A species of bacteria can synthesize the amino acid histidine so it does not require histidine in its growth medium. A key enzyme, which we will call histidine synthetase, is necessary for histidine biosynthesis. When these bacteria are given histidine in their growth media, they stop synthesizing histidine intracellularly. Based on this observation alone, propose three different regulatory mechanisms to explain why histidine biosynthesis ceases when histidine is in the growth medium. To explore this phenomenon further, you measure the amount of intracellular histidine synthetase protein when cells are grown in the presence and absence of histidine. In both conditions, the amount of this protein is identical. Which mechanism of regulation would be consistent with this observation?

Which of the following statements most accurately describes the relationship between the two passages? A. Passage One expresses the emotional urgency of the colonial situation, while Passage Two expresses the rational conclusions generated by that situation. B. Passage Two presents the complaints of the colonies in much less detail than Passage One does. C. Passage One is more detached than Passage Two. D. Details in the two passages reveal that the authors had dissenting opinions about the colonial situation. E. Both passages expect the reader to arrive at his or her own conclusion.

Target Corporation provides the following footnote relating to its retirement plans in its 2017 10-K report: Defined Contribution Plans Team members who meet eligibility requirements can participate in a defined contribution 401(k) plan by investing up to 80 percent of their eligible earnings. as limited by statute or regulation. We match 100 percent of each team member's contribution up to 5 percent of eligible earnings.

Company match contributions are made to funds designated by the participant, none of which are based on Target common stock. Benefits expense related to these matching contributions was $219 million,$197 million, and $224 million in 2017, 2016, and 2015, respectively.

a. Does Target have a defined contribution or defined benefit pension plan? Explain.

A sporting goods manufacturer produces regulation soccer balls at two plants. The costs of producing $x_{1}$ units at location 1 and $x_{2}$ units at location 2 are given by $C_{1}\left(x_{1}\right)=0.02 x_{1}^{2}+4 x_{1}+500$ and $C_{2}\left(x_{2}\right)=0.05 x_{2}^{2}+4 x_{2}+275$ respectively. If the product sells for $50 per unit, then the profit function for the product is given by$P\left(x_{1}, x_{2}\right)=50\left(x_{1}+x_{2}\right)-C_{1}\left(x_{1}\right)-C_{2}\left(x_{2}\right)$. Find (a) P(250, 150), (b) P(300, 200), and (c) P(600, 400).

Most of the following selections were taken from letters-to-the-editor columns of news papers and magazines. Identify any fallacies that may be committed, giving a brief explanation for your answer. Then, if a fallacy is identified, discuss the possible factors that led the arguer to commit the fallacy. A parent would never give a ten-year-old the car keys, fix him or her a martini, or let him or her wander at night through a dangerous part of town. The same holds true of the Internet. Watch what children access, but leave the Net alone. Regulation is no substitute for responsibility.

Optimal goal target in soccer. When attempting to score a goal in soccer, where should you aim your shot? Should you aim for a goalpost (as some soccer coaches teach), the middle of the goal, or some other target? To answer these questions, Chance (Fall 2009) utilized the normal probability distribution. Suppose the accuracy $x$ of a professional soccer player's shots follows a normal distribution with a mean of 0 feet and a standard deviation of 3 feet. (For example, if the player hits his target, $x=0$; if he misses his target 2 feet to the right, $x=2$; and if he misses 1 foot to the left, $x=-1$.) Now, a regulation soccer goal is 24 feet wide. Assume that a goalkeeper will stop (save) all shots within 9 feet of where goalkeeper who stands in the middle of the goal. If the player aims for the right goalpost, what is the probability that he will score?

Draw the structure of histidine at $\mathrm{pH} 1$, and show how the positive charge in the second basic group (the imidazole ring) can be delocalized.

A $100$-kVA, $8000/277$-V distribution transformer has the following resistances and reactances:

$$\begin{aligned} R_p & = 5\ \Omega & \quad \quad & R_S = 0.005\ \Omega\\ X_p & = 6\ \Omega & \quad \quad & X_S = 0.006\ \Omega\\ R_C & = 50\ \text{k}\Omega & \quad \quad & X_M = 10\ \text{k}\Omega \end{aligned}$$

The excitation branch impedances are given referred to the high-voltage side of the transformer.

(a) Find the equivalent circuit of this transformer referred to the low-voltage side.

(b) Find the per-unit equivalent circuit of this transformer.

(c) Assume that this transformer is supplying rated load at $277$ V and $0.85$ PF lagging. What is this transformer’s input voltage? What is its voltage regulation?

(d) What are the copper losses and core losses in this transformer under the conditions of part (c)?

(e) What is the transformer’s efficiency under the conditions of part (c)?

Use the following information for this exercise .

The table shows regulation distances between hurdles in women's and men's races. In both the women's and men's events, the race consists of a straight track with 10 equally spaced hurdles.

Find the distance from the last hurdle to the finish line for the women's race.

Use the following information for this exercise .

The table shows regulation distances between hurdles in women's and men's races. In both the women's and men's events, the race consists of a straight track with 10 equally spaced hurdles.

Find the distance from the last hurdle to the finish line for the men's race.

Optimal goal target in soccer. When attempting to score a goal in soccer, where should you aim your shot? Should you aim for a goalpost (as some soccer coaches teach), the middle of the goal, or some other target? To answer these questions, Chance (Fall 2009) utilized the normal probability distribution. Suppose the accuracy $x$ of a professional soccer player's shots follows a normal distribution with a mean of 0 feet and a standard deviation of 3 feet. (For example, if the player hits his target, $x=0$; if he misses his target 2 feet to the right, $x=2$; and if he misses 1 foot to the left, $x=-1$.) Now, a regulation soccer goal is 24 feet wide. Assume that a goalkeeper will stop (save) all shots within 9 feet of where goalkeeper who stands in the middle of the goal. If the player aims for halfway between the right goalpost and the outer limit of the goalkeeper's reach, what is the probability that he will score?

A sporting goods manufacturer produces regulation soccer balls at two plants. The costs of producing $x_1$ units at location 1 and $x_2$ units at location 2 are given by $C_1\left(x_1\right)=0.02 x_1^2+4 x_1+500$ and

$$C_2\left(x_2\right)=0.05 x_2^2+4 x_2+275$$

respectively. If the product sells for $50 per unit, then the profit function for the product is given by

$$P\left(x_1, x_2\right)=50\left(x_1+x_2\right)-C_1\left(x_1\right)-C_2\left(x_2\right) .$$

Find P(250,150).

Go to www.federalreserve.gov and select the "Banking Information & Regulation" tab. Then click on the links "Banking Data" and "Large Commercial Banks." Once there, select the most recent quarterly data release. a. Which of the following banks has the most consolidated assets? b. Which of the following banks has the most domestic assets? c. What percentage of US GDP are the bank's domestic assets listed in part b? (Hint: You can find U.S. GDP at http://research.stlouisfed.org/fred2/ series/GDP?cid=106 using the links "Gross Domestic Product (GDP)" and then "Current-dollar and 'real' GDP.")

Modulation of Acetyl-CoA Carboxylase Acetyl-CoA carboxylase is the principal regulation point in the biosynthesis of fatty acids. Some of the properties of the enzyme are described below.
(a) Addition of citrate or isocitrate raises the $V_{\max }$ of the enzyme as much as 10 -fold. (b) The enzyme exists in two interconvertible forms that differ markedly in their activities:

$$\text { Protomer (Inactive) } \rightleftharpoons \text { filamentouspolymer (active) }$$

Citrate and isocitrate bind preferentially to the filamentous form, and palmitoyl-CoA binds preferentially to the protomer.
Explain how these properties are consistent with the regulatory role of acetyl-CoA carboxylase in the biosynthesis of fatty acids.