Origin of Cells

Processes of life

Reproduce, Metabolism, Growth, Movement, Excretion, Response, Nutrition

Components of Earth's early atmosphere

Water vapour, High CO2, Methane, Ammonia, Hydrogen, UV Radiation

Who conducted an experiment simulating the early atmosphere to create non living molecules

Miller and Urey

What was in Miller and Urey's closed system

Low O2 levels, high radiation, high temperature, lightning, hydrogen, high CO2, ammonia and methane

What did Miller and Urey's experiment lead to

The formation of long chain hydrocarbons and 15 of 20 amino acids

Issues with Miller and Urey's experiment

Not definitive list of components, carbon compounds might've been brought to Earth by meteorites, If gases came from Mantle methane + ammonia not present

Louis Pasteur results with swan neck flask not broken

Remained clear as microbes were trapped in the neck or not formed

Louis Pasteur results with broken neck

Microbes could enter from the air and form

Louis Pasteur results with tilted flask

Allowed microbes to enter trhough the neck

Formation of simple organic molecules…

From inorganic compounds

Assembly of carbon compounds into…

polymers

To be a cell it is a polymer that can…

Replicate

Packaging of molecules into compartments with…

an internal chemistry different from surroundings

Inorganic molecules have

No hydrogen and carbon + usually small molecule

Organic molecules have

Both carbon and hydrogen in the same molecule + Large molecules/many + They form from inorganic precursors

Cell formation step 1

Inorganic molecules

Cell formation step 2

Organic monomers

Cell formation step 3

Polymer

Cell formation step 4

Self Replication

Cell formation step 5

Packaging of molecules into a cell

Vesicles

A self contained unit with a cell membrane

What were one of the first compounds were…

Fatty acids

These fatty acids when in water display

Polarity in water either hydrophillic and hydrophobic

The head of the fatty acid is …. and the tail is ….

Hydrophillic and Hydrophobic

Micelles form from a

Single fatty acid layer (an aggregate created through the self assembly of amphipathic molecules)

amphiphilic molecules contain both a

Hydrophobic and hydrophillic part

Lipid bilayers are composed of

Hydrophilic heads that interact with the water on the outside environment and a hydrophobic tails that face each other in the inner structure.

How did lipid bilayers organise

They organise into a small cell sized double layer vesicles, which are often refereed to as liposomes

What was the first genetic material

RNA

Why is it believed that RNA is the first genetic material

Can spontaneously organise from nucleotides

RNA can control chemical reactions

Simpler than DNA that is universal for passing to genetic info

They self replicate

What RNA molecules have been found to catalyze reactions

Ribosymes

Emergent Property

A characteristic of a complex system that is not present in its individual components but arises from their interactions and organisation

Cell Theory: All organisms are composed of…

one or more cells

Cell Theory: Cells are the…

smallest unit of life

Cell Theory: All cells come from

pre-existing cells

Protocell

Self organised, compartmentalised structure with basic metabolism but lacking a fully developed genetic system

Virus

A parasitic non cellular infectious particulate

Amino acids spontaneously form

Proteins

Fatty acids can be concentrated into

Membranes

Definition of Life

A self sustaining chemical system capable of Darwinian evolution