Question

1. What are the properties of life? The shared traits of all life give us a description of LUCA

2. Describe these two theories for the origin of biological monomers in the Archean world: chemical evolution and extraterrestrial origin.. Describe the Miller & Urey experiments. What is the significance of the detection of both D and L forms of amino acids in a ‘freshly-harvested’ meteorite?

3. Why is dilution such a problem for biochemistry? While the biochemistry of life occurs in aqueous solution, these reactions can not occur in a dilute solution.

4. How could each of the following act as an early catalyst for pre-cellular biochemistry: clay minerals, hydrothermal vents, warm little pools.

5. What are the characteristics of biological catalysts?

Answer 1

1. All living organisms share several key characteristics or functions such as growth and development, reproduction, homeostatsis, energy production etc. LUCA(last universal common ancestor) has been discovered and it could help to establish how life began on earth. All organisms now living on Earth have a common descendent.The LUCA is a single celled organism which gives rise to archea and bacteria. Usually found in deep vents and small ponds.

2.Chemical evolution theory states that the formation of complex molecules from the simple molecules through a chemical reaction in an ocean.

Extraterrestrial life is the hypothetical life that didn't originate on Earth but is from the outside world. This life may contain simple prokaryotes and to highly complex civilized organisms.

Miller Urey Experiment- It was a chemical experiment that maintained the conditions which may be present in the Early Earth phase. Different compounds were used like water, ammonia, hydrogen and methane and all were sealed packed in a flask. Slight boiling and continuous spark was given to the setup.
By using paper chromatography he identified 5 amino acids in general that were glycine, alpha and beta- alanine, aspartic acid and aminobutyric acid.
D and L are the isomeric forms of the amino acids . L forms are manufactured in the cells which are later involved in protein synthesis while presence of D-Amino acids occur in various cell walls of bacteria. There presence determines the existence of life in a freshly harvested meteorite.

3.Dilution refers to the process of adding additional solvent to a solution to decrease its concentration. This process keeps the amount of solute constant, but increases the total amount of solution, thereby decreasing its final concentration.

4. A. Clay minerals plays an important role in chemical evolution and origin of life as the clay minetals have ability to take up, protect (against ultraviolet radiation), concentrate, and catalyze the polymerization of, organic molecules.

B. Alkaline hydrothermal vents focuses on acetyl CoA and CO2 fixation pathway. The idea that acetogenesis and methanogenesis were the earlier form of energy metabolism, overall chemical design of methanogenesis and acetogenesis suggests that simple organic reactions catalysed by transition metal sulphides, as in CODH/ACS and pyruvate synthase, are the starting point of biochemistry.

C. Warm little pond concept, where molecules underwent reactions that led to the formation of prebiotic compounds like amino acids. Over time, these small prebiotic compounds would have undergone further reactions to produce more and more complex molecules.

5. Enzymes are the biocatalyst. Biocatalyst speed up the rate of chemical reaction without changing itself. Enzymes are madeup of amino acids hence proteins which are folded with a specific shape, hence they are specific thats why particular substrate can fit in their active sites.every enzymes are proteins but all proteins are not enzymes.

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