BW Abitur Biology Bilingual EN cheat sheet

Prokaryotic cells lack membrane-bound organelles and a nucleus; their DNA lies in a nucleoid, and ribosomes are 70S (50S + 30S subunits).

Eukaryotic ribosomes are 80S (60S + 40S); the rough ER bears ribosomes and produces secretory and membrane proteins, while the smooth ER synthesises lipids and detoxifies.

Fluid-mosaic model: the phospholipid bilayer is amphipathic, with hydrophilic heads outward; cholesterol modulates fluidity, and integral proteins span the bilayer while peripheral proteins attach to its surface.

Simple diffusion follows the concentration gradient without energy or carriers; facilitated diffusion uses channel or carrier proteins down the gradient; active transport (e.g. Na+/K+-ATPase, 3 Na+ out, 2 K+ in per ATP) moves solutes against the gradient.

Osmosis: water moves across a semipermeable membrane toward higher solute concentration; in a hypertonic solution an animal cell shrinks (crenation), in a hypotonic solution it swells or lyses, and a plant cell becomes turgid because of the cell wall.

Enzymes lower activation energy, are not consumed, and are highly specific at their active site; rate rises with substrate concentration until Vmax, and above the optimum temperature or away from optimum pH denaturation reduces activity.

Compartmentalisation: mitochondria and chloroplasts have double membranes; lysosomes hold hydrolytic enzymes at acidic pH; the Golgi apparatus modifies, sorts and packages proteins; the cytoskeleton (microtubules, actin filaments) supports transport and shape.

Endosymbiotic theory: mitochondria and chloroplasts derive from engulfed prokaryotes, evidenced by their own circular DNA, 70S ribosomes and double membranes.

ATP hydrolysis (ATP + H2O → ADP + Pi) releases about 30 kJ/mol under cellular conditions and drives endergonic reactions by coupling; ATP is regenerated by respiration and photophosphorylation.

Glycolysis in the cytosol: glucose (6C) → 2 pyruvate (3C), net 2 ATP and 2 NADH per glucose; it requires no oxygen.

Pyruvate oxidation and the citrate cycle in the mitochondrial matrix yield per glucose 6 NADH, 2 FADH2 and 2 ATP (substrate-level phosphorylation); oxidative phosphorylation on the inner membrane yields about 26–28 ATP.

Chemiosmosis: electron transport chains pump H+ into the intermembrane space; the proton gradient drives ATP synthase. Oxygen is the terminal electron acceptor in aerobic respiration, forming water.

Anaerobic fermentation regenerates NAD+: lactate fermentation (pyruvate + NADH → lactate) in muscle, and alcoholic fermentation (pyruvate → acetaldehyde + CO2 → ethanol) in yeast.

Light reactions in the thylakoid membrane: water is split (photolysis) at photosystem II, releasing O2; electrons pass PSII → plastoquinone → cytochrome complex → PSI → NADP+, producing ATP and NADPH.

Calvin cycle in the stroma: RuBP (5C) + CO2 → 2 × 3-phosphoglycerate via RuBisCO; ATP and NADPH reduce it to triose phosphate, and RuBP is regenerated. Photorespiration at high O2 and low CO2 lowers yield; C4 and CAM plants reduce it.

Enzyme kinetics: Michaelis–Menten gives v = Vmax·[S]/(Km + [S]); Km is the substrate concentration at half Vmax and is inversely related to affinity. Competitive inhibitors raise apparent Km at unchanged Vmax; non-competitive inhibitors lower Vmax.

Mendel's laws: segregation (two alleles separate in meiosis) and independent assortment (genes on different chromosomes recombine independently). Monohybrid F2 ratio 3:1, dihybrid 9:3:3:1.

Test cross with a homozygous recessive partner reveals the genotype of a dominant phenotype; a 1:1 ratio indicates heterozygosity.

DNA replication is semi-conservative: helicase unwinds, primase lays RNA primers, DNA polymerase III extends 5'→3' on leading (continuous) and lagging (Okazaki fragments) strands, and ligase seals nicks.

Transcription: RNA polymerase reads the template strand 3'→5', synthesising mRNA 5'→3'; in eukaryotes introns are spliced out before export.

Translation: ribosomes read mRNA codons 5'→3'; tRNA anticodons pair by complementary base pairing; AUG is start, UAA/UAG/UGA are stop codons; the genetic code is degenerate and nearly universal.

Mutation types: substitution (missense, nonsense, silent), insertion or deletion causing frameshift; point mutations in somatic cells affect only the individual, germline mutations are inherited.

Restriction enzymes cut palindromic recognition sites, often producing sticky ends; DNA ligase joins fragments. Gel electrophoresis separates fragments by size, with smaller fragments migrating farther.

PCR cycles: denaturation (~95 °C), primer annealing (~55–65 °C), extension by Taq polymerase (~72 °C); each cycle doubles the target, so n cycles give about 2^n copies.

CRISPR-Cas9 uses a guide RNA to direct Cas9 nuclease to a complementary sequence, producing a double-strand break repaired by non-homologous end joining (knockout) or homology-directed repair (insertion).

Resting potential about −70 mV: Na+/K+-ATPase maintains gradients (high Na+ outside, high K+ inside); K+ leak channels dominate membrane permeability.

Action potential sequence: depolarisation to threshold (~−55 mV) → voltage-gated Na+ channels open (rapid upstroke to ~+30 mV) → Na+ inactivation and K+ efflux (repolarisation) → brief hyperpolarisation → refractory period.

All-or-none principle: stimulus strength is coded by action potential frequency, not amplitude; conduction velocity increases with axon diameter and myelination (saltatory conduction at nodes of Ranvier).

Chemical synapse: depolarisation opens Ca2+ channels, vesicles fuse, neurotransmitter is released into the cleft, binds postsynaptic receptors, and is removed by reuptake or enzymatic breakdown.

Excitatory postsynaptic potentials depolarise (e.g. Na+ influx); inhibitory postsynaptic potentials hyperpolarise (e.g. Cl− influx); summation of EPSPs and IPSPs at the axon hillock decides firing.

Sensory transduction converts stimulus energy into receptor potentials; adequate stimulus specificity, adaptation (phasic vs tonic receptors) and amplification shape perception.

Eye: light hyperpolarises photoreceptors (rhodopsin, bleaching), signals pass bipolar cells to ganglion cells; rods are sensitive in dim light, cones mediate colour (trichromatic) and acuity at the fovea.

Hearing: sound waves vibrate the tympanic membrane, ossicles amplify, the cochlea's basilar membrane is tonotopically organised, and hair cells transduce via bending of stereocilia.

Darwin's mechanism: heritable variation plus differential reproductive success (natural selection); selection acts on phenotypes, and populations, not individuals, evolve.

Hardy–Weinberg equilibrium p² + 2pq + q² = 1 holds with no mutation, no migration, random mating, infinite population and no selection; deviations indicate evolutionary forces.

Selection types: directional (one extreme favoured), stabilising (intermediate favoured), disruptive (both extremes favoured); sexual selection acts via mate choice and competition.

Speciation: allopatric (geographic isolation), sympatric (e.g. polyploidy, host shifts); reproductive isolation (prezygotic or postzygotic) defines biological species.

Evidence for evolution: fossil record and transitional forms, homologous structures (common ancestry), analogous structures (convergent evolution), vestigial organs, biogeography, molecular homology (DNA, protein sequences).

Phylogeny: cladograms show shared derived characters (synapomorphies); monophyletic groups include an ancestor and all descendants; molecular clocks use mutation rates to date divergence.

Human evolution: bipedalism precedes brain enlargement in the fossil record; Homo sapiens originated in Africa and spread with interbreeding with Neanderthals and Denisovans.

Biodiversity has genetic, species and ecosystem levels; genetic drift is strong in small populations (bottleneck, founder effect), reducing variation.

Population growth: exponential dN/dt = rN under unlimited resources; logistic dN/dt = rN(K − N)/K with carrying capacity K; r-strategists vs K-strategists differ in reproduction and survival.

Trophic levels transfer roughly 10 % of energy to the next level; energy flows one way and is lost as heat, while matter cycles.

Carbon cycle: photosynthesis fixes CO2, respiration and combustion release it; nitrogen cycle: nitrogen fixation (e.g. Rhizobium), nitrification, denitrification; phosphorus cycles without a gaseous phase.

Interspecific interactions: competition (−/−), predation and parasitism (+/−), mutualism (+/+), commensalism (+/0); the niche concept underlies competitive exclusion.

Ecosystem stability rises with biodiversity and food-web complexity; keystone species have disproportionate effects on community structure.

Human impact: greenhouse gases (CO2, CH4) drive warming; eutrophication from nitrate and phosphate causes algal blooms and oxygen depletion; bioaccumulation concentrates persistent pollutants up the food chain.

Conservation strategies: protected areas, habitat corridors, ex situ measures, species reintroduction; sustainability balances resource use with regeneration rates.

Ecological footprint and the precautionary principle are evaluation tools: compare per-capita resource use with biocapacity and weigh uncertainty before intervention.

Innate immunity: physical barriers (skin, mucus), phagocytes (macrophages, neutrophils), inflammation, complement, and natural killer cells; it acts fast and is non-specific, without memory.

Adaptive immunity is specific and has memory: B cells produce antibodies (humoral), T cells mediate cellular responses (helper CD4+, cytotoxic CD8+).

Antibody structure: Y-shaped, two heavy and two light chains, variable regions form the antigen-binding site; IgG, IgM, IgA, IgE and IgD differ in function and location.

Clonal selection: an antigen selects and activates lymphocytes bearing matching receptors, which proliferate and differentiate into effector cells and memory cells.

Vaccination exposes the immune system to antigens (attenuated, inactivated, subunit, mRNA) without disease, generating memory cells and often herd immunity.

Allergy is a type I hypersensitivity: IgE bound to mast cells cross-links on allergen contact, triggering histamine release (sneezing, vasodilation, anaphylaxis).

HIV infects CD4+ helper T cells, progressively destroying cellular immunity; AIDS is defined by opportunistic infections and a CD4+ count below a threshold.

Antibiotic resistance evolves by selection of resistant bacteria under antibiotic pressure; completing prescribed courses and prudent use slow resistance.

Hypothesis: a testable, falsifiable statement; distinguish independent variable (manipulated), dependent variable (measured) and controlled variables (held constant).

Control groups (negative control without treatment, positive control with known effect) allow attribution of effects to the independent variable.

Reliability: repeat measurements and increase sample size; validity: the method measures what it claims (e.g. controls, calibration, appropriate assay).

Data description: mean as central tendency, standard deviation as spread, error bars; overlapping error bars suggest non-significant differences.

Statistical significance: a p-value below the chosen level (commonly 0.05) indicates an unlikely result under the null hypothesis; significance is not the same as biological relevance.

Correlation does not imply causation; confounding variables must be excluded by randomisation, blinding or blocking.

Model evaluation: check assumptions, scale and simplifications; models (e.g. membrane, enzyme, population) are approximations with defined limits.

Scientific communication: structure IMRaD (Introduction, Methods, Results, Discussion), cite sources, present units and significant figures correctly, and describe trends with data evidence rather than opinion.

Prokaryotic cells lack membrane-bound organelles and a nucleus; their DNA lies in a nucleoid, and ribosomes are 70S (50S + 30S subunits).

Eukaryotic ribosomes are 80S (60S + 40S); the rough ER bears ribosomes and produces secretory and membrane proteins, while the smooth ER synthesises lipids and detoxifies.

Fluid-mosaic model: the phospholipid bilayer is amphipathic, with hydrophilic heads outward; cholesterol modulates fluidity, and integral proteins span the bilayer while peripheral proteins attach to its surface.

Simple diffusion follows the concentration gradient without energy or carriers; facilitated diffusion uses channel or carrier proteins down the gradient; active transport (e.g. Na+/K+-ATPase, 3 Na+ out, 2 K+ in per ATP) moves solutes against the gradient.

Osmosis: water moves across a semipermeable membrane toward higher solute concentration; in a hypertonic solution an animal cell shrinks (crenation), in a hypotonic solution it swells or lyses, and a plant cell becomes turgid because of the cell wall.

Enzymes lower activation energy, are not consumed, and are highly specific at their active site; rate rises with substrate concentration until Vmax, and above the optimum temperature or away from optimum pH denaturation reduces activity.

Compartmentalisation: mitochondria and chloroplasts have double membranes; lysosomes hold hydrolytic enzymes at acidic pH; the Golgi apparatus modifies, sorts and packages proteins; the cytoskeleton (microtubules, actin filaments) supports transport and shape.

Endosymbiotic theory: mitochondria and chloroplasts derive from engulfed prokaryotes, evidenced by their own circular DNA, 70S ribosomes and double membranes.

ATP hydrolysis (ATP + H2O → ADP + Pi) releases about 30 kJ/mol under cellular conditions and drives endergonic reactions by coupling; ATP is regenerated by respiration and photophosphorylation.

Glycolysis in the cytosol: glucose (6C) → 2 pyruvate (3C), net 2 ATP and 2 NADH per glucose; it requires no oxygen.

Pyruvate oxidation and the citrate cycle in the mitochondrial matrix yield per glucose 6 NADH, 2 FADH2 and 2 ATP (substrate-level phosphorylation); oxidative phosphorylation on the inner membrane yields about 26–28 ATP.

Chemiosmosis: electron transport chains pump H+ into the intermembrane space; the proton gradient drives ATP synthase. Oxygen is the terminal electron acceptor in aerobic respiration, forming water.

Anaerobic fermentation regenerates NAD+: lactate fermentation (pyruvate + NADH → lactate) in muscle, and alcoholic fermentation (pyruvate → acetaldehyde + CO2 → ethanol) in yeast.

Light reactions in the thylakoid membrane: water is split (photolysis) at photosystem II, releasing O2; electrons pass PSII → plastoquinone → cytochrome complex → PSI → NADP+, producing ATP and NADPH.

Calvin cycle in the stroma: RuBP (5C) + CO2 → 2 × 3-phosphoglycerate via RuBisCO; ATP and NADPH reduce it to triose phosphate, and RuBP is regenerated. Photorespiration at high O2 and low CO2 lowers yield; C4 and CAM plants reduce it.

Enzyme kinetics: Michaelis–Menten gives v = Vmax·[S]/(Km + [S]); Km is the substrate concentration at half Vmax and is inversely related to affinity. Competitive inhibitors raise apparent Km at unchanged Vmax; non-competitive inhibitors lower Vmax.

Mendel's laws: segregation (two alleles separate in meiosis) and independent assortment (genes on different chromosomes recombine independently). Monohybrid F2 ratio 3:1, dihybrid 9:3:3:1.

Test cross with a homozygous recessive partner reveals the genotype of a dominant phenotype; a 1:1 ratio indicates heterozygosity.

DNA replication is semi-conservative: helicase unwinds, primase lays RNA primers, DNA polymerase III extends 5'→3' on leading (continuous) and lagging (Okazaki fragments) strands, and ligase seals nicks.

Transcription: RNA polymerase reads the template strand 3'→5', synthesising mRNA 5'→3'; in eukaryotes introns are spliced out before export.

Translation: ribosomes read mRNA codons 5'→3'; tRNA anticodons pair by complementary base pairing; AUG is start, UAA/UAG/UGA are stop codons; the genetic code is degenerate and nearly universal.

Mutation types: substitution (missense, nonsense, silent), insertion or deletion causing frameshift; point mutations in somatic cells affect only the individual, germline mutations are inherited.

Restriction enzymes cut palindromic recognition sites, often producing sticky ends; DNA ligase joins fragments. Gel electrophoresis separates fragments by size, with smaller fragments migrating farther.

PCR cycles: denaturation (~95 °C), primer annealing (~55–65 °C), extension by Taq polymerase (~72 °C); each cycle doubles the target, so n cycles give about 2^n copies.

CRISPR-Cas9 uses a guide RNA to direct Cas9 nuclease to a complementary sequence, producing a double-strand break repaired by non-homologous end joining (knockout) or homology-directed repair (insertion).

Resting potential about −70 mV: Na+/K+-ATPase maintains gradients (high Na+ outside, high K+ inside); K+ leak channels dominate membrane permeability.

Action potential sequence: depolarisation to threshold (~−55 mV) → voltage-gated Na+ channels open (rapid upstroke to ~+30 mV) → Na+ inactivation and K+ efflux (repolarisation) → brief hyperpolarisation → refractory period.

All-or-none principle: stimulus strength is coded by action potential frequency, not amplitude; conduction velocity increases with axon diameter and myelination (saltatory conduction at nodes of Ranvier).

Chemical synapse: depolarisation opens Ca2+ channels, vesicles fuse, neurotransmitter is released into the cleft, binds postsynaptic receptors, and is removed by reuptake or enzymatic breakdown.

Excitatory postsynaptic potentials depolarise (e.g. Na+ influx); inhibitory postsynaptic potentials hyperpolarise (e.g. Cl− influx); summation of EPSPs and IPSPs at the axon hillock decides firing.

Sensory transduction converts stimulus energy into receptor potentials; adequate stimulus specificity, adaptation (phasic vs tonic receptors) and amplification shape perception.

Eye: light hyperpolarises photoreceptors (rhodopsin, bleaching), signals pass bipolar cells to ganglion cells; rods are sensitive in dim light, cones mediate colour (trichromatic) and acuity at the fovea.

Hearing: sound waves vibrate the tympanic membrane, ossicles amplify, the cochlea's basilar membrane is tonotopically organised, and hair cells transduce via bending of stereocilia.

Darwin's mechanism: heritable variation plus differential reproductive success (natural selection); selection acts on phenotypes, and populations, not individuals, evolve.

Hardy–Weinberg equilibrium p² + 2pq + q² = 1 holds with no mutation, no migration, random mating, infinite population and no selection; deviations indicate evolutionary forces.

Selection types: directional (one extreme favoured), stabilising (intermediate favoured), disruptive (both extremes favoured); sexual selection acts via mate choice and competition.

Speciation: allopatric (geographic isolation), sympatric (e.g. polyploidy, host shifts); reproductive isolation (prezygotic or postzygotic) defines biological species.

Evidence for evolution: fossil record and transitional forms, homologous structures (common ancestry), analogous structures (convergent evolution), vestigial organs, biogeography, molecular homology (DNA, protein sequences).

Phylogeny: cladograms show shared derived characters (synapomorphies); monophyletic groups include an ancestor and all descendants; molecular clocks use mutation rates to date divergence.

Human evolution: bipedalism precedes brain enlargement in the fossil record; Homo sapiens originated in Africa and spread with interbreeding with Neanderthals and Denisovans.

Biodiversity has genetic, species and ecosystem levels; genetic drift is strong in small populations (bottleneck, founder effect), reducing variation.

Population growth: exponential dN/dt = rN under unlimited resources; logistic dN/dt = rN(K − N)/K with carrying capacity K; r-strategists vs K-strategists differ in reproduction and survival.

Trophic levels transfer roughly 10 % of energy to the next level; energy flows one way and is lost as heat, while matter cycles.

Carbon cycle: photosynthesis fixes CO2, respiration and combustion release it; nitrogen cycle: nitrogen fixation (e.g. Rhizobium), nitrification, denitrification; phosphorus cycles without a gaseous phase.

Interspecific interactions: competition (−/−), predation and parasitism (+/−), mutualism (+/+), commensalism (+/0); the niche concept underlies competitive exclusion.

Ecosystem stability rises with biodiversity and food-web complexity; keystone species have disproportionate effects on community structure.

Human impact: greenhouse gases (CO2, CH4) drive warming; eutrophication from nitrate and phosphate causes algal blooms and oxygen depletion; bioaccumulation concentrates persistent pollutants up the food chain.

Conservation strategies: protected areas, habitat corridors, ex situ measures, species reintroduction; sustainability balances resource use with regeneration rates.

Ecological footprint and the precautionary principle are evaluation tools: compare per-capita resource use with biocapacity and weigh uncertainty before intervention.

Innate immunity: physical barriers (skin, mucus), phagocytes (macrophages, neutrophils), inflammation, complement, and natural killer cells; it acts fast and is non-specific, without memory.

Adaptive immunity is specific and has memory: B cells produce antibodies (humoral), T cells mediate cellular responses (helper CD4+, cytotoxic CD8+).

Antibody structure: Y-shaped, two heavy and two light chains, variable regions form the antigen-binding site; IgG, IgM, IgA, IgE and IgD differ in function and location.

Clonal selection: an antigen selects and activates lymphocytes bearing matching receptors, which proliferate and differentiate into effector cells and memory cells.

Vaccination exposes the immune system to antigens (attenuated, inactivated, subunit, mRNA) without disease, generating memory cells and often herd immunity.

Allergy is a type I hypersensitivity: IgE bound to mast cells cross-links on allergen contact, triggering histamine release (sneezing, vasodilation, anaphylaxis).

HIV infects CD4+ helper T cells, progressively destroying cellular immunity; AIDS is defined by opportunistic infections and a CD4+ count below a threshold.

Antibiotic resistance evolves by selection of resistant bacteria under antibiotic pressure; completing prescribed courses and prudent use slow resistance.

Hypothesis: a testable, falsifiable statement; distinguish independent variable (manipulated), dependent variable (measured) and controlled variables (held constant).

Control groups (negative control without treatment, positive control with known effect) allow attribution of effects to the independent variable.

Reliability: repeat measurements and increase sample size; validity: the method measures what it claims (e.g. controls, calibration, appropriate assay).

Data description: mean as central tendency, standard deviation as spread, error bars; overlapping error bars suggest non-significant differences.

Statistical significance: a p-value below the chosen level (commonly 0.05) indicates an unlikely result under the null hypothesis; significance is not the same as biological relevance.

Correlation does not imply causation; confounding variables must be excluded by randomisation, blinding or blocking.

Model evaluation: check assumptions, scale and simplifications; models (e.g. membrane, enzyme, population) are approximations with defined limits.

Scientific communication: structure IMRaD (Introduction, Methods, Results, Discussion), cite sources, present units and significant figures correctly, and describe trends with data evidence rather than opinion.