Mastering Chapter 12&13

DNA replication produces two identical DNA molecules, called BLANK, which separate during mitosis

sister chromatid(s)

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

chromatin

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

mitotic spindle(s)

The beginning of anaphase is indicated by which of the following?

Cohesin is cleaved enzymatically.

In eukaryotic cells, chromosomes are composed of _____.

DNA and proteins *

Which of the following is found in binary fission but not in mitosis?

Duplicated chromosomes attach to the plasma membrane.

Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle?

G1 *In mammalian cells, this checkpoint is termed the restriction point.

Which of the following correctly matches a phase of the cell cycle with its description? A- G2: cell division B-M: duplication of DNA C-G1: follows cell division D-S: immediately precedes cell division E-All of the above are correctly matched.

G1: follows cell division *After mitosis and cytokinesis, the newly formed daughter cells enter the G1 phase.

Phases of the cell cycle

Many organisms contain cells that do not normally divide. These cells exit the cell cycle before the G1 checkpoint. Once a cell passes the G1 checkpoint, it usually completes the cell cycle--that is, it divides. 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.

How is plant cell cytokinesis different from animal cell cytokinesis?

Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow.

Why do some species employ both mitosis and meiosis, whereas other species use only mitosis?

They need both if they are producing animal gametes. *The form of cell division that produces animal gametes is meiosis, not mitosis. The production of gametes in plants is a function of both mitosis and meiosis.

Which of these phases encompasses all of the stages of mitosis but no other events?

This is mitosis

A cleavage furrow is _____.

a groove in the plasma membrane between daughter nuclei

After chromosomes condense, the BLANK is the region where the identical DNA molecules are most tightly attached to each other

centromere(s)

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

centrosome(s)

In most eukaryotes, division of the nucleus is followed by BLANK, when the rest of the cell divides

cytokinesis

In dividing cells, most of the cell's growth occurs during BLANK

interphase

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

interphase *These are the events of interphase.

During mitosis, microtubules attach to chromosomes at the BLANK

kinetochore(s)

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

the mitotic phase *The mitotic phase encompasses both mitosis and cytokinesis