Cell Origins

What are the 3 parts of cell theory?

Living organisms are made up of cells.

Cells are the basic unit of life.

All cells come from pre-existing cells

What is spontaneous generation?

The idea that life can come from inorganic material.

What is the implication of the third statement in cell theory?

We can trace all our cells back to a zygote, and trace those back to LUCA

Was LUCA the first cell?

No! There were cells before LUCA.

When did life emerge?

3.8 BYA

How old was the Earth when life first emerged?

750 Million Years Old

What are the steps of the Oparin-Haldane Hypothesis?

Inorganic Molecules → Organic Molecules→ Polymerization→ Self-replicating Polymers→ Packing into Membranes

What did the Miller-Urey Exp test?

Step 1 of the Oparin-Haldane Hypothesis

What are the parts of the Miller-Urey Exp?

Flask of Water, Flask of gas, Condenser, Trap

What was the function of the flask of water in the Miller-Urey Exp?

Simulate Earth’s Oceans

What was the function of the flask of gasses in the Miller-Urey Exp?

Simulate Earth’s Atmosphere

Which gasses were in the Miller-Urey Exp?

Water, Methane, Ammonia, Hydrogen Gasses

What was the function of the condenser in the Miller-Urey Exp?

Simulate the water cycle of the Early Earth.

What was the function of the trap in the Miller-Urey Exp?

To collect the products of the rxn

What were the results of the Miller-Urey Exp?

Several organic molecules formed, including 2 amino acids

What is polymerization?

When monomers connect to make a chainlike polymer

Amino acids polymerize ____

Spontaneously

Fatty acids can polymerize when?

When there is a sufficiently high concentration

RNA nucleotides link together when?

They are exposed to a catalyst found in clay or water

What is the RNA world hyp?

RNA was the first method of genetic storage

Why is RNA world plausible?

RNA is able to self-replicate and form ribozymes

What is a ribozyme?

An enzyme-like structure made of RNA

Where are ribozymes still found in modern cells?

Ribosomes

Why is DNA more stable than RNA?

Deoxyribose is more stable, double strand enhances stability, Thymine is more resistant to mutations

Membranes can exist in what two forms?

Micelles & Bilayers

What was the first cell membrane likely made of?

Fatty Acid

Where are micelles found in day to day life?

Soap

How do micelles come together to form vesicles?

Multiple micelles merge into a flat sheet, which randomly curves around and merges into a vesicle

How did phospholipids form?

When glycerol, phosphate, & fatty acids are exposed to early Earth’s atmosphere, phospholipids form

How did protocells form?

Layers of membrane built up in the bottom of hydrothermal pools, in between which RNA can get trapped, and as the membrane lifts off, the RNA can turn trapped in vesicles

How do we know the genes of LUCA?

By comparing shared genes between Bacteria & Archea

How many genes were inherited from LUCA?

355

LUCA’s Genes indicate what?

That it was an obligate anaerobe which lived in extreme temperatures

What type of cell was LUCA? (Referring to how it gets its energy)

Chemoautotroph

Life most likely originated where?

Hydrothermal vents