Life and the Atmosphere Flashcards
What are the key characteristics that distinguish life from non-living matter?
Complex cycles of material and energy exchange.
Darwinian evolution.
Different chemical structure, primarily involving carbon.
Why is carbon essential for life?
It can form diverse three-dimensional structures and participate in various chemical reactions, unlike silicon.
What elements predominantly compose life?
Hydrogen (H), Oxygen (O), Carbon (C), Nitrogen (N), Sulfur (S), and Phosphorus (P).
What role do carbohydrates play in cellular activities?
Serve as fuel sources for cellular activities through oxidation reactions.
What fundamental similarities are shared by all living organisms?
Cellular structure, biochemical processes like metabolism and replication, and use of common molecules such as carbohydrates, amino acids, lipids, and nucleic acids.
What is the significance of lipids in cells?
Store energy efficiently and contribute to cell membrane structure.
What are the building blocks of proteins, and what roles do proteins play?
Amino acids are the building blocks.
Proteins act as enzymes, structural components, and signaling molecules.
What are nucleic acids responsible for?
Carry genetic information and instructions for cellular processes. DNA is transcribed into RNA, which directs protein synthesis.
What evidence supports the existence of early life on Earth?
Fossils, stromatolites, carbon isotopes, and biomarkers.
What does the RNA World Hypothesis suggest?
RNA may have preceded DNA, serving as a precursor to life’s fully developed systems due to its information-carrying capacity and enzymatic properties.
What challenges exist in the transition from organic molecules to self-replicating systems?
Concentrating monomers, overcoming water dilution, and achieving selective chirality in polymers.
How might mineral surfaces aid in the formation of life?
Providing catalytic sites for chemical reactions, concentrating organic molecules, and protecting them from environmental degradation, thereby facilitating the synthesis of complex organic compounds necessary for life.
What role does life play in thermodynamic processes?
Life maximizes entropy production in the larger system by efficiently dissipating energy, creating order from disorder.
What are the three energy revolutions in the history of life?
Chemoautotrophy and Photoautotrophy.
Oxygenic Photosynthesis.
Aerobic Respiration.
How does the planetary fuel cell concept relate to life?
It converts chemical potential into electrical current, requiring oxidized and reduced molecules to maintain energy potential, with life playing a key role in charging and utilizing this system.
