The Biology of Food - Essay Example

?Yiting Liu Nov 21 The Biology of food The information for a protein stored inside a cell, and, which is passed on to the cell’s offspring, is the basic information essential in its functioning. The basic information is stored in DNA codes (genes). The genes are coupled together on chromosomes. Chromosomes are located in the nucleus of the cell. In each cell, DNA molecules are packed into threadlike formation. Each chromosome consists of DNA packaged around histones. Histones are structures which aid in support of chromosome structure. To use this information, cells must be able to get the information out of storage. Genes are required to direct the production of functional molecules; also known as proteins. A process known as gene expression does this. Gene expression consists of two steps: transcription, and translation. Gene information is necessary in the production of proteins. Transcription is the first step done to get the information out of storage. The information stored in the DNA of a gene is relocated to an RNA (mRNA) molecule located in the cell nucleus; this process is called transcription. The DNA of a gene serves as a template for harmonizing base pairing. RNA polymerase II catalyzes the configuration of a pre- mRNA molecule; which is developed to form a mature mRNA. The mRNA transports the information from the DNA located in the nucleus into the cytoplasm. The second major step in gene expression, translation step follows in the cytoplasm. Three start factor proteins (IF1, IF2, and IF3) bind to the small subunit of the ribosome, resulting to a pre-initiation mRNA complex. The mRNA complex and methinine carrying tRNA, bind to the mRNA in close proximity to the AUG start codon; forming the initiation complex. The mRNA intermingles with the large ribosomal subunits, which releases the initiation factors. The large ribosomal subunit binds to the small ribosomal subunit to complete the initiation complex. This triggers the next phase- elongation phase. The ribosome moves along the mRNA in the 5’ to 3’ route; this step requires elongation factor G. The tRNA that matches up to the second codon binds to the A site, GTP is cleaved to form GDP; which is then released along with EF-TU necessary for recycling by EF-Ts subsequently. Peptide bonds are formed via a peptidyl transferase activity. This procedure is repeated until the tRNA molecules have read all codons; amino acids joined to the tRNA have been connected in the growing polypeptide chain appropriately. With each mRNA, base sequence, codes for a specific amino acid. Each codon identifies a particular amino acid. Therefore, the mRNA sequence is used as a template to bring together the chain of amino acids that make up a protein. Transfer RNA joins the protein; by linking one amino acid within the interval. Protein production comes to a halt when the ribosome comes across a stop codon in mRNA. The stop codons are UAA, UAG, and UGA; Trna can recognize these codons. In place of the tRNA, release factors bind and facilitate the release of the mRNA from the ribosome and consequent dissociation of the ribosome. This sting of amino acids built by chromosomes finally acquires its activity during gene regulation, when gene expression is taking place. Signals from the location and or other cells activate transcription facets. The transcription features are proteins, which bind to the dogmatic locations of the gene. The rate of transcription can then be increased or decreased; establishing the amount of protein and product made. This is paramount as the string-of-stuff will resemble and act differently as per the specified activities. Environmental mutagens (like oxygen radicals) can result to DNA modifications causing mutations. These radicals react with DNA yielding lesions such as base modifications, cross-links, and strand breaks. A highly reactive hydroxyl radical, counters the DNA. This is done by the addition to double bonds of the DNA bases, as well as the blocking of the hydrogen atom from the methyl assemblage of thymine and C-H bonds of 2’ deoxyribose. This leads to the formation of covalent bonds amid opposite pyrimidine bases on the DNA; the end product is pyrimidine dimmers. The DNA bases react with the reactive and free radical oxygen. The compounds formed are due to the damage done to the DNA bases. Studies have shown that the accumulation of mutations is an essential mechanism in the aging process. DNA repair is a complex process involving many different enzymes; this results to the elimination of damage that can cause mutations. This repair system has a specific standard of quality and it is allowed a certain margin of error. Therefore, incorrect or incomplete repairs lead to mutations. There is a base change in the DNA. A single base change after replication leads to an alteration in information on the DNA strands. The action of mis-pairing/ change of bases occurs. Environmental mutagens change the original DNA; by altering the nucleotide bases, and in some cases changing the shape of DNA. These alterations lead to errors in DNA replication and transcription. The replication mistakes can lead to the deletion of genes, extra production of chromosomes, missing chromosomes, and translocation of portions of chromosomes (Dizdaroglu et al, 106). Mechanisms of transcription and translation will be affected. Several changes occur; i.e. single base substitutions, insertions and deletions, duplications, and translocations. Translation will be affected, in that mRNA efficiency will be decreased. The process of initiating the proper start codon will be interfered in cases of a mutation. The codon created by the mutation may interfere with the initiation at the start codon. Codon change leads to the novel formation of amino acids. The new amino acids would be added to create a protein. At the primary level of protein organization, the order of amino acids will change ; causing a major shift in the shape of the protein. At the secondary level, the arrangement of ?- helixes and ? sheets will be different. At the tertiary level, the end outlook of the protein subunit will be entirely different. At the quaternary level, the protein will take a different structure and will not be able to perform its original function in the case of a mutation (Clark & Pazdernik, 721). The botanical name of bell peppers is capsicum annum; its original name is chili. Christopher Columbus set out on a voyage to India in 1492. Other than ending up in India, he ended up in West Indies; which he assumed was India. He deliberated that the chili with the seeds inside were a deviation of pepper. He took the chilies back to Europe and told the king that he came with pepper. Columbus confused the bell peppers to be hot chilies. Bell peppers originated in Europe. Peppers were named by Christopher Columbus and other Spanish explorers who were in search of peppercorn plants. The pepper seeds were taken to Spain in 1493 and spread to Europe by Columbus. The different variations of the eye or hair color are as a result of melanin. The variation in the eye and hair color is dependent on the quantity of melanin. This is linked to genetic variations (DNA structure) in sequence. Genetic variations can be as a result of mutation. These variations result in production of enzyme molecules by alleles with lots, little, and immediate activity. This results in masses of pigment, little pigment, and moderate amount of pigment respectively. The entire amount of pigment is dependent on the total amount of enzyme activity. Genetic variations can lead to differences in the transcript levels for a similar gene found in different individuals. A piece of one chromosome is transferred to a non-homologous chromosome, and the two non-homologues swap segments. This can alter the phenotype in several ways. This leads to matching differences in protein levels. The different genetic variations echo transcription autonomous mechanisms; resulting to different phenotypes. Thus, the differences in the eye and hair color. The translocated genes are influenced by different promoters and enhancers, altering their expression. Phenotype/ observable traits are as an interaction of the environment and genes. Genes determine phenotype variation. This is dependent on the inherited copy of every gene from the parents. The total amount of pigments (hair and skin) will depend on the full amount of enzymatic activity. The connection of genotype and phenotype relates to the dominant and recessive patterns. Genotype-phenotype relationships are linked to genetic dominance. The connection between alleles is seen to code for the same trait, hair/ eye color. The aspect of dominance determines the phenotype obtained from an organism’s genes. Dominance variations draw attention to the various phenotypes. The gene for lactase, LCT enables the splitting of galactose and glucose; sugars which make up lactose. The intolerance allele lacks the lactase gene until the era of modern genetics; not anyone without the lactase gene would survive infancy. While the tolerance allele, contains the lactase gene. Intolerance allele leads to no production of lactase gene. The lactase genes in most lactose-intolerant and lactose-tolerant individuals are controlled differently. The effect of this DNA difference is that the intolerant individuals have no ability to digest lactose, unless they take some medications will enable lactose digestion. These people experience difficulty when they digest lactose products. Lactose intolerant individuals lack the lactase gene to aid in gene expression; located in cells, in the epithelium of the small intestine. Whilst a lactose intolerant individual ingests a lactose product, it passes the gut exclusive of being broken down. The bacteria in the gut then react to the elevated levels by shifting their metabolism to run on the sugar. This leads to the production of a lot of gas; causing flatulence, pain, and diarrhoea. Lactose tolerant selection commenced 80 centuries ago, in the midst of cattle domestication. Milk was stored in skin bags and or bladders, where it was fermented. Milk was consumed after its fermentation initially. Europe had developed a cheese-making culture, but everyone was lactose-intolerant. Then someone with the mutation wandered over from Kazakhstan, introducing the allele to north-central Europe. Consuming dairy products enabled the dominant factor of the tolerance allele. Thus, dairy farming enabled this allele to become common in Europe. The aspect of natural selection also contributed to this. This is based on the fact that exposure to milk, and milk products had a deep significance that the individuals who had the mutated allele had a better chance of survival at the earlier stages of their lives. They were more liable to mate and produce offsprings who contained the allele. After many generations, allele frequency has increased significantly. Amanda’s parents contain alleles both for lactose tolerance and lactose intolerance, but the lactose tolerance allele is dominant in both parents. Amanda inherited lactose intolerance alleles from her parents, making the lactose intolerant allele recessive to lactose-tolerance; explaining why she is lactose intolerant. Origin/ location, as well as the cooking technique and ingredients used, makes cuisines different from each other. Similar types of food plants originate in clusters relatively near each other; as they belong to the same species. Different phenotype may be as a result of mutations that showed up in one plant, and might have been propagated. These plants are alike and may even have the same taste or almost similar taste. Such types of plants are related to each other. These plants have diversified/ evolved into what they are now. The factors that contributed to diversity include; history, chance, genes, and necessity. The factor of polyploidy is also to consider in this case. Different genes determine different color and taste types. It is impossible for species to mutate so as to survive. This is because mutation occurs in a random basis. There is no method to prevent mutations as well trigger mutations. Mutation happens by chance. Thus, it is impossible for species to mutate so as to survive. Mutation is a biological mistake/ accident; it cannot happen by chance. What is possible is species can adapt to their environment. For instance, how a plant can adapt in a dry environment by acquiring narrow leaves. Evolution refers to the natural selection of organisms. Evolution consists of passing on traits that are optimum for the environment. The basic rules of Genetics include: 1. DNA is subject to mutation 2. Individual organisms inherit their DNA from their parents 3. Some individuals have more offspring than others Antibiotic resistance can be passed on to a progeny from a parent, even if the progeny has never used the antibiotic. This is based on the fact that many antibiotic resistance genes produce enzymes that catalyze the antibiotic. Once the antibiotic is broken down, it is harmless. A cell containing the antibiotic gene will pass it to the offspring; just as other genes are passed on to other cells. In addition, using the same drug to treat a bacterial infection is useless. Increasing the dosage may breed a more resistant bacteria strain, using a new antibiotic completely clear away the bacteria. Unnecessary use of antibiotics also leads to the development of resistance bacterial strains. The bacterial strains have been able to survive and arisen in the last few decades due to the development of fit genomes. Bacterial strains genetic composition changes with time, with the parent strains passing on resistant traits to the daughter cells. This has resulted into stronger antibiotic resistance strains over time. Some strains died when an animal was administered the antibiotics, but some survived and passed on the traits to their off springs. The bacterial strains adapted to the harsh antibiotic environment after antibiotic administration; emerging as antibiotic resistant. In the last few decades, the bacterial strains have evolved into being more adaptable to the environment, killing the animal in the end, and inhabiting in the body of any individual who will consume the undercooked meat. Works cited Clark, David P, and Nanette J. Pazdernik. Molecular Biology. Waltham, MA: Academic Press, 2013. Print. Dizdaroglu, Miral, and Ali E. Karakaya. Advances in Dna Damage and Repair: Oxygen Radical Effects, Cellular Protection, and Biological Consequences. New York: Plenum Press, 1999. Print. Read More