Chapter 12

During _____ the cell grows and replicates both its organelles and its chromosomes.

interphase

Nucleoli are present during _____.

interphase

During mitosis, microtubules attach to chromosomes at the ____

kinetochore (s)

During prophase, the microtubules of the mitotic spindle ____

lengthen

During anaphase, the nonkinetochore microtubules _____and move past each other, and the kinetochore microtubules ____

lengthen; shorten

During which stage of mitosis are chromosomes lined up in the center of the cell?

metaphase

During _____ both the contents of the nucleus and the cytoplasm are divided.

the mitotic cycle

Eukaryote has:

- Before separation, duplicated chromosomes condense. - Two copies of the duplicated chromosome are attached at their centromeres before separating. - Nuclear envelope fragments, permitting chromosome separation. - Replicated chromosomes separate by attaching to some other structural feature of the cell. - Chromosomes replicate before cell division.

Bacteria has: Chromosome separation begins at the origin of replication on DNA.

- Chromosome separation begins at the origin of replication on DNA. - Replicated chromosomes separate by attaching to some other structural feature of the cell. - Chromosomes replicate before cell division.

Phases of interphase:

- The first step in preparing for division is to replicate the cell's DNA in the S phase. - In the G2 phase, the centrosome replicates. - In early M phase, the centrosomes move away from each other toward the poles of the cell, in the process organizing the formation of the mitotic spindle. - At the end of the M phase when mitosis is complete, the cell divides (cytokinesis), forming two genetically identical daughter cells.

Cell plate:

- Vesicles from the Golgi apparatus move along microtubules, coalesce at the plane of cell division, and form a cell plate. - The cell plate consists of the plasma membrane and cell wall that will eventually separate the two daughter cells.

T/F: For Bacteria, animals, and plants: - The presence of a cell wall prevents the cell from dividing by constriction

Bacteria & animals = false Plants = True

T/F: For Bacteria, animals, and plants: - Cells divide by constriction of a ring of protein

Bacteria & animals = true. Plants = false

To which part of the centromere do mitotic spindle fibers attach during prometaphase?

Kinetochore

Which stage of mitosis is characterized by the disintegration of mitotic spindles and the formation of two new nuclear membranes?

Telophase

If the motor proteins were blocked in the kinetochore: 1) Will this cell elongate during mitosis? 2) Will the sister chromatids separate from each other? 3) Will the chromosomes move to the poles of the cell?

1) Yes 2) Yes 3) No

T/F: For Bacteria, animals, and plants: - Tubulin or tubulin like molecules function in binary fission (in bacteria) or cytokinesis (in animals and plants)

Bacteria and plants = true Animals = false

What two types of movement are responsible for separating sister chromatids during anaphase?

Kinetochore microtubules that depolymerize at the kinetochore proteins and polar microtubules that overlap and lengthen the cell.

What is the difference between a chromatid and a chromosome?

A chromatid is one half of a replicated chromosome, whereas a chromosome consists of DNA wrapped around proteins in a highly organized manner.

In which mitotic phase are the sister chromatids separated and pulled to opposite poles?

Anaphase

What two types of defects does a cancerous cell possess?

Cancerous cells possess defects that make proteins required for cell growth active and tumor suppressor genes inactive.

Two important checkpoints that regulate the cell's progression through the cell cycle occur in the _____ and _____ phases of the cell cycle.

G1;G2

Spindle fibers attach to kinetochores during _____.

Prometaphase

What role(s) do gap phases play in the cell cycle?

They allow cells to replicate organelles and manufacture additional cytoplasm

Which answer correctly identifies a cell-cycle checkpoint with a criterion for passing it? a) G2 checkpoint: Chromosomes have replicated successfully. b) G1 checkpoint: Chromosomes have replicated successfully. c) S checkpoint: DNA is undamaged. d) Metaphase checkpoint: DNA is undamaged.

a) G2 checkpoint: Chromosomes have replicated successfully.

Centromeres divide and sister chromatids become full-fledged chromosomes during _____.

anaphase

The ____ are the organizing centers for microtubules involved in separating chromosomes during mitosis.

centrosome(s)

During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called _____

chromtin

The division of the cytoplasm following mitosis is called _____

cytokinesis

Which statement is correct concerning the relationship between chromosomes and either genes, chromatin, or sister chromatids? a) Genes are the DNA-protein material that makes up entire chromosomes. b) Chromatin is a length of DNA in a chromosome that codes for a protein or RNA. c) Each unreplicated chromosome consists of two sister chromatids. d) Each replicated chromosome consists of two sister chromatids.

d) Each replicated chromosome consists of two sister chromatids.

During telophase, the nonkinetochore microtubules ____

disassemble

The _____ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.

mitotic spindle(s)

In which mitotic phase do the chromosomes condense and does the mitotic spindle begin to form?

prophase