...Structure of DNA DNA Structure and replication can be described as the molecule of inheritance. There are many complex issues to its structure and forms of inheritance. One scientist researched the structure of DNA at a time during the 19th century when there was no knowledge of DNA’s role in heredity. By the 1950s a series of discoveries convinced the scientific community that DNA acts as the hereditary material. To describe DNA would be like a blueprint found in every cell in all living organism. Living organisms are made of cells. Every cell has a nucleus, and chromosomes. Human beings have 46 chromosomes that are paired into 23 chromosomes that contain hundreds of genes. The genes contain the formula for proteins that make most of the body. The structural proteins form various essential parts of the body such as skin, hair, and muscle. These chromosomes can be described as a twisted ladder held together by a backbone that is made up of sugar phosphate. Long coils of DNA (Deoxyribonucleic Acid) store all the information that the body needs such as the physical features of how one will look and their everyday functions. The DNA is a thread formed by two strands, twisted together to form a Double Helix. The Double Helix looks like...
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...Associate Program Material DNA Worksheet Answer the following in at least 100 words: 1. Describe the structure of DNA. DNA molecules are composed of two strands that form a helical ascending spiral. They fit together like the opposing teeth of a zipper and are held together by weak interactions called hydrogen bonds. These two strands is a long string of subunits called nucleotides, each attached to the one immediately about it and the one immediately below it to form a long chain. Each nucleotide contains a five-carbon sugar. The five-carbon sugar contains a five-membered ring with an oxygen atom as one of the vertices. Each nucleotide also features a phosphate group and a nitrogen-containing base; these bases are typically represented by adenine, cytosine, thymine, and guanine. The base is attached to carbon 1 of the sugar, biologist denote each of the carbons in the sugar using a number from 1 through 5, where 1 represents the carbon to which the base is attached. 2. How does an organism’s genotype determine its phenotype? The genotype of an organism is the sum total of all the genes that it inherits. It is sort of like a blue print that is designed to serve as a guide in the development of the organism, so that it will become the same kind of creature as the parent or parents that it came from. The phenotype, the organism’s physical trait arises from the actions of a wide variety of proteins. For example structural proteins help make up the body of an...
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...The discovery of the structure of DNA James Watson, Francis Crick, Maurice Wilkins, Rosalind Franklin What did they discover about DNA? James Watson, along with Francis Crick, studied the molecular structure of DNA that had been extracted from cells and showed how it could serve as the chemical basis of inheritance. Although it is commonly known that everything they "discovered" they stole from Rosalind Franklin, who proceeded to obligingly die. That said they're incorrectly famous for discovering that DNA is composed of sequences of purines and pyramidines hydrogen-bonded together and held in place by two sugar-phosphate strands that form a double helix due to more hydrogen bonding. Maurice Wilkins is not credited for the actual discovery of the structure of DNA rather that distinction goes to James Watson and Francis Crick and is known as the Watson-Crick model. Wilkins did share in the Nobel prize because his work in spectroscopic studies on nucleic acids led to the use of X-ray crystallography to define the Watson-Crick model of DNA. Rosalind Franklin discovered the molecular structures of DNA, RNA, viruses, coal and graphite. She was a British biophysicist and X-ray crystallographer who was best known for her work on the X-ray diffraction images of DNA which led to discovery of DNA double helix. Rosalind Franklin's critical contributions to the Crick and Watson model include an X-ray photograph of B-DNA (called photograph 51), that was briefly shown to James Watson...
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...Science Article: 4-Strand DNA Structure Found in Cells Everyone knows that DNA is a double-stranded helix that coils on itself to create a dense chromosome. But scientists have discovered that there is a square-shaped type of DNA structure that can be easily created in the lab by folding synthetic DNA strands that are rich in guanine. A type of hydrogen bonding puts these DNA structures together, and scientists believe that these “G-quadruplex structures” occasionally form in DNA of living cells. Shankar Balasubramanian at the University of Cambridge, UK, provided strong evidence that G-quadruplexes are unusual structures might have important biological functions. These structures have protective tips of chromosomes, also known as telomeres. According to this article, there have been studies in cancer cells that have shown that small molecules that bind and stabilize G-quadruplex structures cause DNA damage at telomeres. Scientists believe that these quadruplex structures can be created in other areas in order to regulate cancer-causing genes. Balasubramanian and his colleagues engineered an antibody that tightly fits to the G-quadruplex structures but does not fit with the double helix. He believes that if they learn to better control the genes or other cellular processes that become diseased such as cancer. I found this article very interesting mainly because I had cancer at a young age and knowing that they are getting closer and closer to finding a cure makes me feel...
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...Nitrogenous bases in DNA DNA is the principle molecule responsible for carrying genetic information within almost all living organisms for their development. They also provide some of the apparatus by which the instructions are carried out. This excludes viruses, as they use RNA, to carry their genetic information. (Image 1: DNA molecule, nucleotide, base pairing. Reference: http://www.britannica.com/EBchecked/topic/422006/DNA-sequencing ) Structurally, the DNA molecule consists of two intertwined strands, the margins of which are chains of sugar and phosphate groups. The chains are linked by pairs of substances called bases, of which there are: adenine, guanine, thymine and...
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...In 1962 James Watson along with Francis Crick and Maurice Wilkins were awarded a Noble Prize for the paper that they published about the discovery of the double-helix model of deoxyribonucleic acid or DNA. The discovery of the helical structure of DNA is considered as one of the most important achievements in the field of the science history. However, James Watson does not deserve the recognition of discovering the helical model of DNA. Watson should lose his nobel prize, not only did he not give any credit to the person who was really the one responsible in discovering the helical shape of DNA he is also making rude and prejudiced opinions. Few people know Rosalind Franklin, a scientist who devoted herself in the scientific study of the structure...
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...Nucleic Acids Competency 208.5.1 Melissa Kelleher, RN The Structure of DNA • DNA is composed of units called nucleoCdes, (Wolfe, 2000). • NucleoCdes are composed of a phosphate group, a deoxyribose sugar, and a nitrogenous base, (Wolfe, 2000). – Purines – nitrogenous bases that composed of two rings, (Wolfe, 2000). – Pyrimadines – nitrogenous bases composed of one ring, (Wolfe, 2000). The Structure of DNA • DNA is a double helix structure of nucleoCdes wound together in an anCparallel direcCon, (Wolfe, 2000). – Hydrogen bonds form between the nitrogenous bases, (Wolfe, 2000). – Base pairs only bond in specific pairs, (Wolfe, 2000). • Adenine bonds only with thymine, (Wolfe, 2000). • Guanine bonds only with cytosine, (Wolfe, 2000). • Deoxyribose sugars line up in one direcCon, considered the 51 to 31 direcCon, in one strand of DNA, and in the opposing direcCon, considered the 31 to 51 direcCon...
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...DNA Worksheet REVISED Part1: Basic structure of DNA The nucleotide bases of a DNA consists of specific codes and particular strands of this codes are known as the genes. The genes codes for a particular protein which eventually be a specific trait. The pairing of the base in a DNA molecule is very specific. Adenine usually pairs with Thymine while Guanine normally pairs with Cytosine. A segment of a gene from DNA usually gives the necessary directions to build a RNA molecule and eventually translated into a protein (Simon, Reece and Dickey, 2010). Reason why DNA is referred to as a protein recipe DNA is referred to as a protein recipe because its molecules are made up of amino acid proteins which are in form of a long strand. The DNA structure is composed of codons. Basically, the DNA codes for RNA codon or a transcription which is used to form proteins which is the translation of the codon. Each group of tri-codons are then read by the ribosomes where for each group of 3 such codons, there is an amino acid. These amino acids are then bound together to make a protein chain. The complexity of a protein depends on the number and type of chains (Simon, Reece and Dickey, 2010). Part 2: Differences between DNA and RNA DNA is used for long-term storage of genetic information, transmission of genetic information so as to make other cells and new organisms and to transfer the genetic code to the ribosomes from the nucleus to manufacture proteins. On the other hand, RNA is used...
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...head: SIGNIFICANCE OF DNA Significance of DNA Significance of DNA Deoxyribonucleic acid (DNA) was first discovered in 1869 by Johann Friedrich Miescher, but it was not until the 1950s while studying viral replication did Alfred Hershey and Martha Chase determine DNA was Genetic material. In 1953 James Watson and Francis Crick discovered DNA was a double helix (a double helix looks like a twisted ladder). The discovery of Watson and Crick opened the door helping describe the significance and importance of DNA as the molecule of inheritance while addressing the structure of the DNA molecule, and why is a molecule of DNA so perfect for the job it performs. I will look at what exactly does DNA code for, how is that translated into actual traits, what are mitosis and meiosis, what are the similarities and differences, and what do mitosis and meiosis allow for. I will show how traits are passed from parents to offspring and lastly describe how knowledge of DNA and genetics can help in my life. The Significance and Importance of deoxyribonucleic Acid (DNA) as the Molecule of Inheritance The significance and importance of DNA “is the body’s instruction manual for making you who you are. It is present in any living being. It carries all the instructions and materials the body needs to function”(Leving, 2008). The DNA in cells is all the same for individuals, which create a specific identity for each individual. Discuss Briefly the structure of the DNA Molecule and Why is...
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...studies with a microbiologist, where he was assigned to write a thesis paper on phages, a simple type of virus. These studies proved difficult due to Watson’s lack of chemical knowledge, and his supervisor realized that more information about phages, proteins, and genes would become apparent if they understood the structure. In attempt to acquire some basic chemical experience, Watson began a short internship at a lab where he nearly caused a catastrophic explosion. Following this unfortunate incident, Watson’s knowledge of chemistry remained unimpressive, as shortly thereafter, the...
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...for centuries have been studying genetics on how they pass traits, how their structure matches their function, and generally how they work. How Living Organisms pass Traits Genetics are how the next generation of a species is formed. There are two different ways a new generation is formed and traits are passed, asexual and sexual reproduction. With sexual reproduction is requires two partners and leads to genetic diversity. Asexual and sexual reproduction are both very different strategies of reproduction. Sexual reproduction requires two parents, and gives the child a unique combination of genes from both parents. Sexual reproduction is typically used by more complex organisms, leading to the parents most likely raising their offspring. Asexual reproduction requires only one parent, and the offspring is an exact copy of the parent through a process called mitosis (ISN pg. 93). Mitosis is a part of the cell cycle division process that occurs when...
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... date Question: Discuss what are the nucleotides and nucleic acids in human health and disease Almost all living cells contain two very important substances, deoxyribonucleic acid or DNA and ribonucleic acid or RNA. These molecules carry instructions for making proteins. The help specify the amino acid sequence and thus which proteins will be made. When nucleotides join together they form the functional units of the structure of DNA and RNA where DNA contains one less hydroxyl group than RNA. Nucleotides serve as a source of energy therefore playing an important role in metabolism, for example mitochondria produce ATP or Adenosine triphosphate. They also serve as co-factors in enzymatic reactions and participate in cell signalling for example as Camp messengers. A single nucleotide is made up of three smaller molecules, a phosphate group which helps to form the sugar phosphate backbone via phosphodiester bonds which is between the three carbon sugar of one atom and the four carbon sugar of another, a pentose sugar, deoxyribose or ribose, and a nitrogenous base thymine, adenine, guanine and cytosine or uracil in RNA. These bases can be purines which are double ringed structures or...
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...DNA and Protein Synthesis • Describe the structure of DNA and the steps of protein synthesis. The first stage is transcription, The DNA helix is untwisted by the enzyme dna helixase. Then the DNA is split into two as the hydrogen bonds are broken between the complementary base pairs, The second step is translation, which occurs in the cytoplasm and requires ribosomes. A small ribosomal subunit attaches to the bottom of the mRNA strand, and a large ribosomal subunit to the top of the mRNA. Then the synthesis can begin. For it to start the first codon (base triplet) must be methionine. Then the anticodons on a tRNA with an amino acid comes into the large ribosome unit and matches with a codon. • Describe the relationships between the following terms: o DNA- the heredity material of the cell o Chromatin material- the combination of DNA and proteins that make up the nucleus o Gene- a molecular unit of heredity of a living organism o Chromosome- an organized structure of DNA and protein found in cells • Use the following gene in protein synthesis: TAGGACCATTTTAGCCCC o Show the mRNA. o Show the tRNA. o Name the amino acids that will be placed in the polypeptide chain. (Use the codon table in Ch. 17 of Campbell Biology.) • A gene will direct the making of polypeptide chains, and polypeptide chains form proteins. All enzymes are proteins. Therefore, how would you explain carrying a gene for a trait that does not show up in the offspring? Genes can...
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...Chapter 6 Blast program for sequence comparisons and blast p-values- test whether 2 or more sequences (protein or DNA) share a common evolutionary origin (p >10^-3 = due to chance) Lack of relationship between number of genes in a genome and its biological complexity 10-nm versus 30-nm chromatin fibers – condensed chromatin= 30nm wide, “beads-on-a-string” =10nm wide nucleosome core histone composition (2 each of H2A, H2B, H3, and H4) – Histones exists as octamers. Core is wrapped by 147 bp, about 2turns of DNA= CONSERVED IN ALL EUKARYOTES two turns of DNA around histone core (147 bp) variable size of DNA between nucleosomes (15-90 bp) – depends on species structure of 30 nm fiber and role of H1 histone – resting chromatin will be 30nm wide, H1 binds where DNA enters and exits nucleosome core histone tail modifications (acetylation, methylation, phosphorylation) – methylation & DEacetylation condensing of chromatin (30nm) acetylation DE-condensing of chromatin (10nm) phosphorylation & ubiquitination chromatin remodeling euchromatin versus heterochromatin chromosome scaffold – hold the 30nm chromatin loops attached, genes far apart on the chromosome are close at the base of the loops called SARS (Scaffold Associated Proteins) width of fully condensed metaphase chromosomes (500-750 nm) – 500-750nm wide chromosome banding and FISH (fluorescence in situ hybridization) – identification of karyotypes (chromosome composition) allows painting of each...
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...asking the tutor • All questions are compulsory. 1 mark may reflect 1 answer point. (No half mark is awarded in the finals marks) (Source: Final examination, Dec 2012) Q1. (a) Amino acids are the building blocks of proteins. Figure 1.1 shows the dipeptide molecule. [pic] Figure 1.1 i) Briefly explain the formation of dipeptide from two amino acids. (3 marks) ii) Name the molecular unit that could determine the structure of a protein. (1 mark) (Source: Final examination, Apr 2012) Q2 (a) Figure 2.1 shows a representation of a phospholipid molecule and Figure 2.2 shows the detailed structure of a fat molecule. [pic] [pic] Figure 2.1 Figure 2.2 (i) Based on Figure 2.1, name the parts of the molecule labeled as A, B and C. (3 marks) (ii) Based on Figure 2.1 and 2.2, briefly describe the chemical structure of lipids that account for their insolubility in water. (1 mark) (iii) During a practical session, Ms. Chan demonstrated to the students that when water and oil were added to a test tube,...
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