Pagan Bio100 Exam 2/ Origins of Life Sect.

2 Hypothesis on How Organic Compounds were Created

1. Prebiotic Soup Hypothesis 2. Iron-sulfur world Hypothesis (primordial pizza) Known Fact of Early Earth - organic chemicals/compounds were synthesized (made/created)

LUCA

Last Universal Common Ancestor. The shared ancestor that multiple organisms come from

iron-sulfur world hypothesis

Life formed at cracks of ocean floor -> hydrothermal vents

Sources of Energy for Life on Early Earth

Lightning Volcanic Activity Radiation (cosmic, UV)

What was the earth free from in its earliest years?

Molecular Oxygen (O2)

problems with primordial soup hypothesis

all conditions wouldn't have been met on earth bc the surface area is so huge (diluted)

Heterotroph

an organism deriving its nutritional requirements from complex organic substances. (can not make its own food, obtains energy from food it consumes)

Autotroph

an organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide. (makes its own food, synthesizes, gets food using external energy source ie. sunlight lightning)

Life Appeared...

as soon as the earth cooled down enough to inhabit 3.8 billion years ago (prokaryotic)

RNA

genetic material that came first at the evolution of life

alkaline vents

release water that has a high pH and is warm rather than hot, an environment that may have been more suitable for the origin of life

endosymbiotic theory

theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms

four undeniable facts of life

there is life on earth all life is made of same components (use ATP, made of carbon etc) life is complex (cells molecularly crowded, 3d) all life is related

Prokaryotic Organism Characteristics

+Bacteria and Archea +Dna not enclosed in nucleus +Lack Organelles

Important questions about the origin of life

+Did life's building blocks come from different environments? +What role did the environment play in life's origin? +Biological evolution started once life appeared, not before!

Eukaryotic characteristics

+all other known organisms +Highly organized with organelles enclosed by membranes +contains cytoplasm and nucleoplasm

Oparin and Haldane

+believed organic compounds could form from basic raw materials +Oparin and Haldane were two scientists who proposed in the 1920s that the primitive atmosphere contained the following gases: methane, ammonia, hydrogen, and water. They believed that these gases collided, producing chemical reactions that eventually led to organic molecules.

primordial pizza hypothesis

+life began in clay surfaces organized in compartment- forming structures,"powered" by iron-sulfur chemistry +hypothesis that life began in rocks rich in iron sulfide near deep-sea hydrothermal vents

Prebiotic Soup Hypothesis

+organic compounds were formed near earth's surface +the idea that the earliest life emerged in a "soup-like" liquid environment, drawing upon energy from cosmic rays, volcanic eruptions, and the Earth's internal heat

Miller-Urey Experiment

+tested Oparin's hypothesis by attempting to remake early reducing atmosphere and produce organic compounds from inorganic materials +showed biologically important organic compounds could be formed from inorganic chemicals through natural processes

Anaerobes

Bacteria that grow in the absence of oxygen and are destroyed by oxygen (do not need oxygen in their metabolic (life) processes)

Aerobes

Bacteria that require oxygen to grow (need oxygen in their metabolic (life) process)

Biogenic (life-generating elements)

C - carbon H - hydrogen O - oxygen N - nitrogen P - Phosphorus S -Sulfur only form in stars (we are stardust)

The Origin of Life can be rephrased as...

The Origins of Replication and Metabolism

Mitochondria and Chloroplasts characteristics that support claim

Use their own DNA as their genetic material •Use the same 20 amino acids •Have a lipid bilayer cell membrane •Self-replicate •Produce proteins using their own ribosomes •They are sensitive to the same antibiotics used to kill prokaryotic pathogens

Abiogenesis

life from non life

Why Eukaryotes are thought to evolve from prokaryotes

mitochondria and chloroplasts are similar to bacteria and cyanobacteria