CHP. 9 and 10 HW

Which of the following checkpoints does not occur late in G1?

A check that chromosome replication has been successfully completed

A certain species of animal has six pairs of chromosomes. How many DNA molecules are present in the nuclei of these animals during G2 phase?

24

Are sister chromatids present in all part of this phase?

G1: no S: yes G2: yes

Is the DNA condensed in all or part of this phase?

G1: no S: no G2: no

Does the cell contain twice as much DNA in this phase as it did in the G1 phase?

G1: no S: yes G2: yes

Which of the following best describes the relationship between a chromosome and sister chromatids?

Joined identical copies of a duplicated chromosome are called sister chromatids.

The chromosomes line up in the center of the cell during which phase of mitosis?

Metaphase

The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?

Prophase

The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?

Telophase

What must happen before a cell can begin mitosis?

The chromosomes must be duplicated.

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

After chromosomes condense, the __________(s) is the region where the identical DNA molecules are most tightly attached to each other.

centromere(s)

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

chromatin

At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________.

cytokinesis

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

cytokinesis

There are 12 chromosomes.

false

True or false. Mitosis takes place during M phase of the cell cycle, which is longer than interphase.

false, Mitosis does indeed take place during M phase, but M phase is shorter than interphase; cells spend most of their time in interphase.

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

interphase.

During mitosis, microtubules attach to chromosomes at the

kinetochore(s).

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

mitotic spindle(s)

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

sister chromatid(s)

Each chromatid contains a single molecule of double-stranded DNA.

true

Each chromatid within a chromosome contains the same set of genes.

true

Each chromosome contains both DNA and protein.

true

There are 12 chromatids.

true

This video highlights the duplication and distribution of a single chromosome. Human cells have 46 chromosomes in their nuclei. When considering all 46 chromosomes, how many sister chromatids are there total in a human cell immediately after interphase?

92

The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?

Anaphase