Practice Questions

TLS Online TPP Program

#Question id: 5118

Which of the following is not a mechanism by which cells communicate with each other?

#SCPH01 Biochemistry

transcription factors are secreted from one cell and taken up by the target cell, where they influence gene expression
cell surface molecules on adjacent cells interact and initiate a signal transduction process that influences cellular behavior and gene expression
cells form gap junctions with adjacent cells, allowing the passage of small molecules
cells secrete proteins and small hydrophilic molecules, which interact with cell surface receptors on target cells and initiate a signal transduction process that influences cellular behavior and gene expression

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TLS Online TPP Program

#Question id: 15620

#SCPH01 Biochemistry

Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. What does this result tell you about the relationship between the lac3– and lac1- mutations?

TLS Online TPP Program

#Question id: 15620

#SCPH06 I Botany

Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. What does this result tell you about the relationship between the lac3– and lac1- mutations?

TLS Online TPP Program

#Question id: 15620

#SCPH28 | Zoology

Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. What does this result tell you about the relationship between the lac3– and lac1- mutations?

TLS Online TPP Program

#Question id: 15621

#SCPH01 Biochemistry

Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. If the merodiploid were Lac–,

a) the two mutations lie in the different gene.

b) Both mutation are complement each other

c) the two mutations lie in the same gene.

d) Both of the mutations is dominant to wild type.

what could you conclude about the relationship between the lac3– and lac1– mutations from these statements?

TLS Online TPP Program

#Question id: 15621

#SCPH06 I Botany

Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. If the merodiploid were Lac–,

a) the two mutations lie in the different gene.

b) Both mutation are complement each other

c) the two mutations lie in the same gene.

d) Both of the mutations is dominant to wild type.

what could you conclude about the relationship between the lac3– and lac1– mutations from these statements?

TLS Online TPP Program

#Question id: 15621

#SCPH28 | Zoology

Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. If the merodiploid were Lac–,

a) the two mutations lie in the different gene.

b) Both mutation are complement each other

c) the two mutations lie in the same gene.

d) Both of the mutations is dominant to wild type.

what could you conclude about the relationship between the lac3– and lac1– mutations from these statements?