Biology 1202B Study Guide - Psychrophile, Panspermia, Cell Membrane

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February 2011 Biology 1002B Page 1 of 7
Student Number __________________________ Code 222 Code 222 Code 222
Circle the best single letter choice for each of the following questions before transferring
your answers to your computer sheet. Note: All questions have 4 choices.
1. The Miller Urey experiment was a breakthrough in our understanding of the origins of life.
However, which of the following questions was not answered by the Miller-Urey experiment?
A. How could purine and pyrimidine bases have been synthesized outside of cells?
B. How could amino acids have been synthesized in the absence of H2O?
C. How did the racemization of biologically important molecules occur?
D. How did cells come to synthesize only one form of each amino acid?
2. Which of the following molecules was absent from the Earth’s atmosphere when life first
A. H2O
B. O2
C. H2S
D. NH3
3. The hypothesis of an "RNA World" (in which RNA played the roles of modern DNA, RNA and
protein) is now widely accepted as correct.
Which of the following discoveries was most significant in supporting the RNA World concept?
A. That some RNA molecules can catalyze reactions.
B. That RNA, like DNA can be double-stranded.
C. That some RNA molecules can encode proteins.
D. That ribosomes contain RNA.
4. Which of the following statements about the origins of life are correct?
1. The Earth is estimated to be between 4 and 5 billion years old.
2. The hypothesis of Panspermia is supported by the discovery of extremophiles.
3. Meteorites have been found that contain amino acids.
4. In laboratory experiments clay has been shown to accelerate the formation of lipid vesicles.
5. DNA is more resistant to breakdown than RNA
A. 2 and 4
B. 1, 2 and 3
C. 1, 3, 4, 5
D. All of the above statements are correct
5. Which measurement is the transit method for detecting extrasolar planets based on?
A. Detecting the gravitational influence of a planet on its parent star.
B. Detecting periodic shifts in apparent brightness of stars.
C. Detecting evidence of water in the spectra of stars.
D. Directly observing planets using powerful optical telescopes.
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February 2011 Biology 1002B Page 2 of 7
Student Number __________________________ Code 222 Code 222 Code 222
6. If water was a nonpolar molecule, which of the following physical characteristics would it have?
A. It would have zero heat capacity.
B. It would sublimate at lower temperatures.
C. It would form hydrogen bonds with other molecules.
D. It would be a solid at temperatures found on Earth.
7. While some of the values used for the Drake Equation parameters are very good estimates,
others are essentially guesses. Which of the following values for Drake Equation parameters has
the least scientific support?
A. fc = 0.1
B. f
= 0.5
C. ne= 2
D. Ns= 100 billion
8. When it comes to searching for extra-terrestrial intelligence, the term "communicating
civilization" is important. How old is our "communicating civilization”?
A. 10 years
B. 100 years
C. 500 years
D. 150,000 years
9. Which of the following statements best compares the enzymes found in psychrophilic (low
temperature adapted) organisms with those found in mesophiles or thermophiles?
A. Psychrophilic enzymes contain a greater proportion of hydrophilic amino acids.
B. Psychrophilic enzymes are more resistant to denaturation by urea treatment.
C. Psychrophilic enzymes are more flexible at their optimal growth temperature.
D. Psychrophilic enzymes have a tertiary structure based on weaker bonding arrangements.
10. Which of the following statements about a denatured protein is correct?
A. It can never regain the native conformation
B. It lacks any primary structure.
C. It is of higher energy state than the native conformation.
D. Its hydrophobic residues are buried, away from water.
11. Which one of the following genes is not constitutively expressed?
A. Pyruvate dehydrogenase complex kinase in humans.
B. Hemoglobin apoprotein in humans.
C. Light harvesting proteins of the Chlamydomonas chloroplast.
D. Cytochrome c oxidase in mice.
12. For a given gene, high rates of transcription do not necessarily lead to correspondingly high
rates of translation. Why not?
A. High rates of protein turnover in the cytosol.
B. Inhibition of transcription factor binding.
C. Increase in rate of mRNA decay.
D. Increase in transcript abundance.
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