Organisms living together in a community influence each other directly or indirectly under natural conditions. All vital process of living such as growth, nutrition, reproduction required interactions between individuals of same species, or between species which are inter and intra-related. Such relationships of individuals in a population of an ecosystem …
Read More »Polysaccharides: The Long Chain of Simple Sugars
Polysaccharides are polymeric carbohydrate molecules composed of long chains of monosaccharide unit bound together by glycosidic linkage. Example: starch, glycogen, cellulose, chitin etc. Characteristics of polysaccharide On hydrolysis, they yield monosaccharide units which are usually similar. D glucose is the commonest component of polysaccharide. They have high molecular weight. They …
Read More »Disaccharides: Bonding of Two Simple Sugars
A disaccharide, also called double sugar, is the sugar formed when two monosaccharides (simple sugars) are joined by a glycosidic linkage. Like monosaccharides, disaccharides are soluble in water. Three common examples are sucrose, lactose, and maltose. Disaccharides are one of the four chemical groupings of carbohydrates (monosaccharides, disaccharides, oligosaccharides, and polysaccharides). The most common …
Read More »Protein: Discovery, Characteristics, and Structures
The word protein refers to a type of molecule in food that can be broken down into amino acids. They are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. Protein accounts on average about 1/4th to 1/3rd of …
Read More »DNA Replication in Eukaryotes: Linear Replication
DNA replication in eukaryotes is a complex and unique process involving many enzymes and thousands of ORI at a single time. Unlike the prokaryotic DNA, it involves a linear mode of replication. Why does linear DNA replication involve multiple origins at a time? The large linear chromosomes in eukaryotic cell …
Read More »Replication in Circular DNA: Theta Model
Following Meselson and Stahl’s work, investigators confirmed that other organisms also use semiconservative replication. There are, however, several different ways that semiconservative replication can take place, differing principally in the nature of the template DNA—whether it is linear or circular—and in the number of replication forks. Replicon and Origin of …
Read More »Translation: mRNA to Protein
Translation takes place on ribosomes; indeed, ribosomes can be thought of as moving protein-synthesizing machines. A ribosome attaches near the 5′ end of an mRNA strand and moves toward the 3′ end, translating the codons as it goes. Synthesis begins at the amino end of the protein, and the protein …
Read More »Post-transcriptional Modification
The process of transcription is very similar in prokaryotes and eukaryotes, but there are major differences in the relation between the transcript and the mRNA used for polypeptide synthesis in eukaryotes. In prokaryotes, the immediate product of transcription (the primary transcript) is mRNA; by contrast, the primary transcript (also called …
Read More »Genetic Code
The four bases in DNA – A, T, G, and C are sufficient to specify the 20 amino acids in proteins because each codon is three bases in length. Each sequence of three adjacent bases in mRNA is a codon that specifies a particular amino acid (or chain termination). The …
Read More »Cronquist’s System of Classification
Arthur Cronquist was the Senior Curator of New York Botanic Garden and Adjunct Professor of Columbia University. He presented an elaborate interpretation of his concept of classification in The Evolution and Classification of Flowering Plants (1968), The further edition of his classification was published in “An Integrated System of Classification …
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