Honor BIology 2/13/1

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

Unless the chromosomes were stained to show band patterns, a karyotype would usually be unable to show _____.

An inversion

A cell replicates its entire chromosomal DNA only _____.

Before it is about to divide

Which of the following conditions would result in inhibition of cell division due to density-dependent factors?

Being completely surrounded by other cells

Why are individuals with an extra chromosome 21, which causes Down syndrome, more numerous than individuals with an extra chromosome 3 or chromosome 16?

Extra copies of the other somatic chromosomes are probably fatal.

A cleavage furrow forms in an animal cell during _____.

cytokinesis

Cytochalasin B is a chemical that disrupts microfilament formation. This chemical would interfere with _____.

formation of a cleavage furrow

An organism has a haploid chromosome number n = 4. How many tetrads will form during meiosis?

four

In anaphase I, _____.

homologous chromosomes move toward opposite poles

Chromatids are _____.

identical copies of each other if they are part of the same chromosome

In humans, the _____ determines the sex of the offspring because _____.

male ... the male can contribute either an X or a Y chromosome Submit

Variation occurs when chromosomes are shuffled in _____.

meiosis

During meiosis, homologous chromosomes sometimes "stick together" and do not separate properly. This phenomenon is known as _____.

nondisjunction

The exchange of parts between nonhomologous chromosomes is called _____.

reciprocal translocation

During anaphase II, _____.

sister chromatids separate and migrate toward opposite poles

At a critical point in meiosis, the chromosomes do not replicate. This occurs between _____.

telophase I and prophase II

One event occurring during prophase is _____.

the beginning of the formation of the mitotic spindle

During cell division, what role do centrosomes play?

they organize the microtubules

At which point do centrosomes begin to move apart to the opposite poles of the cell in a dividing human liver cell?

Prophase

The term binary fission is best applied to _____.

Prokaryotes

Which of the following is a normal human female?

XX

If a fragment of a chromosome breaks off and then reattaches to the original chromosome at the same place but in the reverse direction, the resulting chromosomal abnormality is called _____.

an inversion

Single sister chromatids are found in cells at mitotic _____.

anaphase and telophase