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Title: microbio Post by: emily on Aug 1, 2011 Can anyone help me with these questions?
1) Bacterial cells coordinate chromosome replication and cell division with growth so that cell division always follows replication. Which of the following statements is (are) correct? A) newborn cells have the chromosome organized in such a way that the origin region is located near one end (about 1/4 the cell length) and the terminus region near the other end of the cell. B) replication forks move clockwise and counterwise around the chromosome. C) the terminus region of the chromosome is the last region to move to the cell center where it is replicated D) all the above are correct 2) If a nucleotide pair substitution occurs in the B-galactosidase gene of the lactase operon, you would expect that the mutant, A) would be unable to synthesize the altered protein product B) would be unable to regulate expression of the lactose operon C) might synthesize an inactive B-galactosidase D) might not be able to synthesize lactose 3) Selection A) allows you to isolate a particular mutant from a mixture of wild-type and mutant organisms B) requires a medium containing two carbon/energy sources C) allows you to count the total number of bacteria in a culture D) allow cells to use the more efficient carbon/energy source first, from a mixture of two sugars 4) Assume that your favorite organism is sensitve to the antibiotic streptomycin and that you want to select rare steptomycin-resistant mutants from the wild-type population. You could do this by plating the culture on A) glucose medium B) lactose medium C) glucose medium plus streptomycin D) glucose plus lactose medium 5) Mismatch mutations can be repaired by A) error-prone translesion synthesis B) error-free excision repair C) recombination enzymes D) all the above Title: Re: microbio Post by: how_mendel on Aug 1, 2011 1) Bacterial cells coordinate chromosome replication and cell division with growth so that cell division always follows replication. Which of the following statements is (are) correct?
A) newborn cells have the chromosome organized in such a way that the origin region is located near one end (about 1/4 the cell length) and the terminus region near the other end of the cell. B) replication forks move clockwise and counterwise around the chromosome. C) the terminus region of the chromosome is the last region to move to the cell center where it is replicated D) all the above are correct 2) If a nucleotide pair substitution occurs in the B-galactosidase gene of the lactase operon, you would expect that the mutant, A) would be unable to synthesize the altered protein product B) would be unable to regulate expression of the lactose operon C) might synthesize an inactive B-galactosidase D) might not be able to synthesize lactose 3) Selection A) allows you to isolate a particular mutant from a mixture of wild-type and mutant organisms B) requires a medium containing two carbon/energy sources C) allows you to count the total number of bacteria in a culture D) allow cells to use the more efficient carbon/energy source first, from a mixture of two sugars 4) Assume that your favorite organism is sensitve to the antibiotic streptomycin and that you want to select rare steptomycin-resistant mutants from the wild-type population. You could do this by plating the culture on A) glucose medium B) lactose medium C) glucose medium plus streptomycin D) glucose plus lactose medium 5) Mismatch mutations can be repaired by A) error-prone translesion synthesis B) error-free excision repair C) recombination enzymes D) all the above I'm not 100% sure. Title: Re: microbio Post by: bio_man on Aug 2, 2011 Hey, for (1) I originally thought it was B as well, but looking more into it, perhaps Howard is correct because in E. coli, replication occurs around the cell centre (i.e., the mid-cell position). I would still go with (B) though.
B-galactosidase is required for the metabolism of lactose, but doesn't have to do with the expression of other genes in the lactose operon, so I too, disagree with (B). Could be (A) or (C). I split your new questions into a new thread. Title: Re: microbio Post by: emily on Aug 2, 2011 I found out 2 is C. So ur right, howard :)
Title: Re: microbio Post by: how_mendel on Aug 4, 2011 |