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