Smartwork5: Chapter 6 Hw

Which is correct concerning types of cell division?Choose one: A. Binary fission and mitosis produce cells identical to the parent cell. B. Prokaryotes can undergo asexual or sexual reproduction. C. Binary fission is more complex than mitosis. D. Mitosis and meiosis are found in prokaryotes.

A. Binary fission and mitosis produce cells identical to the parent cell.

The total weight of DNA in a human cell before replication is 6 picograms. Which choice lists the correct weight for the stage?Choose one: A. G2 phase = 12 picograms B. G1 phase = 12 picograms C. mitosis = 24 picograms D. cytokinesis = 3 picograms

A. G2 phase = 12 picograms

Scientists Ana Soto and Carlos Sonnenschein from Tufts University spent a year purifying the secret ingredient lurking in their lab equipment plastic until they finally identified a compound called nonylphenol, a chemical used to make detergents and hard plastics. They determined this was the compound that triggered human breast tumor cell growth in their plastic tubes, just like the hormone estrogen. Which of the following apply to the action of nonylphenol? Choose one or more: A.Nonylphenol gives permission to the cell to divide when it should not divide. B.Nonylphenol interferes with the G0 checkpoint. C.Nonylphenol interferes with the G1 checkpoint. D.Nonylphenol, when applied to rat uterine cells, causes them to divide normally.

A.Nonylphenol gives permission to the cell to divide when it should not divide. B.Nonylphenol interferes with the G0 checkpoint. C.Nonylphenol interferes with the G1 checkpoint.

What happens at the first checkpoint of the cell cycle (after G1)?Choose one or more: A.The size of the cell is checked to determine if the cell is large enough at that point. B.The genetic information of the cell is checked to see if the DNA is undamaged. C.The plasma membrane of the cell is checked to make sure it is intact. D.The nutrient level in the cell is checked to see if there is an adequate nutrient supply.

A.The size of the cell is checked to determine if the cell is large enough at that point. B.The genetic information of the cell is checked to see if the DNA is undamaged. D.The nutrient level in the cell is checked to see if there is an adequate nutrient supply.

How is the second cell cycle checkpoint (after G2) different than the first?Choose one: A. The nutrient supply is checked to make sure it is adequate. B. The DNA is checked to make sure it is fully replicated .C. The size of the cell is checked to make sure it is large enough to proceed. D. The DNA is checked to make sure it is intact.

B. The DNA is checked to make sure it is fully replicated.

Two ruined experiments separately exposed the health risks of chemicals in everyday products.In 1989, biologists Ana Soto and Carlos Sonnenschein at Tufts University in Massachusetts were studying how the hormone estrogen regulates the growth of cells in the female reproductive system. One day, suddenly and surprisingly, cells in the flasks began growing even when estrogen had not been added. The two scientists immediately stopped their experiments and began searching for the cause. But after weeks of searching, Soto and Sonnenschein still could not identify a source of contamination. Almost 10 years later, in August 1998, geneticist Patricia Hunt at Case Western Reserve University in Ohio stared dumbfounded at another experimental anomaly. Hunt was studying why older women are at increased risk of having children with chromosomal abnormalities. Hunt's experiment was almost complete when she went in to check on the control mice one last time. In this case, the control was a group of healthy mice whose hormone levels had not been altered. Using a light microscope, Hunt examined mouse oocytes at the moment just before the eggs are produced. She was shocked. The cells were a mess—the chromosomes scrambled. A whopping 40 percent of the resulting eggs had chromosomal. Which of the following are observations from the two failed experiments mentioned in this chapter?Choose one or more: A.Forty percent of the eggs resulting from the treatment mouse oocytes were showing chromosomal defects. B.A component of the experimental system, besides the experimental treatment, affected human breast tumor cell growth and development. C.The hormone estrogen caused human breast tumor cell growth. D.The hormone progesterone caused human breast tumor cell growth. E.Forty percent of the eggs resulting from the control mouse oocytes were showing chromosomal defects.

B.A component of the experimental system, besides the experimental treatment, affected human breast tumor cell growth and development. C.The hormone estrogen caused human breast tumor cell growth. E.Forty percent of the eggs resulting from the control mouse oocytes were showing chromosomal defects.

In 1989, biologists Ana Soto and Carlos Sonnenschein at Tufts University in Massachusetts were studying how the hormone estrogen regulates the growth of cells in the female reproductive system, specifically in human breast tumor cells. Suddenly, the cells in plastic containers were growing without the presence of estrogen. Which of the following statements are true about this experiment?Choose one or more: A.Estrogen was identified as the chemical used to manufacture hard plastics, like the plastic cell culture tubes. B.Nonylphenol in the plastic tubes of the cell culture activated mitotic division. C.Nonylphenol mimics the action of estrogen. D.Estrogen activates mitotic division in these cells. E.Estrogen was discovered as a "trade secret" ingredient in the creation of the plastic test tubes.

B.Nonylphenol in the plastic tubes of the cell culture activated mitotic division. C.Nonylphenol mimics the action of estrogen. D.Estrogen activates mitotic division in these cells.

Which of the following steps occur during prophase of mitosis? Choose one or more: A.The chromosomes replicate, showing two sister chromatids. B.The chromosomes condense. C.The nuclear envelope breaks down. D.The chromosomes attach to the mitotic spindle.

B.The chromosomes condense. C.The nuclear envelope breaks down. D.The chromosomes attach to the mitotic spindle.

Label the following diagram of the cell cycle.

Beginning at the repeat symbol on the diagram: Cells in G0 phase are not actively dividing. Cell has grown and is ready to replicate DNA. DNA replication occurs. Cell is checked before cell division. Replicated DNA is separated. DNA is divided equally between daughter cells

Label the diagram of the DNA in a cell at different stages of the cell cycle.

Beginning from left to right: Gap phase S phase Newly replicated chromosome Tightly packaged chromatid Beginning of mitosis

Label the stages and substages of the cell cycle.

Beginning from left to right: interphase mitosis prophase metaphase anaphase telophase cytokinesis

Meiosis and fertilization introduce genetic diversity in multiple ways. Place the following processes that introduce genetic diversity in the offspring in order by when they occur, from the beginning of meiosis I until after its completion.

Beginning of Meiosis 1: Crossing Over Independent Assortment Fertilization After completion of Meiosis 1

In what phase of meiosis does the process of independent assortment of chromosomes begin—when maternal and paternal homologues line up randomly at the equator of the cell?Choose one: A. anaphase II B. anaphase I C. metaphase I D. metaphase II

C. metaphase I

Which of the following statements apply to cancer in females?Choose one or more: A.The lung and bronchus is the most common site of incidence of cancer in females. B.Breast cancer is the most deadly type of cancer in females. C.The breast is the most common site of incidence of cancer in females. D.Cancer of the lung and bronchus is the most deadly type of cancer in females.

C.The breast is the most common site of incidence of cancer in females. D.Cancer of the lung and bronchus is the most deadly type of cancer in females.

Which of the following statements are true about cancer in males?Choose one or more: A.The prostate is the most deadly site of cancer in males. B.The lung and bronchus is the site with the highest rate of incidence of cancer in males. C.The lung and bronchus is the most deadly site of cancer in males. D.The prostate is the site with the highest rate of incidence of cancer in males.

C.The lung and bronchus is the most deadly site of cancer in males. D.The prostate is the site with the highest rate of incidence of cancer in males.

What percentage of males survive prostate cancer?Choose one: A. 18.9% B. 0.1% C. 0.02% D. 81.1%

D. 81.1%

Why did it make sense that the BPA leaching from the corroded plastic in Hunt's experiment could have affected the chromosomes of the mouse egg cells? Choose one: A. Bisphenol A, once locked in plastic, stays inside of those plastic products. B. BPA was equally effective as other substitutes for hormone replacement therapy for women needing estrogen. C. Bisphenol A is another name for the hormone estrogen. D. BPA had been utilized as a hormone replacement therapy in the 1930s for women who needed estrogen.

D. BPA had been utilized as a hormone replacement therapy in the 1930s for women who needed estrogen.

What is the most likely outcome of cell cycle checkpoints being ignored?Choose one: A. Normal cells are produced at a higher rate during wound healing. B. Abnormal cells are produced at a very slow rate. C. Miscarriage occurs. D. Cancer develops.

D. Cancer develops.

If you observed one skin cell becoming two identical skin cells, what would you never observe?Choose one: A. cytokinesis B. spindle formation C. sister chromatids D. crossing-over

D. crossing-over

What is the outcome of mitosis?Choose one: A. two cells that are identical to the parent cell but not to each other B. two cells that are identical to each other but not to the parent cell C. four nonidentical cells D. two cells that are identical to each other and identical to the parent cell

D. two cells that are identical to each other and identical to the parent cell

In the diagram, label the steps of independent assortment during meiosis.

From top to bottom: Homologous chromosomes can be oriented in two ways during metaphase I. Maternal and paternal homologues are sorted into two daughter cells. Four possible combinations of gametes are generated by meiosis II.

Sort the following statements as they apply to meiosis I only, meiosis II only, or both.

Meiosis 1: The cell begins this phase as a diploid cell. Homologous pairs of chromosomes line up at the center of the cell before separating. Two cells form as a result of cytokinesis. Independent assortment occurs here. Meiosis 2: The cell begins this phase as a haploid cell. Four cells form as a result of cytokinesis. Pairs of sister chromatids are pulled apart during anaphase. Both: Cytokinesis follows this step. Haploid cells result.

Arrange the following steps of meiosis in the correct order. Note that not all steps of meiosis are included here.

Metaphase 1 Anaphase 1 Telophase 1 Prophase 2 Metaphase 2 Anatphase 2

Sort the following statements as they apply to prokaryotic cell division or eukaryotic cell division.

Prokaryotic: Replicates circular chromosomes Cells reproduce via binary fission. Eukaryotic: Replicates linear chromosomes Cells reproduce via mitosis or meiosis. DNA is contained in a nucleus. Both: Can generate clones Can undergo asexual reproduction

Label the following diagram of chromosomes that have undergone crossing-over.

Top to bottom then left to right: metaphase I metaphase II after cytokinesis II (gametes) recombined chromosome parental chromosome