Biology Chapter on Early Life and Photosynthesis

A biological process that allows organisms to sustain themselves, replicate, and adapt to their environment. It involves self-sustenance, replication, and mutation.

Living systems are open, self-organizing entities that constantly interact with their environment. They thrive on the flow of information, energy, and matter.

A hypothesis suggesting that organisms interact with their inorganic surroundings on Earth to create a self-regulating system that maintains conditions suitable for life. It highlights the interconnectedness of living and non-living components.

The ability of a living organism to maintain a stable internal environment by adjusting to external changes. It's key for survival.

The smallest unit of life that can function independently. It has a well-defined boundary (cell membrane) and contains all the essential components for life.

The process by which living organisms produce new individuals similar to themselves. It's essential for the continuation of life.

Changes in the genetic makeup of an organism, leading to variations within a species. It's a driving force behind evolution.

The process by which organisms with traits better suited to their environment survive and reproduce more successfully. It leads to the evolution of species over time.

A branch of biology that studies the complexity of biological structures, functions, and how organisms and species evolve by focusing on intricate interactions within bionetworks and fundamental relational patterns essential for life.

A field of theoretical sciences focused on identifying and modeling the relational patterns essential for life. It overlaps partially with complex systems theory and systems biology, but it delves more into the complexities and relational patterns of living systems.

The conditions under which life can exist and thrive, defined by factors like suitable temperature, liquid water, and a breathable atmosphere.

The range of orbital distances around a star where a planet can have liquid water on its surface, implying potential for life.

The theory that life on Earth was created by a supernatural force, typically a divine being. This view is held by many religions, including Christianity, Islam, and some African traditional faiths.

The core argument against the special creation theory, which states that it relies on mystical concepts and cannot be scientifically proven or tested.

Areas of the galaxy where life is more likely to exist because they have planets in the habitable zone of stars with conditions suitable for life.

A star slightly cooler and smaller than our Sun, located in the constellation Lyra, approximately 1200 light-years away from Earth. It has five planets, two of which (Kepler-62e and Kepler-62f) are within its habitable zone.

The theory that life arose from non-living matter.

A scientist who disproved spontaneous generation by showing that sterile broth only became contaminated when exposed to air containing microbes.

The process of forming complex organic molecules from simpler molecules, like those found in the early Earth's atmosphere.

The process of forming a self-sustaining, self-replicating system from the complex organic molecules produced during chemical evolution.

Early Earth's atmosphere contained simple molecules like methane, ammonia, and water vapor, which were used to synthesize organic molecules needed for life.

Energy sources like sunlight and lightning provided the energy needed for the formation of organic molecules on early Earth.

The formation of monomers, like sugars and amino acids, from simple molecules like methane and ammonia.

The linking of monomers into larger polymers, like proteins and nucleic acids.

The process where organisms started using pre-existing energy-rich substances in their environment to produce energy.

Photosynthesis evolved to harness the inexhaustible energy from the sun.

As reducing agents like H2S became scarce, photosynthesis evolved to use the more prevalent H2O, producing oxygen as a byproduct.

The accumulation of oxygen in the atmosphere led to the evolution of oxygen-based energy metabolism, a more efficient way to use energy.

The ozone layer, which protects life from harmful UV rays, formed as atmospheric oxygen levels increased due to photosynthesis.

The process where a polynucleotide (DNA or RNA) guides the synthesis of a polypeptide (protein) chain.

RNA molecules that have catalytic activity, meaning they can act as enzymes.

A simple structure that shows evidence of life. It is a compartment with a membrane separating it from the external environment, preventing it from dissolving.

Early life forms proposed by Oparin, formed from the spontaneous aggregation of molecules, creating a membrane and a distinct internal environment.

The spontaneous separation of a solution into two phases, one with a higher concentration of polymers and another with a lower concentration.

Small, spherical structures formed from proteinoids (protein-like molecules). These structures resemble primitive cells, with a double-layered membrane.

A sequence of chemical reactions that enable organisms to obtain energy and build essential molecules.

The development of metabolic pathways was driven by competition for nutrients, as early life forms struggled to survive in their environment.

The Strecker synthesis is a chemical reaction that produces amino acids from aldehydes or ketones. The three steps are: 1) Reaction of an aldehyde or ketone with ammonia to form an imine. 2) Cyanide addition to the imine. 3) Hydrolysis of the aminonitrile to form the amino acid.

Polynucleotides, like DNA and RNA, are long chains of nucleotide monomers. Similarly, polypeptides are long chains of amino acid monomers, and polysaccharides are long chains of sugar monomers.

Condensation reactions involve the joining of two molecules with the release of a small molecule, often water. This is a common way to build polymers. The reverse reaction, hydrolysis, uses water to break down polymers.

Condensing agents help drive condensation reactions by removing water from the reaction environment. This shifts the equilibrium toward product formation.

Carbodiimides are a type of condensing agent that have a high-energy intermediate. This intermediate makes the condensation reaction more favorable and reactive.

The early Earth's atmosphere lacked a significant amount of oxygen, which meant there was no ozone layer to shield UV radiation from the sun. Consequently, the atmosphere was highly reducing, meaning it contained a lot of hydrogen and other reducing agents like methane and ammonia.

Fatty acids were formed under harsh conditions of high temperature and pressure, requiring significant hydrogen. This is problematic for the prebiotic synthesis of fatty acids because such extreme conditions were unlikely to exist consistently in the early Earth's environment.

The prebiotic synthesis of nucleotide bases involves the polymerization of hydrogen cyanide (HCN). Subsequent steps involve further reactions and modifications to create the nitrogenous bases found in DNA and RNA.