I was having a trouble on a couple of questions on the TBR 3 during my review.
40.To obtain the curve for CO2 that appears in Figure 1, what must be true about the signs of β and γ in Equation 1?
A. Both β and γ must be positive.
B. Both β and γ must be negative.
C. β must be positive, and γ must be negative.
C is the best answer. The curve for CO2 in Figure 1 has a slope that is positive at all temperatures, but the magnitude of the slope decreases as the temperature increases. This means that as the temperature is increasing, Cp (the heat capacity) is increasing by a gradually lower amount. For that to be true, ß must be positive and γ negative in Equation 1, or vice versa. This eliminates choices A and B. The T2 term (in γT2) ultimately has a greater influence in determining the curve's shape, so the change in the value of T2 must be primarily responsible for decreasing the combined value of γT2 over time, given that the slope is gradually decreasing. The T term (in ßT) accounts for the initial positive slope. The curve's shape overall can be explained only if ß is positive and has a greater absolute value than γ, while γ is negative with a relatively small absolute value. The best answer is C.
134.The results of gel filtration through agarose beads and carboxymethyl-cellulose beads can BEST be explained by saying that the larger proteins have elution times through agarose beads that are:
A. faster, while carboxymethyl-cellulose beads cause the positively charged proteins to be hindered by attraction to the beads.
B. faster, while carboxymethyl-cellulose beads cause the negatively charged proteins to be hindered by repulsion from the beads.
C. slower, while carboxymethyl-cellulose beads cause the positively charged proteins to be hindered by attraction to the beads.
D. slower, while carboxymethyl-cellulose beads cause the negatively charged proteins to be hindered by repulsion from the beads.
Answer: A
If anyone has done TBR 3, how did you know the charge of the beads? Thats the key but I seem to have missed something along the way...
40.To obtain the curve for CO2 that appears in Figure 1, what must be true about the signs of β and γ in Equation 1?
A. Both β and γ must be positive.
B. Both β and γ must be negative.
C. β must be positive, and γ must be negative.
C is the best answer. The curve for CO2 in Figure 1 has a slope that is positive at all temperatures, but the magnitude of the slope decreases as the temperature increases. This means that as the temperature is increasing, Cp (the heat capacity) is increasing by a gradually lower amount. For that to be true, ß must be positive and γ negative in Equation 1, or vice versa. This eliminates choices A and B. The T2 term (in γT2) ultimately has a greater influence in determining the curve's shape, so the change in the value of T2 must be primarily responsible for decreasing the combined value of γT2 over time, given that the slope is gradually decreasing. The T term (in ßT) accounts for the initial positive slope. The curve's shape overall can be explained only if ß is positive and has a greater absolute value than γ, while γ is negative with a relatively small absolute value. The best answer is C.
134.The results of gel filtration through agarose beads and carboxymethyl-cellulose beads can BEST be explained by saying that the larger proteins have elution times through agarose beads that are:
A. faster, while carboxymethyl-cellulose beads cause the positively charged proteins to be hindered by attraction to the beads.
B. faster, while carboxymethyl-cellulose beads cause the negatively charged proteins to be hindered by repulsion from the beads.
C. slower, while carboxymethyl-cellulose beads cause the positively charged proteins to be hindered by attraction to the beads.
D. slower, while carboxymethyl-cellulose beads cause the negatively charged proteins to be hindered by repulsion from the beads.
Answer: A
If anyone has done TBR 3, how did you know the charge of the beads? Thats the key but I seem to have missed something along the way...
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