A student had to work out the magnification of the image in Fig. 4.1. The student first measured the scale bar length in millimetres with a millimetre ruler. State what must be done next to reach the correct answer.
One role of the lipid droplets shown in Fig. 4.1 is the storage of triglycerides. The triglycerides in a lipid droplet are enclosed by a single layer (monolayer) of phospholipids. Suggest and explain why phospholipids, rather than triglycerides, are used for the outer monolayer of the lipid droplet.
The lysosomes and vacuole of S. cerevisiae contain acid hydrolases (hydrolytic enzymes) that operate at an acid pH. Explain why lysosomes require hydrolases to perform their function.
Complete Fig. 4.2 so that it shows the ring structure of one $\alpha$-glucose molecule.
A student tested a trehalose solution and correctly concluded that trehalose is a non-reducing sugar. Outline the steps the student used and state the results obtained.
Explain the meaning of a larger $K_m$ value.
Regulatory trehalase is present only in the cytosol, the fluid portion of the cytoplasm. Non-regulatory trehalase has been detected on the outer surface of the cell surface membrane and also within the cell. State the intracellular location where non-regulatory trehalase is most likely found and explain why.
Explain whether the two types of trehalase, regulatory and non-regulatory, may both be described as intracellular enzymes.
Using Fig. 4.3 and the two different trehalase enzymes made by \textit{Saccharomyces cerevisiae}, state and explain what can be inferred about the trehalase found in \textit{Saccharomyces boulardii}.