Chapter 2.6 - Prokaryotic and eukaryotic cells

Question 1

What are the differences that prokaryotic cells have compared to eukaryotic cells?

Answer 1

1. No membrane-bound organelles
2. Smaller ribosomes(70S)
3. No enclosed nucleus : plasmids that are free in the cytoplasm
4. A cell wall containing peptidoglycan
5. A slime capsule : protects the cell from physics and chemical attacks
6. One or more flagella
7. Mesosome : invagination of plasma membrane, synthesis of plasma membrane, replication of DNA, and protein synthesis
8. Pili : hair-like projections for attaching to other cells

Question 2

What is the size of prokaryotic cells?

Answer 2

0.1 to 10 μm

Question 3

What is the endosymbiotic theory?

Answer 3

The theory that mitochondria and chloroplasts, and possibly other eukaryotic organelles, were formerly free-living bacteria(prokaryotes)

Question 4

What is the evidence to support the endosymbiotic theory?

Answer 4

Mitochondria and chloroplasts have common characteristics with prokaryotes:
- Both replicate by binary fission
- Both contain their own circular, non-membrane bound DNA
- They both transcribe mRNA from their DN
- They both have 70S ribosomes to synthesise their own proteins
- They both have double membranes