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TLS Online TPP Program

#Question id: 5220

In comparing the genomes of humans and those of other higher primates, it is seen that humans have a large metacentric pair we call chromosome #2 among our 46 chromosomes, while the other primates of this group have 48 chromosomes and any pair like the human #2 pair is not present; instead the primate groups each have two pairs of midsize acrocentric chromosomes. What is the most likely explanation?

#Unit 11. Evolution and Behavior

  1. The ancestral organism had 48 chromosomes and at some point a centric fusion event occurred and provided some selective advantage.

  2. The ancestral organism had 46 chromosomes, but primates evolved when one of the pairs broke in half.

  3. At some point in evolution, human ancestors and primate ancestors were able to mate and produce fertile offspring, making a new species.

  4. Chromosome breakage results in additional centromeres being made in order for meiosis to proceed successfully.

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TLS Online TPP Program

#Question id: 12188

#Unit 2. Cellular Organization

The series of events by which APC/C promotes the separation of sister chromatids at anaphase.
A. all the kinetochores have attached to spindle microtubules and the spindle apparatus is properly assembled and oriented.
B. Cdc20 specificity factor associated with APC/C directs it to ubiquitinylate securin and mitotic cyclins. 
C. A protease known as separase cleaves the cohesin subunit Scc1 (Rad21), breaking the protein circles linking sister chromatids.
D. anaphase begins as poleward force exerted on the kinetochores moves the split sister chromatids toward opposite spindle poles.
E. Following securin degradation and a decrease in mitotic CDK activity.
Which of the following series is correct?
TLS Online TPP Program

#Question id: 12187

#Unit 2. Cellular Organization

How cells know whether sister kinetochores are properly attached to the mitotic spindle?
TLS Online TPP Program

#Question id: 12186

#Unit 2. Cellular Organization

In 2001, the Nobel Prize in Physiology or Medicine was awarded to three cell cycle scientists. Paul Nurse was recognized for his studies with the fission yeast S. pombe, in particular for the discovery and characterization of the wee1+ gene. What did the characterization of the wee1+ gene tell us about cell cycle control?
TLS Online TPP Program

#Question id: 12185

#Unit 2. Cellular Organization

Mitotic CDKs affect nuclear envelope components by specific mechanism. Which of the following statement is not related to this mechanism?
TLS Online TPP Program

#Question id: 12184

#Unit 2. Cellular Organization

Following graph represent Control of S phase onset in S. cerevisiae by regulated proteolysis of the S phase inhibitor Sic1. 
Which of the following is correct according to graph?
TLS Online TPP Program

#Question id: 12183

#Unit 2. Cellular Organization

Following statements are regarding to regulation of S phase and mitotic cyclin levels in budding yeast.
A. In late anaphase, the anaphase-promoting complex (APC/C) ubiquitinylates S phase and mitotic cyclins.
B. In late anaphase, the anaphase-promoting complex (APC/C) phosphorylates S phase and mitotic cyclins.
C. During exit from mitosis and G1, Cdh1 is dephosphorylated and active; during S phase and mitosis, Cdh1 is phosphorylated and dissociates from APC/C, and APC/C becomes inactive.
D. During exit from mitosis and G1, Cdh1 is phosphorylated and active; during S phase and mitosis, Cdh1 is dephosphorylated and dissociates from APC/C, and APC/C becomes inactive.
E. The G1/S phase CDKs, which themselves are not APC/CCdh1 substrates, phosphorylate Cdh1 at the G1–S phase transition.
F. The G1/S phase CDKs, which themselves are not APC/CCdh1 substrates, ubiquitinylates Cdh1 at the G1–S phase transition.
Which of the following combination is correct?