First-year university biology: what the modules cover and how to practise

What first-year biology modules cover

Other first-year courses may also include ecology, evolution and organism biology, as the daily paper does. Check your module handbook for the exact syllabus and exam format.

The core topics

• Macromolecules: proteins, nucleic acids, carbohydrates and lipids, and how structure gives function.
• Molecular genetics: DNA replication, transcription, translation, mutation and gene regulation.
• Metabolism and bioenergetics: enzymes, respiration and photosynthesis.
• Cells: organelles, membranes and transport, membrane potentials and cell signalling.
• Physiology: how animal organ systems work and are controlled.
• Genetics and evolution: Mendelian and population genetics, natural selection and speciation.
• Ecology: populations, communities, energy flow and nutrient cycles.

Worked examples

Population genetics: Hardy-Weinberg

In a population at Hardy-Weinberg equilibrium, 4% of individuals show a recessive trait, so q² = 0.04 and q = 0.2. Then p = 0.8, and the proportion of carriers is:

So about 32% of the population carry the allele without showing the trait.

Mendelian genetics: a dihybrid cross

Crossing two AaBb individuals, with the genes on different chromosomes, gives phenotypes in a 9 : 3 : 3 : 1 ratio, and the chance of an aabb offspring is ¼ × ¼ = 1/16.

Membrane potentials: the Nernst equation

With K⁺ at 5 mM outside and 140 mM inside a cell at 37 °C, the equilibrium potential is about 61.5 × log₁₀(5 ÷ 140) ≈ −89 mV, close to a typical resting potential because the resting membrane is most permeable to K⁺.

Molecular genetics: from gene to protein

A coding sequence of 900 nucleotides, including the stop codon, contains 300 codons. The stop codon codes for no amino acid, so the protein has 299 amino acids.

Work out the odds of a trait from a cross in our Genetics & DNA course, then press Mark to check your answer in the course:

Use the daily paper as practice

Uni-Sine publishes a free daily University Biology: Year 1 paper. It is a short timed practice paper: 8 questions worth 25 to 35 marks, with a suggested 40 to 55 minutes, marked when you finish. It is not your university's exam, so use it alongside your module's problem sheets and past papers.

• What it covers well: macromolecules, molecular genetics and gene regulation, metabolism and bioenergetics, membrane transport and potentials, cell signalling, animal physiology, Mendelian and population genetics, evolution and ecology.
• What it does not cover: practical and data-handling skills, and gives little space to plant biology, microbiology and immunology, which some first-year courses include.

Common mistakes in first-year biology

• Using Hardy-Weinberg when its assumptions fail. It needs random mating, no selection, migration or mutation, and a large population.
• Counting the stop codon as an amino acid. It ends translation without adding one.
• Assuming independent assortment for linked genes. Genes close together on a chromosome break the 9 : 3 : 3 : 1 ratio.
• Learning pathways without the logic. Ask what each step achieves and how it is controlled.

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