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Description
Flashcards by louisa.slinger4825, updated more than 1 year ago
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Created by louisa.slinger4825
over 12 years ago
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| Question | Answer |
| Outline the difference between DNA and RNA | DNA is double stranded while RNA is single stranded DNA contains a deoxyribose sugar and RNA a ribose sugar. DNA contains the nitrogen base thymine, and RNA has uracil. There is only 1 type of DNA but RNA has messenger and transfer. |
| Outline the production of messenger RNA | The DNA molecule in the nucleus partly unzips and the code of nitrogen bases on the DNA is transferred to messenger RNA. Adenine bonds to Uracil and Guanine bonds to Cytosine, any non-coding sequences are removed at this point and the mRNA travels through the nuclear membrane to the cytoplasm. |
| Outline the role of transfer RNA | tRNA picks up amino acids in the cytoplasm and brings them to the mRNA that is attached to the ribosome. The first and second amino acids brought to the ribosome attach together, forming a peptide bond. |
| Outline the formation of the polypeptide chain(s) | The amino acids that link together will be determined by the order of bases on the mRNA, this linking continues down the code on the mRNA until a stop codon is reached and then the chain of amino acids is released by the ribosome. This chain of amino acids is a polypeptide chain. |
| Outline the formation of the protein from polypeptide chains | The forming of protein occurs by the long polypeptide chain folding in particular shapes. The way they fold largely depends on the order of amino acids. They fold several times to give their final structure. |
| Describe the technique of gene splicing using restriction enzymes and ligases to produce recombinant DNA | The gene for insulin production in humans can be pasted into the DNA of Escherichia coli, a bacterium that inhabits the human digestive tract. This is done by cutting the appropriate gene from human DNA and pasting, or splicing, it into plasmid DNA, a special kind of DNA that takes a circular form and can be used as a vehicle for this editing job. It is cut using a class of enzymes called restriction enzymes. There are well over a hundred restriction enzymes, each cutting in a very precise way a specific base sequence of the DNA molecule. With these scissors used singly or in various combinations, the segment of the human DNA molecule that specifies insulin production can be isolated. This segment is "glued" into place using an enzyme called DNA ligase. The result is an edited, or recombinant, DNA molecule. The bacterial cells divide very rapidly making billions of copies of themselves, and each bacterium carries in its DNA a faithful replica of the gene for insulin production. Each new E. coli cell has inherited the human insulin gene sentence.` |
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