Biology Chapter 11

All cancers are caused by viruses.

false

Prophase

first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus

Prophase I (Meiosis)

homologous chromosomes pair up and form tetrads, crossing over occurs

Sexual reproduction results:

in a new generation with the same number of chromosomes as each parent. from combining genetic material from two gametes. in a new generation that is not genetically identical to its parents. in offspring that are not genetically identical.

Homologous chromosomes separate from each other in:

meiosis I.

Cancer-causing genes found in some viruses are called:

oncogenes.

Interphase

period of the cell cycle between cell divisions Pre-synthesis (growth) DNA Replication (synthesis) Post-synthesis (growth)

Four stages of mitosis

prophase, metaphase, anaphase, telophase

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

proto-oncogene

Metaphase

second phase of mitosis, during which the chromosomes line up across the center of the cell

cell cycle

series of events that cells go through as they grow and divide

Anaphase

the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles Sister chromatids separate!!!!!

What is the function of the centromere?

to attach the sister chromatids to each other

Asexual reproduction occurs in:

unicellular eukaryotes. animal cells. plant cells. bacterial cells.

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

46

In what way is cytokinesis in plant cells similar to binary fission in a bacterium?

Cell wall material is deposited to separate the daughter cells

Homologous chromosomes

Chromosomes that have the same sequence of genes and the same structure carry information for the same traits

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

Cytokinesis does not occur.

Telophase II meiosis

Cytokinesis occurs, four haploid cells are the result

Telophase I (Meiosis)

Cytokinesis occurs, the result are two haploid daughter cells

Which of the following statements is true regarding binary fission?

DNA replication during binary fission is a bidirectional process, occurring in opposite directions.

sister chromatids

Identical copies of a chromosome; full sets of these are created during the S subphase of interphase.

Metaphase of meiosis II

Individual chromosomes line up along the equator, attached at their centromeres to spindle fibers

Which of the following is NOT true about the eukaryotic cell cycle?

Interphase is typically the shortest of the two stages of the cell cycle.

Which of the following statements regarding the cell cycle is true?

It has many major cell cycle checkpoints. 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.

The prokaryotic protein FtsZ is evolutionarily related to eukaryotic tubulin. What does this mean?

The gene sequence for FtsZ is similar to tubulin. 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.

Metaphase of meiosis I

The pairs of homologous chromosomes are moved by the spindle to the equator of the cell. The homologous chromosomes, each made up of two chromatids, remain together.

Which of the following statements is NOT true about gamete formation in mammals?

The polar bodies formed during meiosis in the female can participate in fertilization with sperm.

Evidence exists (especially in dinoflagellates) that mitosis evolved from binary fission. For example, in certain eukaryotic cells during mitosis, DNA is attached to the membrane of the nucleus (much like a circular chromosome of a bacterium is attached to the plasma membrane).

True

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, at the kinetochore

cell division in prokaryotes

binary fission

How does meiosis generate genetic diversity?

both crossing over and random alignment at metaphase I

What cellular process(es) is/are responsible for the increase in protein content associated with the gap phases of the cell cycle?

both gene expression and protein synthesis

The amount of _____ is fairly constant throughout the cell cycle, but the amount of _____ varies.

cyclin-dependent kinase/DNA

Anaphase I (Meiosis)

Homologous pairs are separated Sister chromatids remain intact

A graduate student is planning an experiment to evaluate the expression of PDGF-related genes in her cell population of interest. As a control, she hopes to confirm the expression of genes that are present in all dividing cells. For her controls, she should evaluate the expression of:

CDKs.

Which of the following statements regarding cancer—according to Hanahan and Weinberg—are true?

Cancer cells typically secrete factors that promote blood vessel formation. Cancer cells can sometimes metastasize and travel throughout the body. Mutations in growth factor receptors are sometimes required for cancer cell division. Cancer cells can resist cell-death signals.

Which of the following is a characteristic of meiotic cell division?

Cell division results in the formation of four daughter cells. Cell division requires two rounds of nuclear division. Cell division results in the production of gametes.

Meiosis

Cell division that produces reproductive cells in sexually reproducing organisms (two rounds of of cell division)

Which of the following is not a characteristic of meiotic cell division?

Daughter cells are genetically identical.

Predict what would happen if crossing over between homologous chromosomes occurred as part of mitosis.

Daughter cells would not be genetically identical, and they could contain two copies of the same allele.

Cytokinesis

Division of the cytoplasm during cell division

Look carefully at the image of the human karyotype shown in Figure 11.3. What is the significance of the small differences between homologous chromosomes?

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

Meiosis I

Homologous chromosomes separate

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

It would limit the spread of the infection through cell division.

Mitosis vs. Meiosis

Mitosis: one division forming 2 identical cells (clones); Meiosis: two divisions forming 4 genetically different cells

What would happen if a chromosome only connected to the mitotic spindle at one of its kinetochores?

One of the daughter cells would have an extra copy of that chromosome. The sister chromatids would not separate. The chromosome would not line up properly at metaphase.

cell division

Process by which a cell divides into two new daughter cells Mitosis (nuclear dividson) Cytokinesis (cytoplasmic division)

cell division (mitosis)

Produces 2 exact copies. Growth and repair/development Start with 46 chromosomes Ends with 46 Chromosomes

Prophase II

The first phase of meiosis II. Prophase II is identical to mitotic prophase, except that the number of chromosomes was reduced by half during meiosis I.

When in the cell cycle would you find sister chromatids?

S and G2

How must spindle microtubules attach to chromosomes during prometaphase of meiosis I?

Spindle microtubules from one pole must attach to both kinetochores in a pair of sister chromatids.

Which of the following statements is TRUE if a cell has a mutation in the p53 gene such that the p53 protein is no longer able to be phosphorylated?

The cell would proceed through the cell cycle even in the presence of DNA damage.

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

The cells would be smaller than normal.

Meiosis I

The first division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell.

Which of the following steps in prokaryotic binary fission is CORRECT?

The two replicated chromosomes remain attached to the plasma membrane. DNA is replicated bidirectionally from a single point on the circular chromosome. The cell continues to grow outward symmetrically, separating the two chromosomes. Cell wall material is laid down at the midpoint to separate the two daughter cells.

Why are the X and Y chromosomes not considered homologous?

They do not carry the same set of genes, and mammalian males carry two very different sex chromosomes.

During what step in meiosis do the daughter cells become haploid?

anaphase II

Mitosis

division of the nucleus

Meiosis II

the second phase of meiosis consisting of chromatids separating, along with the two diploid cells splitting in two

Which of the following has the MOST similarity in nucleotide sequence?

sister chromatids

Anaphase II of meiosis

sister chromatids separate

Meiosis II

sister chromatids separate

Studies of rapidly dividing embryonic animal cells revealed:

that the production of cyclin proteins is followed by activation of CDK enzymes. that inhibition of protein production blocks mitosis. a cyclic activation of protein kinases in sync with the cell cycle. a cyclic production of certain proteins in sync with the cell cycle.

Telophase

the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.