HMB300H1 Chapter Notes - Chapter 2: Bromine, Natural Abundance, Molar Mass

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apricotclam643

5 Jun 2012

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UTSG

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Human Biology

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HMB300H1

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In 1774, antoine lavoisier (1774-1794) performed an experiment in which he heated a sealed glass vessel containing a sample of tin and some air. He found that the glass before heating and the glass after heating were the same. Through further investigation, he proved that the product of the reaction, tin calx, consisted of the original tin together with a portion of the air. This proved that oxygen from air is essential to combustion and it led to the formulation of the law of conservation of. Mass: the total mass of substance present after a chemical reaction is the same as the total mass of substances before the reaction. Problem: a 0. 455g sample of mg is allowed to burn in 2. 315 g of o2 gas. After the reaction, no magnesium remains and the mass of unreacted oxygen is 2. 015g. Mass before reaction: 0. 455g magnesium + 2. 315g oxygen = 2. 770 g.

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An experimenter is working with an enzyme that, on a per milligram basis, produces a certain number of Î¼mol of product per minute at optimal temperature and pH. The product of the enzyme-catalyzed reaction is a desirable fine chemical, and thus the researcher designs a pilot biosynthetic reaction to produce a target number of Î¼mol of the desired product. The experimenter starts the reaction by adding 1.0 milligram of the enzyme. The rate of product formation reveals that the enzyme activity is normal. (The researcher is able to continually remove the product as it is produced.) To the astonishment of the experimenter, an assistant inexplicably adds some sodium hydroxide to the reaction after 1 min. (The assistant misunderstood the protocol.) Thirty seconds after the reaction was stopped by the addition of the NaOH, the experimenter adds additional buffer and is pleased to see that the reaction is proceeding again, but at 77% of its normal activity. Furthermore, it takes 3Â½ minutes longer to produce the target amount of product than it should have. Had the enzyme been allowed to produce an additional 90 Î¼mol of product prior to the addition of base, and then, 30 seconds later, the addition of buffer, it would have taken 3 minutes longer to produce the target number of Î¼mol of product. Given this information, what is the specific activity of the enzyme (Î¼mol of product per minute per milligram of enzyme)? Enter your answer to the nearest ones.

Answer should be 77. I just need to know how to get the correct answer.

An alternative to semi-conservative replication is conservativereplication in which the parent strands come apart only temporarilyto serve as templates for synthesis of daughter strands but thencome back together again as they were originally and the two newdaughter strands then also form a duplex molecule. What singlefeature of the Meselsohn Stahl experiment allowed this conservativereplication hypothesis to be rejected? (Hint:To answer thisquestion you can consider the banding pattern produced on thecesium chloride density-gradient centrifugation following one roundof replication in the Meselsohn Stahl experiment.)

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A new drug is produced in a bioreactor. The process is termed batch operation, since the reactants are added all at the beginning, the system is sealed and the reaction takes place, and then the products are removed. Within this processing system, the concentration of drug in the reactor increases as thereaction proceeds. Consider an accounting equation that tracks the drug only during the time that the reaction is occurring. Is the system open or closed or isolated? Is the system dynamic or steady state? Is the system reacting or nonreacting? What time of accounting equation would be used: differential, algebraic or integral? Is the property conserved?

HMB300H1 Chapter Notes - Chapter 2: Bromine, Natural Abundance, Molar Mass

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