Unit 3 Ch 11

The assembly of what cytoskeletal protein is initiated by the M cyclin-CDK complex?

microtubules

A gene associated with promoting normal cell division is called:

proto oncogene

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

proto- oncogene

At the start of mitosis, how many centromeres 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.

Which of the following statements is true regarding binary fission? Proteins only anchor the original circular genome to the plasma membrane; the copy produced by DNA replication is free-floating. In binary fission, cell division is typically asymmetrical, with one daughter cell appearing much smaller than the other. Tubulin, rather than FtsZ, is responsible for cell division during binary fission. DNA replication during binary fission is a bidirectional process, occurring in opposite directions. None of the answer options is correct.

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

A researcher is studying a population of cells with two major phases. The first phase is relatively short (it lasts approximately one hour), whereas the second stage is much longer (it lasts approximately 12 hours) and is characterized by an increase in the DNA content of cells. This second stage is most likely:

Interphase

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

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

How does meiosis generate genetic diversity?

both crossing over and random alignment at metaphase I

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

Cell cycle checkpoints: act as a brake on cell division if something is not right. provide opportunities to check if the cell has carried out steps necessary for cell division. can involve the protein p53.

All of these choices are correct.

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

Binary Fission

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.

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.

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.

Which of the following statements about viruses are true? Viruses contain multiple genes, and each of these genes is an oncogene. 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. None of the answer options is correct.

None of the answer options is correct.

What would happen if crossing over occurred between sister chromatids?

Nothing would happen because sister chromatids are genetically identical or nearly identical.

In which phase of mitosis does the mitotic spindle form?

Prophase

Replication of DNA in a eukaryote occurs during which phase of the cell cycle?

S phase

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.

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

The cells would be smaller than normal.

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.

How do CDKs promote cell division?

They phosphorylate other proteins

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

actin

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

anaphase II

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

daughter cells are genetically identical