KU BIOL 150 CH.11 Learning Curve

At the start of mitosis, how many sister chromatids are present in a human cell?

46

Why don't plant cells use a contractile ring to divide their daughter cells?

A contractile ring can't "pinch" a cell wall.

Asexual reproduction occurs in: -animal cells. -plant cells. -bacterial cells. -unicellular eukaryotes.

All of these choices are correct

The division of the cell's cytoplasm in a eukaryotic cell is known as:

Cytokinesis

Muscle cells in the mammalian heart are multinucleate, meaning that multiple nuclei are present in the cytoplasm of individual large cells. Predict what is different about the cell cycle in a muscle cell.

Cytokinesis does not ocur

Which statement is true regarding binary fission?

DNA replication of the circular bacterial chromosome during binary fission is a bidirectional process, starting at one point but progressing in opposite directions.

Which of the statements about viruses is true? -Viruses are a type of prokaryotic cell. -Viruses are the root cause of most, if not all, cancers. -Human cancers have not been associated with viruses. -Viruses contain multiple genes, and each of these genes is an oncogene.

None of the answer options is correct

Nondisjunction results when:

Pairs of chromosomes fail to separate during anaphase.

In which phase of mitosis do chromosomes condense?

Prophase

Crossing over occurs during which step in meiosis?

Prophase I

What type of gene is c-src (cellular-src)?

Proto-oncogene

Reproduction by mitotic cell division:

Results in two daughter cells that are genetically identical

Why are the X and Y chromosomes not considered homologous?

They do not carry the same set of genes.

Which of the answer choices is true about gametes?

They fuse to form a new organism during fertilization.

What is the function of histone proteins?

To package DNA in eukaryotic chromosomes

True or False: Nondisjunction can occur in both mitosis and meiosis.

True

True or False: Some types of leukemia are the result of constitutively active (that is, "always on") growth factor receptors.

True

Which statement regarding the cell cycle is true? -It is regulated by cyclins and CDKs. -Different levels of cyclins are observed at different cell cycle stages. -It can be "paused" by the action of p53. -It has many major cell cycle checkpoints.

All of these choices are correct

Cell division is regulated by: -signals that indicate that DNA has been replicated. -signals that indicate that the cell has reached a sufficient size. -growth factor signals. -signals about the nutritional status of the cell.

All of these choices are correct.

When do sister chromatids separate in meiosis?

Anaphase II

At which checkpoint would a cell become arrested if a chromosome was not properly aligned in the spindle?

At a checkpoint early in the mitotic phase

The microtubules that form the mitotic spindle extend out from the centrosome. Where would you expect to find the plus (fast-assembling) end of a spindle microtubule?

Away from the centrosome and toward the kinetochore

What characteristics do you expect to observe with a microscope if you investigate the division of mitochondria and chloroplasts in eukaryotic cells?

Circular DNA attached to the plasma membrane and binary fission

Non-sister chromatids are:

Copies of homologs but not fully identical chromosomes

A protein that has regular up-and-down pattern of abundance during the cell cycle and that triggers progress of the cell cycle by activating kinases is called a:

Cyclin

A _____ is an enzyme that adds phosphate groups to other proteins. If this enzyme is only active when bound to a specific protein that fluctuates in concentration in synchrony with the cell cycle, then it is a _____.

Cyclin; cyclin-dependent kinase

If you analyze the sequences of the two copies of any of the chromosomes shown in the karyotype, there would be slight sequence differences. What could account for the small differences between a few of the homologous chromosomes

Each homologous chromosome in a pair is from a different parent.

Meiosis _____ is sometimes called reductional division because _____.

I; the number of chromosomes is reduced by half

Suppose you analyze a time-lapse video of a cell under a microscope, and you observe what appears to be four chromatids tightly aligned along their lengths. Which of the answer choices is an interpretation of this observation?

The chromatids represent a bivalent and the cell is probably in Prophase I of meiosis

During meiosis I:

Diploid cells become haploid

Sexual reproduction results in an increase in genetic diversity because: -during metaphase I, the bivalents line up in a random orientation so that gametes inherit a random set of maternally and paternally derived chromosomes. -during fertilization, the gametes that fuse are random so that a large number of chromosomal combinations are possible in the new organism. -during prophase I, genes that are paternally and maternally derived recombine so that the gametes have chromosomes that are different from the parents' chromosomes.

All of these choices are correct

True or False: All cancers are caused by viruses.

False

Which of the answer choices is part of the process of binary fission in prokaryotes?

Formation of a new cell wall

A human cell with a total of 23 chromosomes is:

Haploid

Polar bodies are:

Haploid

Suppose you are observing some cells with a microscope, and you see a cell that appears to be dividing. You can see that as the cell starts to pinch in half, the DNA seems to be attached to the plasma membrane via a membrane protein. On further analysis, you find that this organism's DNA is circular - that is, it consists of a closed loop. What can you conclude about this organism and its mode of cell division?

It is a prokaryote that is dividing by binary fission.

Why would a compound that interferes with bacterial cell wall synthesis be useful for treating a bacterial infection?

It would limit growth of the bacterial population through cell division.

A person has the genotype XXY. What syndrome does this person have and what sex is the person?

Klinefelter; male

At which stage of the cell cycle could you see sister chromatids with a microscope?

M

A malignant cancer differs from a benign tumor in that:

Malignant cancers invade surrounding tissue and benign cancers do not.

Second-division nondisjunction occurs when:

Sister chromatids fail to separate during anaphase II.

What would happen to the daughter cells if the G2 phase of the parent cell is shortened?

The cells would be smaller than normal

There are laboratory techniques that allow researchers to determine the amount of DNA in cell nuclei. If you measure the amounts of DNA at the end of mitosis and at the end of meiosis, how do they compare to the starting cell (starting from prophase during mitosis and from prophase I during meiosis)?

The daughter cells at the end of mitosis have one-half the amount of DNA, and the daughter cells at the end of meiosis have one-fourth the amount of DNA.

What important difference is there between meiosis in males and females?

The division of cytoplasm differs between males and females.

A researcher is evaluating the expression of p53 in cells she is culturing in the laboratory. She notices that in a small group of cells, high levels of phosphorylated p53 occur in the nuclei. What can she deduce about these cells?

These cells likely contain damaged DNA

Synapsis is best described as:

The pairing of homologous chromosomes in prophase I.

What protein forms the contractile ring during cytokinesis in animal cells?

Actin

The prokaryotic protein FtsZ is evolutionarily related to eukaryotic tubulin. What does this mean? -The amino acid sequence for FtsZ is similar to tubulin. -The overall protein structure of FtsZ is similar to tubulin. -The two proteins evolved from a common ancestral protein. -The gene sequence for FtsZ is similar to tubulin.

All of these choices are correct

What properties are associated with a malignant cancer? -It invades surrounding tissue. -It is metastatic. -It is fast growing.

All of these choices are correct

What would happen if a pair of sister chromatids only connected to the mitotic spindle at one of their kinetochores? -The sister chromatids would not separate. -The chromosome would not line up properly at metaphase. -One of the daughter cells would have an extra copy of that chromosome.

All of these choices are correct

The process of cell division in a prokaryotic cell is called:

Binary fission

How does meiosis generate genetic diversity?

Both crossing over at prophase I and random alignment of homologs at metaphase I

A zygote is:

Diploid

Which of the answer choices is a characteristic of meiotic cell division?

Meiotic cell division results in halving the number of chromosomes.

A researcher is studying phases of the cell cycle in a population of cells during which there is an increase in the DNA content. This stage is most likely:

S phase

True or False: The alignment of chromosomes at metaphase of meiosis II is most similar to the alignment of chromosomes during metaphase of mitosis.

True

True or False: There are no discernible phenotypic effects for an individual with the genotype XYY.

True