origins of life

what three key processes does genetic information transfer to proteins in?

1. transcription

2. translation

3. mutations

why is water key in biology?

• good transporting agent because its a solvent

• critical for biochemical reactions

• osmosis balances constituion of solute on either side fo the cell to remain rigid

• helps maintain cell membranes

• universal solvent

why is a stable temperature important for biological growth?

• heat required for thermal energy for chemicl reactions to occur

• when its too hot porteins denature

what is a psychrophile?

adapted to cold temperatures under 20 degrees

what is a mseophile?

adapated to moderate temperatures (15 to 45)

what is a thermophile?

hot temperature ( 45 to 80 degrees)

what is a hyperthermophile?

adapted to extra hot temperatures

why is Ph signifcant in cells?

concentration gradient of H⁺ ions across a cell membrame si responsible for the generation of energy within the cell

what is a neutrophile?

organism adpated to a Ph of 5 to 9

what is an acidophile?

adapted to a ph under 2

what is an alkaliphile?

adpated to ph above 10

what is the main nutrient for all organisms?

carbon

what are autrophs?

convert inorganic to organic carbon

what are heterotraphs?

consume organic carbon from their enviroment

what are phototrophs?

energy comes for the conversion of solar energ into chemical energy

what are chemotrophs?

energy can also come from redox reactions using organic or inorganic molecules from the enviroment

what was Earth’s primordial soup?

mixture of water and simple molecules where ingredients for life such as lipids could form

which experiment supported the idea of earths prmordial soup?

1953 Miler-Urey experiment generated amino acids and where hit with lightning strikes

what did Darwin propose with the idea of primordial soup?

‘warm little ponds of primordial soup mixture with repeated wetting and drying cycles could have generated early life

what is the RNA world hypothesis?

the theory that life arose from self replicating RNA molecules

what experiment supported the RNA world hypothesis?

in 2019, a chemical pathway was discovered that can generate the nucleobases of RNA from a wetting and drying primordial soup solution

how does the RNA world hypothesis model work?

• RNA molecules will self replicate and become increasingly more abundant and may also catalyse replication of neighbouring molecules

• different types of RNA compete with each other as thy replicate

• eventually DNA and protein molecules emerge from these evolved RNA’s

what is the metabolism first hypothesis?

places the evolution of metabolic networks before DNA or RNA

what is the process of the metabolism first hypothesis?

• chemical gradients seeded life to begin as a series of self sustaining chemical reaction netwoks that produced complex biomolecules

• these would have provided the necessary complex molecules and energy needed to fuel primitive cells

which enviroment has been proposed to be a suitable place for life to start under the metabolism first hypothesis?

hydrothermal vents

why are hydrothermal vents promising potential enviroments for the origins of life?

• have hot temperatures, energy gradients, abundant biochemical compounds and diverse mineral surfaces

• protected from UV stress and impact events

• the most primitive bacterial are chemosynthetic thermophilrs suggesting a deep lineage ancestor that was adapted to hydrothermal vent enviroments

what is the strongest evidence for the metabolism first hypothesis?

alkaline vents output transition metals and carbons alongside strong ph and temperatre gradients with recent research showing these conditions can produce proto cells with membranes that contain carbon fixing cycles