origins of cells

Question 1

Abiogenesis

Answer 1

theory that living cells arose from non living matter

Question 2

process theorised to occur over four key stages

Answer 2

1) non - living synthesis of simple organic molecules
2) simple organic molecules became assembled into more complex polymers
3) certain polymers formed the capacity to self replicate
4) these molecules packages into membranes with an internal chemistry different to their surroundings

Question 3

Miller-Urey Experiment

Answer 3

Stanley Milelr and Harold Urey recreated the conditions of pre biotic Earth using a system of closed flasks and tubes to prove the theory

Question 4

experiment step by step:

Answer 4

1) water boiled to vapour (reflect previous high temp. of earth)
2) water was mixed with variety of gasses to create a reducing atmosphere (no oxygen)
3) mixture was exposed to an electrical discharge
4) mixtape was then allowed to cool
5) after this time the condensed mixture was analysed and found to contain traces of simple organic molecules

Question 5

conditions needed for initial formation of biological life

Answer 5

1) reducing atmosphere and high temperatures or electrical discharges to catalyse chemical reactions
2) cells can only be formed by the division of pre existing cells

Question 6

Louis Pasteur

Answer 6

Law of biogenesis is largely attributed to Louis Pasteur, who demonstrated that bacterial growth in nutrient broth emerged due to contamination of pre existing cells

Question 7

Method and process of Louis Pasteur experiment

Answer 7

1) Broths were stored in vessels that contained long tubings that dod not allow external dust particles to pass
2) the broths were boiled for sterilisation of any micro organisms present
3) growth only occurred in the broth if the flask was open, exposing the contents to containment’s outside
4) this concluded that emergent bacterial growth came from external contaminants and did not spontaneously occur

Question 8

Endosymbiont

Answer 8

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

Question 9

Evolving of Eukaryotes

Answer 9

Eukaryotic cells are believed to have evolved from early prokaryotes that were engulfed by phagocytosis. Over generations, the engulfed cell lost some of its independent utility and became a supplemental organelle

Question 10

Evidence of Endosymbiosis

Answer 10

Mitochondria and chloroplasts are both organelles suggested to have arisen via endosymbiosis. Key features show evidence:
1) Membranes (double membrane bound)
2) Antibiotics (susceptibility)
3) Division (mode of replication)
3) DNA (precedes and structural composition)
4) Ribosomes (size)