Review Questions Flashcards
what is the central dogma of molecular genetics?
states that genetic info goes from DNA to RNA to protein
which of the following is not true about pyrimidines & purines?
A. pyrimidines have a 2 ring nitrogenous base.
B. purines have a 2 ring nitrogenous base.
C. purines always bind to pyrimidines when a DNA helix is formed.
D. purines and pyrimidines make up the “rungs” of the DNA ladder.
E. purines and pyrimidines bind together using hydrogen bonds
A. pyrimidines have a 2 ring nitrogenous base
what is the difference b/w the 3’ and the 5’ ends of a DNA molecule?
the 3’ end of DNA is where the carbon the sugar molecule at the farthest end of the DNA molecule is the 3’ carbon within the ring structure. the 5’ end is where the carbon on the sugar molecule at the DNA terminus is the 5’ carbon
which model of DNA replication describes one parental strand and one new strand of DNA make up each new helix?
A. semiconservative
B. conservative
C. dispersive
D. redundancy
E. degeneracy
A. semiconservative
describe the process of DNA replication, including the roles of topoisomerase and DNA helicase, and the definitions of Okazaki fragments and the replication fork.
DNA helicase unzips the DNA helix creating the replication fork. Leading strand is made continuously while lagging strand is made discontinuously. Topoisomerase prevents DNA from overcoiling during replication.
what is the redundancy of the genetic code?
more than one codon codes for many amino acids
what are the 3 major differences b/w RNA and DNA?
- RNA contains ribose instead of deoxyribose as its sugar.
- contains uracil instead of thymine
- is usually single stranded
distinguish b/w transcription and translation and describe the process that takes place within the ribosome during translation.
transcription is the process of DNA becoming RNA.
translation is RNA becoming a protein.
describe the kinetic effects of increasing substrate concentration while enzyme concentration remains constant.
when substrate concentration is low, the reaction proceeds slowly.
increases in substrate concentration greatly increase reaction rate.
at very high levels of substrate, a maximum will be reached (Vmaximum)
what determines enzyme specificity?
determine by the unique 3D spatial structure of the active site
which of the following is appropriate to use for a procedure that involves simultaneously heating and distilling a reaction mixture?
A. erlenmeyer flask
B. erlenmeyer flask w/ a hose barb
C. volumetric flask
D. round bottom flask
E. either A or B
D. round bottom flask
round shape gives it extra strength to withstand heat and vacuum
what is the best piece of glassware to use to transfer exactly 50mL of liquid?
A. 50 mL beaker
B. 50 mL erlenmeyer flask
C. 50 mL volumetric pipet
D. 50 mL volumetric flask
E. 500 mL graduated cylinder
C. 50 mL volumetric pipet
calibrated to deliver 1 volume w/ great accuracy
what should be used to titrate 50mL of 0.1 N HCL w/ 0.2 N NaOH?
A. 10 mL buret
B. 30 mL buret
C. 30 mL graduated pipet
D. 50 mL volumetric pipet
E. 50 mL graduated cylinder
B. 30 mL buret
a scientist is setting up an experiment w/ 20 samples, each consisting of 0.5 g of a solid. He will pipet 2 mL of liquid into each sample, allow them to stand for 1 hour and then remove 1 mL for analysis. Which of the following is the best glassware to use?
A. erlenmeyer flask
B. beakers
C. volumetric flasks
D. round bottom flasks
E. test tubes
E. test tubes
which of the following will provide the most accurate and precise measurement of a sample at approx. pH 5?
A. pH meter calibrated at pH 5.00
B. pH meter calibrated at pH 4.01 and pH 10.00
C. pH meter calibrated at pH 7.00
D. pH meter calibrated at pH 7.00, pH 4.01, and pH 10.00
E. litmus paper
D. pH meter calibrated at pH 7.00, pH 4.01, and pH 10.00
for best accuracy & precision, 3 point calibration is best
