A2.1 Origin of Cells Flashcards

Front

What were the conditions on early Earth?

Back

Lack of free oxygen, higher concentrations of carbon dioxide and methane, higher temperatures, and high levels of ultraviolet light.

Front

What is the pre-biotic formation of carbon compounds?

Back

Carbon compounds may have formed spontaneously by chemical processes that do not now occur.

Front

What are the necessary requirements for the evolution of the first cells?

Back

Catalysis (e.g., RNA molecules with enzyme properties), self-replication of molecules (e.g., RNA), and emergence of compartmentalization.

Front

What is the significance of the Miller–Urey experiment?

Back

Produced amino acids from abiotic molecules, showing organic molecules can form from non-living matter.

Front

What is needed for life to form?

Back

The formation of a membrane-bound compartment.
Biochemistry (enzymes and genetic code) to allow for replication

Front

What role does RNA play in early cells?

Back

RNA may have acted as both genetic material and enzymes.

Front

What evidence supports the existence of a last universal common ancestor?

Back

The universal genetic code and shared genes across all organisms.

Front

What approaches are used to estimate dates of the first living cells? What is the estimate?

Back

-radioactive dating of fossilized stromatolites
- molecular clock using DNA evidence and mutation rates

--first cell is thought to appear more than 3.5 billion years ago.

Front

What evidence for the evolution of the last universal common ancestor exists?

Back

--Fossilized evidence from hydrothermal vents and conserved DNA/RNA sequences (genes shared among all living things).

--the likelihood of other forms of life having evolved but becoming extinct due to competition from the last

universal common ancestor (LUCA) and descendants of LUCA