At Time Zero,an Hfr Strain (Strain 1)was Mixed with an F^-

question 15

Essay

At time zero,an Hfr strain (strain 1)was mixed with an F^- strain,and at various times after mixing,samples were removed and agitated to separate conjugating cells.The cross may be written as:
HFr 1: $a ^ { + } b ^ { + } c ^ { + } d ^ { + } e ^ { + } f ^ { + } g ^ { + } h ^ { + } S t r ^ { 5 }$
$\mathrm { F } :$$a^{-} b^{-}-d^{-} e^{-}f ^{-}g^{-}h^{-}S tr{ }^{R}$

No order is implied in the above listing.The samples were then plated onto selective media to measure the frequency of h⁺Str^R recombinants that had received certain genes from the Hfr cell.The following graph shows the percentage of recombinants against time in minutes.
a)Draw a linear map of the Hfr chromosome indicating:
(1)the point of insertion (origin).
(2)the order of the genes a⁺,b⁺,e⁺,g⁺,and h⁺.
(3)the shortest distance between consecutive genes on the chromosome in minutes.
b)An additional four Hfr strains (strains 2 $\times$ 5)were obtained.Each carried the wild-type alleles of the genes listed below.They were mated individually to the same F^- strain shown above (carrying the recessive alleles of all genes).With interrupted mating,the times of first appearance in minutes of individual Hfr markers in exconjugants were determined,as shown in the following chart.
$\begin{array}{ll}&\text { Minutes }\\\text { Hfr marker }& \mathrm{Hfr} 1& \mathrm{Hfr} 2 &\mathrm{Hfr} 3 &\mathrm{Hfr} 4 &\mathrm{Hfr} 5\\a^{+} && 2&&20 \\b^{+} && &11\\c^{+} & &12 &28&10\\d^{+} & &24&&&5\\e^{+} &&&&35&50 \\f^{+} &&&88&&35\\g^{+} &\\h^{+} \end{array}$

Draw the genetic map showing:
(1)the positions of genes a $\times$ through h.
(2)the origins of the Hfrs (including strain 1).
(3)the orientation of the origins.
(4)the shortest distance between consecutive genes or origins.

Recognize the importance of environmental factors and community infrastructure in disease prevention.

Understand the historical development of public health initiatives and their impact on community health.

Analyze the role of government and non-governmental organizations in the advancement of public health.

Identify key figures and their contributions to public health and nursing.

---

Definitions:

Random Elements

Unpredictable factors that can affect outcomes in various systems or processes, often incorporated into models and decision-making to account for uncertainty.

Policy Changes

Refers to modifications or adjustments made to existing rules, regulations, or guidelines within an organization, institution, or government.

Real-Life System

Refers to complex, operational systems that function in the real world, often encompassing human, technological, and environmental components.

Time-Consuming

Activities or processes that require a significant amount of time to complete, often implying inefficiency or labor intensity.