ခုတစ္ေလာ ေခါင္းထဲမွာ အေတြးေတြ ေခ်ာက္ေအာင္ လာလာစားေနတဲ႔ အသံုးအႏွဳန္းေတြပါ။ အရွည္ကိုေတာ႔ မလုိက္ႏိုင္ေသးလို႔ အဓိပၸါယ္ဖြင္႔ဆိုခ်က္တစ္ခ်ိဳ႔ကို တင္လိုက္ပါတယ္။ အသံုး၀င္ႏိုင္ပါေစ။
What is Polymerization?
Without polymers, mankind couldn't exist. People use manmade plastics such as polypropylene and polyvinyl chloride (i.e., PVC) in hospitals, schools and their own homes. Yet, man-made plastic accounts for only a small percentage of polymers. Rubber and cellulose, which are natural polymers, are used to make everything from tires to cellophane to rayon. Deoxyribonucleic acid (i.e., DNA) and protein are also natural polymers.
As important as polymers are, they wouldn't exist without monomers, which are small, single molecules such as hydrocarbons and amino acids. These monomers bond together to form polymers. The process by which these monomers bond is called polymerization.
Allele
One of the variant forms of a gene at a particular locus, or location, on a chromosome. Different alleles produce variation in inherited characteristics such as hair color or blood type. In an individual, one form of the allele (the dominant one) may be expressed more than another form (the recessive one).
Pseudogene
A sequence of DNA that is very similar to a normal gene but that has been altered slightly so it is not expressed. Such genes were probably once functional but over time acquired one or more mutations that rendered them incapable of producing a protein product.
Crossing over
The term coined by Morgan and Cattell (1912) for the occurrence of new combinations of linked characters. With the acceptance of the chromosome theory, the term is applied to the breaking during meiosis of one maternal and one paternal chromosome, the exchange of corresponding sections of DNA, and the rejoining of the chromosomes. This process can result in an exchange of alleles between chromosomes and gives rise to new character combinations. Compare recombination.
Gene Conversion
A meiotic process of directed change in which one allele directs the conversion of a partner allele to its own form. In asci of Ascomycete fungi a 4:4 ratio of alleles is expected after meiosis, yet 6:2 and 5:3 ratios are sometimes observed. A model of recombination, produced by Holliday, suggests that gene conversion may be explained by repair of heteroduplex DNA.
Genomic imprinting
Genomic imprinting is a genetic phenomenon by which certain genes are expressed in a parent-of-origin-specific manner. Imprinted genes are either expressed only from the allele inherited from the mother (eg. H19 or CDKN1C), or in other instances from the allele inherited from the father (eg. IGF2). Forms of genomic imprinting have been demonstrated in insects, mammals and flowering plants.
What is Polymerization?
Without polymers, mankind couldn't exist. People use manmade plastics such as polypropylene and polyvinyl chloride (i.e., PVC) in hospitals, schools and their own homes. Yet, man-made plastic accounts for only a small percentage of polymers. Rubber and cellulose, which are natural polymers, are used to make everything from tires to cellophane to rayon. Deoxyribonucleic acid (i.e., DNA) and protein are also natural polymers.
As important as polymers are, they wouldn't exist without monomers, which are small, single molecules such as hydrocarbons and amino acids. These monomers bond together to form polymers. The process by which these monomers bond is called polymerization.
Allele
One of the variant forms of a gene at a particular locus, or location, on a chromosome. Different alleles produce variation in inherited characteristics such as hair color or blood type. In an individual, one form of the allele (the dominant one) may be expressed more than another form (the recessive one).
Pseudogene
A sequence of DNA that is very similar to a normal gene but that has been altered slightly so it is not expressed. Such genes were probably once functional but over time acquired one or more mutations that rendered them incapable of producing a protein product.
Crossing over
The term coined by Morgan and Cattell (1912) for the occurrence of new combinations of linked characters. With the acceptance of the chromosome theory, the term is applied to the breaking during meiosis of one maternal and one paternal chromosome, the exchange of corresponding sections of DNA, and the rejoining of the chromosomes. This process can result in an exchange of alleles between chromosomes and gives rise to new character combinations. Compare recombination.
Gene Conversion
A meiotic process of directed change in which one allele directs the conversion of a partner allele to its own form. In asci of Ascomycete fungi a 4:4 ratio of alleles is expected after meiosis, yet 6:2 and 5:3 ratios are sometimes observed. A model of recombination, produced by Holliday, suggests that gene conversion may be explained by repair of heteroduplex DNA.
Genomic imprinting
Genomic imprinting is a genetic phenomenon by which certain genes are expressed in a parent-of-origin-specific manner. Imprinted genes are either expressed only from the allele inherited from the mother (eg. H19 or CDKN1C), or in other instances from the allele inherited from the father (eg. IGF2). Forms of genomic imprinting have been demonstrated in insects, mammals and flowering plants.
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