BIOC40H3 Chapter Notes -Kinetochore, Cell Plate, Nucleolus

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lavenderguinea-pig875

18 Jan 2013

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The biochemical reactions governing the cell cycle are evolutionary conserved in eukaryotes. Progression through the cycle is regulated at 3 check points. The key enzymes that regulate the cycle are cyclin-dependent protein kinsases or cdks. Protein kinases are enzymes that phosphorylate proteins using atp. Most multi cellular eukaryotes use several protein kinases that are active during different phases of the cell cycle. All depend on regulatory subunits called cyclins for their activities. Three cyclins (a, b, and d) regulate the tobacco cell cycle. G1/ s cyclins: cyclin d active in late g1. S cyclins: cyclin a active in late s phase. M cyclins: cyclin b active just prior to mitotic phase. The critical restriction point in late g1 commits the cell to another round of cell division and is regulated by d type cyclin. Plant hormones that promote cell division including cytokinins and brassinosteroids, appear to do so through an increase in cyclin d3 (plant d-type cyclin)

Related Questions

Different cyclin-dependent protein kinases (CDKs) regulate the transition of eukaryotic cells from one phase of the cell cycle to another: from G1 to S, S to M, or M to G1. Describe the different mechanisms by which the enzyme activity of the CDKs is regulated over time during the cell cycle and how such mechanisms are altered in different cancers. In some cells such as trophoblasts (cells of the placenta) and megakaryocytes (precursors to blood platelets), cells will undergo repeated rounds of G1 and S phase without G2 or M phases â what is the advantage of this cell cycle for such cells?

Briefly describe how transcription, phosphorylation, protein-protein interactions and proteasome-mediated turnover are involved in cell cycle regulation (like G1,S,G2,M Phases).

I understand that phosphorylation is related to to cyclin dependent kinases (CDKs), but unsure about the rest. Is the proteasome part related to ubiqutin in some way?

blushprairie-dog817

Part A:

In prokaryotes and eukaryotes cell reproduction is similar in that it requires some kind of signal to proceed, DNA replication, careful separation of the DNA into two equal portions, and division of the cytoplasm. How is cell reproduction different in prokaryotes and eukaryotes?

Select one:

a. In a eukaryotic organism, the signals for cell division are usually not related to the environment but to the function of the entire organism.

b. Eukaryotic cells constantly divide whenever environmental conditions are adequate and the cells are large enough.

c. The linear chromosomes in prokaryotes are constantly being updated.

d. Prokaryotic cell division requires cytokinesis before mitosis because of their small size.

e. The sexual phase of most prokaryotes (bacteria) is essential to the rapid cell division required for infection.

Part B:

What does the name Cyclin Dependent Kinase stand for?

Select one:

a. A protein important to the cell cycle that is dependent on DNA synthesis.

b. An enzyme that cuts DNA so that chromosomes can segregate.

c. An enzyme that phosphorylates other proteins using ATP only when the protein Cyclin is bound to the enzyme.

d. An enzyme that rolls along microtubules dragging a vesicle.

e. An enzyme that connects chromosomes to the spindle fiber.

Part C:

The Cell Cycle is divided into Mitosis, Cytokinesis, and Interphase. Mitosis can be ordered into the following phases:

Select one:

a. Prophase/Prometaphase/Metaphase/Anaphase/Telophase

b. Anaphase/Prometaphase/Metaphase/Prophase/Telophase

c. Metaphase/Anaphase/Telophase/Prophase/Prometaphase

d. Telophase/Prophase/Prometaphase/Metaphase/Anaphase

e. Anaphase/Telophase/Prophase/Prometaphase/Metaphase

Part D:

The Cell Cycle is divided into Mitosis, Cytokinesis, and Interphase. Interphase can be ordered into the following phases:

Select one:

a. S/G1/G2

b. G2/G1/S

c. G1/S/G2

d. G2/S/G1

e. G1/G2/S

amethystyak657

BIOC40H3 Chapter Notes -Kinetochore, Cell Plate, Nucleolus

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