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Mastering Bio 12-15
Question | Answer |
---|---|
Nucleoli are present during _____. | interphase |
Chromosomes become visible during _____. | prophase |
Centromeres divide and sister chromatids become full-fledged chromosomes during _____. | anaphase |
Spindle fibers attach to kinetochores during _____. | prometaphase |
During prophase a homologous pair of chromosomes consists of _____. | two chromosomes and four chromatids |
During _____ both the contents of the nucleus and the cytoplasm are divided. | mitotic phase |
In some organisms, such as certain fungi and algae, cells undergo the cell cycle repeatedly without subsequently undergoing cytokinesis. What woul | large cells containing many nuclei |
Cytochalasin B is a chemical that disrupts microfilament formation. How would this interfere with cell division? | cleavage |
A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle. Which of the following would result if colchicine is added to a sample of cells in G2? | The chromosomes would coil and shorten but have no spindle to which to attach |
Which of the following does not occur during mitosis? | replication of the dna |
Independent assortment of chromosomes is a result of | the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. |
Which of the following defines a genome? | complete set of an organisms genes |
What is crossing over? | the exchange of homologous portions of nonsister chromatids |
If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents? | It has half the amount of DNA as the cell that began meiosis. |
When we see chiasmata under a microscope, that lets us know which of the following has occurred? | prophase I |
If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of the same cell at metaphase of meiosis I would be | 2x |
How many different combinations of maternal and paternal chromosomes can be packaged in gametes made by an organism with a diploid number of 8 (2n = 8)? | 16 |
When constructing a Punnett square, the symbols on the outside of the boxes represent _______, while those inside the boxes represent _______. | gametes, progeny |
If an organism with the genotype AaBb produces gametes, what proportion of the gametes would be Bb? | none |
Which of the following differentiates between independent assortment and segregation? | The law of independent assortment requires describing two or more genes relative to one another |
Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division? | anaphase I of meiosis |
Mendel's second law of independent assortment has its basis in which of the following events of meiosis I? | alignment of tetrads at the equator |
SRY is best described in which of the following ways? | a gene region present on the Y chromosome that triggers male development |
Which of the following statements is true of linkage? | The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. |
What is a nondisjunction? | An error in cell division that causes homologous chromosomes or sister chromatids to move to the same side of the dividing cell |
What kind of cell results when a diploid and a haploid gamete fuse during fertilization? | triploid cell |
Of the following chromosomal abnormalities, which type is most likely to be viable in humans? | trisomy |
If a diploid cell undergoes meiosis and produces two gametes that are normal, and one with n ā 1 chromosomes, and one with n + 1 chromosomes, what type of error occurred? | A nondisjunction error occurred in meiosis II, in which both sister chromatids of a chromosome migrated to the same pole of the cell. |
If a diploid cell undergoes meiosis and produces two gametes with n + 1 chromosomes and two gametes with nā 1 chromosomes, what type of error occurred? | A nondisjunction error occurred in meiosis I, in which both members of a homologous pair migrated to the same pole of the cell. |
In general, the frequency with which crossing over occurs between two linked genes depends on what? | how far apart they are on the chromosome |