Stanley L. Miller and Harold C. Urey’s Experimental Support for Oparin’s Chemical Evolution Theory: Apparatus and Procedure: Miller and Urey devised a spark-discharge apparatus, a glass chamber, to experimentally validate Oparin’s chemical evolution theory. The apparatus was sterilized, evacuated, and filled with methane, ammonia, and hydrogen gases in a 1:2:2 ratio. A tube introduced water … Read more
1. Industrial melanism, a prime example of natural selection studied by Kettlewell, involved two UK peppered moth varieties: Biston betularia and Biston carbonaria. 2. In pre-industrial Britain, Biston betularia outnumbered Biston carbonaria. B. Betularia was greyish-white, while B. carbonaria had a melanic form. 3. Nocturnal moths rested on tree trunks during the day. White-winged moths … Read more
1. Adaptive radiation, a pivotal process in evolution, entails the transformation of an original species into a diverse array of varieties. 2. A notable illustration of adaptive radiation is found in Darwin’s Finches. During Charles Darwin’s exploration of the Galapagos Islands, he observed a variety of small birds known as finches. 3. Darwin’s observations suggested … Read more
The wings of a butterfly and a bat are analogous, meaning they share similar functions but do not have a common evolutionary origin. Examples of analogous structures include: 1. Butterfly wings and bird wings may appear similar, but they are not anatomically alike, despite serving similar functions. 2. The eyes of an octopus and mammals … Read more
The Lac operon, proposed by Francois Jacob and Jacques Monod, is predominantly found in prokaryotes like E. coli, representing the first identified gene regulatory process in bacteria. Comprising an operator, promoter, three structural genes (lacZ, lacY, lacA), and a terminator, the operon governs the regulation of lactose, including its transport and metabolism. The structural genes … Read more
Translation is the term used to describe the polymerization of amino acids into a polypeptide, constituting the biological process by which proteins are synthesized is called translation. Translation happens in following main steps: Initiation, Elongation, Translocation, Termination Initiation: 1. The initiation phase involves the assembly of ribosomes around the target mRNA. 2. Ribosomes, known as … Read more
Transcription The Central Dogma elucidates the process by which DNA encodes proteins, unfolding in three phases: replication, transcription, and translation. Following DNA replication of its two strands, information is transcribed into RNA. The process of transcription in protein synthesis is as follows: 1. Transcription is the initial step in protein synthesis, where m-RNA is formed … Read more
DNA replication DNA replication is the biological mechanism that generates two identical copies of DNA from a single original DNA molecule. The steps involved in the process of DNA replication are as follows: 1. Helicase initiates DNA replication by unzipping the double helix, breaking hydrogen bonds between complementary bases. 2. This separation forms a replication … Read more
Chromosomes exhibit diverse structures classified into four types based on the centromere’s position: 1. Metacentric: In metacentric chromosomes, the centromere is centrally located, resulting in arms of nearly equal length. This configuration gives the chromosome a characteristic ‘V’ shape during anaphase. 2. Sub-metacentric: Characterized by a centromere positioned away from the middle, sub-metacentric chromosomes have … Read more
Criss-cross inheritance is a pattern where genes are transmitted from father to daughter and then to her son, meaning from male to female and subsequently from female to male (grandson). In simpler terms, it is described as the transfer of genes from a grandfather to his grandson through his daughter. 1) The inheritance pattern of color … Read more