Atoms: Atomic Number, Mass Number and Percentage composition

Atoms
ATOMIC NUMBER AND MASS NUMBER   Atoms:THE ATOMIC NUMBER Atoms:The atomic number of an element is the number of protons present in the atomic nucleus of the element. It is denoted by letter Z and increased by one when the... Read more

PARTS OF THE ATOM/CONSTITUENTS OF ATOMS

PARTS/CONSTITUENTS OF THE ATOM PARTS OF THE ATOM: Atoms are made up of many smaller particles, three of which are of direct interest to the chemist. The three particles which are also regarded as “fundamental particles” are the proton, the... Read more

Atomicity: Definition and Types

Atomicity Atomicity is the total number of atoms contained in a molecule. For example, each molecule of nitrogen (N2) is made up of two Nitrogen atoms. So, atomicity of Nitrogen is 2, valency is sometimes used in the same sense... Read more

Dalton’s Atomic Theory, Modifications and Modern Atomic Theory

Dalton’s Atomic Theory, Modifications and Modern Atomic Theory DALTON’S ATOMIC THEORY ATOMIC THEORY: The idea that elements are made from atoms is termed the Atomic theory. In 1808, John Dalton presented his famous atomic theory which states as follows: All... Read more

GENE EXPRESSION: PROKARYOTES AND EUKARYOTES

CONTROL OF GENE EXPRESSION IN PROKARYOTES “GENE EXPRESSION”  An organism’s DNA encodes all of the RNA and protein molecules required to construct its cells. Yet organisms are able to differentially express their genes to make cell-specific products necessary for cellular... Read more

TRANSLATION AND MECHANISM OF TRANSLATION

TRANSLATION Translation is a complex process that requires mRNA, tRNA, ribosomes, amino acids, and energy in the form of GTP. Once the mRNA transcript is created and processed, it can exit the nucleus through nuclear pores. Once in the cytoplasm,... Read more

TRANSCRIPTION AND MECHANISM OF TRANSCRIPTION

TRANSCRIPTION Transcription is the process of making an RNA copy of a gene sequence. This copy, called a messenger RNA (mRNA) molecule, leaves the cell nucleus and enters the cytoplasm, where it directs the synthesis of the protein, which it... Read more

MUTATION: DEFINITION AND TYPES

MUTATION “MUTATION” The genetic code shows that for the amino acids with multiple codons, the first two bases are usually the same, and the third base in the codon is variable. We refer to this variable third base in the... Read more

DNA Repair: Oncogene and Tumor Suppressor Gene

DNA REPAIR “DNA REPAIR” The structure of DNA can be damaged in a number of ways such as exposure to chemicals or radiation. DNA is very susceptible to damage and if the damage is not corrected, it will subsequently be... Read more

TELOMERES AND CENTROMERES:Definition and Function

TELOMERES AND CENTROMERES Simplified TELOMERE “TELOMERES AND CENTROMERES” A telomere is a region of repetitive nucleotide sequences at each end of a chromosome, which protects the end of the chromosome from deterioration or from fusion with neighbouring chromosomes. DNA replication... Read more