1.5b LUCA

Question 1

All forms of life share a common set of features: (6)

Answer 1

1. cells defined by a membrane composed of a bilayer of lipid molecules
2. A genetic system based on DNA
3. A system of information transfer: DNA to RNA to protein
4. Ribosomes as the central feature of a protein assembly machinery
5. reliance to proteins as the major structural and catalytic molecule
6. use of ATP as the currency of chemical energy
7. common pathways of energy transformation

Question 2

The two major characteristics between eukaryotic cells from prokaryotic cells (2)

Answer 2

1. The separation of DNA and cytoplasm by a nuclear envelope
2. The presence in the cytoplasm of membrane bound organelles with specialized functions (mitochondria, endoplasmic regulus aka ER and gogi complex)

Question 3

Tell me about LUCA (5)

Answer 3

• lived without O2 (was anaerobic)
• fixed CO2 into organic molecules
• possessed a set of reactions similar to the reverse citric acid cycle
• was dependent upon H2 as a source of hydrogen atoms and electrons, was able to convert N2 into ammonia
• lived in a hot environment (thermophilic)

Question 4

chromosome structure for bacteria, archaea and eukaryotic

Answer 4

circular for all except Eukarya who has a linear

Question 5

DNA location for bacteria, archaea and eukarya

Answer 5

nucleoid for both bacteria and archaea

nucleus for eukarya

Question 6

chromosome segregation for bacteria, archaea and eukarya

Answer 6

binary fission
binary fission

mieosis/mitosis

Question 7

Ribosomes for bacteria, archaea and eukarya

Answer 7

70s
70s
80s

Question 8

membrane enclosed organelles for bacteria, archaea and eukarya

Answer 8

absent
absent
present