Transitional Vertebrate Fossils FAQ
wrote this FAQ as a reference for answering the "there aren't any transitional fossils" statement that pops up on talk.origins several times each year.
transition mutation
a base pair substitution in which the orientation of the purine and pyrimidine bases on each DNA strand remain the same; i.e., AT to GC, TA to GC ...
transition state
The activated state of a molecule that has partly undergone a chemicalreaction.
Please contribute to this project, if you have more information about this term feel free to edit this page ...
The mitochondrial permeability transition (mPT) involves the opening of a non-specific pore in the inner membrane of mitochondria, converting them from organelles whose production of ATP sustains the cell, to instruments of death.
transitions: replacement of a purine base with another purine or replacement of a pyrimidine with another pyrimidine
transversions: replacement of a purine with a pyrimidine or vice versa.
Transition vesicles pinch off from the surface of the endoplasmic reticulum carrying
integral membrane proteins
soluble proteins awaiting processing
processing enzymes ...
Transition mutation
A base substitution mutation where a purine is replaced by a different purine, or a pyrimidine is replaced by a different pyrimidine.
transition reaction Biochemical process of converting 3-carbon pyruvate into 2-carbon acetyl and attaching it to coenzyme A (CoA) so it can enter Kreb's cycle. Carbon dioxide is also released and NADH is formed (from NAD and H) in this process.
Transition A mutation which has changed one purine (A, G) into the other, or one pyrimidine (C, T) into the other. See transversion.
Translation The process of copying a mRNA into a polypeptide chain mediated by the ribosomes.
transition A type of point mutation in which one purine or pyrimidine is replaced by another base of the same type. Examples: A-G and C-T.
Transition-state intermediate. In a chemical reaction, an unstable and high-energy configuration assumed by reactants on the way to making products.
Transition
The term proposed by Freese (1959) for a mutation caused by the substitution in DNA or RNA of one purine by the other, and similarly with the pyrimidines. (Cf. transversion.)
Related Terms:
Mutation ...
Transition in the species composition of a biological community, often following ecological disturbance of the community; the establishment of a biological community in an area virtually barren of life.
ecology ...
Transition mutation
- A base-pair substitution mutation resulting in the replacement of one purine by another purine or of one pyrimidine by another pyrimidine
Translation ...
transition state - structure that forms transiently in the course of a chemical reaction and has the highest free energy of any reaction intermediate; a rate-limiting step in the
reaction.
transitional mutants A type of mutation in which a single purine-pyrimidine base pair is replaced by another.
transitional zone A zone in which populations from two or more adjacent communities meet and overlap.
The transition state in a reaction is the point at which the original bonds have stretched to their limit. Transition states are only in existence for extremely brief (10-15 s) periods of time.
The transition to eukaryotic cells appears to have occurred during the Proterozoic Era, about 1.2 to 1.5 billion years ago. However, recent genetic studies suggest eukaryotes diverged from prokaryotes closer to 2 billion years ago.
The transition to modern humans is one that people argue about. Did it happen subsequent to that time? Did it happen over a broad front? Did it happen to one group of individuals or one small tribe, who then became modern humans?
As a transition step from fact gathering to principle development, the task force worked to define problems presented by genetic information in the areas of underwriting, reimbursement, and records management.
Problem 3: Transition to a 2- or 3-layered embryo
At what stage of animal development do cells first move from the surface of the embryo into the interior, resulting in a two- or three-layered embryo?
A. ...
However, depending upon a number of factors, including the exact composition of the bilayer and temperature, plasma membranes can undergo phase transitions which render their molecules less dynamic and produce a more gel-like or nearly solid ...
An antibody selected for its ability to catalyze a chemical reaction by binding to and stabilizing the transition state intermediate. Catalytic RNA (ribozyme). A natural or synthetic RNA molecule that cuts an RNA substrate. Cation.
Its epithelium is of a transitional character, and resembles that found in the bladder (see Fig. 1141).
A focus on new model organisms such as viruses and bacteria, along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of molecular genetics.
When a protein is made in the ER, something called a transition vesicle is made. This vesicle or sac floats through the cytoplasm to the Golgi apparatus and is absorbed.
As an inert system, it will experience a phase transition to a phase known as denaturalization, or it will go through a phase of disintegration.
Redox-potential discontinuity. That depth below the sediment-water interface marking the transition from chemically oxidative to reducing processes
Red tide. A dense outburst of phytoplankton (usually dinoflagellates) often coloring water red brown ...
Catalytic antibodies Antibodies generated by using transition-state analogs of a particular reaction as antigens. Such antibodies often function as catalysts for the reaction. Also called abzymes.
The bladder is lined by an interesting transitional epithelium which allows it to expand so that the urine can be stored. Urine is released by the bladder into the urethra, the tube which leads to the exterior.
And these are [a] critical transition from a diploid cell to a haploid cell to allow normal reproduction to occur, ...
It is described in terms of calcite or aragonite mineralogy and the transition between different zones of organization within the shell. Distinct zones of organization are called ultrastructure zones.
 See also: Trans, Organ, Cells, Human, Protein
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