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Why are Rf values always less than 1?
Rf values are distance of substance from origin divided by distance of solvent front from origin. As the substance travels with the solvent, the solvent will always have a greater or equal value to the distance travelled by substance. This means the highest value of Rf is 1.
What does a frequency of recombination of 50 percent indicate?
A recombination frequency is a measure of how likely it is that two genes are linked. It will also tell how likely it is that a crossing over event will occur between those two genes. Thus, for an RF=50% it is random as to whether or not the genes will be inherited together or whether crossing over will separate them (i.e. they independently assort). Traditionally, following Mendel's Second Law (that alleles of genes independently assort), an RF=50% means that the two genes are on different chromosomes; a slightly more complicated corollary is that the two genes need not be on different chromosomes but may be on the same chromosome just very far apart from each other. Thus, the smaller the RF (maximum RF is 50%), the more likely it is that two genes are linked.
what are the following processes releases energy to be used by a cell?
Chemical reactions that release energy are called exergonic. Cellular processes that release energy are called catabolic, or catabolism. {I remember this by thinking 'What does a cat do with its claws to your furniture - it breaks things down.' Also, anabolic steroids are for 'building up'.} The main energy producing catabolic reactions occur using Respiration that releases usable biochemical energy in the form of Atp.
CSF oligoclonal banding?
DefinitionCSF oligoclonal banding is a test to look for inflammation-related proteins in the cerebrospinal fluid (CSF), the clear fluid that flows in the space surrounding the spinal cord and brain.Oligoclonal bands are proteins called immunoglobulins, which suggest inflammation of the central nervous system. The presence of oligoclonal bands may be a sign of multiple sclerosis.Alternative NamesCerebrospinal fluid - immunofixationHow the test is performedA sample of CSF is needed. A lumbar puncture (spinal tap) is the most common way to collect this sample. For information on this procedure, see the article on lumbar puncture.Other methods for collecting CSF are rarely used, by may be recommended in some cases. They include:Cisternal punctureVentricular punctureRemoval of CSF from a tube that is already in the CSF, such as a shunt or ventricular drain.After the sample is taken, it is sent to a laboratory for evaluation.How to prepare for the testSee: Lumbar punctureHow the test will feelSee: Lumbar punctureWhy the test is performedThis test helps support, but does not confirm, the diagnosis of multiple sclerosis(MS). The presence of oligoclonal bands in the CSF can also be seen in other illnesses.Normal ValuesNormally, one or no bands should be found in the CSF.Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.What abnormal results meanThere are two or more bandings found in the CSF and not in the blood. This may be a sign of multiple sclerosis or other inflammatory processes.What the risks areSee: Lumbar punctureReferencesGriggs RC, Jozefowicz RF, Aminoff MJ. Approach to the patient with neurologic disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier. 2007: chap 418.
Do all leaves extracts contain the same pigments?
Yes, all leaves contain the same pigments but they contain it at different concentrations. Like in the summer all leaves are green (they all contain chlorophyll) and in the autumn, almost all leaves turn brown, orange, or yellow (contain carotenes, lutein, or xanthophylls). These are only seen when the chlorophyll breaks down like in the autumn, but they are not seen when the chlorophyll comes back like in the spring and summer.
What is the maximum and RF value can be?
The maximum RF value that can be obtained is 1.0. This means that the substance travels the full distance of the chromatography medium being used. Any RF value greater than 1 is not physically possible.
What is the relationship between chain length and Rf value?
As a general rule the longer the carbon chain the greater the Rf value.
What is the Significance of Rf value?
· Used in identification pusposes · Use to determine the affinity of the solute to the solvent - Greater Rf , greater affinity of solute to the solvent
Why are Rf values always less than 1?
Rf values are distance of substance from origin divided by distance of solvent front from origin. As the substance travels with the solvent, the solvent will always have a greater or equal value to the distance travelled by substance. This means the highest value of Rf is 1.
What is the RF value for red ink blue ink and green ink?
the Rf value value is 8.44 as the particles are lighter than the solvent
What is the rf value of cocaine?
Rf is about .45
What is the Rf value of salicylamide?
It will depend on the solvent system you are using.
If solute B is more soluble in water than A which one should have the larger Rf value?
If solute B is more soluble in water than solute A, then solute B should have a smaller Rf value than solute A. This is because solute B will travel less distance with the solvent front compared to solute A, resulting in a smaller Rf value for solute B.
What is rf value and how is determine?
the mobility of any component in a particular solvent is referred to as its RF value. Mathematically, RF value = distance travelled by solute/ distance travelled by the solvent
Why can't an RF value of more than 1 be calculated?
An RF (retention factor) value greater than 1 cannot be calculated because it represents the ratio of the distance traveled by a compound to the distance traveled by the solvent front on a chromatography plate. If a compound travels further than the solvent front, it suggests that the compound has not interacted properly with the stationary phase, which is not a valid scenario in chromatography. Therefore, RF values are always between 0 and 1, indicating that the compound can only travel a distance equal to or less than the solvent front.
What is an rf value used for?
The rf value is shorthand for the retention value of a substance. It is used in chromatography to determine the components of an unknown sample.
What is the significance of Rf value in chromatography?
The Rf value, or retention factor, in chromatography is a measure of how far a compound travels in relation to the solvent front in a chromatogram. It helps in identifying and characterizing compounds based on their movement and separation in the chromatographic system. Comparing Rf values can aid in qualitative analysis, determination of purity, and identification of unknown components within a sample.
