Molecular Diagnostics Chapter 2 Study Questions with Correct Answers

Molecular Diagnostics Chapter 2 Study Questions with Correct Answers 1. Multiple products are generated from the same gene by what mechanism? - ANSWER Alternative splicing 2. Thalassemias arise from changes in what part of the beta-globin gene? - ANSWER Splice recognition unit 3. When gene expression is regulated by mechanisms other than the interaction of cis elements and trans factors, the regulation is called what? - ANSWER Epigenetics 4. Genomic imprinting is accomplished primarily through what? - ANSWER Methylation 5. The most frequently methylated base in vertebrates is what? - ANSWER Cytosine 6. MicroRNAs, short endogenous RNA, perform what function in the eukaryotic cell? - ANSWER Repressing gene expression 7. What mechanism may explain the difference in symptoms in Prader-Willi and Angelman syndromes? - ANSWER Genomic imprinting 8. Alteration of the nucleotide sequence of RNA after transcription is called? - ANSWER RNA editing 9. distal elements - ANSWER control elements are distant to the promoter 10.Epigenetics - ANSWER the study of influences on gene expression that occur without a DNA change 11.What are three types of epigenetic changes? - ANSWER 1. histone modification 2. nucleic acid methylation 3. noncoding RNA 12.Chromatin - ANSWER granular material visible within the nucleus; consists of DNA tightly coiled around proteins 13.Nucleosome - ANSWER Bead-like structure in eukaryotic chromatin, composed of a short length of DNA wrapped around 8 of histone proteins (2A, 2B, histone 3, histone 4) 14.RNAi - ANSWER RNA interference; injecting double stranded RNA into a cell turns off expression of a gene with the same sequence as the RNA RNA - ANSWER long non-coding RNA, 200-100,000 nt, regulate chromatin structure through: folding of secondary structure attracts proteins that would normally bind to cis DNA, acts as a decoy preventing transcription scaffolding by folding of RNA into hairpins can bring together proteins that would normally not interact bring together trans factors bound to enhancers and cis sites through scaffolding of hairpins can acts a guide or adaptor for proteins during transcription 16.XIST gene - ANSWER encodes an RNA that binds to and inactivates the X chromosome, lncRNA 17.The type of transcription producing RNA that is continually required and relatively abundant in the cell is call ____________ transcription - ANSWER constitutive mirs - ANSWER miRNA mimics that target oncomirs to be used as therapeutic agents 19.DNMT1 - ANSWER methylates hemimethylated DNA (DNA methyltransferase) 20.Dnmt3 - ANSWER methylates unmethylated DNA 21.DNMT3L - ANSWER nonfunctional methylase because it lacks catalytic enzyme 22.Euchromatin - ANSWER The less condensed form of eukaryotic chromatin that is available for transcription. More acetylated less methylated 23.Heterochromatin - ANSWER Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed. silencing - ANSWER whole regions of chromosomes are shut off while the same regions in other cells remain active, ie. one X chromosome in females during embryo development ion effect - ANSWER a change in phenotype that occurs when the position of a gene changes from one chromosomal site to a different location 26.Describe the lac operon - ANSWER - First operon to be understood - Promotor + 3 genes - Turns on and off depending on the presence of lactose/glucose - Codes for lactose-digesting enzymes. 27.Induction - ANSWER a repressor binds to an inducer allowing gene transcription to occur as seen in the lac operon ssion - ANSWER repressor and corepressor bind to each other to effectively turn off transcription as seen in the arg operon ation - ANSWER an activator binds to the operator turning on gene transcription as seen in the Mal operon 30.Attenuation - ANSWER loops formed RNA transcript through hydrogen bonding which can either allow or precent transcription 31.Do eukaryote have operons? - ANSWER No mal elements - ANSWER control elements are located close to the promoter