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BS161 Biology Final Exam With Answers (81 Solved Questions)

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    VERSION 3 In messenger RNA, the protein-coding sequence is present in: Question options: exons. introns. exons and the poly(A) sequence. introns and the poly(A) sequence. - exons. Which process produces multiple proteins from the same primary transcript in the same cell? Question options: chromatin remodeling histone modification alternative splicing combinatorial control - alternative splicing Alternative splicing allows for: Question options: two or more different proteins to be made from a single processed mRNA. different polypeptides to be made from a single gene. multiple genes to be used to code for a single polypeptide chain. enhanced recognition of an mRNA by a ribosome. increased stability of a mature mRNA. - different polypeptides to be made from a single gene.

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    RNA splicing provides an opportunity for regulating gene expression because: Question options: the same exons may be spliced together in different sequences to produce different proteins from the same primary transcript. methylation of the poly(A) tail controls how rapidly the primary transcript can be broken up and spliced back together again. the same introns may be spliced together in different sequences to produce different proteins from the same primary transcript. methylation of spliceosomes controls how rapidly primary transcripts are processed and sent to the cytoplasm. - the same exons may be spliced together in different sequences to produce different proteins from the same primary transcript. In both prokaryotic and eukaryotic gene expression, Question options: Introns are removed from genes before translation RNA must be transported out of the nucleus for translation One type of RNA corresponds to only one type of protein Transcription requires RNA polymerase binding to promoter regions - Transcription requires RNA polymerase binding to promoter regions In prokaryotes: (Select all correct answers.) Question options: translation of an mRNA cannot begin until transcription is completed. the primary RNA transcript needs a "cap" at the 5' end for the initiation of translation. the translation of mRNA can begin even before transcription is completed. the DNA is packaged into nucleoid. - the translation of mRNA can begin even before transcription is completed. the DNA is packaged into nucleoid. In prokaryotes, the AUG codon that starts translation is: Question options: the AUG nearest the 5' cap on the mRNA. adjacent to the 5' cap on the mRNA.

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    at the 5' end of the mRNA. adjacent to a Shine-Dalgarno sequence. - adjacent to a Shine-Dalgarno sequence. What occurs in positive transcriptional regulation to result in transcription? (Hint: Is there a difference between a promoter and the activator binding site? See text book and notes if you are not sure.) Question options: The activator protein binds to the activator binding site The repressor protein binds to the activator binding site The repressor protein binds to the promoter region The activator protein binds to the promoter region - The activator protein binds to the activator binding site When a group of functionally related genes located next to one another along the bacterial DNA is transcribed as a single molecule of mRNA, that mRNA is said to be: Question options: polyproteinacious. polycistronic. polymeric. polynomial. polytranslational. - polycistronic. In an operon, different genes have _____ start codon and _____ stop codon. Question options: the same; the same the same; their own their own; their own their own; the same - their own; their own An operon is a: (Hint: The term 'structural gene' means a gene that encodes a protein. It is discussed in the textbook.) Question options: region of DNA, found in both prokaryotes and eukaryotes, that controls gene expression.

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    region of DNA consisting of the promoter, the operator, and coding sequences for structural proteins. constitutively expressed gene encoding a repressor protein, such as lacI. region of DNA that consists of the promoter and operator sequences, but excludes the structural genes which are regulated by these sequences. single molecule of RNA encoding more than one protein in prokaryotes. - region of DNA consisting of the promoter, the operator, and coding sequences for structural proteins. A region of prokaryotic DNA consisting of an operator, promoter, and coding sequence for several functionally related genes is called a(n): Question options: opera. closed reading frame. organized genomic region. operation. operon. - operon. A specific sequence of DNA that a prokaryotic repressor can bind to is called an: Question options: Poly(A) tail Operator Promoter TATA box - Operator The binding of a regulatory molecule to an operon blocks the transcription process. Which of the following statements is correct? Question options: This molecule functions as a repressor This molecule functions as an activator This molecule binds to the promoter region This is an example of positive regulation - This molecule functions as a repressor Question 16, 5 in class 26 - look at d2l

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    Which of the following are constitutively (always) expressed in prokaryotic cells which have the lac operon? Question options: the gene for RNA polymerase the gene for the beta-galactosidase enzyme the gene for the lactose transporter the lacI gene, which encodes the repressor protein - the lacI gene, which encodes the repressor protein the gene for RNA polymerase Which statement about LacI and the lac operon is correct? (Hint: Are the promoter and operator the same?) Question options: LacI is active and binds to the lac operator when lactose is present The lac operon transcription is reduced when LacI binds to DNA LacI can bind to the promoter region of the lac operon LacI is the only protein involved in the regulation of the lac operon - The lac operon transcription is reduced when LacI binds to DNA Which of the following is necessary for high levels of expression of the lac operon? Question options: Low levels of lactose Low levels of cAMP Low levels of glucose LacI binding to the operator - Low levels of glucose Bacteria with a mutation eliminating the function of the lacZ gene (lacZ -): (Hint: See textbook, if you are not sure what lacZ means.) Question options: can more efficiently utilize lactose for energy cannot utilize lactose for energy cannot transport lactose into the cell can more easily cleave lactose into sugars - cannot utilize lactose for energy

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    The _____ of lactose _____ the binding of the lac repressor protein to the operator and potentially _____ transcription of the structural genes in the operon. Question options: presence, does not affect, does not affect absence, increases, increases presence, decreases, increases absence, decreases, increases - presence, decreases, increases The lacZ and lacY genes, which produce the enzymes that transport lactose into cells and then breaks it down, are transcribed when: Question options: lactose is absent and glucose levels are high. lactose is present and glucose levels are low. lactose is present, regardless of the level of glucose in the cell. glucose levels are high and lactose levels are low. glucose levels are low, regardless of the level of lactose in the cell. - lactose is present and glucose levels are low. question 23, 25, 26, 27, 31, 31 - D2L class 26 Alternative splicing regulates gene expression by: Question options: creating mutations in RNA. altering mRNA sequences. altering DNA sequences in chromosomes. degrading specific domains in proteins. - altering mRNA sequences. Which condition will result in maximum expression of the lac operon? Question options: high glucose and high lactose low glucose and low lactose high glucose and low lactose low glucose and high lactose - low glucose and high lactose

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