Cell structure OCR A A-Level Biology 2025

Which microscope allows viewing of the internal ultrastructure of organelles at the highest resolution?

• Light microscope

• Scanning electron microscope

• Transmission electron microscope

• Compound microscope

What is the approximate maximum resolution of a light microscope?

• 200 nm

• 0.2 nm

• 1–20 nm

• 500 nm

Which microscope produces 3D images of a cell’s surface?

• Light microscope

• TEM

• SEM

• Confocal microscope

Typical magnification of a light microscope is:

• ×1500–2000

• ×500,000

• ×100,000

• ×50

Which statement correctly distinguishes magnification and resolution?

• Magnification is clarity, resolution is size

• Magnification enlarges, resolution distinguishes two points

• Resolution enlarges, magnification distinguishes points

• Both terms mean the same

The eyepiece graticule is used to:

• Stain cells

• Measure cell structures in a slide

• Increase magnification

• Fix cells to a slide

Calibration of an eyepiece graticule requires:

• A differential stain

• A stage micrometer

• A TEM

• A pipette

Which is the correct magnification formula?

• Magnification = Image size / Actual size

• Magnification = Actual size / Image size

• Magnification = Resolution × Image size

• Magnification = Stage micrometer / Eyepiece units

When calibrating an eyepiece graticule, the stage micrometer has 1 mm divided into 100 divisions. If 1 graticule division = 10 µm, how many µm does 5 divisions equal?

• 50 µm

• 5 µm

• 500 µm

• 100 µm

Which microscope would you choose to view a whole eukaryotic cell’s surface in 3D?

• TEM

• SEM

• Light microscope

• Phase-contrast microscope