BIO 235 Practice Exam for 4 Questions and Answers 100% Pass

BIO 235 Practice Exam for 4 Questions and Answers 100% Pass 1) The nucleotide sequence of the attenuator region in the leader of the trp mRNA - a) Contains features of a transcription termination site Depurination - the loss of a purine base from a nucleotide Deamination - the removal of an amino group from an organism, particularly from an amino acid attenuator region - region of RNA sequence that forms an alternate secondary structures that govern the level of transcription of attenuated operons. Transcription factors and other regulatory proteins that alter the chromatin structure without altering the chemical structure of the histones are called: - Chromatin-remodeling complexes 2 100% Pass Guarantee Katelyn Whitman, All Rights chromatin remodeling complexes - protein machines that use the energy of ATP hydrolysis to change the position of the DNA wrapped around nucleosomes The type of histone modification that decreases the positive charge of the histone proteins and loosens the binding of the histone proteins to the DNA is: - Acetylation; this will increase transcription rates acetylation - addition of acetyl group histone proteins - A simple protein bound to DNA, involved in the coiling of chromosomes This process affects the expression of genes by changing chromatin structure and is characterized by CpG sites and acts primarily on cytosine. - DNA Methylation histone methylation - the condensing of chromatin structure (heterochromatin), prevents transcription DNA methylation - The addition of methyl groups to bases of DNA after DNA synthesis; may serve as a long-term control of gene expression. 3 100% Pass Guarantee Katelyn Whitman, All Rights Chromatin Immunoprecipitation (ChIP) - can determine if proteins can bind to a particular region of DNA in the chromatin of living cells If glucose and lactose are both in the environment in an E. coli bacterial cell, the regulation of the lac operon will allow which of the two to be processed first? - Glucose will be processed and utilized first, and then once it is used up, lactose will be utilized lac operon - a gene system whose operator gene and three structural genes control lactose metabolism in E. coli Increases in DNA methylation can repress transcription in multiple ways: - a) Methylated CpG sites in the vicinity of the promoter can interfere with transcription b) Methylated CpG sites attract methyl-CpG-binding proteins and other remodeling complexes DNA transcription - the formation of an RNA strand complementary to the DNA strand by RNA polymerase 4 100% Pass Guarantee Katelyn Whitman, All Rights 1) Which of the following DNA mutations can result in the mRNA transcript having a significant portion of its codons changed? - frameshift mutation frameshift mutation - mutation that shifts the "reading" frame of the genetic message by inserting or deleting a nucleotide missense mutation - A base-pair substitution that results in a codon that codes for a different amino acid. neutral mutation - a mutation that has no effect on sur