Biology · Genetics
Punnett Square Calculator
Mono- and dihybrid genetic crosses. Genotypes, phenotypes and offspring ratios based on Mendel's Laws.
Open toolBiology simulators and calculators for genetics, cytology, metabolism, photosynthesis, cellular respiration, ecology, evolution and populations.
Biology with simulators
Biology Tools for High School and University Entrance Exams
Biology simulators and calculators for genetics, cytology, metabolism, photosynthesis, cellular respiration, ecology, evolution and populations.
Biology · Cytology
Cell Division Simulator
Mitosis and meiosis step by step. Follow the phases with a visualization of the dividing cell.
Open toolBiology · Cytology
Interphase Simulator
G₁, S and G₂ phases of interphase. See DNA replication before mitosis.
Open toolBiology · Health
BMI and Basal Metabolic Rate
Calculate your BMI, basal metabolic rate (BMR) and total daily energy expenditure (TDEE).
Open toolBiology · Health
Target Heart Rate
Estimated maximum heart rate, heart rate reserve and cardiovascular training zones.
Open toolBiology · Botany
Photosynthesis Simulator
Light, CO₂, water, temperature and limiting factors of glucose production.
Open toolBiology · Cytology
Cellular Respiration Simulator
Glycolysis, Krebs cycle, available oxygen and estimated ATP production.
Open toolBiology · Ecology
Food Chain Energy
The 10% rule, trophic levels and ecological pyramids.
Open toolBiology · Evolution
Natural Selection Simulator
Selective pressure, survival and change in phenotype frequency per generation.
Open toolBiology · Ecology
Population Growth
Exponential and logistic growth with rate, time and carrying capacity.
Open tool10 of 10 tools
Articles and study paths
Use these routes as study guides. They connect theory, examples and related tools.
Punnett square step by step
Understand genotypes, phenotypes, gametes and offspring ratios.
Mitosis, meiosis and interphase
Compare the stages of the cell cycle and follow DNA replication.
Photosynthesis and cellular respiration
Relate energy input, glucose, oxygen and ATP production.
Ecology in exams
Review the 10% rule, trophic levels and ecological pyramids.
Solved exercises
Exercise 1
In Aa × Aa, what is the expected genotypic ratio?
The cross gives 1 AA, 2 Aa and 1 aa, that is, a 1:2:1 ratio.
Practice with the toolExercise 2
If a producer has 10,000 kcal, how much reaches the primary consumer under the 10% rule?
About 10% of the energy passes to the next level: 1,000 kcal.
Practice with the toolExercise 3
Which phase of interphase duplicates the DNA?
DNA replication happens in the S phase of interphase.
Practice with the toolCommon mistakes in Biology
- Confusing genotype, the combination of alleles, with phenotype, the observable trait.
- Saying energy is recycled in a food chain; it flows through and is dissipated as heat.
- Mixing up mitosis and meiosis without considering the final number of cells and chromosomes.
- Treating photosynthesis and cellular respiration as simple opposites; they are connected, but they are not the same thing.
Recommended pairings
To study better, follow these pairs of tools: