Exam 11: Sexual Reproduction and Meiosis

Homologous chromosomes pair along their length during prophase I of meiosis.While two homologues are paired, genetic exchange may occur between them in a process called ________.

At the end of meiosis II, each of the four resulting cells contains

A cell in G₂ before meiosis begins, compared with one of the four cells produced at the end of meiosis II, has

Which of the following statements about crossing over is false?

A life cycle that regularly alternates between haploid and diploid stages is found in all of the following EXCEPT

Non-disjunction 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.A cell biologist examines the final products of meiosis in an earthworm (2n=36) and finds 2 cells with 20 chromosomes, and 2 cells with 16 chromosomes.Most likely this was because

Edouard van Beneden proposed that an egg and a sperm, each containing half the complement of chromosomes found in somatic cells, fuse to produce a single cell called a(n) ______.

The cell produced by the fusion of an egg and a sperm is the

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

The pairing of homologous chromosomes is called

During anaphase I, which best represents segregation of the chromatids that make up one pair of homologues? (M represents a maternal chromatid and P represents a paternal chromatid.Assume no crossing over occurs.)

Compared to asexual reproduction, the main advantage of sexual reproduction is that it

One of a pair of chromosomes with similar genetic information and from different sources like the sperm and egg.

Which of the following produces new cells that are genetically identical to the original cell?

A geneticist examines a somatic cell from a fly during metaphase of mitosis and determines that 16 chromatids are present.If a germ-line cell from this species divides by meiosis, then at the end of meiosis I (including the first cytokinesis) each cell will contain

All of the following increase genetic variation EXCEPT

In 95% of cases of Down's syndrome, there is one extra chromosome (number 21) in every cell.This aneuploid condition is most likely the result of

If there were no suppression of DNA replication between meiotic divisions but cytokinesis proceeded normally, what is the most likely outcome of meiosis?

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

During meiosis, sister chromatids are held together by