Chapter 10 Biology 1610

Animation: Cell Proliferation Signaling Pathway Growth factor receptors are typically found in the The growth factors illustrated in this system are positive regulatory growth factors. Why are they considered 'positive' growth factors. How does myc become active?

cell membrane. They increase the rate of cell proliferation. It dissociated from Rb.

Place the description of the binary fission stage in the correct sequence of events.

1. Site-specific DNA replication 2. Replication enzymes spread out 3. Replication terminus formed 4. Chromosome duplication 5. DNA partitioning 6. FtsZ protein activity 7. Septum completion and pinching

Animation: How the Cell Cycle Works Which of the following represents the correct order of the phases of the cell cycle? The division of the cytoplasm is called Which of the following represents the correct order of the phases of mitosis? Using the chart at the beginning of the animation and your knowledge of cells, what stage of the cell cycle do most cells spend the majority of their lives?

G1 -> S -> G2 -> M cytokinesis. prophase -> metaphase -> anaphase -> telophase G1

Complete the sentences on the cell cycle with the correct terms.

G1 is the longest phase. During synthesis the cell replicates its genome. G2 is a growth phase after DNA synthesis. Process by which cellular chromosomes are divided and separated from each other is called mitosis. It is during cytokensis when the cytoplasm divides. The resting phase of the cell cycle is called G0.

Animation: Control of the Cell Cycle The success of DNA replication is assessed during the ______ phase. The cell cycle is regulated by checkpoints during the _______ phases. A eukaryotic cell that receives a "go-ahead" signal at the G1 checkpoint of the cell cycle will DNA repair enzymes will be highly active during what phase of the cell cycle?

G2 G1, G2, and M complete the cycle and divide. G2

Homologous chromosomes and sister chromatids

Homologous Chromosomes: Maternal and paternal pairs, In humans, there are 23 of these, Numbered in a karyotype. Sister Chromatids: Attached to each other by cohesion, Replica of single chromosome, Formed during interphase, Separated during mitosis

Place the appropriate characteristic with the corresponding stage of mitosis.

Interphase: Replicating DNA, Cell prepares for division Prophase: Chromosomes become visible, Spindles first form Metaphase: Chromosomes align at equator, The spindle checkpoint arrests cells in this stage Anaphase: Centromeres split and move apart, Sister chromatids separate Telophase: Chromosomes at poles, Nucleus reformation Cytokinesis: Cells divide, Cleavage furrow on plate forms.

Cell cycle checkpoints

The G1/S Checkpoint is the primary point of the cell cycle that is influenced by external signals. The spindle checkpoint ensures that all of the chromosomes are attached to microtubules. The G2/M checkpoint assesses whether DNA is damaged, and also whether DNA replication has completed. Passage through checkpoints is controlled by Cdk enzymes.

Estimates are that p53 is mutated in 50% of all human cancers. If the gene that encodes p53 is mutated such that p53 is non-functional, what processes would be affected? Check all that apply.

The ability to halt the cell cycle in response to DNA damage. The ability to repair DNA damage. The ability to stimulate cell death processes if the cell is irreparably damaged.

In a human somatic cell (normal body cell) that is in G1, what would be true about chromosome number and structure? Check all that apply.

These cells would be considered diploid (2n). These cells would contain homologous chromosomes.

Animation: Mitosis and Cytokinesis Which of the following events do NOT occur in prophase of mitosis? Which of the following statements about microtubules during anaphase is TRUE? Why do chromosomes condense during prophase? Docetaxel is a drug that is used in the treatment of cancer. It interferes with cell division by inhibiting microtubule depolymerization. Specifically, what effect will this have on mitosis?

chromosomes are replicated those attached to chromosomes shorten, while those that are unattached elongate So that they will not be damaged when they are moved around the cell It will prevent sister chromatids from separating during anaphase.

Animation: The Function of Cohesin Cohesin complexes The arms of the sister chromatids dissociate from each other during ________ of mitosis. The sister chromatids of a chromosome fully separate during ________ of mitosis. When does cohesin first associate with the sister chromatids?

hold a chromosome's sister chromatids together. prophase anaphase During S phase

The protein ________ checks for damaged DNA, thereby acting as a "quality control" for the cell.

p53