Origin of cells.

What did Earth’s early atmosphere consist of?

CO2, methane, nitrogen ammonia

What is the consequence of greenhouse gases like CO2 and methane on earths early temp.

greenhouse gases absorb longwave radiation emmited by the earth and re-radiate it back to earths surface, raising temperature.

How do cells as the smallest unit of life survive (whats required for them to survive).

Why are viruses considered non-living?

No metabolism, no growth, depend on host cell.

Explain what the miller-urey experiment showed and how it worked.

Showed that organic molecules needed for life could be formed from inorganic compounds.

What are the 4 requirements for the evolution of cells.

Production of organic molecules

Self replicating

Compartmentalisation

Self assembly

How do phospholipid bilayers of fatty acids help in vesicles.

Amphipathic fatty acids form phospholipid bilayers separates internal and external chemistry

What are the 3 steps of cell membranes to end up with phospholipid bilayer.

protocell membranes formed from fatty acids

triglycerides formed

phosphorylation occurred and fatty acid was replaced by phosphate to form phospholipids.

Explain RNAs role as the presumed first genetic material

DNA and enzymes were too complex to exist in early Earth.

Thus, RNA was probably the genetic material in origin of life due to: it storing genetic information

functioning as a catalyst

can self replicate

more simple than DNA

What is the evidence for the RNA first hypothesis?

1. RNA has the bases to store genetic info

2. RNA seqeunces can replicate

3. modern cells use RNA as a catalyst

What is the metabolism first hypothesis

life originated from complex chemical reactions occuring before DNA or RNA. it suggests that metabolic pathways being present before RNA or DNA

What is the lipid first hyptothesis?

life could have originated from self-assemblying lipids forming cell membranes.

Explain the last universal common ancestor and its evidence.

shows common ancestry. shows a common ancestor from which all species stem from.

Very similar DNA sequences.