1.5 Origin of cells

Question 1

Original cell formation

Answer 1

The first cells must have arisen from non-living material.

Question 2

Original cell formation (Non-living Synthesis)

Answer 2

(abiogenesis)
The first cells must have arisen from non-living material.

Question 3

Chloroplasts and mitochondria have features suggesting they evolved from:

Answer 3

independent prokaryotes
- They have their own genes on a circular DNA molecule
- They have their own 70s ribosomes
- They transcribe their own DNA and use mRNA to synthesize some of their own proteins.
- They can only be produced by division of pre-existing mitochondria and chloroplasts.

Question 4

Biogenesis

Answer 4

Biogenesis describes the principle that living things only arise from other living things by reproduction (not spontaneous generation)

Question 5

Pasteur’s experiments

Answer 5

Proved biogenesis
- demonstrated that emergent bacterial growth in nutrient broths was due to contamination by pre-existing cells

Question 6

Endosymbiosis

Answer 6

An endosymbiont is a cell which lives inside another cell with mutual benefit

Question 7

Evidence for Endosymbiosis

(MAD DR)

Answer 7

Membranes (double membrane bound)
Antibiotics (susceptibility)
Division (mode of replication)

DNA (presence and structural composition)
Ribosomes (size)