Beginners Guide to Molecular Biology
Life: A definition
It is generally accepted that for something to be considered alive it must demonstrate each of the following characteristics: Movement, Reproduction, Consumption, Growth, Organization, and Stimulus Response.
Cell Biology: Structure and components of the cell
Cells are the smallest structural components of life, and they come in a variety of shapes and sizes. Organisms are composed of cells, and cells arise from other cells. Cell components include the cell wall, cell membrane, nucleus, nucleolus, endoplasmic reticulum (smooth and rough), mitochondria, microtubules, microfilaments, lysosomes, Golgi apparatus, centrioles, secretory vesicles, and ribosomes.
Example of Cells
Cells come in many different shapes and sizes and may be simple or complex depending on their function. Examples include plant cells, animal cells, blood cells, nerve cells, skin cells, and so on.
Mitosis: Normal cell division
Mitosis is nuclear division of the cell, resulting in the creation of two identical daughter cells. The phases of mitosis are prophase, prometaphase, metaphase, and telophase.
Meiosis: Cell division and gametogenesis
Meiosis is a form of cell division that produces gametes. During the formation of gametes, the number of chromosomes is reduced by half.
From Chromosome to DNA: Unfolding our story
The DNA in cells is packed into structures called chromosomes. Humans normally have 23 pairs of chromosomes in each of their cells.
DNA Structure: The molecule of DNA unplugged
Deoxyribonucleic acid, or DNA, is the genetic material that organisms inherit from their parents. It is a double-stranded helical macromolecule that contains deoxyribose sugar and the bases adenine, cytosine, guanine, and thymine.
From DNA to RNA: Sending the message...transcription
Transcription is the transfer of genetic information from DNA into an RNA molecule. This process occurs in the nucleus of the cell.
RNA Structure: The messenger and its helpers
Ribonucleic acid, or RNA, is a type of nucleic acid made up of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine, cytosine, guanine, and uracil.
From RNA to Protein: The cell factory
DNA translation is the process that converts the information stored in the messenger RNA into protein. This process occurs on the surface of ribosomes.
Protein Structure and Diversity
Proteins are biological polymers made from amino acid monomers. There are thousands of different types of proteins, each having a unique three-dimensional structure that corresponds to a specific function. There are seven major classes of proteins: structural proteins, contractile proteins, storage proteins, defensive proteins, transport proteins, signal proteins, and enzymes.
Amino acids are organic molecules containing a carboxyl group and an amino group. Proteins are formed from just 20 separate amino acids.
Molecular Engineering: Expression systems
An expression system is a system made specifically to produce gene products. It consists of a gene and the molecular equipment necessary for the transcription of DNA into mRNA and then the translation of mRNA into protein.