UNIDAD 3-TAREA FINAL-PASO 2. resumen del texto

 

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Origin of life studies

 

The Oparin-Haldane hypothesis explains the origin of life on Earth in three steps: the formation of organic molecules, the formation of polymers, and the formation of protocells. Scientists propose and test hypotheses about natural processes based on geological evidence.

 Keywords:  life, molecules, polymers, protocells, Oparin-Haldane hypothesis.

The Oparin-Haldane hypothesis proposes that the origin of life on Earth involved the formation of organic molecules, the creation of polymers, and the development of protocells.

Miller-Urey experiment

Stanley Miller and Harold Urey performed the Miller-Urey experiment, which supported the first step of the Oparin-Haldane hypothesis. They simulated early conditions on Earth and observed the formation of organic molecules, including the essential amino acids for life. Using a gas chamber with reducing compounds and electrical sparks, the experiment produced a variety of organic compounds in a short period of time. The results provided information about the possible origins of life on Earth.

 

Keywords: Stanley Miller, experiment, organic, molecules, key.

 

In the Miller-Urey experiment, Stanley Miller and Harold Urey recreated the environmental conditions of early Earth and observed the formation of organic molecules, including key elements for life. Using a gas chamber with reducing compounds and electrical sparks, the experiment produced a variety of organic compounds in a short period of time. The results provided information about the possible origins of life on Earth.

Organic molecules from meteors

 

The daily bombardment of meteorites and comet dust on Earth has revealed the presence of numerous organic molecules in them. Analyzes of space dust and meteorites have shown that they contain these molecules. 4 billion years ago, when the Earth was young, the amount of cometary dust and meteorites arriving was much greater. Many scientists believe that this extraterrestrial organic matter contributed significantly to the organic molecules available at the time life originated on Earth.

 

Keywords: meteorites, comet, dust, Earth, life.

 

The presence of organic molecules in meteorites and comet dust reaching Earth supports the idea that these cosmic objects are an important source of organic compounds. Billions of years ago, when our planet was young, the amount of organic matter arriving was even greater, which may have influenced the origin of life on Earth.

Enzymatic activity and hereditary information in one polymer: the RNA World hypothesis

Thomas Cech's discovery that some RNA molecules can catalyze their own site specificity led to a Nobel Prize, the term "ribozymes" to denote catalytic RNA molecules, and the revival of the hypothesis that RNA molecules were the original hereditary molecules, predating DNA. This raised the possibility that RNA molecules could encode hereditary information and catalyze their own replication. DNA as the first hereditary molecule presented real problems for origin-of-life researchers, since DNA replication requires protein enzymes (DNA polymerases) and RNA primers, so it is hard to imagine how such a complex hereditary system could have evolved from scratch. With catalytic RNA molecules,

 

Keywords: Thomas Cech, ribozymes, RNA, hereditary, replicate.

 

Thomas Cech's discovery of ribozymes, RNA molecules capable of catalyzing their own cleavage, raised the possibility that RNA was from the original hereditary molecule and could encode information and replicate without the need for protein enzymes. This has important implications for understanding the origin of life on Earth.

 

 

 

Protocells: self-replicating and metabolic enzymes in a bag

Cells, constituents of all life on Earth, have lipid membranes that separate their internal content, the cytoplasm, from the environment. These membranes allow cells to maintain high concentrations of molecules such as nucleotides, necessary for the efficient functioning of self-replicating RNAs. In addition, cells maintain large concentration differences (concentration gradients) of ions across the membrane to drive transport processes and cellular energy metabolism.

 

Keywords: cells, lipid, concentrations, gradients, metabolic.

 

Cells use lipid membranes to separate their internal contents from the environment, allowing them to maintain high concentrations of molecules and generate concentration gradients to drive transport and metabolic processes.