restriction point

Examples of restriction point in the following topics:

• Regulation of the Cell Cycle at Internal Checkpoints

  • A checkpoint is one of several points in the eukaryotic cell cycle at which the progression of a cell to the next stage in the cycle can be halted until conditions are favorable (e.g. the DNA is repaired).
  • The G1 checkpoint, also called the restriction point (in yeast), is a point at which the cell irreversibly commits to the cell division process.
  • At this point, the cell also checks for DNA damage.

• History of DNA Research

  • However, there remained questions of how many strands came together, whether this number was the same for every helix, whether the bases pointed toward the helical axis or away, and ultimately, what were the explicit angles and coordinates of all the bonds and atoms.
  • In their modeling, Watson and Crick restricted themselves to what they saw as chemically and biologically reasonable.

• Molecular and Cellular Cloning

  • The MCS is a short DNA sequence containing multiple sites that can be cut with different commonly-available restriction endonucleases.
  • Restriction endonucleases recognize specific DNA sequences and cut them in a predictable manner; they are naturally produced by bacteria as a defense mechanism against foreign DNA.
  • Many restriction endonucleases make staggered cuts in the two strands of DNA, such that the cut ends have a 2- or 4-base single-stranded overhang.
  • In this way, any DNA fragment generated by restriction endonuclease cleavage can be spliced between the two ends of a plasmid DNA that has been cut with the same restriction endonuclease .

• The Work of Breathing

  • Examples of restrictive diseases are respiratory distress syndrome and pulmonary fibrosis.
  • In these types of restrictive diseases, the intrapleural pressure is more positive and the airways collapse upon exhalation, which traps air in the lungs.
  • The ratio of FEV1 (the amount of air that can be forcibly exhaled in one second after taking a deep breath) to FVC (the total amount of air that can be forcibly exhaled) can be used to diagnose whether a person has restrictive or obstructive lung disease.

• Genetic Maps

  • Some genetic markers used in generating genetic maps are restriction fragment length polymorphisms (RFLP), variable number of tandem repeats (VNTRs), microsatellite polymorphisms, and the single nucleotide polymorphisms (SNPs).
  • RFLPs (sometimes pronounced "rif-lips") are detected when the DNA of an individual is cut with a restriction endonuclease that recognizes specific sequences in the DNA to generate a series of DNA fragments, which are then analyzed by gel electrophoresis.
  • The DNA of every individual will give rise to a unique pattern of bands when cut with a particular set of restriction endonucleases; this is sometimes referred to as an individual's DNA "fingerprint."

• Integration of Signals from Mechanoreceptors

  • The relative density of pressure receptors in different locations on the body can be demonstrated experimentally using a two-point discrimination test.
  • The subject reports if they feel one point or two points.
  • If the two points are felt as one point, it can be inferred that the two points are both in the receptive field of a single sensory receptor.
  • If two points are felt as two separate points, each is in the receptive field of two separate sensory receptors.
  • The points could then be moved closer and re-tested until the subject reports feeling only one point.

• Characteristics of Amniotes

  • This was a significant development that distinguished them from amphibians, which were restricted to moist environments due their shell-less eggs.

• Nephron: The Functional Unit of the Kidney

  • The third part of the renal tubule is called the distal convoluted tubule (DCT); this part is also restricted to the renal cortex.

• Changing Human Behavior in Response to Biodiversity Loss

  • Many nations have laws that protect endangered species: for example, forbidding hunting, restricting land development, or creating preserves.
  • Captive breeding is the process of breeding rare or endangered species in human-controlled environments with restricted settings, such as wildlife preserves and conservation facilities.

• Phylogenetic Trees

  • The point where a split occurs, called a branch point, represents where a single lineage evolved into a distinct new one.
  • When two lineages stem from the same branch point, they are called sister taxa.
  • Another point to mention on phylogenetic tree structure is that rotation at branch points does not change the information.
  • A branch point indicates where two lineages diverged.
  • When two lineages stem from the same branch point, they are sister taxa.