Chapter 11 learning curve

How would the loss of p53 activity affect a cell?

-DNA damage could accumulate. -The G1/S checkpoint would be unregulated. -CDK activity would be altered.

Why are the X and Y chromosomes not considered homologous?

they do not carry the same set of genes

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

true

nondisjunction can occur is mitosis AND in meiosis. T or F

true

Which of the following could be a proto-oncogene?

a gene encoding a cell-surface receptor a gene encoding a protein kinase a gene encoding a growth factor a gene encoding a G-protein

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

actin

In which phase of mitosis do spindle microtubules shorten?

anaphase

Asexual reproduction occurs in:

animal, bacterial, plant, unicellular eukaryotes

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

How does meiosis generate genetic diversity?

both crossing over at prophase I and random alignment of homologs 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 transcription and translation

A phragmoplast functions to:

form a new cell wall.

A malignant cancer differs from a benign tumor in that:

malignant cancers invade surrounding tissue and benign cancers do not.

The assembly of what cytoskeletal structures are initiated by the M cyclin-CDK complex?

microtubules

Cell cycle checkpoints

provide opportunities to check if the cell has carried out steps necessary for cell division. can be blocked by the protein p53. act as a brake on cell division if something is not right.

Reproduction by mitotic cell division:

results in two daughter cells that are genetically identical

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

the cells would be smaller than normal

Mitotic cell division is considered asexual because:

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

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.

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

Daughter cells would not be genetically identical

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

G0

What is the role of the protein FtsZ in prokaryotes?

It forms a ring at the site of constriction.

Which statement regarding the cell cycle is true?

1.) regulated by cyclins and CDKs 2.) different levels of cyclins are observed at different cell cycle stages 3.) it can be "paused" by the action of p53 4.) has many major cell cycle checkpoints

In human cells, at the end of mitosis and after cytokinesis, how many chromatids have moved into each daughter cell?

46

Recall the experiments of Peyton Rous and his colleagues. If he had found that filtered cancer cell extract could not cause cancer when injected into healthy animals, what could he have deduced?

An intact cancer cell is necessary to cause cancer. A large protein may cause cancer. Cancer may be caused by bacteria.

Would genetic recombination result if crossing over occurred between sister chromatids?

No, because sister chromatids are genetically identical or nearly identical

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 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.