Chapter 10
A bacterial chromosome consists of:
a circular DNA molecule many times larger than the cell.
Eukaryotic chromosomes consist of:
linear DNA molecules complexed with positively charged histone proteins.
Nucleosomes are best described as:
eukaryotic DNA associated with histone proteins.
What is the function of nucleosomes?
To prevent DNA strands from tangling.
Nucleosomes are organized into large coiled loops held together by:
scaffolding proteins.
The cell cycle of a typical somatic cell consists of __________ and M phase.
interphase
The M phase of the cell cycle involves two main processes:
mitosis and cytokinesis
Once nerve cells become mature, they don't usually undergo cell division. Based on your knowledge of the cell cycle, you would predict that mature nerve cells become arrested in the __________ of the cell cycle.
G0 phase
Chromosomes are duplicated during __________ of the cell cycle.
S phase
Which of the following represents the overall sequence of events during mitosis?
If a cell is in G2:
it has twice the amount of DNA present in a telophase nucleus.
During prophase, __________ is(are) compacted into visible chromosomes.
chromatin
The __________ is responsible for the separation of the chromosomes during __________ of mitosis.
mitotic spindle; anaphase
__________ contain identical DNA sequences and are held together by __________ during mitosis.
Sister chromatids; centromeres
The mitotic spindle is made of:
microtubules.
The kinetochore serves which of the following functions?
Kinetochores attach to microtubules during mitosis.
All of the following events occur during prometaphase EXCEPT:
the duplicated chromosomes become visible with the light microscope.
A cell is in metaphase if:
the chromosomes are aligned at the midplane of the cell.
Duplicated centrioles move to opposite poles of a dividing __________ cell during __________ of the cell cycle.
animal; prophase
The chromosome makeup of an individual organism is called a:
karyotype.
Chromosomes are condensed to their greatest extent during __________ of mitosis.
metaphase
Cytokinesis in animal cells involves contraction of a ring of __________ microfilaments.
actin plus myosin
Cytokinesis in plant cells occurs via the formation of a(n):
cell plate.
If a cell is dividing by binary fission then you know that:
the cell is prokaryotic.
To prevent disastrous consequences, the eukaryotic cell cycle is controlled by:
a series of cell cycle checkpoints.
Which of the following statements concerning the cell cycle is FALSE?
M-Cdk inhibits mitosis.
The correct number of chromosomes is maintained during sexual reproduction by:
meiosis, which reduces the chromosome number by half.
Animal cells are stimulated to divide by mitosis by:
growth factors.
If meiosis did not occur in sexually reproducing organisms, then:
chromosome number would double in each generation.
What evolutionary advantage is provided by sexual reproduction?
increased genetic diversity
Plant hormones known as __________ stimulate mitosis.
cytokinins
Homologous chromosomes undergo synapsis during:
prophase I.
A maternal homologue and a paternal homologue synapse to form:
a tetrad.
During which phase does crossing-over occur?
prophase I
A zygote contains the __________ number of chromosomes.
diploid
In a human cell at prophase I, there are __________ tetrads.
23.
An animal with a diploid number of 36 chromosomes will have __________ chromosomes in its gametes and __________ chromosomes in its somatic cells.
18;36
During prophase I, each chiasma represents:
a site of crossing-over.
During which of the following stages of meiosis do the sister chromatids separate?
anaphase II
Which of the following events does not occur in prophase II?
formation of chiasmata
The sources of genetic variation during meiosis are:
crossing-over and the random assortment of maternal and paternal chromosomes.
Which of the following events does not occur during meiosis I?
separation of sister chromatids
Figure 10-1 Use the figure to answer the corresponding question(s). Refer to Figure 10-1. Which of the following combinations of letters accurately represents two sister chromatids?
A and C
Figure 10-1 Use the figure to answer the corresponding question(s). Refer to Figure 10-1. Which of the following combinations of letters accurately represents two homologous chromatids?
A and D
The formation of female gametes is termed:
oogenesis
Which of the following are NOT produced by meiosis?
zygotes
Figure 10-2 Use the figure to answer the corresponding question(s). Refer to Figure 10-2. The chromosome complement of item 6 in the life cycle is:
haploid
Figure 10-2 Use the figure to answer the corresponding question(s). Refer to Figure 10-2. The process occurring at arrow 3 in the associated figure is:
meiosis
Gametophyte plants produce gametes using:
mitosis
Sporophyte plants produce spores using:
meiosis