Define the terms genome and proteome.

Explain why modern classification systems based on genome sequencing are more accurate than early classification methods that relied on observing physical characteristics of bacteria (such as the arrangement of flagella) under an optical microscope.

In a study of bacterial morphology, a student measures the length of an Escherichia coli cell in a printed electron micrograph.

• The measured length of the bacterium's image is $7.2cm$.
• The actual length of the bacterium is $1.6\mu m$.

Calculate the magnification of the image. Show your working.