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Biol308 Entire Study Questions that you will need to know

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BIOL 308
Bruce Wolff

Study questions for the lectures 14 1 What informations could you obtain from a genetic approach of studying mutants defective in a particular processIsolate genomic clone sequence it and determine amino acid sequence This sequence can be compared with that of the healthy organisms to deduce protein function in the organism which is not equivalent in the mutant Firstly genetic approach begins at the gene level comparing a normal gene to a mutantIt allows you to deduce amino acid sequence of the mutant protein and compare that with the sequence of the known protein to gain insight into the functioning of the proteinYou can also use expression vectors to express this protein in other cells ie in vitro tests on bacteria or other cell lines2 How would you define permissive conditions in respect to temperature sensitive mutantsTemperaturesensitive mutants exhibit the wildtype phenotype under low temperatures but exhibit the mutant phenotype at higher temperatures Thus conditions are permissive when the mutants are allowed to grow normally or under lower temperatures3 Define or compare and contrast a gene expression transcription replication translation b gene alleleGene expression is the process by which the information from a gene is used in the synthesis of functional protein or RNA product Transcription is the process of synthesizing heteronuclear RNA transcripts from a gene and is made by cell machinery using the template strand of DNA RNA contains uracil instead of thymine in the nucleotide sequence and is similar to the coding strand Translation is the process of synthesizing peptide sequences from mRNA using cell machinery Genes are sequences of nucleotides in a genome that contain information coding for the synthesis of a functional protein or RNA product Alleles are alternative sequences of a particular gene more specifically two homologous chromosomes may contain different sequences of a specific gene at a particular locus and thus contain different alleles4 Explain by using your own words the meaningsignificance of gene expressionGene expression is the process of using the information stored in a genetic sequence to synthesize functional RNA or protein When a gene is expressed transcription occurs and translation occurs to form protein productGene expression is the use of the genetic information stored in a gene to create a functional protein or RNA product 5 What are the roles of model organisms in molecular biology studies Choose two model organisms and explain your reasoningModel organisms are used in molecular biology studies because they have many benefits including simplicity relative ease to use cheapness and often short reproductive times They are also used as standards because so much information has been collected on them and continue to be collected In this way vast and specific amounts of information about these model organisms are obtained and can be extrapolated to other organisms including humans For example mice can be used to model mammalian species such as humans due to highly conserved biological pathways and processes and they have relatively quick turnover rates compared to other similar organisms Escherichia coli are used to model metabolic processes due to their simplicity and the conservation of metabolic processes throughout many species 6 What are three main functions of DNA Explain the importance of each of them1 To store genetic informationallows for reproduction of cells into others and for production of protein and RNA products for cell function 2 To replicate faithfullyallows for production of nearly identical viable organisms to continue the species life cycle 3 To mutateallows for variability in gene sequence and frequency allowing for selection and evolution to occur7 What is are the roles of phosphodiester bonds in DNA structure What is are the roles of hydrogen bonds in DNA structure What is are the roles of hydrophobic interactions in DNA structurePhosphodiester bonds provide the rigid backbone for DNA structure and also help stabilize the molecule as they are negatively charged and repel from each other allowing Hbonding to occur between the bases instead Hydrogen bonds in DNA structure provide minimal stabilization but also allow for hydbridization between strands due to complementary hydrogen bonding between A and T and between G and C Hydrophobic interactions make it favourable for DNA strands to be hybridized in order to minimize the water molecules that form the cage around the moleculethus provide an entropically favorable way for DNA duplex formation8 What noncovalent interactions are involved in maintaining the doublehelical conformation of DNAIonic forces hydrogen bonds van der Waals forces and the hydrophobic effect are involved in maintaining the doublehelix formation 9 Learn to recognize nitrogenous bases ATGCU and respective nucleotidesOKANNH GOHN CNNO UOHO COHORT 10 Describe MeselsonStahl experiment and explain how it showed that DNA replication is semiconservativeBacteria were grown in 15N and their DNA bases all contained this isotope of nitrogen The cells were then transferred to a 14N containing medium After cell replication one distinct band was observed after centrifugation one for 15N14N DNA This was because as in the semiconservative model for DNA replication each strand from the original 15N DNA was used to synthesize a new DNA using new 14N nucleotides Thus one strand for each of the new DNA molecules after replication had 15N and the other had 14N After the second replication only a 14N14N band and a thinner 15N14N band was observed The 14N14N was due to new replication using the 14N strand on the 15N14N strand and new 14N nucleotides The 1415N strand was due to new DNA synthesis using the 15N strands on some molecules This experiment showed that DNA was being replicated by each strand being used as a template for a new molecule and the original DNA duplex split and the strands were used to make new ones complementary to them11 What is meant by saying that a DNA strand has polarity That two strands of DNA are antiparallel That the strands are complementary to one another
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