Algae, Tree, Herbs, Bush, Shrub, Grasses, Vines, Fern, Moss, Spermatophyta, Bryophyta, Fern Ally, Flower, Photosynthesis, Eukaryote, Prokaryote, carbohydrate, vitamins, amino acids, botany, lipids, proteins, cell, cell wall, biotechnology, metabolities, enzymes, agriculture, horticulture, agronomy, bryology, plaleobotany, phytochemistry, enthnobotany, anatomy, ecology, plant breeding, ecology, genetics, chlorophyll, chloroplast, gymnosperms, sporophytes, spores, seed, pollination, pollen, agriculture, horticulture, taxanomy, fungi, molecular biology, biochemistry, bioinfomatics, microbiology, fertilizers, insecticides, pesticides, herbicides, plant growth regulators, medicinal plants, herbal medicines, chemistry, cytogenetics, bryology, ethnobotany, plant pathology, methodolgy, research institutes, scientific journals, companies, farmer, scientists, plant nutrition
Select Language:
 
   
 
 
Can't find? Try Deep Search with ePlantScience.com  
 
Share |
 
   
Main Menu
If navigation gets difficult, please click the main subject or sitemap to get the list of sub-categories
 
 
 
 
 
Related websites
 
 
 
 
 
 
 
 
Section: Genetics » Mutations » Molecular Level (Mechanism)
 
 
If you like this page, please click:  
 
 
  Effect of physical conditions on nucleotide sequence
 
     
 
Content
⇒ Mutations: 3.  Molecular Level (Mechanism)
⇒ Mutations and nucleotide sequences in nucleic acid 
⇒ Effect of chemical mutagens on nucleotide sequence
⇒ Effect of dyes on nucleotide sequence
⇒ Effect of physical conditions on nucleotide sequence
⇒ Effect of radiations on nucleotide sequence
⇒ Spontaneous mutations and nucleotide sequence
⇒ Mutation and amino acid sequences in proteins (including colinearity hypothesis)
⇒ Suppressor mutations, tRNAs and ribosomes

Exposure to low pH. At low pH (below 4), some bases become positively charged and strand separation occurs, which may be lethal. At pH 4 or above, this effect is negligible. But low pH can effect DNA by two additional reactions which are active even above pH 4.

(a) Depurination. Complete removal of adenine (A) or guanine (G) at low pH has been reported. At pH 1-6, guanine (G) is liberated initially more readily than adenine (A). This will lead to base pair substitutions which could be either transversions or transitions (Fig. 23.27).

(b) Backbone breakage. At low pH (even as low as 1-6), backbone breakage also occurs. Whenever the sugar-phosphate backbone breaks, it should be lethal.
  
Four different possibilities following depurination in GC base pair. Note that both transversion and transition may be induced.
Fig. 23.27. Four different possibilities following depurination in GC base pair. Note that both transversion and transition may be induced.

Exposure to high temperatures. High temperature causes strand separation and should be lethal. Besides this, it also causes some depurination of DNA.
 
     






     
     
 
 
     
 
Copyrights 2009 © ePlantScience.com