Lecture 19 Homework Review Today: Apoptosis and Cancer. Monday April 23rd- Cell-Cell Interactions/Tissues Thursday April 26 th -Early Development and Stem Cells Monday April 30 th - Review Final Exam May 9 th 12-1:30pm in this classroom
Monday April 23rd- Cell-Cell Interactions/Tissues
Thursday April 26th -Early Development and Stem Cells
Monday April 30th- Review
Final Exam May 9th 12-1:30pm in this classroom
For Exam III- You are not responsible for any material in assigned chapters relating to Plants!
2. Which of the following changes occurs when a skeletal muscle fiber contracts?A) The A bands ShortenB) The I Bands ShrinkC) The Z lines slide farther apartD) The Thin Filaments ContractE) The Thick Filaments Contract
Dark Band- A band
Light Band- I band
3.Consider an Individual Microtubule: muscle fiber contracts?
What must happen at the end of the microtubule in order for it to stop shrinking and start growing?
-Binding of GTP Tubulin Heterodimers to form a GTP Cap
How would a change in the tubulin concentration affect this switch?
Increase in Tubulin Heterodimers- Promote Rescue
Decrease in Tubulin Heterodimers- Continue Shrinking
What would happen if only GDP, but no GTP, were present in the solution?
MT Depolymerization would occur
What would happen if the solution contained a nonhydrolyzable form of GTP?
MT Continued Polymerization until no available Heterodimers left
4. Nucleation of Actin Monomers or Microtubule Heterodimers is the Slow Step in the formation of Actin and Microtubule Filaments in vitro. How do cells bypass the slow step in vivo in the formation of A) MT filaments – MTOCs and B) Actin Filaments? ARP COMPLEX
5) What is the role of Nexin in the Axoneme of Cilia and Flagella. What would happen if it wasn’t present? Couldn’t bend-filaments would slide
A) Provides Energy Needed for Tubulin to Polymerize
B) Occurs Because the Pool of Free GDP Has Run Out
C) Tips the Balance in Favor of Assembly
D) Allows the Behavior of Microtubules called Dynamic Instability
True or False and Why?
No cell goes from G1 directly to M
True or False and Why?
2) Rb is a transcription factor that must be phosphorylated in order for expression of G1/S and S phase Cyclins. FALSE- not functioning as a transcription factor in this case- but as inhibitor of transcription factor
True or False and Why? answers.
3) Once a Cyclin binds to a CDK, the kinase is active and can immediately begin phosphorylating targets.
Anaphase A Movement
Plus End of Kinetochore Microtubules Dissassembles
Minus End Directed Motor
(Dynein) Proteins Pull
Toward Spindle Pole
Pac Man Mechanism
Toward Minus End
5) When a cell that is in the process of replicating DNA is fused with a cell in G1:
B) DNA synthesis begins immediately in the original G1 nucleus
C) The two Nuclei Fuse and Further Division is Arrested
D) The Chromosomes of the Original G1 Nucleus condense in preparation for mitosis
E) The original G1 cell will divide immediately
6.) Sister chromatids: fused with a cell in G1:
A) Are created when DNA is replicated
B) Are attached at the centromere prior to Division
C) Are separated during anaphase
D) Have matching copies of the chromosome’s DNA
E) all of the above
7.) In some cases, Mitosis occurs without cytokinesis occurring. This will result in:
A) Cells with more than one nucleus
B) Cells that are unusually small
C) Cells lacking nuclei
D) Destruction of chromosomes
E) Cell cycles lacking an S phase