microscopes

Question 1

Contrast how an optical microscope and a transmission electron microscope work and contrast the limitations of their use when studying cells.

Answer 1

TEM use electrons and optical use light;

2. TEM allows a greater resolution;
3. (So with TEM) smaller organelles / named cell structure can be observed

OR

greater detail in organelles / named cell structure can be observed;

4. TEM view only dead / dehydrated specimens and optical (can) view live specimens;
5. TEM does not show colour and optical (can);
6. TEM requires thinner specimens;
7. TEM requires a more complex/time consuming preparation;
8. TEM focuses using magnets and optical uses (glass) lenses

Question 2

The scientists used a transmission electron microscope to study the structure of the amoeba. Explain why.

Answer 2

High / better resolution;

2. Shorter wavelength;
3. To see internal structures / organelles / named organelles;

Question 3

Explain why the shapes of the two organelles labelled A appear different.

mitochondria different shapes

The diagram shows part of an animal cell as seen through an electron microscope.

Answer 3

idea of sections or cuts;
idea of mitochondria orientated differently or in different positions / description of 3D structure of mitochondria, e.g. sausage-shaped;