Biology - Ch. 6 - Inquizitive EC

While studying a novel drug, you begin to suspect that a chemical within it may be causing cells to become stuck at the G1 checkpoint. Which of the following would likely be true for cells affected by this drug's action?

- CORRECT - The cells would be of adequate size to divide. (Since the G1 checkpoint pauses the cell before beginning DNA replication, the cell would have plenty of time to become big enough to divide.) The cells would be unable to perform DNA replication. (Since the G1 checkpoint pauses the cell before beginning DNA replication, the cell would never enter into the S phase.) - INCORRECT - Cells would divide even if there weren't enough nutrients available. (Becoming stuck at a checkpoint would prevent any cell division from occurring.) The cells would be unable to perform DNA replication. (Since the G1 checkpoint pauses the cell before beginning DNA replication, the cell would never enter into the S phase.) Chromosomes would be damaged during DNA replication. (Any chromosome damage would occur during the S phase.)

While studying a newly discovered prokaryotic organism, you notice that it uses binary fission to multiply. Based on your knowledge of the structures and processes of eukaryotes and prokaryotes, predict how this form of division would differ from mitosis and meiosis. - unlike mitosis and meiosis, binary fission holds the nucleus intact. - unlike in meiosis, the resulting cells will contain two copies of the chromosome. - unlike mitosis and meiosis, binary fission requires fewer resources and less energy. - unlike in mitosis and meiosis, the mitotic fibers bind to a circular chromosome instead of a linear one.

- unlike mitosis and meiosis, binary fission requires fewer resources and less energy. Since prokaryotes are smaller and lack a nucleus and other organelles, their division is less complex and requires less energy.

Uncontrolled cell division can lead to one of the most deadly diseases in the United States. Which disease is it?

CANCER Cancer begins with a single cell that divides uncontrollably—a rogue cell. Sooner or later, a tumor mass is formed.

Soto and Shonnenschein finally identified nonylphenol in the flasks they were using. Nonylphenol can do which of the following? - interfere with the G0/G1 checkpoint - activate meiotic division. - activate mitotic division

CORRECT - interfere with the G0/G1 checkpoint. (Nonylphenol causes cells to divide, even when they wouldn't normally.) - activate mitotic division (In the presence of nonylphenol, cells divide in an uncontrolled manner.) INCORRECT - activate meiotic division. (Meiotic division forms gametes for sexual reproduction. This wasn't one of the effects of nonylphenol.)

The two cells resulting from meiosis are diploid, and they are further divided into four haploid cells. T/F?

FALSE In the S phase preceding meiosis, DNA has replicated, but the cell is still diploid because it has the same number of centromeres as the parent cell. The two cells resulting from meiosis I are haploid. Each haploid cell contains pairs of sister chromatids, so they must divide again to generate the four haploid gamete cells.

The two cells resulting from meiosis are diploid, and they are further divided into four haploid cells. T/F?

FALSE In the S phase preceding meiosis, DNA has replicated, but the cell is still diploid because it has the same number of centromeres as the parent cell. The two cells resulting from meiosis I are haploid. Each haploid cell contains pairs of sister chromatids, so they must divide again to generate the four haploid gamete cells.

Drag the labels to their appropriate locations on the figure. MEIOSIS I & MEOSIS II

MEIOSIS I In prophase I, homologous chromosomes pair. In metaphase I, homologous chromosomes line up at the center of the cell. In anaphase I, the chromosomes move to the poles by the shortening of the mitotic spindle. Cytokinesis I marks the first cell division, resulting in two haploid cells. However, each haploid cell contains pairs of sister chromatids, so they must divide again. MEIOSIS II prophase II The stages of meiosis II are similar to mitosis, but the genetic results are different. In prophase II the DNA condenses. In metaphase II, the sister chromatids line up at the center of the cell. In anaphase II, the chromatids move to the poles by the shortening of the mitotic spindle. Cytokinesis II marks the second cell division, resulting in four haploid cells.

LOOK AT IMAGE - WHICH PROCESS IS SHOWN? mitosis meiosis binary fission

Meiosis - Unlike mitosis, meiosis involves two cell divisions as well as crossing-over, and the process results in four genetically diverse haploid gametes.

Match each type of cell division to its description. CELL DIVISION: MEIOSIS MITOSIS BINARY FISSION DESCRIPTION: asexual sexual diploid cells result

asexual = MITOSIS & BINARY FISSION sexual = MEIOSIS diploid cells result = MITOSIS & BINARY FISSION - Mitosis and binary fission are both types of asexual cellular reproduction resulting in diploid cells. In contrast, meiosis is involved in sexual reproduction and results in haploid gamete cells.

The G1 and G2 phases are also known as ____________________. During G1 and G2, the cell increases in both size and protein content. These phases serve as ________________ to make sure the conditions are suitable for the next phase in the ______________________________.

gap phases checkpoints cell cycle

Match each type of cell division to its description. Answers will be used more than once. DESCRIPTIONS: -produces genetically diverse daughter cells -chromosomes don't cross-over -chromosomes cross-over -produces genetically identical daughter cells TYPE OF CELL DIVISION: -Meiosis -Mitosis -Binary fission

produces genetically diverse daughter cells = MEIOSIS chromosomes don't cross-over - MITOSIS & BINARY FISSION chromosomes cross-over = MEIOSIS produces genetically identical daughter cells = MITOSIS & BINARY FISSION Mitosis and binary fission are two types of cellular division resulting in two identical daughter cells. In contrast, meiosis involves crossing-over (exchange) of genetic material and results in genetically diverse gamete cells.

Match each process to its description: Meosis II Mitotsis Meosis I

separates homologous chromosomes = Meosis I results in diploid cells = Mitosis separates sister chromatids = Meosis II & Mitosis --> Mitosis and meiosis II both lead to the separation of sister chromatids, although mitosis results in diploid cells and meiosis results in haploid gametes. Meiosis I results in the separation of homologous chromosomes, resulting in haploid cells that contain sister chromatids and setting the stage for meiosis II.

The process of binary fission, carried out by bacteria and archaea, more closely resembles the eukaryotic process of mitosis than meiosis.....T/F?

TRUE Mitosis and binary fission are both types of cellular division resulting in two genetically identical daughter cells.