Bio 200 Exam 2 LABS Questions and
Answers
Initiation of transcription at the correct location starts when sigma binds at the -10
and -35 sequences of the DNA. The core RNA polymerase enzyme then binds to the
DNA and starts to separate the DNA strands at the promoter in order to create a new
strand based on RNA-DNA basepairing.
Which of these choices is the general outline for the Central Dogma Workshop
exercises? - ANSWER-DNA structure, Transcription, Translation, Genetic Diseases
Why are some genes constitutively expressed while the expression of others is
regulated? - ANSWER-Some gene products are needed at all times, and other gene
products are only produced under some conditions to avoid waste and respond to
stimuli.
While there are some genes that should be 'on' as much as possible, most genes
are used only when the situation is correct. This helps avoid wastefully producing
mRNA and protein when unnecessary (both mRNA and protein require many ATP to
make a single molecule). This also allows the cell to respond appropriately to
changing conditions.
This sequence element is used as the binding site of sigma and RNA polymerase,
which transcribes the DNA message into mRNA. All genes have one of these sites. -
ANSWER-Promoter- The promoter is most importantly the starting point for
transcription for a gene or operon.
Polymerase-blocking proteins, such as the LacI (repressor) protein, bind at these
sites to physically block movement of the transcribing RNA polymerase. - ANSWER-
Operator- The repressor protein can physically block transcription by binding at the
operator (between the transcriptional starting point and the mRNA sequence).
Which of these choices is an important DIFFERENCE between the Enzyme Lab
Procedure and this week's Gene Regulation Procedure? - ANSWER-The Gene
Regulation Lab uses E. coli bacteria as a source of enzyme instead of the
concentrated factory-produced Lacteeze used in the Enzyme lab.
Why is transcriptional regulation is more common and/or efficient than translational
regulation? - ANSWER-Translational regulation would require mRNA to be made for
every gene at all times, which is wasteful.
Because it happens at an earlier step (before expensive intermediate molecules are
produced) translation is more efficient. Because efficiency is so heavily selected for
Answers
Initiation of transcription at the correct location starts when sigma binds at the -10
and -35 sequences of the DNA. The core RNA polymerase enzyme then binds to the
DNA and starts to separate the DNA strands at the promoter in order to create a new
strand based on RNA-DNA basepairing.
Which of these choices is the general outline for the Central Dogma Workshop
exercises? - ANSWER-DNA structure, Transcription, Translation, Genetic Diseases
Why are some genes constitutively expressed while the expression of others is
regulated? - ANSWER-Some gene products are needed at all times, and other gene
products are only produced under some conditions to avoid waste and respond to
stimuli.
While there are some genes that should be 'on' as much as possible, most genes
are used only when the situation is correct. This helps avoid wastefully producing
mRNA and protein when unnecessary (both mRNA and protein require many ATP to
make a single molecule). This also allows the cell to respond appropriately to
changing conditions.
This sequence element is used as the binding site of sigma and RNA polymerase,
which transcribes the DNA message into mRNA. All genes have one of these sites. -
ANSWER-Promoter- The promoter is most importantly the starting point for
transcription for a gene or operon.
Polymerase-blocking proteins, such as the LacI (repressor) protein, bind at these
sites to physically block movement of the transcribing RNA polymerase. - ANSWER-
Operator- The repressor protein can physically block transcription by binding at the
operator (between the transcriptional starting point and the mRNA sequence).
Which of these choices is an important DIFFERENCE between the Enzyme Lab
Procedure and this week's Gene Regulation Procedure? - ANSWER-The Gene
Regulation Lab uses E. coli bacteria as a source of enzyme instead of the
concentrated factory-produced Lacteeze used in the Enzyme lab.
Why is transcriptional regulation is more common and/or efficient than translational
regulation? - ANSWER-Translational regulation would require mRNA to be made for
every gene at all times, which is wasteful.
Because it happens at an earlier step (before expensive intermediate molecules are
produced) translation is more efficient. Because efficiency is so heavily selected for
