Chap 8 Quiz Q's
In humans, the haploid number of chromosomes is 23. Independent assortment has the possibility of producing _____ different gametes.
2^23
Imagine that a human skin cell went through mitosis but did not undergo cytokinesis. How many chromosomes would be in the cell?
92
Which of the following statements regarding cell division is false?
Cell division is common in eukaryotes but rare in prokaryotes.
Which of the following conditions would result in inhibition of cell division due to density-dependent factors?
being completely surrounded by other cells
Asexual and sexual reproduction differ in that sexual reproduction _____.
can produce great variation among the offspring
A cleavage furrow forms in an animal cell during _____.
cytokinesis
Observations of cancer cells in culture support the hypothesis that cancer cells _____.
do not exhibit density-dependent inhibition
The diploid phase of the human life cycle begins with _____.
fertilization
Cytochalasin B is a chemical that disrupts microfilament formation. This chemical would interfere with _____.
formation of cleavage furrow
An organism has a haploid chromosome number n = 4. How many tetrads will form during meiosis?
four
At the conclusion of meiosis I, the daughter cells are _____.
haploid and the sister chromatids are joined
Chromatids are _____.
identical copies of each other if they are part of the same chromosome
A fragment of chromosome 21 reattaches to chromosome 21, but in the reverse direction. What is the name given to this change?
inversion
When we say that an organism is haploid, we mean that _____.
its cells each have one set of chromosomes
Variation occurs when chromosomes are shuffled in _____.
meiosis
At which stage of mitosis are chromosomes lined up in one plane in preparation for their separation to opposite poles of the cell?
metaphase
During cell division, what role do centrosomes play?
organize microtubles
Crossing over occurs during _____.
prophase 1
Synapsis occurs during _____.
prophase 1
Which of the following shows mitosis in the correct chronological order?
prophase, prometaphase, metaphase, anaphase, telophase
The exchange of parts between nonhomologous chromosomes is called _____.
reciprocal translocation
Benign tumors differ from malignant tumors in that the cells of a benign tumor _____.
remain confined to their original site
The kinetochores are _____.
sites at which microtubules attach to chromosomes
One event occurring during prophase is _____.
the beginning of the formation of the mitotic spindle
Mitosis and cytokinesis result in the formation of _____; meiosis and cytokinesis result in the formation of _____.
two diploid cells ... four haploid cells
A cell replicates its entire chromosomal DNA only _____.
before it is about to divide
During binary fission, one copy of the duplicating chromosome moves to the opposite end of the cell. What does this achieve?
It ensures that each daughter cell receives one copy of the chromosome.
If the diploid number of chromosomes in a certain animal is 6 (2n = 6), there are three sets of two homologous chromosomes each, or three pairs. How do these three pairs align and separate in meiosis?
They align and assort independently to form any of eight different combinations.
Crossing over is important because it _____
allows the exchange of genes between homologous chromosomes
