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Free DNA Structure and Function Read Download - video Dailymotion
4/22/ · Download full-text PDF. Read full-text. Download citation. Copy link Link copied. DNA structure and function A. Travers and G. Muskhelishvili. Huppert JL & . 4/12/ · read for donwoad blogger.com?book= 10/27/ · interior structure of DNA some hydrophobic driving force as well • pair structure allows template for semi-conservative copying Information in DNA sequence is the genome • genes are stretches of information in the sequence that encode for particular function (usually a particular protein, but sometimes also an RNA sequence).
Dna structure and function pdf download
In Microbial Metabolism, we discussed three classes of macromolecules: proteins, lipids, and carbohydrates, dna structure and function pdf download. In this chapter, we will discuss a fourth class of macromolecules: nucleic acids. Like other macromolecules, nucleic acids are composed of monomers, called nucleotides, which are polymerized to form large strands.
Each nucleic acid strand contains certain nucleotides that appear in a certain order within dna structure and function pdf download strand, dna structure and function pdf download, called its base sequence. The base sequence of deoxyribonucleic acid DNA is responsible for carrying and retaining the hereditary information in a cell.
In Mechanisms of Microbial Genetics, we will discuss in detail the ways in which DNA uses its own base sequence to direct its own synthesis, as well as the synthesis of RNA and proteins, which, in turn, gives rise to products with diverse structure and function. In this section, we will discuss the basic structure and function of DNA. The building blocks of nucleic acids are nucleotides. Nucleotides that compose DNA are called deoxyribonucleotides. A nucleoside comprises the five-carbon sugar and nitrogenous base.
The nitrogenous bases adenine A and guanine G are the purines; they have a double-ring structure with a six-carbon ring fused to a five-carbon ring. The pyrimidines, cytosine C and thymine Tare smaller nitrogenous bases that have only a six-carbon ring structure, dna structure and function pdf download. Individual nucleoside triphosphates combine with each other by covalent bonds known as 5ʹ-3ʹ phosphodiester bonds, or dna structure and function pdf download whereby the phosphate group attached to the 5ʹ carbon of the sugar of one nucleotide bonds to the hydroxyl group of the 3ʹ carbon of the sugar of the next nucleotide.
During the polymerization process, deoxynucleotide triphosphates dNTP are used. To construct the sugar-phosphate backbone, the two terminal phosphates are released from the dNTP as a pyrophosphate. The resulting strand of nucleic acid has a free phosphate group at the 5ʹ carbon end and a free hydroxyl group at the 3ʹ carbon end.
The two unused phosphate groups dna structure and function pdf download the nucleotide triphosphate are released as pyrophosphate during phosphodiester bond formation. Pyrophosphate is subsequently hydrolyzed, releasing the energy used to drive nucleotide polymerization. By the early s, considerable evidence had accumulated indicating that DNA was the genetic material of cells, and now the race was on to discover its three-dimensional structure.
Around this time, Austrian biochemist Erwin Chargaff 1 — examined the content of DNA in different species and discovered that adenine, thymine, guanine, and cytosine were not found in equal quantities, and that it varied from species to species, dna structure and function pdf download, but not between individuals of the same species.
Other scientists were also actively exploring this field during the midth century. Pauling had earlier discovered the structure of protein α helices, using X-ray diffraction, and, based upon X-ray diffraction images of DNA made in his laboratory, he proposed a triple-stranded model of DNA. Unfortunately, by then Franklin had died, and Nobel prizes at the time were not awarded posthumously.
Work continued, however, on learning about the structure of DNA. Which scientists are given most of the credit for describing the molecular structure of DNA? Watson and Crick proposed that DNA is made up of two strands that are twisted around each other to form a right-handed helix.
The 3ʹ end of each strand has a free hydroxyl group, while the 5ʹ end of each strand has a free phosphate group. The sugar and phosphate of the polymerized nucleotides form the backbone of the structure, whereas the nitrogenous bases are stacked inside.
These nitrogenous bases on the interior of the molecule interact with each other, dna structure and function pdf download pairing, dna structure and function pdf download. These grooves are locations where proteins can bind to DNA. Base pairing takes place between a purine and pyrimidine.
The base pairs are stabilized by hydrogen bonds; adenine and thymine form two hydrogen bonds between them, whereas cytosine and guanine form three hydrogen bonds between them.
In the laboratory, exposing the two DNA strands of the double helix to high temperatures or to certain chemicals can break the hydrogen bonds between complementary bases, thus separating the strands into two separate single strands of DNA single-stranded DNA [ssDNA]. This process is called DNA denaturation and is analogous to protein denaturation, as described in Proteins. The ssDNA strands can also be put back together as double-stranded DNA dsDNAthrough reannealing or renaturing by cooling or removing the chemical denaturants, allowing these hydrogen bonds to reform.
What are the two complementary base pairs of DNA and how are they bonded together? DNA stores the information needed to build and control the cell. The transmission of this information from mother to daughter cells is called vertical gene transfer and it occurs through the process of DNA replication.
DNA is replicated when a cell makes a duplicate copy of its DNA, then the cell divides, resulting in the correct distribution of one DNA copy to each resulting cell. DNA can also be enzymatically degraded and used as a source of nucleosides and nucleotides for the cell. Unlike other macromolecules, DNA does not serve a structural role in cells.
Historically, women have been underrepresented in the sciences and in medicine, and often their pioneering contributions have gone relatively unnoticed. For example, although Rosalind Franklin performed the X-ray diffraction studies demonstrating the double helical structure of DNA, it is Watson and Crick who became famous for this discovery, dna structure and function pdf download, building on her data.
There still remains great controversy over whether their acquisition of her data was appropriate and whether personality conflicts and gender bias contributed to the delayed recognition of her significant contributions.
Today, women still remain underrepresented in many fields of science and medicine. In academia, the number of women at each level of career advancement continues to decrease, with women holding less than one-third of the positions of Ph. Why do such disparities continue to exist and how do we break these cycles? The situation is complex and likely results from the combination of various factors, including how society conditions the behaviors of girls from a young age and supports their interests, both professionally and personally.
Some have suggested that women do not belong in the laboratory, including Nobel Prize winner Tim Hunt, whose public comments suggesting that women are too emotional for science 9 were met with widespread condemnation. Contributions by women in science should be made known more widely to the public, and marketing targeted to young girls should include more images of historically and professionally successful female scientists and medical professionals, encouraging all bright young minds, including girls and women, to pursue careers in science and medicine.
Possibilities include bacterial infection e. His physician orders a stool sample to identify possible causative agents e. The physician instructed Alex to drink lots of fluids to replace what he was losing and discharged him from the hospital.
ETEC produces several plasmid-encoded virulence factors that make it pathogenic compared with typical E. These include the secreted toxins heat-labile enterotoxin LT and heat-stabile enterotoxin STas well as colonization factor CF. Dna structure and function pdf download LT and ST cause the excretion of chloride ions from intestinal cells to the intestinal lumen, causing a consequent loss of water from intestinal cells, resulting in diarrhea.
CF encodes a bacterial protein that aids in allowing the bacterium to adhere to the lining of the small intestine. Purines always base pairs with pyrimidines. Adenine binds to guanine. Base pairs are stabilized by hydrogen bonds.
Base pairing occurs at the interior of the double helix. Hydrogen bonds between complementary bases break. Phosphodiester bonds break within the sugar-phosphate backbone. Hydrogen bonds within the sugar-phosphate backbone break. Phosphodiester bonds between complementary bases break. Dna structure and function pdf download work of Rosalind Franklin and R. Gosling was important in demonstrating the helical nature of DNA.
What is the role of phosphodiester bonds within the sugar-phosphate backbone of DNA? In considering the structure of the DNA double helix, how would you expect the structure to differ if there was base pairing between two purines?
Between two pyrimidines? Learning Objectives Describe the biochemical structure of deoxyribonucleotides Identify the base pairs used in the synthesis of deoxyribonucleotides Explain why the double helix of DNA is described as antiparallel. DNA Nucleotides The building blocks of nucleic acids are nucleotides. Thymine is unique to DNA. Note the 5ʹ and 3ʹ ends of this nucleic acid strand.
Discovering the Double Helix By the early s, considerable evidence had accumulated indicating that DNA was the genetic material of cells, and now the race was on to discover its three-dimensional structure. The 5ʹ end is the one where carbon 5 is not bound to another nucleotide; the 3ʹ end is the one where carbon 3 is not bound to another nucleotide. Key Concepts and Summary Nucleic acids are composed of nucleotideseach of which contains a pentose sugar, a phosphate group, and a nitrogenous base.
Deoxyribonucleotides within DNA contain deoxyribose as the pentose sugar. DNA contains the pyrimidines cytosine and thymineand the purines adenine and guanine. Nucleotides are linked together by phosphodiester bonds between the 5ʹ phosphate group of one nucleotide and the 3ʹ hydroxyl group of another. A nucleic acid strand has a free phosphate group at the 5ʹ end and a free hydroxyl group at the 3ʹ end.
Chargaff discovered that the amount of adenine is approximately equal to the amount of thymine in DNA, and that the amount of the guanine is approximately equal to cytosine. These relationships were later determined to be due to complementary base pairing. Watson and Crick, building on the work of Chargaff, Franklin and Gosling, and Wilkins, proposed the double helix model and base pairing for DNA structure.
DNA is composed of two complementary strands oriented antiparallel to each other with the phosphodiester backbones on the exterior of the molecule. The nitrogenous bases of each strand face each other and complementary bases hydrogen bond to each other, stabilizing the double helix.
Heat or chemicals can break the hydrogen bonds between complementary bases, denaturing DNA. Cooling or removing chemicals can lead to renaturation or reannealing of DNA by allowing hydrogen bonds to reform dna structure and function pdf download complementary bases.
DNA stores the instructions needed to build and control the cell. This information is transmitted from parent to offspring through vertical gene transfer. Footnotes 1 N. Kresge et al. Watson, F. Wilkins et al. Franklin, R. Day et al. Seabury et al. Accessed June 10,
DNA Structure, Function \u0026 Replication
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Check Pages 1 - 41 of DNA Gyrase: Structure and Function - Informa in the flip PDF version. DNA Gyrase: Structure and Function - Informa was published by on Find more similar flip PDFs like DNA Gyrase: Structure and Function - Informa. Download DNA Gyrase: Structure and Function - Informa PDF for free. DNA (DNA = deoxyribonucleic acid) • DNA is the genetic material of all living cells and of many viruses. • DNA is: an alpha double helix of two polynucleotide strands. • The genetic code is the sequence of bases on one of the strands. • A gene is a specific sequence of bases which has the information for a particular protein. • DNA is self-replicating - it can make an identical copy. DNA (DNA = deoxyribonucleic acid) • DNA is the genetic material of all living cells and of many viruses. • DNA is: an alpha double helix of two polynucleotide strands. • The genetic code is the sequence of bases on one of the strands. • A gene is a specific sequence of bases which has the information for a particular protein. • DNA is self-replicating - it can make an identical copy File Size: KB.
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