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31 Mar 2018

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?

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2 Apr 2018

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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

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

1)What are the inputs of photosynthesis?

2)What are the outputs of photosynthesis?

3)Light-Dependent Reactions

Where does the first stage of photosynthesis, the light-dependent reactions, occur within a chloroplast?

Where does the energy come from that drives these reactions?

What molecule donates an electron to the reaction center of photosystem II?

How is the energy of an electron changed as it moves along the ETC?

How does the electrical charge of the thylakoid membrane affect protons (H+) within the chloroplast?

Where does the electron that is donated to photosystem I come from?

What are the final products of this series of reactions?

What happens to each of the final products from this series of reactions?

4)Light-Independent Reactions (Calvin Cycle)

a.Where does the second stage of photosynthesis, the Calvin Cycle, occur within a chloroplast?

b.What are the direct inputs for these reactions?

c.What are the three steps to the Calvin cycle?

d.What are the final products of this reaction?

e.What role does rubisco play in the Calvin Cycle?

1)What experiment was performed that allowed for scientists to finally agree that DNA is the genetic material within living organisms?

a.Understand the materials and scientific techniques used to come to this result.

2)What group of experiments led to the discovery of the mechanism used in DNA replication?

a.Understand the materials and scientific techniques used to come to this result.

i.What is a cesium chloride gradient?

ii.Where do 14N and 15N respectively fall along this gradient?

b.The results revealed that DNA replicates using which of the three proposed models?

i. Describe the mechanism of each model.

3)What is the role of the following proteins in DNA replication?

a.Helicase

b.Single strand binding proteins

c.Topoisomerase

d.DNA polymerase III

e.DNA polymerase I

f.Primase

g.Ligase

4)What extra steps are taken to be sure the lagging strand does not shorten each time DNA is replicated?

a.What is the role of telomerase in these âstepsâ?

5)In DNA repair, which enzyme has âproof-readingâ capabilities?

1)Which type of cells within our bodies use mitosis to reproduce?

2)Does mitosis create a cell that is different or the same as the parent cell undergoing division?

3)Describe the DNA found in sister chromatids.

4)Describe the DNA found in homologous chromosomes.

5)What occurs during the following stages of the cell cycle?

a.G₁ Phase

b.S Phase

c.G₂ Phase

d.M Phase

What are the phases of mitosis? What events occur in each phase?

1)Does mitosis separate homologous chromosomes, sister chromatids, or both?

2)What is cytokinesis?

a.Which fibers of the cytoskeleton contract to pinch parent and daughter cells apart from one another in animals?

b.How do microtubules move chromosomes to the two poles of a dividing cell?

3)How are centrioles involved in this process?

a.How do plants form two complete cells during cytokinesis?

4)How do bacterial cells reproduce?

5)The cell cycle is controlled at âcheckpointsâ. What occurs at each of the following checkpoints?

a.G₁ Checkpoint

b.G₂ Checkpoint

c.M Checkpoint

6)How do cyclin and cdk act to control the G2 checkpoint?

7)If presented with the schematic of the M checkpoint, you should be able to explain perturbations to the system as well as if the cell will divide or stall at metaphase.

8)Cancerous cells form when the cell cycle checkpoints do not function correctly and continues to divide even though it is damaged in some way. How does the protein p53 function to keep these cells from dividing?

9)Normal cells follow certain rules of growth that cancerous cells do not follow. What are these rules (provide a short definition for each as well)?

10)What is the difference between a benign tumor and a malignant tumor?