Exam qs + answers

Question 1

Eukaryotic cells produce and release proteins.

Outline the role of organelles in the production transport and release of proteins from eukaryotic cells. (4)

Answer 1

1. DNA in nucleus is code (for protein);
2. Ribosomes/rough endoplasmic recticulum produce protein;
3. Mitochondria produce ATP (for protein synthesis);
4. Golgi apparatus package/modify;
   OR
   Carbohydrate added/glycoprotein produced by golgi apparatus;
5. Vesicles transport
   OR
   Rough endoplasmic recticulum transports;
6. Vesicles fuse will cell surface membrane;
   Accept exocytosis at cell membrane

Question 2

Suggest why a nucleus is not visible in an image of a plant cell taken by a transmission electron microscope. (1)

Answer 2

A section/slice (so nucleus in another part of cell)
OR
(Nucleus) not stained

Question 3

Describe how you could make a temporary mount of a piece of plant tissue to observe the position of starch grains in the cell when using an optical (light) microscope. (4)

Answer 3

1. Add a drop of water to (glass) slide;
2. Obtain thin section (of plant tissue) and place on slide/ float on drop of water;
3. Stain with / add iodine in potassium iodide
4. Lower cover slip using a mounted needle

Question 4

The photograph was taken using a transmission electron microscope. The structure of the organelles visible in the photograph could not have been seen using an optical (light) microscope. Explain why. (2)

Answer 4

1. Has low resolution / not high enough resolution;
2. (Because) wavelength of light not short enough / too long;
   Accept larger wavelength

Question 5

Give one reason why antibiotics are not affective against viruses. (1)

Answer 5

Virus do not have a cell wall for antibiotics to attach

Question 6

Explain why the homogenate was filtered before spinning at low speed in the centrifuge. (2)

Answer 6

1. To remove any remains tissue and large debris
2. As it could contaminate the sediment and interfere with results