Slovakia Maturita Biology cheat sheet

Living systems share organisation levels: molecule → organelle → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere.

All organisms share: cellular organisation, metabolism, growth, reproduction, response to stimuli, homeostasis, heredity and adaptation.

Prokaryotic cells lack a membrane-bound nucleus and membrane-bound organelles; eukaryotic cells possess both.

Autotrophs fix inorganic carbon (photosynthesis or chemosynthesis); heterotrophs obtain carbon from organic compounds.

Viruses are acellular and are not classified as living organisms under the cellular criterion.

Homeostasis maintains internal stability through negative feedback loops that reverse deviations from a set point.

Biological species concept: members interbreed in nature and produce fertile offspring.

Water is the universal solvent of life; its polarity, high specific heat and high heat of vaporisation stabilise living systems.

Prokaryotic cell: nucleoid DNA, 70S ribosomes, plasma membrane, cell wall (peptidoglycan in bacteria), no mitochondria or ER.

Eukaryotic organelles: nucleus, mitochondria, plastids, ER, Golgi apparatus, lysosomes, vacuoles, cytoskeleton.

Mitochondria and chloroplasts are semiautonomous: they contain their own circular DNA and 70S ribosomes (endosymbiotic theory).

Semipermeable membrane: passive transport (diffusion, osmosis, facilitated diffusion) needs no ATP; active transport and endocytosis/exocytosis require ATP.

Enzyme kinetics: reaction rate rises with substrate concentration and temperature to an optimum; above the optimum protein denatures irreversibly.

DNA structure: antiparallel double helix, deoxyribose, phosphate, bases A-T and G-C (two and three hydrogen bonds respectively).

Replication is semiconservative; transcription synthesises mRNA from a DNA template; translation at the ribosome reads mRNA codons with tRNA anticodons.

Mitosis yields two genetically identical diploid cells; meiosis yields four genetically distinct haploid cells through two divisions with crossing-over in prophase I.

Photosynthesis: light reactions in thylakoids (ATP, NADPH, O2 from water); Calvin cycle in the stroma fixes CO2.

Cellular respiration: glycolysis in cytoplasm, Krebs cycle in the matrix, oxidative phosphorylation on the inner mitochondrial membrane.

Mendel's first law (segregation): two alleles of a gene separate during gamete formation; second law (independent assortment) applies to unlinked genes.

Monohybrid cross Aa × Aa gives a 3:1 phenotype ratio; a testcross with a homozygous recessive parent reveals the genotype of the dominant phenotype.

Dihybrid cross AaBb × AaBb gives a 9:3:3:1 phenotype ratio when genes are unlinked.

Complete dominance, incomplete dominance (intermediate phenotype) and codominance (both alleles expressed) are distinct inheritance patterns.

Multiple alleles: the ABO blood group has alleles IA, IB, i; IA and IB are codominant and both dominant over i.

Sex-linked traits (e.g. haemophilia, colour blindness) are carried on the X chromosome; males XY express them from a single allele.

Autosomal recessive disorders (phenylketonuria, cystic fibrosis) appear in offspring of two unaffected carriers.

Human karyotype has 46 chromosomes: 22 pairs of autosomes plus XX (female) or XY (male).

Mutation types: substitution (point), insertion/deletion (frameshift), chromosomal structural changes and changes in chromosome number (aneuploidy, polyploidy).

Hardy-Weinberg: p + q = 1 and p² + 2pq + q² = 1 describe allele and genotype frequencies in an ideal, non-evolving population.

Viruses are acellular obligate intracellular parasites: nucleic acid (DNA or RNA) inside a protein capsid; some have an envelope.

Bacteriophage T4 has a head with DNA, a tail and tail fibres; it injects its genome into the host cell.

Lytic cycle: adsorption → penetration → replication → assembly → lysis; lysogenic cycle integrates viral DNA as a prophage.

Bacterial shapes: cocci (spheres), bacilli (rods), spirilla (spirals); bacterial cell wall contains peptidoglycan.

Bacteria reproduce asexually by binary fission; genetic recombination occurs via transformation, transduction and conjugation (pili).

Cyanobacteria are photosynthetic prokaryotes that fix nitrogen in heterocysts; they are not algae.

Fungal cell walls contain chitin; fungi are heterotrophic absorbers and may be saprophytic, parasitic or mutualistic (mycorrhiza, lichens).

Fungal groups: Zygomycetes, Ascomycetes, Basidiomycetes, Deuteromycetes; yeasts are unicellular ascomycetes that reproduce by budding.

Pathogenic examples: influenza and HIV (RNA viruses), tobacco mosaic virus (RNA), tuberculosis (Mycobacterium tuberculosis), candidiasis (Candida albicans).

Plant cell: cellulose cell wall, large central vacuole, chloroplasts with chlorophyll a and b, plasmodesmata connecting adjacent cells.

Non-vascular plants (mosses) lack true roots, stems and leaves and depend on water for fertilisation; vascular plants have xylem and phloem.

Seed plants: gymnosperms have naked seeds on cone scales; angiosperms enclose seeds in fruit derived from the ovary.

Monocots: one cotyledon, parallel venation, scattered vascular bundles, floral parts in threes; dicots: two cotyledons, net venation, bundles in a ring, parts in fours or fives.

Root: epidermis with root hairs, cortex, endodermis, pericycle, central vascular cylinder; root hairs absorb water and mineral ions.

Stem secondary growth: vascular cambium produces secondary xylem (wood) inward and secondary phloem outward; cork cambium forms bark.

Leaf: epidermis with stomata and guard cells, palisade mesophyll, spongy mesophyll, vascular bundles; stomata regulate gas exchange and transpiration.

Photosynthesis equation: 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2; chlorophyll absorbs mainly red and blue-violet light.

Transpiration pull drives water ascent through xylem; phloem transports assimilates from source to sink.

Pollination transfers pollen to the stigma; double fertilisation in angiosperms produces the zygote and the triploid endosperm.

Animal symmetry: radial (Cnidaria, adult Echinodermata) versus bilateral (most Bilateria); sponges (Porifera) are asymmetrical.

Diploblastic animals have ectoderm and endoderm (Cnidaria); triploblastic animals add mesoderm (Platyhelminthes onward).

Acoelomate (Platyhelminthes), pseudocoelomate (Nematoda) and coelomate (Annelida, Mollusca, Arthropoda, Chordata) body plans.

Open circulatory system in molluscs and arthropods; closed circulation in annelids and vertebrates.

Arthropod features: chitinous exoskeleton, jointed appendages, segmented body, moulting (ecdysis); insects have three body regions and six legs.

Echinoderms have a water vascular system, tube feet and secondary radial symmetry as adults; development is deuterostome.

Chordate defining features: notochord, dorsal hollow nerve cord, pharyngeal slits, post-anal tail (at least in embryos).

Vertebrate classes: fish (gills, scales), amphibians (moist skin, metamorphosis), reptiles (amniotic eggs, dry scales), birds (feathers, endothermic), mammals (hair, mammary glands).

Mammal groups: monotremes (egg-laying), marsupials (pouch), placentals (placenta); all mammals are endothermic and have a four-chambered heart.

Digestive and respiratory systems: fish use gills, amphibians and mammals use lungs; birds have air sacs and unidirectional airflow.

Skeletal system: about 206 bones; axial skeleton (skull, vertebral column, ribs, sternum) and appendicular skeleton (limbs, girdles).

Muscle types: skeletal (striated, voluntary), smooth (non-striated, involuntary), cardiac (striated, involuntary, intercalated discs).

Digestion: mechanical breakdown plus enzymes - amylase (starch), pepsin (protein, acidic stomach), lipase (fats), trypsin (protein, alkaline small intestine).

Blood: plasma, erythrocytes (haemoglobin, O2 transport), leucocytes (immunity), thrombocytes (clotting); ABO and Rh antigens determine blood groups.

Heart: four chambers, pulmonary and systemic circulation; SA node is the natural pacemaker; systole is contraction, diastole relaxation.

Respiration: gas exchange in alveoli by diffusion; diaphragm and intercostal muscles drive ventilation.

Excretion: nephron units in the kidney; filtration in the glomerulus, reabsorption in the proximal tubule, urine formation and ADH regulation.

Nervous system: CNS (brain, spinal cord) and PNS; neurone resting potential is negative inside, depolarisation propagates the action potential; synapse uses neurotransmitters.

Endocrine glands: hypothalamus, pituitary, thyroid (thyroxine), pancreas (insulin, glucagon), adrenal glands (adrenaline, cortisol), gonads.

Immune system: innate (skin, phagocytes, inflammation) versus adaptive (B lymphocytes → antibodies, T lymphocytes → cell-mediated immunity).

Ecological hierarchy: individual → population → community → ecosystem → biosphere; habitat is the place, niche is the functional role.

Population growth: exponential (J-curve, unlimited resources) versus logistic (S-curve, carrying capacity K).

Population density = number of individuals / area; natality, mortality, immigration and emigration change population size.

Species interactions: competition (−/−), predation and parasitism (+/−), mutualism (+/+), commensalism (+/0).

Food chain: producer → primary consumer → secondary consumer → decomposer; energy transfer between trophic levels is roughly 10 %.

Biogeochemical cycles: carbon (photosynthesis, respiration, combustion), nitrogen (fixation, nitrification, denitrification), water, phosphorus.

Ecological succession: primary succession starts on bare substrate; climax community is the relatively stable end stage.

Biodiversity levels: genetic, species and ecosystem diversity; biodiversity is highest in tropical rainforests and coral reefs.

Environmental threats: acid rain (SO2, NOx), eutrophication (nitrates, phosphates), greenhouse effect (CO2, CH4), ozone depletion (CFCs).

Protected areas and Red Lists are conservation tools; invasive species and habitat fragmentation are major causes of biodiversity loss.

Lamarck proposed inheritance of acquired characteristics; Darwin and Wallace proposed natural selection acting on heritable variation.

Natural selection requires variation, heritability, differential fitness and reproduction; it changes allele frequencies over generations.

Evidence for evolution: fossils, comparative anatomy (homologous and analogous structures), embryology, biogeography, molecular homology.

Homologous structures share common ancestry (forelimb bones); analogous structures share function but not ancestry (bird and insect wings).

Speciation: allopatric (geographic isolation) and sympatric (reproductive isolation without geographic separation).

Reproductive isolating mechanisms: prezygotic (temporal, behavioural, mechanical) and postzygotic (hybrid inviability, sterility).

Taxonomic ranks: domain, kingdom, phylum, class, order, family, genus, species; binomial nomenclature uses genus and species in Latin.

Three-domain system: Bacteria, Archaea, Eukarya; five-kingdom system: Monera, Protista, Fungi, Plantae, Animalia.

Coevolution and convergent evolution produce similar adaptations in unrelated lineages under similar selection pressures.

Human evolution: Homo habilis, Homo erectus, Homo neanderthalensis, Homo sapiens; bipedalism and increasing brain size are key trends.

Light microscope: magnification = objective magnification × eyepiece magnification; resolution is limited by the wavelength of light.

Working distance and depth of field decrease with higher magnification; the fine focus knob is used only with the fine adjustment at high power.

Specimen preparation: wet mount, cross-section, staining (iodine for starch, methylene blue for nuclei, eosin for cytoplasm).

Benedict's test detects reducing sugars (brick-red precipitate on heating); Biuret test detects proteins (violet); Sudan III detects lipids (red).

Chromatography separates pigments by differential solubility in the mobile phase; Rf = distance travelled by solute / distance travelled by solvent.

Sterile technique: flame the loop, work near a flame, use sterile Petri dishes and autoclave media; never open a culture of unknown organisms.

Microscopic counting and measurement use a calibrated eyepiece graticule; scale = measured length / actual length.

Safety: goggles and gloves for chemicals, no food or drink in the laboratory, report spills, dispose of biological waste per protocol.

Data handling: record raw measurements with units, calculate means, identify variables (independent, dependent, controlled) and repeat trials for reliability.