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Genetics Lecture


Genetics is the study of genes, heredity, and variation in living organisms.

Deoxyr­ibo­nucleic acid

is a molecule that encodes the genetic instru­ctions used in the develo­pment and functi­oning of all known living organisms and many viruses.

DNA is a nucleic acid; alongside proteins and carboh­ydr­ates, nucleic acids compose the three major macrom­ole­cules essential for all known forms of life.

Ribonu­cleic acid

Ribonu­cleic acid (RNA) is a polymeric molecule. It's implicated in a varied sort of biological roles in coding, decoding, regula­tion, and expression of genes.

DNA and RNA are nucleic acids, and, along with proteins, constitute the three major macrom­ole­cules essential for all known forms of life.

Like DNA, RNA is assembled as a chain of nucleo­tides, but unlike DNA it is more often found in nature as a single­-strand folded unto itself, rather than a paired double­-st­rand.


A zygote is the initial cell formed when two gamete cells are joined by means of sexual reprod­uction.

In single­-celled organisms, the zygote divides to produce offspring, usually through mitosis, the process of cell division.


The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific charac­ter­istic under consid­era­tion.


Ploidy is the number of sets of chromo­somes in the nucleus of a cell.


A phenotype (from Greek phainein, meaning "to show", and typos, meaning "­typ­e") is the composite of an organism's observable charac­ter­istics or traits, such as its morpho­logy, develo­pment, bioche­mical or physio­logical proper­ties, phenology, behavior, and products of behavior (such as a bird's nest).


An allele, or allel, is one of a number of altern­ative forms of the same gene or same genetic locus.

Homozygous & Hetero­zygous

Zygosity is the degree of similarity of the alleles for a trait in an organism.

A cell is said to be homozygous for a particular gene when identical alleles of the gene are present on both homologous chromo­somes.

A diploid organism is hetero­zygous at a gene locus when its cells contain two different alleles of a gene.


Meiosis is a special type of cell division necessary for sexual reprod­uction which occurs or has occurred in all eukary­otes, including animals, plants and fungi, including both multi-­celled and single­-celled organisms.


Mitosis is the process, in the cell cycle, by which the chromo­somes in the cell nucleus are separated into two identical sets of chromo­somes, each in its own nucleus.


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