Grayce P. Storey
Mutation can occur in plants creating a new variety. Mutation is a change in genes or chromosomes which cause a new trait to be inherited.
When mutation occurs in a body cell, only that organism that carries the mutant gene is affected. An example is sickle cell anemia. If mutation occurs in a sex cell, that mutation can be expressed in the next generation. It is a possibility that the characters of the next generation may be changed.
Some mutations are harmful and can reduce an organism’s chance of survival or reproduction.
There are also some helpful mutations. An example is the Katahdin potato. This new potato variety resists diseases that attack other potatoes.
Most mutations are neutral and do not produce any obvious changes.
In 1946, professor Muller, earned the Nobel Peace Prize in physiology, his work concluded that mutation could be produced by an environmental agent, such as X-rays. However, since that time scientists have evidence that ionizing irradiations, various chemicals, and heat shocks are mutgenic agents.
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NITROGENBASES
The structure of DNA resembles a spiral staircase. The rungs in the staircase are formed by pairs of nitrogen bases. The order of the nitrogen bases determine the particular genes of the DNA molecule. The code is the order of nitrogen bases on the DNA molecule. It is the variation in the arrangement of the bases that determines the individual’s heredity.
In RNA, the nucleotide bases are U, C, A, and G. In the RNA the U takes the place of the T. There are 20 amino acids and each have more than one codon. The code for amino acids is based on triplets. The codons for the amino acid phenylalanine are UUU and UUC.
DNA (Deoxyribonucleic Acid)
The key to all of the “why” questions is locked up in the DNA. DNA is the basic substance of heredity and is found in every cell in the body. It contains all of the information needed to make and control every cell of an organism and is there-by called the code of life.
DNA is the major component of chromosomes. There is also a basic protein component in the chromosomes. In some viruses the genetic determinants are RNA rather than DNA. DNA appears to be the heredity material of the majority of life forms.
The DNA molecules have two functions: replicating themselves and directing the synthesis of RNA. Each complementary strand of the double helical structure directs the synthesis of its complementary strand. In the rebuilding process each half of the two complete molecules will specify that its new complement be an exact copy of the original.
“DNA is to serve as a template of RNA synthesis. The biosynthesized RNA molecule copies the base sequence of the DNA, so that it transcribes the information carried in the original genetic code. The function of RNA is to carry the genetic message from DNA to the cytoplasm to conduct protein biosynthesis.” Chromosomes synthesize RNA only in the interphase stage.
DNA is a chemical structure in the body put together like a string of beads. This unit is made up of four bases: T-thymine, A-adenine, C-cytosine, G-guanine. The angular ring shapes represent rings of linked carbon and nitrogen atoms. Each base is attached to a sugar and phosphate molecule. The sugars are rings of carbon and ten or eleven rings of oxygen, and the base is attached directly to the sugar. The base-sugar phosphate units of DNA chain are called nucleotides.
Human DNA is broken up into 46 chromosomes in each of or 60 trillion body cells. If all of our cells’s DNA were laid end to end it would reach the sun and back many times.
DNA STRUCTURE
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