Ch 12 & 13 study module

Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid number of 8?

16

A cell contains 40 chromatids at the beginning of mitosis. How many chromosomes will it contain at the completion of cytokinesis?

20

The egg (ovum) of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic (body) cells of a rabbit?

44

How many chromatids does a human somatic cell contain after interphase and just prior to mitosis?

92

Which event or events occur during anaphase? -The centrioles are at opposite poles -A spindle made of microtubules is present -The centromeres divide -All of the listed responses are correct. -Identical chromatids move to opposite poles

All of the listed responses are correct.

Which of the following structures is/are part of the mitotic spindle? -The aster -Centrosome -All of the listed responses are part of the mitotic spindle. -Kinetochore microtubules -Nonkinetochore microtubules

All of the listed responses are part of the mitotic spindle.

Which of the following statements correctly describes the difference(s) between mitosis and binary fission?

Binary fission involves the replication and division of a single chromosome, whereas mitosis involves the division of multiple, replicated chromosomes.

What is the difference between a benign tumor and a malignant tumor?

Cells of benign tumors do not metastasize; those of malignant tumors do.

__________ are a group of genetically identical individuals produced by a process called __________.

Clones; asexual reproduction

In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?

Cytokinesis

Regarding the role of cohesin protein in maintaining cohesion between sister chromatids, which of the following statements is false? -None of the listed responses is false. -During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs. -During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms. -During meiosis I, cohesion holds sister chromatids together along their lengths as chiasmata form between homologs and during meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms -Cleavage of cohesins between sister chromatid arms at anaphase I allows homologs to separate.

During meiosis II, cohesion holds sister chromatids together along their lengths as the second meiotic spindle forms.

What is the result when a diploid cell undergoes meiosis?

Four haploid cells

Which of the following occurs in meiosis, but not mitosis? -Homologous chromosomes separate. -A spindle apparatus forms. -The nuclear envelope disappears. -The cells formed have the same combination of genes as found in the initial cell. -Sister chromatids undergo disjunction.

Homologous chromosomes separate.A number of key differences between meiosis and mitosis exist. Basically, meiosis reduces the number of chromosome sets from two (diploid) to one (haploid), whereas mitosis conserves the number of chromosome sets. Therefore, meiosis produces cells that differ genetically from their parent cell and from each other, whereas mitosis produces daughter cells that are genetically identical to their parent cell and to each other. In addition, homologous chromosomes separate during anaphase I. This event follows synapsis, an event unique to prophase I.

Which life cycle stage is found in plants but not animals?

Multicellular haploid

Which of the following is a function of mitosis in humans? -Production of eggs -Increasing genetic variability -Production of sperm -Decreasing the number of chromosomes -Multiplication of body cells

Multiplication of body cells

Unless the chromosomes were stained to show band patterns, a karyotype would be least likely to show which of the following?

Part of a chromosome turned around. An inversion, where part of a chromosome is turned around, affects neither the number of chromosomes nor the length of a chromosome, and is generally difficult to detect without staining to show chromosomal bands. An extra or missing chromosome can be detected by counting the number of chromosomes displayed.

Which of the following events does not occur during interphase of the cell cycle? -Production of new mitochondria -Growth of the cell -Production of the endoplasmic reticulum -Separation of the sister chromatids -Protein production -Duplication of the chromosomes

Separation of the sister chromatids

Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope? -Telophase -Interphase -Metaphase -S phase -Anaphase

Telophase

How many genes are present in the human genome?

Tens of thousands

A cell biologist examined the DNA content of a cell from a fruit fly larva during the G1 phase and determined that it had 150 units of DNA. After measuring the DNA content of the same type of cell after the G2 phase, it was discovered that the cell had 300 units of DNA. How is this possible?

The DNA was replicated during the S phase of interphase, which occurs between the two G phases.

Which of the following statements describes a cell that undergoes mitosis but not cytokinesis?

The cell contains more than one nucleus.

Which of the following events occurs during metaphase of mitosis? -The nuclear envelope forms again. -The chromosomes condense. -The chromosomes align along the metaphase plate of the cell. -The nuclear envelope disappears. -The mitotic spindle forms. -The sister chromatids are pulled apart toward opposite sides of the cell.

The chromosomes align along the metaphase plate of the cell.

Which of the following events does not occur during prophase of mitosis? -The mitotic spindle forms. -The chromosomes condense. -The centrosomes move away from each other. -Each duplicated chromosome appears as two identical sister chromatids. -The mitotic spindle breaks down. -Nucleoli disappear.

The mitotic spindle breaks down.

How does the process of mitosis differ between most eukaryotes and other eukaryotes such as diatoms and dinoflagellates?

The nuclear envelope fragments in most eukaryotes but remains intact in diatoms and dinoflagellates.

Which of the following events occurs during prometaphase of mitosis? -The mitotic spindle forms. -The nuclear envelope forms again. -The sister chromatids are pulled toward opposite sides of the cell. -The chromosomes align along the metaphase plate of the cell. -The centrosomes move away from each other. -The nuclear envelope fragments.

The nuclear envelope fragments.

What is a locus?

The precise location of a gene on a chromosome.

Which of the following events occurs during anaphase of mitosis? -Spindle fibers attach to the centromeres of the chromosomes. -The sister chromatids are pulled apart toward opposite sides of the cell. -The nuclear envelope fragments. -The chromosomes align along the metaphase plate of the cell. -The nuclear envelope forms again. -The mitotic spindle forms.

The sister chromatids are pulled apart toward opposite sides of the cell.

Which of the following statements about homologous chromosomes is correct? -They have genes for the same traits at the same loci. -They are found in animal cells but not in plant cells. -They are found in the cells of human females but not in human males. -They are found in haploid cells. -They pair up in prophase II.

They have genes for the same traits at the same loci.

Which of the following events occurs during telophase of mitosis? -Two distinct daughter nuclei form in the cell. -The sister chromatids separate. -The chromosomes align on the metaphase plate. -The chromosomes condense. -DNA replicates. -The nuclear envelope fragments.

Two distinct daughter nuclei form in the cell.

The region of a chromosome holding the two double strands of replicated DNA together is called __________.

a centromere

The life cycle called __________ in plants has two multicellular stages: the __________ and the __________.

alternation of generations; haploid gametophyte; diploid sporophyte

Somatic cells in animals differ from gametes in that somatic cells __________.

are all of the cells of the body except for the gametes and their precursors

The function of the mitotic cell cycle is to produce daughter cells that __________.

are genetically identical to the parent cell (assuming no mutation has occurred)

Sister chromatids differ from nonsister chromatids in that sister chromatids __________.

are products of the S phase of the cell cycle and are two copies of one chromosome

A clone is the product of __________.

asexual reproduction and mitosis

The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________.

chromatin

Somatic cells in humans differs from gametes in that human somatic cells __________.

contain two sets of each of the 23 chromosome types

During interphase, the genetic material of a typical eukaryotic cell is __________.

dispersed in the nucleus as long strands of chromatin

Cytokinesis refers to __________.

division of the cytoplasm

Observations of cancer cells in culture support the hypothesis that cancer cells __________.

do not exhibit density-dependent inhibition

Darwin realized the importance of heritable variation to evolution __________.

even though he never read any of Gregor Mendel's work

A life cycle in which the only multicellular form is haploid is most typical of __________.

fungi

Allelic variation is an important source of __________ in a population.

genetic diversity

A pair of genetic structures carrying genes that control the same inherited characters are called __________.

homologous chromosomes

Chromatids are __________.

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

Characteristic of the bdelloid rotifer is that it __________.

is an example of an animal that has not reproduced sexually in 40 million years

You would know a dividing cell was a plant cell rather than an animal cell if you saw that __________.

it had formed a cell plate

The major contribution of sex to evolution is that __________.

it provides a method to increase genetic variation

The process called __________ reduces the chromosome number by __________.

meiosis; two consecutive cell divisions

The spread of cancer cells to other locations in the body is known as __________.

metastasis

In meiosis, __________ of __________ cross over and form __________.

nonsister chromatids; homologous pairs; chiasmata

The zipper-like complex that forms in meiosis occurs during __________ and is called the __________.

prophase I; synaptonemal complex. Prophase I of meiosis is a very busy time. The prophase I cell shown in the figure below is at a point fairly late in prophase I, when homologous pairing, crossing over, and chromosome condensation have already taken place.

Checkpoints in the cell cycle control system __________.

regulate the cell cycle through a variety of stop and go signals

Genetic diversity requires __________.

sexual reproduction, independent assortment, crossing over between nonsister chromatids of homologous chromosomes, and random fertilization

DNA replication occurs in __________.

the S phase of interphase in both somatic and reproductive cells

One event occurring during prophase is __________.

the beginning of the formation of a spindle apparatus

During binary fission in a bacterium __________.

the origins of replication move apartThe process of cell division is initiated when the DNA of the bacterial chromosome begins to replicate at a specific place on the chromosome called the origin of replication, producing two origins. As the chromosome continues to replicate, one origin moves rapidly toward the opposite end of the cell. While the chromosome is replicating, the cell elongates. When replication is complete and the bacterium has reached about twice its initial size, its plasma membrane pinches inward, dividing the parent cell into two daughter cells. In this way, each cell inherits a complete genome.

Somatic cells in humans contain __________ set(s) of chromosomes and are therefore termed __________.

two; diploid

At the end of mitosis, __________ daughter cells that are genetically __________ are formed, while at the end of meiosis, __________ daughter cells that are genetically __________ are formed.

two; identical; four; distinct