Most proteins have more leucine than histidine residues, but more histidine than tryptophan residues. Correlate the number of codons for these three amino acids with this information.

A thin electronic component with a surface area of $950 cm^2$ is cooled by having a heat sink attached on its top surface. The thermal contact conductance of the interface between the electronic component and the heat sink is $25,000 W/m^2 \cdot K.$ According to the manufacturer, the heat sink has combined convection and radiation thermal resistance of 1.3 K/W. If the electronic component dissipates 45 W of heat through the heat sink in a surrounding temperature of $30^\circ C,$ determine the temperature of the electronic component. Does the contact resistance at the interface of the electronic component and the heat sink play a significant role in the heat dissipation?

Find the power output and the low $T$ heat rejection rate for a Carnot-cycle heat engine that receives $6 \mathrm{~kW}$ at $250^{\circ} \mathrm{C}$ and rejects heat at $30^{\circ} \mathrm{C}$.

How many joules of heat would be required to heat $0.5\,\text{kg}$ of aluminum by $2\,\text{K}$?

Which of these events takes place during the absorptive state?

a. Glycogen is converted into glucose.

b. Glucose is converted into lipids.

c. Ketones are produced.

d. Proteins are converted into glucose.

Answer the following question to test your understanding of the preceding section:
List the three major classes of plasma proteins. Which one is absent from blood serum?

A power transistor is a solid-state electronic device. Assume that energy entering the device at the rate of $1.50 \mathrm{~W}$ by electrical transmission causes the internal energy of the device to increase. The surface area of the transistor is so small that it tends to overheat. To prevent overheating, the transistor is attached to a larger metal heat sink with fins. The temperature of the heat sink remains constant at $35.0^{\circ} \mathrm{C}$ under steady-state conditions. The transistor is electrically insulated from the heat sink by a rectangular sheet of mica measuring $8.25 \mathrm{~mm}$ by $6.25 \mathrm{~mm}$, and $0.0852 \mathrm{~mm}$ thick. The thermal conductivity of mica is equal to $0.0753 \mathrm{~W} / \mathrm{m} \cdot{ }^{\circ} \mathrm{C}$. What is the operating temperature of the transistor?

An engineer proposes a device that will extract heat from the atmosphere, convert some of it to work, and release the remaining heat back into the atmosphere at the same temperature as the input heat. Is this a perpetual-motion machine and, if so, what kind? Explain

Indicate the changes in secondary and tertiary structural levels of proteins for the following: Hamburger is cooked at high temperatures to destroy E. coli bacteria that may cause intestinal illness.

Which process uses special proteins on the surface of the membrane to identify specific molecules for transport into the cell? a. phagocytosis b. pinocytosis c. receptor-mediated endocytosis d. exocytosis

A small building that she lters a water supply pump measures $2 \mathrm{m} \times 3 \mathrm{m} \times 2.4 \mathrm{m}$ high. It is constructed of I-cm thick wood having a thermal conductivity of 0.126 $W \cdot m^{-1} \cdot K^{-1}$. The inside walls are to be maintained at 10 $^{\circ} \mathrm{C}$ when the outside temperature is -18 $^{\circ} \mathrm{C}$. How much heat must be supplied to maintain the desired temperature? How much heat must be supplied if the walls are lined with 10 cm of glass-wool insulation having a thermal conducti vity of 0.0377 $W \cdot m^{-1} \cdot K^{-1}$? Assume there is no heat loss through the floor. Ignore the wood in the second calculation.

What function do histone proteins perform in archaeal chromosomes? How is this function accomplished? What function is performed by histones in eukaryotes that is apparently not performed by archaeal histones?

A peanut butter and jelly sandwich contains carbohydrates, proteins, and fats. Describe what happens to the sandwich when you eat it. Discuss ingestion, digestion, absorption, and elimination.

A lithotripter of height 15 centimeters and diameter 18 centimeters is to be constructed. High-energy underwater shock waves will be emitted from the focus $F$ that is closest to the vertex $V$.

How far from $V$ (in the vertical direction) should a kidney stone be located?