Molecular Biology

  angstrom Ab antibody Ac acetyl group ADP adenosine diphosphate Ala alanine residue (also A) AMP adenosine monophosphate Arg arginine residue (also R) Asn asparagine residue (also N) Asp aspartic acid residue (also D) ATP adenosine triphosphate ATPase adenosine triphosphatase Bq becquerel bp base-pair BSA bovine serum albumin C cytosine base cal calorie (4.18 J) […]

CONVERSION FACTORS Part 1 (Molecular Biology)

SI Units (Adopted 1960) The International System of Units (abbreviated SI), is being implemented throughout the world. This measurement system is a modernized version of the MKSA (meter, kilogram, second, ampere) system, and its details are published and controlled by an international treaty organization (The International Bureau of Weights and Measures) (1). SI units are […]

CONVERSION FACTORS Part 2 (Molecular Biology)

Conversion Factors to SI Units To convert from To Multiply by acre square meter (m2) angstrom meter (m) are square meter (m2) astronomical unit meter (m) atmosphere, standard pascal (Pa) bar pascal (Pa) barn square meter (m2) barrel (42 U.S. liquid gallons) cubic meter (m3) Bohr magneton (/ib) J/T Btu (International Table) joule (J) Btu […]

A-DNA (Molecular Biology)

A-DNA was first recognized as a DNA structure using fiber X-ray diffraction analysis. B-DNA can be converted to A-DNA under conditions of low hydration, and the process is reversible. The A-DNA double helix is short and fat, with the base pairs and backbone wrapped farther away from the helix axis (see Fig. 2 of DNA […]

Abl Oncogenes (Molecular Biology)

The abl gene was first identified as the transforming element of Abelson murine leukemia virus (A-MuLV), a replication-defective retrovirus that was isolated after inoculating Moloney murine leukemia virus (M-MuLV) into prednisolone-treated BALB/c mice (1). A-MuLV induces B-cell lymphomas in vivo and transforms both lymphoid and fibroblastic cells in vitro. The proviral genome of A-MuLV encodes […]

Abscisic Acid (Molecular Biology)

1. History The first evidence for the existence of an acidic inhibitor of coleoptile growth that promoted abscission and seed maturation dates back to the early 1950s, but it was not until 1963 that abscisic acid (ABA) was identified by Frederick Addicott and coworkers (1, 2). Addicott’s team was studying compounds that stimulated abscission in […]

Absorption Spectroscopy (Molecular Biology)

Light in the ultraviolet (UV) and visible (vis) range of the electromagnetic spectrum shows an energy that is equivalent to about 150 to 400 kJ/mol. Light with the appropriate energy is used to promote electrons from the ground state to an excited state. The absorption of energy from the incident light as a function of […]

Acceptor Stem (Molecular Biology)

The acceptor stem is the site of attachment of amino acids to transfer RNA (tRNA). It is formed by 7 base pairs and has 4 single-stranded nucleotides. Nucleotides 1 to 7 from the 5′ end of the tRNA base pair with nucleotides 72-66, respectively, from the 3′ end of the molecule. Whereas the 5′ end […]

Accessible Surface (Molecular Biology)

The surfaces of folded macromolecules, especially proteins, and the internal packing of their atoms have generally been analyzed using the procedure of Lee and Richards (1). The cross section of part of the surface of a native protein is depicted in Figure 1, which demonstrates a number of different surfaces and volumes (see Protein Structure). […]

Acentric Fragment (Molecular Biology)

Fragments of chromosomes that lack centromeres are described as acentric fragments (Fig. 1). They are formed as a result of chromosomal damage. Lacking a centromere, there is no means of attachment to the mitotic spindle, which leads to a failure to segregate replicated chromatids in the acentric fragments to the daughter cells during cell division. […]