Plant Biochemistry and Molecular Biology: Molecules and Mechanisms
Biomolecules and metabolism
Know the structure and functions of carbohydrates, proteins, lipids and nucleic acids. Understand enzyme kinetics, cofactors, inhibition and allosteric regulation. Learn the pathways of photosynthesis and respiration at the biochemical level, plus nitrogen assimilation, sulphur metabolism and secondary metabolites such as alkaloids, terpenes and phenolics.
Molecular biology
Master DNA structure, replication, transcription and translation in the plant context. Understand the genetic code, gene expression, promoters, transcription factors and RNA processing. Learn recombinant DNA techniques: restriction enzymes, vectors, transformation, selection markers, PCR and sequencing. Know the central dogma and its exceptions, including RNA editing and reverse transcription.
Traps
Questions often confuse transcription with translation, or place the light reactions in the stroma. Another trap is identifying the wrong enzyme in a pathway, or assuming all secondary metabolites are waste products. Watch for questions about the genetic code being degenerate but unambiguous.
Rule of thumb
For any pathway, identify substrate, enzyme, cofactor and product. For any molecular technique, state the principle, the reagent and the selection method.
Worked example
A gene is cloned into a plasmid with an antibiotic-resistance marker. Only transformed cells grow on the selective medium; the marker is the selection tool, not the gene of interest.