Ch 12

centrioles

Are located near the nucleus and help to organize cell division.

centrosomes

Areas from which spindle fibers form.

kinetochore motor

kinetochore contains dyneins and other motor proteins. They are attached to the kinetochore's fibrous crown & are capable of "walking" down microtubules from their plus ends near the kinetochore toward their minus ends at the spindle.

meiosis

(genetics) cell division that produces reproductive cells in sexually reproducing organisms

replication

(genetics) the process whereby DNA makes a copy of itself before cell division

prometaphase

2nd stage of mitosis. Nuclear envelope breaks and vanishes. Spindles reaches chromosomes (now short and fat). Proteins connected to sister chromatids move them toward cell center.

anaphase

3rd phase; the chromatids of each chromosome separate at the centromere and move in opposite

malignant tumor

A CANCEROUS tumor that is invasive enough to impair the functions of one or more organs.

mitosis promoting factor

A complex of a cyclin and cyclin-dependent kinase that phosphorylates a number of specific proteins needed to initiate mitosis in eukaryotic cells.

MPF

A cyclin-Cdk complex that causes the cell to move from interphase into mitosis

cell plate

A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis.

binary fission

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

cyclins

A group of proteins whose function is to regulate the progression of a cell through the cell cycle and whose concentrations rise and fall throughout the cell cycle

gametes

A haploid cell such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.

microtubules

A hollow rod of tubulin protein in the cytoplasm of all eukaryotic cells and in cilia, flagella, and the cytoskeleton

benign tumor

A mass of abnormal cells that remains at the site of origin

mitosis

A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei.

asexual reproduction

A reproductive process that involves only one parent and produces offspring that are identical to the parent.

dynein

A special motor protein that moves along the microtubule toward the negative end; responsible for rentrograde axoplasmic transport

centromere

A specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape.

kinetochore

A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle.

tumor

A swelling; an abnormal cell mass resulting from excessive multiplication of cells, varying in size, shape, and color.

telophase

After the chromosome separates, the cell seals off, Final Phase of Mitosis.

mitotic spindle

An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.

protein kinase

An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein.

metaphase plate

An imaginary plane during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles

cell cycle

An ordered sequence of events in the life of a eukaryotic cell, from its origin in the division of a parent cell until its own division into two.

somatic cells

Basically, all the cells in the body except those involved with reproduction.

chromosome

Bodies within the nucleus made in DNA and proteins called the histones

interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

prophase

Centrioles move away from each other pushed towards separate ends, Nuclear membrane disintegrates,. chromatin form chromosomes Longest phase

metaphase

Centromeres of duplicated chromosomes are aligned at plate. Fully formed spindle attach to the sister chromatids from opposite poles

chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

Cdk

Cyclin-dependent kinases. A protein kinase that is active only when attached to a particular cyclin. Activity rises and falls depending on the concentration of the cyclin partner.

cytokinesis

Division of the cytoplasm during cell division

cytokinesis

Division of the cytoplasm following mitosis and meiosis

chromatid

Each half of the chromosome

spindle fibers

Fibers that appear during mitosis. Chromosomes attach to the spindle fibers at the centromere and move back and forth between the poles on the fibers.

gap phases

G1, S or DNA synthesis and G2 - during these phases the cell grows larger and protein synthesis occurs and additional organelles are produced

cell cycle checkpoint

G1/S- checks for DNA damage to ensure faithful replication, G2/M- checks for proper replication, spindle- spindles are properly attached to chromosome to ensure accurate segregation; signals in cytoplasm

G2 phase

Gap 2 phase of the eukaryotic cell cycle, between the end of DNA synthesis and the beginning of mitosis

tumor suppressor

Genes that code for proteins that monitor and check cell cycle progression. When these genes mutate, tumor suppressor proteins lose normal function

histones

Globular protein that assist in DNA packaging in eukaryotes. Histones form octamers around which DNA is wound to form a nucleosome.

metastasis

Invasive growth of cancer cells from the original tumor into distant areas - secondary tumor

S (synthesis) phase

Phase in which the cell synthesizes a replica of the genome

cell division

Process by which a cell divides into two new daughter cells

sister chromatids

Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II.

M (mitosis) phase

The _____ phase involves actual cell division, which produces two identical daughter cells and is sub-divided into prophase, metaphase, anaphase, and telophase

cleavage furrow

The area of the cell membrane that pinches in and eventually separates the dividing cell

daughter cell

The cells that are produced as a result of mitosis. These cells are identical to each other, and also to the original parent cell.

protein phosphorylation

The covalent addition of phosphate group to a side chain of a protein catalyzed by a protein kinase. phosphorylation usually alters the activity or properties of the protein in some way.

p53

______ - This tumor suppressor gene causes cell cycle arrest in G1, providing time for DNA repair. If repair is successful, cells re-enter the cycle. If unsuccessful, apoptosis

oocyte

egg

growth factors

regulatory proteins that ensure that the events of cell division occur in the proper sequence and at the correct rate

G1 phase

the first gap phase of interphase where the cells do most of their growing, cells increase in size and make new proteins and organelles