StudentShare
Contact Us
Sign In / Sign Up for FREE
Search
Go to advanced search...
Free

Components and Processes within a Polymerase Chain Reaction - Assignment Example

Cite this document
Summary
This assignment "Components and Processes within a Polymerase Chain Reaction" presents polymerase chain reaction as a form of scientific technique that is made use of in the amplification of pieces of DNA that result in a great number of copies of a type of DNA sequence…
Download full paper File format: .doc, available for editing
GRAB THE BEST PAPER97.8% of users find it useful

Extract of sample "Components and Processes within a Polymerase Chain Reaction"

Name : xxxxxxxxxxx Institution : xxxxxxxxxxx Course : xxxxxxxxxxx Title : Genetics Tutor : xxxxxxxxxxx @2010 GENETICS Q1. Describe in detail the components and processes within a polymerase chain reaction (PCR). Polymerase chain reaction is a form of scientific technique that is made use of in the amplification of pieces of DNA that result into a great number of copies of a type of DNA sequence. The technique relies on the complementarity of the bases of DNA. It is noted that in the event a DNA molecule is heated then the hydrogen bonds that hold the double helix structures are denatured and thus the molecule is unzipped into single strands (Chamberlain, 1990). However, in the event a DNA solution is cooled then the respective complementary base pairs can be joined and thus it results into the original double helix structures. It is noted that as PCR progresses the DNA generated is made use of as a replication template and thus a chain reaction is set into motion. PCR can therefore be modified and utilized to perform a wide range of genetic manipulations. The components of PCR are as follows: a DNA template that comprises of the DNA needs to be amplified, two primers that are situated complementary to 3’ ends of every sense and anti-sense strand that is the DNA target, Taq polymerase or DNA polymerase which has an optimum temperature of 70 °C, deoxynucleotide triphosphates (dNTPs) that forms the building blocks that DNA polymerase is synthesized to form a new DNA strand, Buffer solution that provides proper chemical environment for optimum stability and activity of the polymerase DNA, monovalent cation for instance potassium ions, divalent cations for instance manganese (Mn2+ ) or magnesium (Mg2+ ) (Chamberlain, 1990). Procedure Below is a diagrammatic representation of the PCR procedure: Denaturing takes place between 94-96 °C, annealing takes place at approximately 65°C and elongation at 72°C. The blue lines are a representation of DNA templates to which the primers (red arrows) anneal and are consequently extended by the use of DNA polymerase (light green circles), the DNA products are represented by green lines which are in turn used as templates with the progression of PCR (Allen, 1991). Q2. Describe the Hardy-Weinberg law, stating and discussing the assumptions on which it is based. Also describe one method one could use to test for deviation from Hardy-Weinberg equilibrium. Hardy-Weinberg law works on the principle that genotype and allele frequencies that are available in a population stagnate from generation to generation. This implies that the frequencies remain in equilibrium unless there is the introduction of specific disturbing influences. The influences that may disturb the balance are non-random mating, selection, meiotic drive, mutations, gene flow, limited population size, random genetic drift and overlapping generations (Sanchez, 2004). The law is based on the assumptions that static allele frequencies that exist in populations have; no mutation that is the alleles are constant, no emigration or migration which implies that there is no allele exchange between populations, a very large population size and lack of selective pressure that advocates for or against any particular genotypes that is lack of natural selection. It is noted that genotype frequencies are stable during random mating. The testing of deviation from Hardy-Weinberg law is mostly performed by Pearson’s chi-squared test. Below is an example of Pearson’s chi squared test: χ2 test for deviation The table shows data to be made use of in the calculation of Hardy-Weinberg principle. Table Genotype White-spotted (AA) Intermediate (Aa) Little spotting (aa) Total Number 1469 138 5 1612 From which allele frequencies can be calculated: and Hardy-Weinberg results are as stipulated below: Chi-square test is as stipulated: There exists 1 degree of freedom. The degrees of freedom that exist in the test for Hardy-Weinberg proportions refer to number of genotypes to the number of alleles. The 5% significance level that is attached to 1 degree of freedom is stipulated at 3.84 and since the chi square amount is less than this then it follows that the null hypothesis of the aforementioned population lies within Hardy-Weinberg frequencies and thus not rejected (Bonetta, 2004). Q3. Describe the structure and function of telomeres. Telomeres are recurring DNA sequences that are situated at the end of linear chromosomes of a large number of eukaryotic organisms and a small number of prokaryotes. Telomeres stand in for incomplete semi-conservative DNA copying at chromosomal ends (Bloom, 2004). The protection against non-homologous end joining (NHEJ) and (HR) homologous recombination make up the vital “capping” function of telomeres that separates them from DNA. More explicitly; double strand breaks (DSBs). Telomere It is noted that a great number of prokaryotes have circular chromosomes that do not suffer from untimely replication termination. Some bacterial chromosomes (for instance Borrelia and Streptomyces) have telomeres and are linear. These chromosomes are different in comparison to those of eukaryotic chromosomes in their functions and structure. Bacterial telomeres structures are in the form of proteins and they are attached to the ends of straight chromosomes and hairpin loops which are single-stranded DNAs located at the termini of linear chromosomes (Allen, 1991). In multi-cellular eukaryotic organisms there is active telomerase in stem cells, germ cells and various kinds of white blood cells. It has been noted that steady shortening of the telomeres which is accompanied by their replication in the body of cells have a vital role in senescence and thus in cancer prevention. This is due to the “fuse” role played by telomeres. However, their aforementioned role dies down after a large amount of cell divisions which results into loss of genetic information available in the chromosome that result with future divisions. Shorter telomeres can also be made use of as an energy sparing mechanism in energy limiting environment. Telomere length ranges from between 300 to 600 base pairs which exist in yeast to a number of kilobases which exist in humans and constitute guanine-rich long repeats of between six to eight base pairs of long repeats. Eukaryotic telomeres are usually known to terminate with 3′ of lone stranded DNA that is overhang and is necessary for the telomere capping and maintenance. Multiple proteins that bind double and single stranded telomere DNA are known to exist. The aforementioned have roles in telomere capping and maintenance. Q4. Describe real time PCR and some of its applications. Give one example of a method used for real time PCR. Real time PCR is a technique of simultaneous DNA amplification and quantification. DNA is mostly amplified by the use of polymerase chain reaction (PCR). Every round of amplification is followed by quantification. The common techniques of quantification are the utilization of fluorescent dyes which intercalate together with modified DNA oligonucleotides and double-strand DNA. These types of DNA fluoresce in the event of their hybridization with complementary DNA. Real-time PCR is integrated with reverse transcription-polymerase chain reaction (RT-PCR) to attach value to low abundance messenger RNA that enables a researcher to be able to quantify the relative gene expression at any given time or in any given tissue or cell type. The joined method is referred to as quantitative RT-PCR (Chamberlain, 1990). Real-time PCR is made use of in diagnosing microbial pathogens. Its high sensitivity, specificity, ease of performance and its short turnaround time for its results make it an efficient technique for antigen-based and conventional culture assays. It is made use of in diagnostic and basic research. In research it is made use of in the provision of quantitative measurements that are necessary for gene transcription. Diagnostic real-time PCR is made use of in the detection of nucleic acids that allow for the detection of cancer, infectious diseases and genetic abnormalities. It is also utilized in the detection of infectious diseases like flu. Real-time PCR methods are inclusive of the following types; RT-PCR (reverse-transcription PCR) and RTQ-PCR. Real-time PCR is joined with reverse transcription to assign value to messenger RNA and non-coding RNA that is available in tissues or cells. The development of PCR technologies that are based on fluorophores and reverse transcription allows for the measurement of the amplification of DNA during PCR that is available in real time which is measured at every PCR cycle. The generated data can be consequently analyzed by the use of computer software to aid in the calculation of relative gene expression. It can also be used in the detection and quantification of various DNA samples to determine the abundance of specific DNA sequences (Bloom, 2000). Q5. The following RFLP results were obtained at a locus in a population. 26/120 51/120 43/120 2.0 kb 0.8 kb Table Genotype 2.0kb 0.8kb 2.0kb/0.8kb Total Number 26 51 43 120 a. Determine the frequencies of the 2.0kb and 0.8 kb alleles. p = 2 × (2.0kb) + (2.0kb/0.8kb)/ 2× ((2.0kb) + (2.0kb/0.8kb) + (0.8kb) = (2 × 26) + 43/ 2 × (26 + 43 + 51) = 0.39 q= 1-p = 0.604 b. What are the expected frequencies of all possible genotypes in this population if you assume Hardy Weinberg equilibrium? Hardy–Weinberg expectation is as follows: Exp (2.0kb) = p2 n = 0.392 × 120 = 18.252 Exp (2.0kb/0.8kb) = 2pqn = 2 × 0.39 × 0.604 × 120 = 56.5344 Exp (0.8kb) = q2 n = 0.6042 × 120 = 43.77792 X2 = ∑ (0-E)2 / E = (26 – 18.252)2 / 18.252 +(43 – 56.5344)2 /56.5344 + (51-43.77792)2 / 43.77792 = 3.289 + 3.240 + 1.191 = 7.72 c. By carrying out a chi squared test, determine whether this population is in Hardy Weinberg equilibrium at this locus. It is therefore rejected since it is more than 1. Q6. A population has four times as many heterozygous individuals as homozygous recessive individuals. Work out the frequency of the recessive gene assuming HWE and a bi-allelic locus. Show your working in full. Let p2 (AA) be homozygotes q 2 (aa) homozygotes with recessive gene. Let it be x. 2pq Aa heterozygotes. Let it be 4x Frequency will therefore be: x/5x × 100 = 20% Frequency is therefore 20. References Chamberlain, J.S., et al. 1990. Multiplex PCR for the diagnosis of Duchenne muscular dystrophy. In PCR Protocols: A Guide to Methods and Applications (M.A. Innis, et al., eds.). Academic Press, New York, pp.272-281. Bloom, M (2000). Polymerase Chain Reaction. Cold Spring Harbor, New York. Allen, R., et al. 1991. Analysis of the VNTR locus AmpliFLP D1S80 by the PCR followed by high resolution PAGE. American Journal of Human Genetics 48:137. Sanchez, J.A et al. (2004). Real-Time Polymerase Chain Reaction. Proc. Natl. Acad. Sci. USA. Bonetta, L. (2004). National Methods. McGraw Hill; New York. Read More
Cite this document
  • APA
  • MLA
  • CHICAGO
(Components and Processes within a Polymerase Chain Reaction Assignment, n.d.)
Components and Processes within a Polymerase Chain Reaction Assignment. https://studentshare.org/biology/2045733-genetics-short-answer-questions-assignment
(Components and Processes Within a Polymerase Chain Reaction Assignment)
Components and Processes Within a Polymerase Chain Reaction Assignment. https://studentshare.org/biology/2045733-genetics-short-answer-questions-assignment.
“Components and Processes Within a Polymerase Chain Reaction Assignment”. https://studentshare.org/biology/2045733-genetics-short-answer-questions-assignment.
  • Cited: 0 times

CHECK THESE SAMPLES OF Components and Processes within a Polymerase Chain Reaction

The Occurrence and Circumstances of Bloom Syndrome

Bloom syndrome is a genetic disorder that occurs due to the inability to conserve the genomic structure of the body.... he mishap in genetics comes because of crossovers of sister chromosomes;the syndrome is brought by autosomal resseciveness of BML gene… Abstract Bloom syndrome is a genetic disorder that occurs due to the inability to conserve the genomic structure of the body (Cohen, 2004)....
15 Pages (3750 words) Essay

THE POLYMERASE CHAIN REACTION (PCR)

THE polymerase chain reaction (PCR) The polymerase chain reaction is basically a different and an innovative technology which is used for amplifying a single piece of DNA for different orders of magnitude resulting in creating millions of copies of one single DNA sequence.... The last and a very important step is extension in which one the primers are annealed to the DNA sequence which is complementary and the temperature is raised to 72 degree Celsius which will also end up in tagging DNA polymerase enzyme....
3 Pages (750 words) Essay

Polymerase Chain Reaction

This essay will examine the polymerase chain reaction (PCR) technique by taking a closer look at its emergence as the preferred technique for multiplying and amplifying DNA.... The advantages of PCR will be highlighted by contrasting the technique with cloning, the components required and the stages of the process. … The polymerase chain reaction was first introduced Kary Mullis in the 1980's (Bartlett et al 2003).... Introduction This essay will examine the polymerase chain reaction (PCR) technique by taking a closer look at its emergence as the preferred technique for multiplying and amplifying DNA....
2 Pages (500 words) Essay

The Polymerase Chain Reaction:

However if it migrates to the 400 bp band position you are considered homozygous for the presence… Presence of bands in both 100 bp and 400 bp position shows you are heterozygous showing polymorphism in one allele and normal gene in the other (+/- or long/short). The 94C step in the procedure results in Deadline: To handed in 2nd of March The polymerase chain reaction: Its use in genetic testing.... If the reaction has worked, what is your genotype for the polymorphism?...
2 Pages (500 words) Essay

Chain-growth polymerization reactions

The termination process follows unless the reaction has contaminants, which can contribute to the addition of monomers (Richardson, and Erik 92).... chain growth polymerization corresponds to a polymerization process or technique in which unsaturated monomer molecules add to the active site of a growing polymer chain.... This process has distinct characteristics because of the limited number… chain growth polymerization can be symbolized using this chemical equation....
2 Pages (500 words) Lab Report

The Protein Synthesis Process

However, all the repeated units in starch are oriented in one direction while in cellulose; every successive unit of glucose is rotated 180 degrees of around the axis of the backbone chain of the polymer.... In experiments, the amylase components do not dissolve in water while Amylopectin dissolves in water....
5 Pages (1250 words) Essay

Moving Societies to Green Governance

According to Cole and Foster, “environmental justice requires democratic decision making, community empowerment, and the incorporation of social structure---for example, existing community health problems, cumulative impacts of processing environmental hazards, the effect of segregative housing patterns----in environmental decision-making processes.... rdquo;4 Cole and Foster correctly noted that that “current environmental decision-making processes have not been effective in providing meaningful participation opportunities for those most burdened by environmental decisions....
9 Pages (2250 words) Term Paper

Polymerase Chain Reaction

… The paper “polymerase chain reaction” is an exceptional example of a science essay.... This essay will examine the polymerase chain reaction (PCR) technique by taking a closer look at its emergence as the preferred technique for multiplying and amplifying DNA.... The paper “polymerase chain reaction” is an exceptional example of a science essay.... This essay will examine the polymerase chain reaction (PCR) technique by taking a closer look at its emergence as the preferred technique for multiplying and amplifying DNA....
2 Pages (500 words) Essay
sponsored ads
We use cookies to create the best experience for you. Keep on browsing if you are OK with that, or find out how to manage cookies.
Contact Us