Abiogenesis
... Abiogenesis , in its most general sense, is
the hypothetical generation of life from non-living matter. Today,
the term is primarily used in
the context of biology ...
Absorption spectrum
... An absorption spectrum is a diagram depicting
the wavelengths of electromagnetic radiation ... material, usually a gas . It can be regarded as
the opposite to an emission spectrum , which is a depiction of
the specific wavelengths emitted by a material.
Let ...
Coenzyme A
... in areas such as fatty acid oxidization and
the citric acid cycle . Its main function is to ... is an important molecule itself. It is
the precursor to HMG CoA, which is a vital component ... ketone synthesis. Furthermore, it contributes
the acetyl group to acetylcholine ...
Actin
... filaments (or microfilaments ), which like
the other two components of
the cellular cytoskeleton form a three-dimensional ... . Actin filaments provide mechanical support for
the cell, ...
Acrosome
... In sperm cells of many higher animals,
the acrosome develops over
the anterior half of its head. It is a cap-like structure derived from
the Golgi apparatus . In Eutherian mammals , ...
Acrosome
... In sperm cells of many higher animals,
the acrosome develops over
the anterior half of its head. It is a cap-like structure derived from
the Golgi apparatus . In Eutherian mammals , ...
Activation energy
...
the activation energy in chemistry is
the energy needed by a system to initiate a ... Activation energy is often used to denote
the minimum energy needed for a specific chemical ...
Active site
...
the active site of an enzyme is
the binding site where catalysis occurs.
the structure and chemical properties ...
Active transport
... Active transport is
the mediated transport of biochemicals , and other ... gradient ). This is achieved by either altering
the affinity of
the binding site or ...
Adaptive radiation
... Adaptive radiation describes
the rapid speciation of a single or a few species ... that was unreachable before. For example,
the Darwin's finches on
the Galapagos islands developed from a single ...
Adenosine triphosphate
... For other uses of
the initials ATP, see ATP (disambiguation)
Adenosine triphosphate ( ATP ) is
the nucleotide known in biochemistry as
the " molecular currency" of intracellular energy ...
Albinism
... resulting in a lack of pigmentation in
the eyes, skin and hair. It is an inherited condition arising from
the combination of recessive genes passed from both ... in eyesight and skin usually result from
the condition. This article is intended to cover ...
Affinity chromatography
... of gel permeation chromatography with
the ability to design a stationary phase that ... a mixture into a buffering solution.
Reduce
the amount of a molecule in a mixture.
... Protocols
General Procedure
Usually
the starting point is an undefined heterogeneous ...
Alcohol
... alcoholic beverage ). This sense underlies
the term alcoholism ( addiction to alcohol). Other ... adjective, as in isopropyl alcohol or by
the suffix -ol , as in isopropanol .
In ... bound to other hydrogen and/or carbon atoms.
the general formula for a simple alcohol containing ...
Albumin
... is a blood plasma protein that is produced in
the liver and forms a large proportion of all plasma protein. It is also found in egg white .
the normal range of albumin concentrations in ... globulin .
Albumin is essential for maintaining
the oncotic pressure needed
for proper distribution ...
Alexander Fleming
... 6 , 1881 – March 11 , 1955 ) discovered
the antibiotic substance lysozyme and isolated
the antibiotic substance penicillin from
the fungus Penicillium notatum .
Biography ...
Allele
... is any one of a number of alternative forms of
the same gene occupying a given locus (position) on a chromosome . An example is
the gene for blossom color in many species of flower - a single gene controls
the color ...
Alfred Russel Wallace
...
1 Early life
2 Exploration and study of
the natural world
3 Theory of evolution
4 Religious views, and application of
the theory to mankind
5 Precursor of ecology, ... was born at Usk , Monmouthshire . He was
the eighth of nine children of Thomas Vere Wallace ...
Allostery
... its activity or efficiency changes in response to
the binding of an effector molecule at a ... are referred to as allosteric activation , while
the opposite is called allosteric inhibition . "Allostery" is derived from
the Greek "other site", referring ...
Alga
...
the algae (singular is alga ) comprise several ... as simple plants , and some are related to
the higher plants . Others represent independent ... in that they are photoautotrophic . Thus,
the algae are no longer considered a natural ...
Allele frequency
... genetics that is used in characterizing
the genetic diversity of a species population , or equivalently
the richness of its gene pool . Allele frequency is ... each of their somatic cells (e.g. two loci in
the cells of diploid species, which contain two ...
Allostery
... its activity or efficiency changes in response to
the binding of an effector molecule at a ... are referred to as allosteric activation , while
the opposite is called allosteric inhibition . "Allostery" is derived from
the Greek "other site", referring ...
Alpha helix
... In proteins ,
the α helix is a major structural motif in ... Corey , and Herman Branson in 1951 based on
the known crystal structures of amino acids and ... Pauling's prediction of planar peptide bonds .
the amino acids in an α helix are arranged in a ...
Alternative splicing
...
Alternative splicing is
the process that occurs in eukaryotes in which
the splicing process of a pre-mRNA can lead to ... adapted to this biochemical process when using
the protein biosynthesis apparatus.
...
Amine
... are organic compounds containing nitrogen as
the key atom in
the amine functional group. Amines have structures ... replaced by alkyl groups or other groups where
the nitrogen is bonded to a carbon atom ...
Ames test
...
the Ames test is a biological assay used in ... said to be mutagenic if it causes a change in
the DNA (deoxyriboneucleic acid) of a living cell or organism.
the test is named after its inventor, Bruce Ames .
...
Anabolism
... Anabolism is
the aspect of metabolism that is characterized by ... of categorizing metabolic processes, whether at
the cellular , organ or organism level is as ... off catabolic processes and vice versa. Most of
the known signals are hormones of various types. ...
Amino acid
... to alpha amino acids: those amino acids in which
the amino and carboxylate functionalities are attached to
the same carbon .
Amino acid residue is what is ... a water molecule has been lost (an H+ from
the nitrogenous side and an OH- ...
Anatomy
... . It is a love sonnet dedicated to describing
the parts of a lover 's anatomy, usually female .
Anatomical drawing of
the human muscles from
the Encyclopdie .
Anatomy ...
AMP
...
the three-letter abbreviation AMP can refer to
the following:
In biology ,
the nucleotide adenosine monophosphate
As a ...
Anaerobic
... means without air , as opposed to aerobic .
the presence or absence of air, or more precisely
the presence or absence of oxygen in
the air, affects various chemical and biological ...
Animal
... are a major group of organisms , classified as
the kingdom Animalia or Metazoa. In general they ... of metamorphosis later on.
Aristotle divided
the living world between animals and plants , and this was followed by Carolus Linnaeus in
the first hierarchial classification. Since then ...
Anaphase
... and φάσις = stage) is
the stage of meiosis or mitosis when chromosomes ... Each chromatid moves to opposite poles of
the cell (opposite ends of
the nuclear spindle ).
Anaphase is preceded by ...
Andrew Huxley
... physiologist and biophysicist , who won
the 1963 Nobel Prize in Physiology or Medicine for his work with Alan Lloyd Hodgkin on
the basis of nerve " action potentials ,"
the electrical impulses that ...
Antibiotic
... An antibiotic is a drug that kills or slows
the growth of bacteria . Antibiotics are one class ... drugs. They are relatively harmless to
the host, and therefore can be used to treat infections .
the term originally described only those formulations ...
Antibiotic resistance
... Antibiotic resistance is
the ability of a microorganism to withstand
the effects of an antibiotic .
Antibiotic resistance ... or plasmid exchange between bacteria of
the same species . If a bacterium carries several ...
Anticodon
... including RNA translation . It is, specifically,
the group of nucleotides on a strand of tRNA that ... strand of mRNA . See also protein synthesis .
the first base on
the anticodon can be modified to another nucleotide ...
Antibody
... An antibody is a protein used by
the immune system to identify and neutralize ...
1 Definition
2 Structure of
the antibody
3 Isotypes
3.1 IgG
3.2 ... 3.4 IgD
3.5 IgE
4 Function
4.1
the humoral immune response
5 Medical ...
Antigen
... response (provokes immunity) when introduced into
the body. An immunogen is always a macromolecule (protein, polysaccharide). Its ability to provoke
the immune response depends on its foreignness to
the host, molecular size, chemical composition and ...
Anton van Leeuwenhoek
... was a tradesman and scientist from Delft , in
the Netherlands . He is best known for his contribution to improvement of
the microscope and his contributions towards
the establishment of cell biology . Using his ...