Cell Cycle

S Phase

DNA is replicated at this time of the cell cycle

M Phase

Shortest part of the cell cycle

G0 Phase

Cells that are in a nondividing state are in which phase

Anaphase

In which phase of mitosis do centromeres uncouple, sister chromatids are seperated, and the two new chromosomes move to opposite poles of the cell

Prophase I

Synapsis of homologous pairs occurs; crossing over may occur

Gametes

In animals, somatic cells are produced by mitosis and _________ are produced by meiosis

Anaphase II

In which phase of meiosis does the centromeres of sister chromatids uncouple and chromatids seperate

G0

Nerve and muscle cells are in this phase

12

If the liver cells of an animal have 24 chromosomes, how many chromosomes does its sperm cells have?

Crossing Over

What term belongs with the following words; Synapsis, tetrads, and chiasmata

Prophase I

Crossing over occurs in which phase of meiosis

Centromere

What is the name for the special region on a duplicated chromosome that holds the sister chromatids together

Prophase I

Synapsis occurs

Prophase I

Crossing over occurs

Interphase

DNA replication occurs

Anaphase I

Homologous pairs seperate

Telophase I

Two haploid daughter cells are created

Metaphase II

Chromatids aling along equator (Meiosis)

Anaphase II

Chromatids move to opposite poles (Meiosis)

Telophase II

Daughter cells divide forming four haploid cells

Metaphase I

Homologous chromosomes or tetrads align at the equator

Metaphase I

Spindle fibers attach to tetrads through their kinetochores (Meiosis)

X or Y

Male sex chromosome abnormalities can be due to abnormal numbers of __________chromsomes

Interphase

In which phase each chromosome replicates to produce two sister chromatids

Prophase

Microtubules grow from the poles to kinetochores of each chromatid during what phase

Telophase

The phase of mitosis which is associated with the formation of the nuclear envelope

G1

At the ____checkpoint, cell growth is controlled

Telophase

A nuclear envelope forms around each set of sister chromatids in what phase

G0

Cells that can no longer divide remain in which phase of the cell cycle

G1

The primary growth phase of the cell

G0

The state of most cells in an animal body

Centromere

The structure to which microtubules attach to

Cytokinesis

The pinching off of the cell membrane that creates two new cells (after mitosis) is called

Spindles

What is the name of the microtubule fibers that pull the sister chromatids apart

Centromeres

What is the name of the attachment point between sister chromatids in a chromosome

Centrioles

What is the name of the structures responsible for generating the spindle fibers

M Phase

The spindle forms in what phase

Chromatin Fibers

These include DNA and protein

S Phase

Refers to DNA synthesis during interphase

Cell Plate Formation

Usually begins during telophase in a plant cell

Meiosis

Ensures that genetic recombination occurs with each generation

Mutations

Are the primary source of genetic variation among asexually reproducing organisms

Mitosis

Provides a way to keep the chromosome number constant, generation after generation

Cytokinesis

This process in a plant cell involves the formation of a cell plate

23

The number of chromsomes in a daughter cell after meiosis in humans; ie haploid daughter cells