TAILIEUCHUNG - Biochemistry, 4th Edition P38

Biochemistry, 4th Edition P38. Continuing Garrett and Grisham's innovative conceptual and organizing framework, "Essential Questions," BIOCHEMISTRY guides students through course concepts in a way that reveals the beauty and usefulness of biochemistry in the everyday world. Streamlined for increased clarity and readability, this edition also includes new photos and illustrations that show the subject matter consistently throughout the text. New end-of-chapter problems, MCAT practice questions, and the unparalleled text/media integration with the power of CengageNOW round out this exceptional package, giving you the tools you need to both master course concepts and develop critical problem-solving skills you can draw upon. | Can DNA Adopt Structures of Higher Complexity 333 Native DNA Denatured DNA FIGURE Steps in the thermal denaturation and renaturation of nucleation phase of the reaction is a second-order process depending on sequence alignment of the two strands 1 . This process takes place slowly because it takes time for complementary sequences to encounter one another in solution and then align themselves in register. Once the sequences are aligned the strands zipper up quickly 2 . Renatured DNA of hybridization is a measure of the sequence similarity or relatedness between the two species. Depending on the conditions of the experiment about 25 of the DNA from a human forms hybrids with mouse DNA implying that some of the nucleotide sequences genes in humans are very similar to those in mice Figure . Mixed RNA DNA hybrids can be created in vitro if single-stranded DNA is allowed to anneal with RNA copies of itself such as those formed when genes are transcribed into mRNA molecules. Nucleic acid hybridization is a commonly employed procedure in molecular biology. First it can reveal evolutionary relationships. Second it gives researchers the power to identify specific genes selectively against a vast background of irrelevant genetic material An appropriately labeled oligonucleotide or polynucleotide referred to as a probe is constructed so that its sequence is complementary to a target gene. The probe specifically base pairs with the target gene allowing identification and subsequent isolation of the gene. Also the quantitative expression of genes in terms of the amount of mRNA synthesized can be assayed by hybridization experiments. Can DNA Adopt Structures of Higher Complexity DNA can adopt regular structures of higher complexity in several ways. For example many DNA molecules are circular. Most but not all bacterial chromosomes are covalently closed circular DNA duplexes as are most plasmid DNAs. Plasmids are naturally occurring self-replicating .

• Sinh học
• Nền tảng của hóa sinh học
• trao đổi chất protein
• RNA trao đổi chất
• nguyên tắc của hóa sinh
• Axit amin
• công nghệ DNA