Chapter 11

In plants and animals, the zygote develops by which of the following processes? Mitosis.

The zygote has…? Two copies of each chromosome.

_________ is a process of nuclear division that reduces the number of chromosomes per cell from 2 sets to 1 set. Meiosis.

The cell produced by the fusion of an egg and a sperm is the…? Zygote.

The fusion of a male gamete with a female gamete is called…? Syngamy.

The pairing of homologous chromosomes is called…? Synapsis.

The pairing of chromosomes along their lengths, which is essential for crossing over, is referred to as…? Synapsis.

You are studying meiosis in an organism where 2n = 24. How many chromosomes will each nucleus have after meiosis II is complete? 12.

The term for one of a pair of chromosomes with similar genetic information and from different sources like the sperm and egg is _________. Homologue.

You are comparing the events of meiosis I in cells from several different organisms. You come across one species in which you do not observe any chiasmata. The best conclusion to make is…? There is no crossing over between non sister chromatids.

Which statement about the reductive division of meiosis is false? During the reductive division, sister chromatids migrate to opposite poles of the cell.

A cell in G2 before meiosis begins, compared with one of the four cells produced at the end of meiosis II, has…? Four times as much DNA and twice as many chromosomes.

Which of the following events occurs first during meiosis? Synapsis of homologous chromosomes.

The most common form of gene therapy involves inserting a normal gene into cells that contain a defective version of the gene. In order to use gene therapy to prevent a man from passing a defective gene on to future generations, you should try to insert normal copies of the gene into…? Germ-line cells.

Nondisjunction is the failure of homologous chromosomes to separate during meiosis I, or the failure of sister chromatids to separate during meiosis II or mitosis. As a result, both homologous chromosomes or both sister chromatids migrate to the same pole of the cell. This produces daughter cells with an imbalance of chromosomes. If 18 pairs of sister chromatids segregate normally during meiosis II in cats (n=19) but we have non-disjunction of 1 pair, then at the end of meiosis II we will have…? 2 cells with 19 chromosomes, 1 with 20, and 1 with 18.

The point of connection between two sister chromatids, before anaphase II of meiosis separates them, is called the…? Centromere.

Which of the following statements about crossing over is false? Crossing over takes place between sister chromatids.

The Rec8 protein holds sister chromatids together during meiosis. If an individual has a mutation that prevents degradation of Rec8, this would most likely prevent…? Normal segregation during meiosis II.

Which of the following is likely to occur if you were to prevent cyclin B from associating with its cyclin-dependent kinase near the end of meiosis I? Activation of DNA replication.

At the end of meiosis II, each of the four resulting cells contains…? One full set of chromosomes, each with 1 molecule of DNA.