Unit 18: Genetics and genetic engineering
Assignment 1
1) Show your understanding of the structure of nucleic acids by describing the similarities and differences between DNA, mRNA and tRNA. Your descriptions should include drawings with labels of the nucleotide structures and the overall structures of each where applicable.
1a) What is DNA?
DNA (Deoxyribonucleic acid) is a molecule found in in the nucleus of all cells in the body which carries our genetic information. DNA is found in the form of chromosomes, with a total of 23 pairs in the human body1. DNA holds the genetic coding for all our characteristics, i.e. our eye colour, body shape, and how we interact with others on a daily basis.
DNA is made up of nucleotides, and a strand of DNA is known as a polynucleotide. A nucleotide is made up of three parts: A phosphate (phosphoric acid), a sugar (Deoxyribose in the case of DNA), and an organic nitrogenous base2 of which there are four. The four bases are as followed: Adenine (A), Cytosine
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(C), Guanine (G), and Thymine (T).3a The structure of a DNA molecule is fairly simple. The phosphate and the Deoxyribose (sugar) join together to form the “Antiparallel backbone” of a DNA strand, with the Deoxyribose of one “free” nucleotide joining to the phosphate of a second nucleotide with a Phosphodiester bond (strong covalent), this occurs with many nucleotides to form a strand of a DNA molecule. However, this only account for one of the two strands required to form a complete molecule of DNA. The second strand is formed in the same way as the first, but in order to understand how they are joined we must look at the four bases that are found in DNA. The bases on one strand of DNA bonds to the second strand of DNA with “weak” Hydrogen bonds through condensation reactions to form a complete polymer of a DNA molecule. However, the different bases can only bond to its complementary base of the other three. Guanine can only bond to Cytosine, and Adenine can only bond to Thymine (and vice versa)3. Cytosine is bonded to Guanine by three Hydrogen bonds, and Thymine is bonded to Adenine with two Hydrogen bonds.4 1b) What is RNA (mRNA and tRNA)? DNA is self-replicating; it makes copies of itself in order to create proteins needed in the body.
In order to do this a polymer of DNA “unzips” into its two strands, a coding strand (left strand) and a template strand (right strand). Nucleotides of a molecule known as mRNA (messenger RNA) then temporarily bonds to the template strand and join together in the same way as nucleotides of DNA. Messenger RNA has a similar structure to that of DNA only it is single stranded. Like DNA, mRNA is made up of nucleotides again consisting of a phosphate, a sugar, and an organic nitrogenous base. However, unlike in DNA, the sugar in a nucleotide of mRNA is different (Ribose) and the nitrogenous base Thymine is replaced by a new base found in RNA known as Uracil (U)3b and like Thymine can only bond to its complimentary base Adenine. As a result of how it bonds to the DNA’s template strand, the mRNA strand formed is almost identical to the coding strand of DNA apart from these
differences. The role of the mRNA is to carry the genetic code from the DNA to the Ribosomes found in the cytoplasm of the cell, via the nuclear pore, where it is read and the corresponding amino acids are assembled into proteins. Ribosomes are protein synthesisers in cells which uses the mRNA code to create proteins from amino acids; they bond amino acids one at a time to form a chain which forms a certain protein. A strand of mRNA is can be broken down into codons; a codon is a triplet of bases on the mRNA which codes for a specific amino acid. The molecule responsible for carrying amino acids from a store in the cytoplasm to the ribosome is another form of RNA known as transfer RNA (tRNA). Each tRNA has three unpaired bases at one end, known as an anticodon, where the complementary amino acid joins. The three bases present will determine which amino acid joins as each different anticodon can only bond to a certain amino acid. A different anticodon on the tRNA molecule bonds to the mRNA and will only bond to its complementary codon on the mRNA strand. The different amino acids are joined together by peptide bonds to form a protein from its “code”
Deoxyribonucleic acid (DNA) is an acclaimed extraordinary discovery that has contributed great benefits in several fields throughout the world. DNA evidence is accounted for in the majority of cases presented in the criminal justice system. It is known as our very own unique genetic fingerprint; “a chromosome molecule which carries genetic coding unique to each person with the only exception of identical twins (that is why it is also called 'DNA fingerprinting ')” (Duhaime, n.d.). DNA is found in the nuclei of cells of nearly all living things.
DNA is the genetic material found in cells of all living organisms. Human beings contain approximately one trillion cells (Aronson 9). DNA is a long strand in the shape of a double helix made up of small building blocks (Riley). The repeat segments are cut out of the DNA strand by a restrictive enzyme that acts like scissors and the resulting fragments are sorted out by electrophoresis (Saferstein 391).
Deoxyribo Nucleic Acid (DNA) is a chromosome found in the nucleus of a cell, which is a double-stranded helix (similar to a twisted ladder). DNA is made up of four bases called adenine (A), thymine (T), guanine (G), and cytosine (C), that is always based in pairs of A with T and G with C. The four bases of A, C, G, and T were discovered by Phoebus Levene in 1929, which linked it to the string of nucleotide units through phosphate-sugar-base (groups). As mention in Ananya Mandal research paper, Levene thought the chain connection with the bases is repeated in a fix order that make up the DNA molecu...
What has to happen for a gene to be transcribed? The enzyme RNA polymerase, which makes a new RNA molecule from a DNA template, must attach to the DNA of the gene. It attaches at a spot called the promoter.
Protein synthesis first begins in a gene. A gene is a section of chromosome compound of deoxyribonucleic acid or DNA. Each DNA strand is composed of phosphate, the five-carbon sugar deoxyribose and nitrogenous bases or nucleotides. There are four types of nitrogenous bases in DNA. They are (A)denine, (G)uanine, (T)hymine, (C)ytosine and they must be paired very specifically. Only Adenine with Thymine (A-T) and Guanine with Cytosine (G-C).
Gene expression can be described as the conversion of information from genes into messenger RNA by way of transcription. Transcription happens in the nucleus, and is where RNA copies of DNA are produced. This process is facilitated by RNA polymerase, where one RNA nucleotide is added to an RNA strand. RNA polymerase is an enzyme used to produce transcripted RNA. It is responsible for constructing RNA chains, in the process previously described as transcription. RNA polymerase polymerizes the ribonucleotides and the 3’ end of RNA transcription. It is essential to life and found in all organisms. Also, it unwinds the DNA molecule, using it as a template, before synthesizing corresponding mRNA strands. mRNA, or messenger RNA, is part of a large group of RNA molecules that communicate information from DNA to ribosomes. mRNA contains adenine, uracil, guanine, and cytosine. Alternative to DNA which has thymine instead of uracil.
Genetic engineering has been around for many years and is widely used all over the planet. Many people don’t realize that genetic engineering is part of their daily lives and diet. Today, almost 70 percent of processed foods from a grocery store were genetically engineered. Genetic engineering can be in plants, foods, animals, and even humans. Although debates about genetic engineering still exist, many people have accepted due to the health benefits of gene therapy. The lack of knowledge has always tricked people because they only focused on the negative perspective of genetic engineering and not the positive perspective. In this paper, I will be talking about how Genetic engineering is connected to Brave New World, how the history of genetic engineering impacts the world, how genetic engineering works, how people opinions are influenced, how the side effects can be devastating, how the genetic engineering can be beneficial for the society and also how the ethical issues affect people’s perspective.
Genes are, basically, the blueprints of our body which are passed down from generation to generation. Through the exploration of these inherited materials, scientists have ventured into the recent, and rather controversial, field of genetic engineering. It is described as the "artificial modification of the genetic code of a living organism", and involves the "manipulation and alteration of inborn characteristics" by humans (Lanza). Like many other issues, genetic engineering has sparked a heated debate. Some people believe that it has the potential to become the new "miracle tool" of medicine. To others, this new technology borders on the realm of immorality, and is an omen of the danger to come, and are firmly convinced that this human intervention into nature is unethical, and will bring about the destruction of mankind (Lanza).
Ribonucleic acid or RNA is a polymeric molecule made up of one or more nucleotides. A polymeric molecule is a very large molecule that is chain- like. It is made up of monomers, which are smaller molecules. A strand of RNA can be thought of as a chain with a nucleotide at each chain link. Whereas, a nucleotide is a group of any type of molecules that are linked together because they form the “building blocks” of DNA (also known as deoxyribonucleic acid, and it is the carrier of genetic information.) Messenger RNA, which is called mRNA, carries the genetic information copied from DNA. Transfer RNA, which is called tRNA is the key to deciphering the code words in mRNA that forms a series of three-base code words. An enzyme is a substance that
DNA (deoxyribonucleic acid) is a self-replicating molecule or material present in nearly all living organisms as the main constituent in chromosomes. It encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. Simply put, DNA contains the instructions needed for an organism to develop, survive and reproduce. The discovery and use of DNA has seen many changes and made great progress over many years. James Watson was a pioneer molecular biologist who is credited, along with Francis Crick and Maurice Wilkins, with discovering the double helix structure of the DNA molecule. The three won the Nobel Prize in Medicine in 1962 for their work (Bagley, 2013). Scientist use the term “double helix” to describe DNA’s winding, two-stranded chemical structure. This shape looks much like a twisted ladder and gives the DNA the power to pass along biological instructions with great precision.
The genetic information of an organism allows for the continuation of life. This genetic information is passed from parent to offspring via the molecule deoxyribonucleic acid (DNA). The structure of the DNA molecule provides a solution for the replication of the existing DNA molecule and furthermore the transmission of heritable information to the next generation. The scope of this essay will discuss how the molecular structure of DNA allows for DNA to replicate and transmit heritable information from one generation to the next.
Human genetic engineering can provide humanity with the capability to construct “designer babies” as well as cure multiple hereditary diseases. This can be accomplished by changing a human’s genotype to produce a desired phenotype. The outcome could cure both birth defects and hereditary diseases such as cancer and AIDS. Human genetic engineering can also allow mankind to permanently remove a mutated gene through embryo screening as well as allow parents to choose the desired traits for their children. Negative outcomes of this technology may include the transmission of harmful diseases and the production of genetic mutations. The benefits of human genetic engineering outweigh the risks by providing mankind with cures to multiple deadly diseases.
Once the DNA is unwinded, only one strand will serve as the template for the process of transcription. Transcription is the process of forming messenger RNA from the bacterial DNA strand. The enzyme RNA polymerase will connect complementary RNA bases to the DNA template strand. These RNA bases are bonded together to form a single stranded mRNA. Therefore this mRNA molecule contains a template based on the DNA.
DNA is read with a two-step cell process. These two steps are transcription and translation. Transcription is the process in which a portion of the cells DNA plays the role of a template for the formation of the RNA molecule. RNA polymerase is then attached to the DNA template and begins to make new strands nucleotides to produce a complementary RNA strand. Transcription factors then help determine which DNA sequences should be transcribed.
Correspondingly, DNA contains two nucleotides with purine bases and two nucleotides with pyrimidine bases. These nucleotides are labeled adenine (A), guanine (G), thymine (T), and cytosine(C). These parts come in pairs which forms the double helix shape of DNA. Adenine is always paired with guanine and thymine is always paired