Lecture 4 - Endosymbiosis

Question 1

Endosymbiotic theory

Answer 1

Cells grew in size due to aerobic respiration providing cells with more energy and these bigger cells engulfed smaller cells and both cells began to live in symbiosis and help each other.

Bigger cell provided shelter, smaller cell provided food.

Question 2

Evidence for endosymbiotic theory

Answer 2

Surrounded by double membrane and inner membrane controls entry/exit

Contain DNA

Can make proteins

Possess characteristics of bacteria – e.g. 70S ribosomes, codon usage

Question 3

Multiple symbionts

Answer 3

The more membrane a chloroplast or mitochondria has, the more symbionts it may have had in the distant past.