chpt 8 homework
How many pairs of autosomes do humans have?
22
In a cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing __________ chromosomes.
5
Which of the following statements correctly describes the behavior of a tetrad during anaphase I of meiosis?
It splits into two pairs of sister chromatids, and one pair goes to each pole of the dividing cell.
Which of the following statements regarding prokaryotes is false?
Prokaryotic chromosomes are more complex than those of eukaryotes.
Which of the following statements regarding sexual and asexual reproduction is true?
Sexual reproduction is more likely to increase genetic variation than is asexual reproduction.
What event will immediately follow the event shown in this image?
The cell will divide into two plant cells.
Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?
The sequences are identical.
Which of the following variations of the sentence "Where is the cat?" is most like a chromosomal deletion?
Where is cat?
Which of the following indicates Turner syndrome?
XO
Which of the following is a normal human female?
XX
Consider the photograph of a karyotype. This is _____.
a photograph of all a person's chromosomes
According to the graph, at what maternal age is the incidence of Down syndrome equal to five times the incidence at age 40?
about 46 or 47
The stage of mitosis during which the chromosomes move toward separate poles of the cell is _____.
anaphase
In many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____.
are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes
A cell replicates its entire chromosomal DNA only __________.
before it is about to divide
A _____________ is a lump of abnormal cells that, although growing out of control, remains at its original site.
benign tumor
Meiosis differs from mitosis in that _____ only occurs in meiosis.
crossing over
A cleavage furrow forms in an animal cell during _____.
cytokinesis
The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called
cytokinesis.
The diploid phase of the human life cycle begins with _____.
fertilization
Which of the following is a feature of plant cell division that distinguishes it from animal cell division?
formation of a cell plate
At the conclusion of meiosis I, the daughter cells are _____.
haploid and the sister chromatids are joined
Eukaryotic cells spend most of their cell cycle in which phase?
interphase
Both mitosis and meiosis are preceded by
interphase.
When we say that an organism is haploid, we mean that _____.
its cells each have one set of chromosomes
During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles?
metaphase
During meiosis, homologous chromosomes sometimes "stick together" and do not separate properly. This phenomenon is known as _____.
nondisjunction
Down syndrome can be the result of _____.
nondisjunction of chromosome 21 during meiosis
Independent orientation of chromosomes at metaphase I results in an increase in the number of
possible combinations of characteristics.
In the telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _____.
prophase
Crossing over occurs during _____.
prophase I
The exchange of parts between nonhomologous chromosomes is called _____.
reciprocal translocation
One version of a gene may encode __________, whereas a different version of the same gene may encode __________.
red eyes; white eyes
During which phase of mitosis does the nuclear envelope re-form?
telophase
The genetic material is duplicated during
the S phase.
At the end of telophase I of meiosis, as cytokinesis occurs, there are __________.
two haploid cells
An individual with a malignant tumor is said to have ________
Cancer
The most common type of cancer is a ___________ ; this type always originates in tissues that line organs.
Carcinoma
Which of the following statements regarding cell division is false?
Cell division is common in eukaryotes but rare in prokaryotes.
During meiosis I, homologous chromosomes form a tetrad and crossing over occurs. What is the outcome of crossing over?
Crossing over creates new combinations of genes present on a single chromosome.
Which of the following statements regarding the differences between mitosis and meiosis is false?
Crossing over is a phenomenon that creates genetic diversity during mitosis
A __________ is an abnormally growing mass of cells that is actively spreading through the body.
malignant tumor
After fertilization, the resulting zygote begins to divide by __________.
mitosis
During which stage of meiosis do synapsis and crossing over occur?
prophase I
Synapsis occurs during _____.
prophase I
Which of the following shows mitosis in the correct chronological order?
prophase, prometaphase, metaphase, anaphase, telophase
The phase of mitosis during which the mitotic spindle begins to form is
prophase.
In meiosis II, _____.
sister chromatids are separated
Homologous chromosomes possess the same genes arranged in the same order but may possess different __________ of some of these genes.
versions
____________ is the spread of cancer cells from their site of origin to other sites in the body.
Metastasis
Which of the following statements regarding the function of mitosis is false?
Mitosis allows organisms to generate genetic diversity
