Cells

Question 1

Compare plant cells to animal cells

Answer 1

Plant cells have a cell wall animal cells don’t
Plant cells have chloroplasts while animal cells don’t

Question 2

Prokaryotic vs Eukaryotic

Answer 2

Circular vs linear dna
Associated with histones vs not
Smaller ribosomes vs larger ribosomes

Question 3

State three differences between dna in a nucleus in a plant cell and dna in a prokaryotic cell

Answer 3

Linear vs circlur
Introns vs no introns
Longer vs shorter
No plasmids vs plasmids
Associated vs not associated

Question 4

Advantage of using TEM over SEM

Answer 4

1. Higher resolution
2. Higher magnification

Question 5

Advantage of using SEM over TEM

Answer 5

3D Imagie

Question 6

Explain advantages and limitations of using a TEM over a SEM

Answer 6

Advantage
1. Electron wavelength longer
2. TEM has higher resolution
3. Small objects can be seen
Limitations
1. Cannot look at living cells
2. Must be in vacume

Question 7

Scientists isolated mitochondria from liver cells. They broken open cells in a ice cold buffered isotonic solution.
Why ?

Answer 7

1. Prevent osmosis so organelle doesn’t burst
2. Reduce enzyme activity so organelles aren’t damaged
3. Maintain constant PH so protein don’t denature

Question 8

Describe and explain how cell fractionation and centrifugation can be used to isolate mitochondria from animal cells

Answer 8

1. Cell homogenisation to break open cells and release organelles
2. Filter to remove whole cells
3. Use isotonic solution to prevent osmotic damage to organelles
4. Keep cold to prevent enzyme damage
5. Use buffer to maintain ph
6. Use differential centrifuge to separate nuclei
7. Respin at higher speed to get mitochondria in pellet