Cell Reproduction -USBT

Chromosomes

rod-shaped structures made of DNA and proteins are

Histones

the DNA in eukaryotic cells wraps tightly around proteins called

Chromatid

one of the two strands of a chromosome; that becomes visible during meiosis or mitosis

Centromere

the region of the chromosome that holds the two sister chromatids together during mitosis

Chromatin

the material that makes up both mitotic and interphase chromosomes; a complex of protiens and DNA strands

Sex Chromosomes

chrosomes that determine the sex of an organism, and they may also carry genes for other characteristics

Autosomes

all of the other chromosomes in an organism

Homologous Chromosomes

two copies of each autosome

Karyotype

photomicrograph of the chromosomes in a normal dividing cell found in a human

Diploid

cells having two sets of chromosomes; cells that have two autosomes for each homologous pair

Haploid

sperm cells and egg cells; contains only one set of chromosomes

Binary Fission

the division of a prokaryotic cell into two offspring cell

cell's chromosome

new cells contain one identical chromosome that resulted from the copying of the original...

eukaryotic

in what cell division, does both the cytoplasm and nucleus divide

Mitosis

new cells with genetic material that is identical to the genetic material, of the original cell

reproduction of unicellular organisms

Mitosis occurs in what?

Asexual Reproduction

the production of the offspring from the one parent

Meiosis

occurs during the formation of gametes

Cell cycle

the repeating set of events that make up the life of a cell

Gametes

haploid reproductive cells

Interphase

the time between cell division

M phase

nucleus of a cell divides

Cytokenisis

the division of the cells cytoplasm

interphase

Cells spend most of lifetime in...

G1

(first stage of interphase) offspring cells grow to mature size

S phase

(next phase of interphase) cell's DNA is copied

G2 phase

time during which cell prepares for cell division

G0

(cells exit G1 and go here) do not copy DNA or prepare for cell division

prophase, metaphase, anaphase, and telophase

4 phases of mitosis

Prophase

the first phase of mitosis

Centrosomes

two pairs of dark spots

Spindle Fibers

the microtubules radiate from the centrosomes in preparation for metaphase.

Mitotic Spindle

equally divide the chromatids between offspring cells during cell division

Polar Fibers

extend across dividing cell, centrosome to centrosome

Metaphase

the second phase of mitosis

Anaphase

the chromatid of each chromosome separate at the centromere and slowly move

Telophase

spindle fibers disassemble and the chromosomes return to a less tightly coiled chromatin state

Cleavage furrow

separates the dividing cell into two cells

Cell Plate

when vesticles from the golgi apparatus join together at the middle of the dividing cell plate to form

Meiosis I and II

stages of the first cell division

Synapis

the pairing of homolgous chromosomes, which does not occur in mitosis

Tetrad

each pair of homologous chromosome that occurs during prophase I

Crossing-Over

portions of chromatids may break off and attach to adjacent chromatids on homologous chromosome

Genetic Recombination

material between maternal and paternal chromosomes exchange places

Independent Assortment

random separation of the homologous chromosome

Metaphase I

tetrads line up randomly along the middle of the dividing cell

Anaphase I

each homologous chromosome moves to an opposite pole of the dividing cell

Telophase I

the chromosomes reach the opposite ends of the cell, and cytokinesis begins

Meiosis I

the original divides and the cell produces two new cells when creating gametes. The first division.

homologous pair

Each new cell contains one chromosome from each...

DNA

Meiosis II occurs in each cell formed during meiosis I and is not preceded by the copying of...

Prophase II

During what, spindle fibers form and to move the chromosomes toward the midline of the dividing cell

Metaphase II

the chromosomes move to the midline of the dividing cell, facing opposite poles of the dividing cell

anaphase II

chromatids separate and move toward opposite poles of the cell

telophase II

a nuclear membrane forms around the chromosomes in each of the four new cells

Cytokinesis II

what occurs during telophase II resulting in four new cells, each of which contains half of the original cell's number of chromosomes

testes and in the ovaries

In humans, meiosis occurs in the...

Spermatogenesis

the production of sperm cells

Oogenesis

the production of mature eggs or ova

cytokinesis I and II of oogenesis

The cytoplasm of the original cell is divided unequally between new cells

Polar Bodies

the other three products of meiosis; eventually degenerate or break down

Sexual Reproduction

production of offspring through meiosis and the union of a sperm and an egg