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ScotlandBiology

Area 1: DNA and the Genome

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do cells become specialised, and why are stem cells important?

Cellular differentiation as the process by which cells express only the genes needed for their function, the difference between embryonic and tissue (adult) stem cells, the meaning of potency, and the therapeutic and research uses of stem cells along with cancer cells.
An SQA Higher Biology answer on cellular differentiation, covering how cells express only the genes for their function, the difference between embryonic and tissue stem cells, the meaning of potency, the therapeutic and research uses of stem cells, and how cancer cells differ from normal cells.
9 min answer →

How do mutations and selection drive evolution, and what does genomic sequencing reveal?

Evolution by natural selection and the three patterns of selection (stabilising, directional and disruptive), the role of gene transfer and genetic drift, speciation, and the use of genomic sequencing and phylogenetics to compare organisms.
An SQA Higher Biology answer on evolution and genomic sequencing, covering natural selection and its three patterns, vertical and horizontal gene transfer, genetic drift, speciation, and how genomic sequencing and phylogenetics compare and classify organisms.
10 min answer →

How is the information in a gene used to make a protein?

Gene expression through transcription and translation, the role of mRNA, tRNA and ribosomes, RNA splicing of the primary transcript, and how one gene can give rise to different proteins.
An SQA Higher Biology answer on gene expression, covering transcription and translation, the structure of RNA, the roles of mRNA, tRNA and ribosomes, RNA splicing of the primary transcript, and how alternative splicing produces different proteins.
10 min answer →

What are mutations and how do they affect proteins and organisms?

Single gene mutations (substitution, insertion and deletion), the effects of frame-shift and point mutations, chromosome structure mutations (deletion, duplication, translocation and inversion), and how mutations provide the raw material for evolution.
An SQA Higher Biology answer on mutations, covering single gene mutations including substitution, insertion and deletion, the difference between point and frame-shift mutations, the four types of chromosome structure mutation, and the importance of mutations to evolution.
10 min answer →

How is DNA replicated accurately before a cell divides?

The replication of DNA by DNA polymerase, requiring a template, primers, free nucleotides and ATP, the formation of leading and lagging strands, and the use of the polymerase chain reaction (PCR) to amplify DNA.
An SQA Higher Biology answer on DNA replication, covering the role of DNA polymerase, primers and free nucleotides, leading and lagging strands, the requirements for replication, and how PCR amplifies DNA in the laboratory.
9 min answer →

How is the structure of DNA suited to storing and copying genetic information?

The structure of DNA as a double-stranded antiparallel molecule of nucleotides, with complementary base pairing and a sugar-phosphate backbone, and the organisation of the genome in eukaryotes and prokaryotes.
An SQA Higher Biology answer on the structure of DNA, covering nucleotides, the antiparallel double helix, complementary base pairing, the sugar-phosphate backbone, and how the genome is organised in prokaryotes and eukaryotes.
9 min answer →