← Human Biology syllabus

ScotlandHuman Biology

Area 1: Human Cells

8 dot points across 8 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do cells release the energy in glucose and transfer it to ATP?

The stages of aerobic respiration (glycolysis, the citric acid cycle and the electron transport chain), the role of ATP, dehydrogenase enzymes and NAD as a hydrogen carrier, and the use of alternative respiratory substrates.
An SQA Higher Human Biology answer on cellular respiration, covering glycolysis and the net yield of ATP, the citric acid cycle in the mitochondrial matrix, the electron transport chain and ATP synthase, the role of NAD and dehydrogenase enzymes, oxygen as final hydrogen acceptor, and alternative respiratory substrates.
11 min answer →

How do human cells divide by mitosis and become specialised, and why are stem cells so valuable?

Cell division by mitosis, the control of the cell cycle, cellular differentiation, and the nature and therapeutic and research value of stem cells (embryonic and tissue).
An SQA Higher Human Biology answer on division and differentiation, covering the phases of mitosis, control of the cell cycle, how cells differentiate by selective gene expression, and the properties and uses of embryonic and tissue (adult) stem cells.
10 min answer →

How do muscle cells keep making ATP during exercise, and why do fast and slow muscle fibres differ?

Lactate metabolism during vigorous exercise (the conversion of pyruvate to lactate, oxygen debt and the reconversion of lactate), and the structure, properties and uses of slow-twitch (type 1) and fast-twitch (type 2) skeletal muscle fibres.
An SQA Higher Human Biology answer on energy systems in muscle cells, covering lactate metabolism during vigorous exercise, the conversion of pyruvate to lactate, oxygen debt and recovery, and the structure, properties and athletic uses of slow-twitch (type 1) and fast-twitch (type 2) muscle fibres.
9 min answer →

How is the information in a gene used to build a protein, and how can one gene give several proteins?

Gene expression through transcription and translation, including the structure and roles of mRNA, tRNA and rRNA, RNA splicing of the primary transcript, and how alternative splicing and post-translational modification produce protein diversity.
An SQA Higher Human Biology answer on gene expression, covering transcription by RNA polymerase, the splicing of introns from the primary transcript, translation at the ribosome using mRNA and tRNA, the role of the genetic code and codons, and how alternative splicing produces protein diversity.
11 min answer →

How is the human genome sequenced and analysed, and how does this support personalised medicine?

The sequencing and analysis of the human genome, the role of bioinformatics in comparing sequences, and the use of genomic and pharmacogenetic information in personalised medicine.
An SQA Higher Human Biology answer on human genomics, covering how the genome is sequenced and analysed, the coding and non-coding sequence of the genome, the role of bioinformatics and comparative genomics, single nucleotide polymorphisms, and how pharmacogenetics and genomics enable personalised medicine.
10 min answer →

How are the chemical reactions of a cell organised into pathways and controlled by enzymes?

Metabolic pathways as integrated, enzyme-controlled chains of reactions (anabolic and catabolic), the role of membranes and cell compartments, and the control of enzyme activity by induced fit, activation energy, and competitive and non-competitive inhibition including feedback inhibition.
An SQA Higher Human Biology answer on metabolic pathways, covering anabolic and catabolic reactions, the role of membranes and reversible and irreversible steps, how enzymes lower activation energy by induced fit, and the control of enzyme activity through competitive, non-competitive and feedback inhibition.
10 min answer →

How do changes to the DNA sequence arise, and what effects do single-gene and chromosome mutations have?

Single-gene mutations (substitution including missense, nonsense and splice-site; insertion and deletion causing frame-shift) and chromosome structure mutations (deletion, duplication, inversion, translocation), and their effects on proteins and phenotype.
An SQA Higher Human Biology answer on mutations, covering single-gene mutations (substitution, insertion and deletion), missense, nonsense and splice-site effects, frame-shift mutations, chromosome structure mutations (deletion, duplication, inversion and translocation), and how mutations alter proteins and phenotype.
10 min answer →

How is DNA structured to store genetic information, and how is it copied accurately before cell division?

The structure of DNA as an antiparallel double helix of nucleotides, the requirements and process of DNA replication by DNA polymerase, and the amplification of DNA by the polymerase chain reaction (PCR).
An SQA Higher Human Biology answer on DNA structure and replication, covering nucleotides, the antiparallel double helix, complementary base pairing, the role of DNA polymerase, primers and ligase in replication, leading and lagging strands, and PCR amplification.
10 min answer →