Cell Cycle
Mitosis & Meiosis
DNA Experiments
DNA Replication
Transcription
100
Does self-fertilization produce offspring that are genetically identical to the parent? Why or why not?
No, because crossing over and independent assortment produce genetic variation.
100
The number of DNA molecules in the nucleus of a diploid (2n) cell ________ . A. equal to the number of unreplicated chromosomes after mitosis B. is equal to twice the number of X-shaped, replicated chromosomes at the start of mitosis C. is equal to the number of chromatids D. depends on the phase of the cell cycle E. all of the above
E. All of the above
100
If protein were the genetic material, what inhibitor would have blocked transformation?
Protease—a protein inhibitor
100
What enzyme fills the gap between Okasaki fragments?
DNA ligase
100
What is the central dogma? Name 2 exceptions.
DNA→ RNA→ Protein Exceptions: Retroviruses; Some genes are transcribed to RNA molecules that do not function as mRNA
200
A certain species of animal has 6 pairs of chromosomes. How many molecules of DNA do the nuclei of these animals have during the G2 phase of the cell cycle?
24 DNA molecules
200
When does crossing over occur?
In meiosis—Late prophase I
200
Why did Hershey and Chase use radioactive phosphorous and sulfur in their experiment?
Phosphorous labeled DNA and sulfur labeled protein; then used to see what isotope was present in the viral genes versus viral capsids
200
In what direction does DNA polymerase synthesize DNA? Why can DNA polymerase only work in one direction?
5’ to 3’ because it can only add nucleotides to a free OH at 3’ end
200
Name three types of post-transcriptional modifications.
Addition of 5’ Cap Addition of Poly-A-tail Splicing
300
What are the two components of MPF (mitosis promoting factor)? What are their levels through the cell cycle?
Cyclin- levels fluctuate Cdk- levels remains constant
300
What type of cell undergoes meiosis (parent)? What is the ploidy before meiosis? What type of cell is produced (daughter)? What is the ploidy after meiosis?
Germ Cells-Diploid; Gametes-Haploid
300
What kinds of band(s) would you see after generation one if the conservative replication theory were correct?
After generation 1, one band at N-14 (low density) and one band at N-15 (high density).
300
What is defective repair system in xerodema pigmentosum?
Excision Repair
300
Name three phases of transcription.
Initiation, Elongation, Termination
400
You have a cell line. Its entire cell cycle is 24 hours long. When you stain an asynchronous population of 400 cells, 50 cells are visible under a microscope. What is the length of M phase?
3 hours
400
What is nondisjunction? What is the ploidy of the daughter cells as a result of nondisjunction?
A mistake in meiosis OR mitosis in which either homologous chromosomes OR sister chromatids fail to separate during anaphase. As a result, daughter cells are aneuploid (trisomy or monosomy).
400
What happened when Griffith infected mice with heat killed S cells? Why did this happen?
Mice survived because heat-killed S cells were no longer virulent (damage to proteins and DNA). Heat killed S cells alone would not kill the mice because it also needs a host cell to provide the transformation factor to become virulent.
400
What is the difference between the roles of DNA polymerase I and DNA polymerase III?
DNA polymerase III replicates DNA. DNA polymerase I removes RNA primer and replaces it with DNA bases.
400
What two molecules must bind together before transcription can begin in bacteria?
RNA polymerase and sigma factor
500
You have a cell line. Its entire cell cycle is 24 hours long. M phase is 1 hour long. You first find mitotic cells 5 hours after thymine labeling and you continue to see labelled mitotic cells for another 8 hours (13 hours after thymine labeling ended). What is the length of G1? S phase? And G2?
G2 is 5 hours. S phase is 7 hours. G1 is 11 hours.
500
Assuming no crossing over or linked genes, a diploid organism with 4 pairs of chromosomes can produce this many different gametes if the genotype is AaBbCcDd.
16
500
How did the metabolic pathway of arginine synthesis test the one-gene, one-enzyme hypothesis?
Various Arg mutants were plated on medium lacking one of the intermediates in the pathway.
500
How does telomerase “fix” the problem of telomere shortening?
Telomerase binds to the unreplicated segment of telomere—forming an overhang. It adds DNA from RNA template to extend the lagging strand, then DNA polymerase binds to complete replication of telomere.
500
For the DNA sequence 5’ TTAGCCAT 3’, what is the RNA transcript of the strand complementary to this DNA sequence?
5’-UUAGCCAU-3’
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