Origins Of Life Flashcards
What does the term ‘Abiogenesis’ refer to?
Life arose from non-living matter under early Earth’s reducing conditions
Abiogenesis suggests that life can originate from chemical processes in the absence of pre-existing life.
What is the RNA World Hypothesis?
RNA molecules can act as catalysts and carry out reactions related to genetic information
This hypothesis posits that RNA was the first molecule capable of both genetic information storage and catalytic functions.
What is the difference in stability between DNA and RNA?
DNA is more stable than RNA
DNA is double-stranded, which contributes to its stability compared to single-stranded RNA.
Where did the first metabolic processes occur?
Deep sea alkaline vents
These environments provided unique conditions for early metabolic reactions.
What role do iron-sulfur clusters play in early metabolism?
They were precursors to enzymes involved in energy metabolism
Iron-sulfur clusters are still present as cofactors for many modern enzymes.
What is the significance of early phototrophs?
They used sunlight to produce energy, leading to oxygenic photosynthesis by Cyanobacteria
This process was crucial for the development of aerobic life.
What was the Great Oxygenation Event?
Oxygen accumulation due to photosynthesis caused mass extinction of anaerobes
This event created an environment for the evolution of aerobic respiration and eukaryotes.
Fill in the blank: The first metabolic processes occurred in _______.
deep sea alkaline vents
True or False: DNA can be extracted as a single-stranded molecule.
False
DNA is typically found as a double-stranded molecule.
What are ribozymes?
RNA molecules that act as catalysts
They play a role in biochemical reactions, similar to protein enzymes.
What type of photosynthesis was developed by Cyanobacteria?
Oxygenic photosynthesis
This process produces oxygen as a byproduct.
What are the earliest fossils known?
Stromatolites
Stromatolites are layered rock formations created by microorganisms that trap sediment.
How old are the earliest fossils?
Approximately 3.5 billion years old
What does radio carbon evidence suggest about early life?
Early life dates back to approximately 3.9 billion years
What are the main components of all organisms?
- Nucleic acids
- Proteins
- Lipids
What was the probable composition of the early atmosphere?
- High levels of H2
- CO2
- NH3
- CH4
- Absent O2
What hypothesis suggests the early atmosphere was reducing?
Oparin-Haldane Hypothesis
What molecules were present in the early atmosphere according to the Oparin-Haldane Hypothesis?
- H2
- CO2
- CH4
- NH3
What type of atmosphere do we have today?
Oxidizing atmosphere with high O2 levels
What did experiments simulating early atmosphere conditions demonstrate?
Formation of amino acids and organic molecules
What role did clay play in the origins of life?
Acted as a catalytic surface for polymerization
Fill in the blank: All organisms are composed of nucleic acids, proteins, lipids, and _______.
Carbohydrates
True or False: The early atmosphere contained high levels of oxygen.
False
What are protocells?
Early forms of cellular life that emerged from polymerization on mineral surfaces
What does LUCA stand for?
Last Universal Common Ancestor
LUCA is theorized to be the most recent organism from which all life on Earth descends.
What type of metabolism did LUCA utilize?
Anaerobic metabolism
Anaerobic metabolism occurs without oxygen.
What were the primary elements involved in LUCA’s metabolism?
H2, C03, N2
These elements likely refer to various forms of carbon and nitrogen compounds, although Tz may need clarification.
What is the significance of the information retrieval system in LUCA?
It relates to the transition from RNA to proteins
This transition is crucial for the development of complex cellular functions.
What is the origin of eukaryotic evolution?
Originated via endosymbiosis
Endosymbiosis is a symbiotic relationship where one organism lives inside another.
What did aerobic bacteria become during eukaryotic evolution?
Mitochondria
Mitochondria are the powerhouses of the cell, responsible for energy production.
What did photosynthetic bacteria become during eukaryotic evolution?
Chloroplasts
Chloroplasts are responsible for photosynthesis in plant cells.
What is the process through which aerobic bacteria contribute to energy production?
Endosymbiosis
This process allows for the integration of aerobic bacteria into eukaryotic cells, enhancing energy production.
