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Northern IrelandBiology

Genetics, Evolution and Ecosystems

7 dot points across 7 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How is biodiversity measured and sampled, how are organisms classified, and why does biodiversity matter?

Biodiversity, classification and sampling: biodiversity at the genetic, species and habitat levels, species richness and evenness, calculating and interpreting a diversity index, the hierarchical classification of organisms and binomial nomenclature, the use of quadrats, transects and mark-release-recapture (the Lincoln index) to sample organisms, and the structural, physiological and behavioural adaptations of organisms to their habitats.
A CCEA A-Level Biology answer on biodiversity, classification and ecological sampling. Covers the genetic, species and habitat levels of biodiversity, species richness and evenness, a diversity index, the classification hierarchy and binomial naming, quadrat and transect sampling, mark-release-recapture and the Lincoln index, and the types of adaptation.
13 min answer →

How do ecosystems work, and how can biodiversity be conserved?

Ecosystems, energy flow and food webs, the carbon and nitrogen cycles, succession, and the principles of conservation and managing human impact.
A CCEA A-Level Biology answer on ecosystems, energy flow and food webs, the carbon and nitrogen cycles, succession, and the principles of conservation and managing human impact.
11 min answer →

How do we manipulate and analyse DNA in biotechnology?

Recombinant DNA technology and genetic engineering, the polymerase chain reaction, gel electrophoresis and DNA profiling, and the applications and ethics of gene technology.
A CCEA A-Level Biology answer on recombinant DNA technology and genetic engineering, the polymerase chain reaction, gel electrophoresis and DNA profiling, and the applications and ethics of gene technology.
11 min answer →

How are characteristics inherited, and how do we predict offspring ratios?

Genes, alleles and genotypes, monohybrid and dihybrid inheritance, sex linkage, codominance, and the use of genetic diagrams and the chi-squared test.
A CCEA A-Level Biology answer on genes, alleles and genotypes, monohybrid and dihybrid inheritance, sex linkage and codominance, and the use of genetic diagrams and the chi-squared test.
12 min answer →

How does the immune system defend the body against pathogens?

Antigens and the difference between the cellular and humoral immune responses, the action of B and T lymphocytes, antibodies and immunological memory, and active and passive immunity and vaccination.
A CCEA A-Level Biology answer on antigens and the cellular and humoral immune responses, the action of B and T lymphocytes, antibodies and immunological memory, and active and passive immunity and vaccination.
11 min answer →

How do populations change genetically over time and form new species?

Natural selection and the sources of variation, the Hardy-Weinberg principle and allele frequencies, types of selection, and the mechanisms of speciation.
A CCEA A-Level Biology answer on natural selection and the sources of variation, the Hardy-Weinberg principle and allele frequencies, types of selection, and the mechanisms of speciation.
12 min answer →

How is the base sequence of a gene used to build a protein, and what happens when a mutation changes that sequence?

Gene expression and mutation: the genetic code as triplets of bases, transcription of a gene into messenger RNA, translation at the ribosome using transfer RNA, codons and anticodons, the role of gene mutation (substitution, insertion and deletion) and how mutations can be silent, harmful or beneficial, and the regulation of gene expression so that different genes are switched on in different cells.
A CCEA A-Level Biology answer on gene expression and mutation. Covers the triplet genetic code, transcription of a gene into mRNA, translation at the ribosome using tRNA, codons and anticodons, gene mutations (substitution, insertion and deletion) and their effects, and the regulation of gene expression in differentiation.
13 min answer →