein production.
- Bt crops
- Genetically modified plants containing a gene from Bacillus thuringiensis that produces insecticidal proteins, providing resistance against specific insect pests.
- Biodiversity hotspot
- A region with exceptionally high species richness and endemism that is under significant threat; examples include the Western Ghats and Eastern Himalayas.
- Biofertilizer
- A preparation containing living microorganisms such as Rhizobium or mycorrhizae that enhances nutrient availability to plants, reducing dependence on chemical fertilizers.
- Ecological pyramid
- A graphical representation of trophic levels in an ecosystem showing numbers, biomass, or energy; energy pyramids are always upright due to the 10% law.
- Photoperiodism
- The response of plants to the relative lengths of day and night, controlling flowering in short-day and long-day plants through phytochrome pigments.