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A point mutation changes one amino acid in a haemoglobin chain without changing the chain length. How can this affect the protein? A. The substitution must convert the chain into a fatty acid B. It can alter interactions and the three-dimensional structure or…
Cut pear tissue normally darkens when oxygen is available because a polyphenol-oxidizing enzyme converts colourless compounds to pigments. A modified line shows no darkening under the same conditions. Suggest why the modified tissue does not darken.
A purified enzyme is tested at a fixed concentration, pH and temperature. Product is measured over very short initial intervals. Why does increasing substrate cease to raise the rate appreciably? A. The enzyme has become the main substrate B. Almost all active…
A model screening experiment compares bacterial growth on agar with and without a test substance. Outline how to carry out this experiment.
An enzyme converts substrate P to product Q. Equal enzyme and substrate concentrations are used at each pH. Which conclusion follows? A. The enzyme rate is independent of pH B. The enzyme is completely inactive at pH9 C. pH influences the measured enzyme…
A model cleaning trial compares a microbial cleaning product, bacteriophages and their combination against a water control on contaminated surfaces. Deduce which treatment is most effective, giving a reason.
In the backbone of an RNA strand, phosphate groups form covalent links directly to which components? A. Ribose sugars B. Only the nitrogenous bases C. Amino acid side chains D. Fatty acid tails
Deduce whether the gel supports successful transformation, giving a reason.
Which structural comparison is correct for a typical nuclear DNA molecule and mature mRNA in a eukaryotic cell? A. DNA is normally double-stranded; mRNA is normally single-stranded B. DNA contains ribose; mRNA contains deoxyribose C. Both contain thymine as…
A fermentation vessel is used to grow microorganisms that manufacture a useful product. Explain why conditions in the vessel must be controlled carefully.