Concept explainers
BPA and Abnormal Meiosis In 1998, researchers at Case Western University were studying meiosis in mouse oocytes (germ cells) when they saw an unexpected and dramatic increase of abnormal events (FIGURE 12.6). Improper segregation of chromosomes during meiosis is one of the main causes or human genetic disorders.
The spike in abnormal meiosis began right after the mouse facility started washing the animals' plastic cages and water bottles in a new, alkaline detergent. The detergent had damaged the plastic, which as a result was leaching bisphenol A (BPA). BPA is a synthetic chemical that mimics estrogen, the main female sex hormone in animals. Though it has since been banned for use in baby bottles, BPA is still widely used to manufacture other plastic items and epoxies (such as the coating on the inside of metal cans of food). BPA-free plastics are often manufactured with a related compound, bisphenol S (BPS), that has effects similar to BPA.
FIGURE 12.6 Abnormalities in meiosis that occurred after exposure to BPA.
Top, the most abnormal meiosis events occurred in mice that were housed in damaged plastic caging with damaged plastic bottles. Damaged plastic releases BPA.
Bottom, fluorescent micrographs show the chromosomes (red) and spindle (green) in nuclei of mouse germ cells in metaphase I. A Normal metaphase; B–D abnormal metaphase.
What is abnormal about metaphase I as it is occurring in the oocytes shown in FIGURE 12.6B, C, and D?
Want to see the full answer?
Check out a sample textbook solutionChapter 12 Solutions
Biology: The Unity and Diversity of Life (MindTap Course List)
Additional Science Textbook Solutions
Genetics: From Genes to Genomes
Biology: Concepts and Investigations
Fundamentals of Anatomy & Physiology Plus Mastering A&P with eText - Access Card Package (10th Edition) (New A&P Titles by Ric Martini and Judi Nath)
Human Anatomy (8th Edition)
Microbiology: An Introduction (13th Edition)
- A cell from a human female has just undergone mitosis. For unknown reasons, the centromere of chromosome 7 failed to divide. Describe the chromosomal contents of the daughter cells.arrow_forwardIn mice, 2n = 40. If a mouse cell divides by mitosis, it will produce two daughter cells that each have ________ chromosomes. If a mouse cell divides by meiosis, it will produce four daughter cells that each have ________ chromosomes. Type the appropriate number to fill in each blank (e.g., 40).arrow_forwardIf the amount (mass) of DNA in a diploid cell during G1 phase prior to meiosis I is 8 pg (picograms), how much DNA would be present in a daughter cell immediately following: A) meiosis I? B) meiosis II? (for your information, this cell will function as a gamete) HINT: Go through the process of meiosis one step at a time. DNA replication would double the amount of DNA in the cell, cell division divides the DNA into two daughter cells.arrow_forward
- MODIFIED TRUE OR FALSE. In the following items, read each statement carefully. I. Mitosis and meiosis are two cellular process that might be quite similar in terms of stages, but technically, different process that have two different functions. II. As an example, mitosis involves the production of genetically different daughter cells whereas meiosis involves the production of genetically identical daughter cells. a. The first statement (I) is correct and the second statement (II) is wrong b. The first statement (I) is wrong and the second statement (II) is correct c. Both statements are correct d. Both statements are wrong I. The continuity of life from one cell to another has its foundation in the reproduction of cells by way of the cell cycle.II. The cell cycle is an orderly sequence of events in the life of a cell from the division of a single parent cell to produce two new daughter cells and are highly conserved across eukaryotes.…arrow_forwardA sperm cell from the fruit fly Drosophila melanogaster contains four chromosomes. How many chromosomes would be present in a spermatogonial cell about to enter meiosis? How many chromatids would be present in a spermatogo- nial cell at metaphase I of meiosis? How many would be present at metaphase II?arrow_forwardDogs have 78 chromosomes in their somatic cells. How many chromosomes are in their gametes?arrow_forward
- Diploid somatic cells of elephants have 56 chromosomes. If nondisjunction of one of a male elephant’s chromosomes occurs in meiosis II, at the end of meiosis the four resulting sperm are expected to have the chromosome complement:arrow_forwardFrom this point on, meiosis is very similar (but not exactly similar) to what happened in mitosis. How many copies of each type of chromosome end up in the daughter cells of meiosis when it is complete?arrow_forwardIn kangaroos, the somatic cells are diploid, having 22 chromosomes. How many chromosomes are present in each cell at metaphase II of meiosis?arrow_forward
- Comparison and contrast of meiosis 1 and meiosis 2. In which organisms does it miosis occur? Mitosis in which organisms does it occur?arrow_forwardNondisjunction, is when a chromosome does not separate during meiosis. When nondisjunction occurs in human sex cells, what kind of outcomes can occur? Why?arrow_forwardGENETICS In a sexually reproducing diploid organism in which 2n=6, a normal meiocyte in reduction should exhibit a total of 3 bivalents at the metaphase plate. Consider the following organism in the previous statement. if there is no crossing over, the number of possible haploids (gamete) genotypes generated by "chromosome shuffling" during meiosis is _____?arrow_forward
- Biology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage LearningBiology: The Unity and Diversity of Life (MindTap...BiologyISBN:9781305073951Author:Cecie Starr, Ralph Taggart, Christine Evers, Lisa StarrPublisher:Cengage LearningHuman Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning