Ch. 11 Learning Curve

Which of the following is not a step in the process of binary fission?

rearrangement of the microtubule cytoskeleton

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

proto-oncogene

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

Cytokinesis

Muscle cells 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.

Imagine that 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 (lasting approximately 12 hours) and is characterized by an increase in the DNA content of cells. This second stage is most likely:

Interphase

The following statements regarding the cell cycle are true:

It has three 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.

Which of the following is not true regarding the protein CDK?

The levels of CDK change with the cell cycle.

Evidence exists (especially in dinoflagellates) that mitosis actually 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

Some types of leukemia are the result of constitutively active (i.e., "always on") growth factor receptors.

True

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

True

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

a contractile ring can't pinch a cell wall

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

away from the centrosome, at the kinetochore

Why are the sex chromosomes not considered homologous?

because they do not carry the same collection of genes, and because males carry two very different chromosomes

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

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

cytokinesis

When in the cell cycle would you find sister chromatids?

S and G2

How many chromosome pairs are there in a human genome>

23

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

46

A gene associated with promoting normal cell division is called:

A proto-oncogene

A cell that is not actively dividing is in what phase of the cell cycle?

G0

In which phase of mitosis do microtubules shorten?

Anaphase

When do sister chromatids separate in meiosis?

Anaphase II

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

Binary Fission

Binary fission:

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

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

Daughter cells are genetically indentical.

What would happen if crossing over occurred as part of mitosis?

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

A zygote is:

Diploid

A human cell with a total of 23 chromosomes would be considered:

Haploid

What is the role of the protein FtsZ?

It forms a ring at the site of constriction

In which place of mitosis do chromosomes line up at the middle of the cell?

Metaphase

What cytoskeletal protein is important to the function of the sperm cells

Microtubules

What cytoskeletal protein is important to the function of the sperm cells?

Microtubules

What would happen to the daughter cells if the G1 phase of the parent cell is shortened?

The cells would be smaller than normal.

How do new cyclin proteins appear in the cytoplasm?

They are made through protein synthesis.

What is a cyclin?

a protein that activates kinases and whose levels change with the cell cycle

In which phase of mitosis do sister chromatids separate?

anaphase

A phragmoplast functions to:

form a new cell wall

Polar bodies are:

haploid cells

Another name for non-sister chromatids is:

homologous chromosomes

What motor proteins are responsible for the activity of the contractile ring during cytokinesis in animal cells?

myosin

Synapsis is best described as:

the alignment of homologous chromosomes in prophase I.

What do the colors in in the human karyotype figure likely represent?

the presence of different genes along the length of DNA.

What is the function of histone proteins?

to organize DNA in eukaryotic chromosomes

The S cyclin-CDK complex:

assures that DNA is not replicated multiple times

How does CDK promote cell division?

It phosphorylates other proteins.

Why would a compound that interferes with bacterial cell wall synthesis be useful for the treatment of an infection?

It would limit the spread of the infection.

In order for a malignant cancer to metastasize, it must:

Lose its connections to adjacent cells Lose its connections to the extracellular matrix Become motile

Which checkpoint would become active if a chromosome was not properly aligned on the spindle?

M phase checkpoint

The division of genetic material in a eukaryotic cell is called:

Mitosis

Which of the following statements regarding tumor suppressors are true?

Mutations affecting tumor suppressors can contribute to the development of cancers.

What would happen if crossing over occurred between sister chromatids?

Nothing, sister chromatids are identical.

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.

A proto-oncogene is a "normal" gene that, if mutated, can become an oncogene and lead to a cell becoming cancerous.

True

In which phase of mitosis do chromosomes condense?

Prophase

Crossing over occurs during which step in meiosis?

Prophase I

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

S Phase

The development of a cancer requires both the _______ of an oncogene and the ________ of a tumor suppressor.

activation; inhibition

Mitotic cell division is considered asexual because:

the daughter cells receive DNA from one parent cell, and the daughter cells are genetically identical.