BIOL 111 1st Edition Final Exam Study Guide From Gene to Protein What are the components and processes of the Central Dogma of molecular biology o Genes program protein synthesis via genetic messages in the form of messenger RNA o DNA RNA Protein How do these processes differ in prokaryotic vs eukaryotic cells o Prokaryotic bacteria cell bacteria cell lacks a nucleus so mRNA is produced by transcription and immediately translated without additional processing o Eukaryotic cell transcription occurs in the nucleus and translation occurs in the cytoplasm What is the genetic code On an exam could you transcribe a piece of template DNA into mRNA and then o Four nucleotides to specify 20 amino acids Translate that mRNA into amino acids to form a short polypeptide Figs 17 4 17 5 see problem on pg 3 What are the three stages of transcription What molecular components DNA sequences enzymes and other proteins are required for each of these stages o Initiation RNA polymerase starts transcription RNA polymerase II TATA box o Elongation RNA polymerase moves along the DNA to unwind the helix shape o Termination termination sequence will have the polymerase detach from the DNA How and why do eukaryotic cells modify their mRNA o RNA processing both ends of the primary transcript are altered o Interior sections f the RNA molecule are cut out and the remaining parts are spliced together Explain how alternative RNA splicing gives rise to more than one polypeptide o The introns are taken out and this causes a process called exon shuffling o Introns increase the probability of crossing over by the exons and this allows exons to code for more than one polypeptide Describe the structure of tRNA How is this molecule synthesized o The tRNA is transcribed from the DNA strand and is synthesized in the nucleus o As mRNA molecule is moved through the ribosome glycine will be added to the polypeptide chain when the codon GGC is presented for translation o The genetic message is translated to amino acids mRNA tRNA is codons amino acids For what discovery was the 2009 Nobel Prize in Chemistry awarded Why was this important o The Nobel Prize in Chemistry 2009 was awarded jointly to Venkatraman Ramakrishnan Thomas A Steitz and Ada E Yonath for studies of the structure and function of the ribosome Describe the role of the three types of RNA mRNA rRNA and tRNA in the assembly of a ribosome and the production of a polypeptide o Messenger RNA mRNA carries the genetic information copied from DNA in the form of a series of three base code words each of which specifies a particular amino acid o Transfer RNA tRNA is the key to deciphering the code words in mRNA mRNA amino acids o Ribosomal RNA rRNA associates with a set of proteins to form ribosomes making the polypeptide chain Describe the events that take place at each of the three tRNA binding sites in the ribosome o P site holds the tRNA carrying the growing polypeptide chain o A site holds the tRNA carrying the next amino acid to be added to the chain o E site discharged tRNAs leave the ribosome from here What are the roles of initiation elongation and release factors in translation Which required energy o Initiation factors required to bring all components of the ribosome together o Elongation factors energy expenditure occurs in first and third steps codon recognition translocation o Release factors causes an addition of a water molecule instead of an amino acid to the polypeptide chain this hydrolyzes the bond and releases the polypeptide How are proteins targeted to specific sites within the cell o The polypeptides are marked by a signal peptide that targets the protein to its destination How do point mutations in DNA affect protein production Which types of mutations are the most serious o If a point mutation occurs in a gene that produces gametes the mutation can be transmitted to offspring o Point mutations are the most serious Trace sickle cell anemia from genotype to phenotype see Figs 5 21 and 17 23 Define mRNA ribosomes triplet code open reading frame template strand codons reading frame RNA polymerase promoter transcription factors TATA box terminator polyadenylation sequence 5 cap poly A tail introns exons spliceosome snRNA t RNA anti codon aminoacyl tRNA synthetase r RNA signal peptide silent mutation mis sense mutation nonsense mutation frameshift mutation Concept checks 17 1 17 6 Self quiz pg 350 1 8 Regulation of Gene Expression Why are cell signaling pathways essential to the regulation of gene expression o Study the stages in gene expression that can be regulated in eukaryotes Fig 18 6 Chromatin is composed of DNA and protein how can each of these be chemically modified to either make DNA more or less accessible to RNA polymerase o Histone modifications ex Histone acetylation DNA methylation and epigenetic inheritance How are Barr bodies and genomic imprinting examples of modifications in chromatin structures that affect gene expression see Fig 15 8 and 15 18 o Describe the cell specific and general components that need to work together to activate genes in specific cell types Figs 18 9 18 10 How can gene expression be regulated after the mRNA transcript is produced What role does miRNA play in regulating gene expression How do early embryonic cells know to adopt one fate instead of another fate Describe the process of cell differentiation What are the roles of transcription factors in this process How are global body patterns anterior vs posterior dorsal vs ventral established in early embryos How do cells become cancerous Describe alterations in cell signaling or alterations in gene regulation that can contribute to cancer development Why is cancer considered to be a multistep disease Define cell signaling reception transduction response histone acetyl methyl Barr body genomic imprinting enhancer DNA binding domain activation domain mediator proteins DNA bending proteins genomic equivalence differential gene expression ubiquitin proteasome miRNA hairpins cytoplasmic determinants induction cell differentiation pattern formation morphogen morphogen gradient hypothesis proto oncogene oncogene tumor suppressor geneIoncept checks 18 2 18 5 Biotechnology Review the process of DNA replication from Ch 16 What is the purpose of PCR gel electrophoresis DNA sequencing Dideoxy chain termination method and cloning DNA Know the components required for each of the above techniques and the processes involved in each technique How have these techniques added
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