Biology Chapter 8 Penn Foster

Front 1

anaphase

Back 1

mitotic phase during which daughter chromosomes move toward the poles of the spindle

Front 2

angiogenesis

Back 2

formation of new blood vessels; one mechanism by which cancer spreads

Front 3

apoptosis

Back 3

programmed cell death involving a cascade of specific cellular events leading to death and destruction of the cell

Front 4

aster

Back 4

short, radiating fibers produced by the centrosomes in animal cells

Front 5

cancer

Back 5

malignant tumor whose nondifferentiated cells exhibit loss of contact inhibition, uncontrolled growth, and the ability to invade tissue and metastasize

Front 6

carcinogenesis

Back 6

development of cancer

Front 7

cell cycle

Back 7

repeating sequence of events in eukaryotes that involves cell growth and nuclear division; consists of the stages G1, S, G2, and M

Front 8

cell plate

Back 8

structure across a dividing plant cell that signals the location of new plasma membranes and cell walls

Front 9

centromere

Back 9

constricted region that holds together sister chromatids

Front 10

centrosome

Back 10

central microtubule organizing center of cells. In animal cells, it contains two centrioles

Front 11

checkpoint

Back 11

in the cell cycle, one of several points where the cell cycle can stop or continue on, depending on the internal signal it receives; ensures that each step of the cell cycle is completed before the next one begins

Front 12

chromatin

Back 12

network of fibrils consisting of DNA and associated proteins observed within a nucleus that is not dividing

Front 13

chromosome

Back 13

structure consisting of DNA complexed with proteins that transmits genetic information from the previous generation of cells and organisms to thet next generation

Front 14

contact inhibition

Back 14

in cell culture, the point where cells stop dividing when they become a one-cell-thick sheet

Front 15

cyclin

Back 15

protein that cycles in quantity as the cell cycle progresses; combines with and activates the kinases that function to promote the events of the cycle

Front 16

cytokinesis

Back 16

division of the cytoplasm following mitosis and meiosis

Front 17

DNA replication

Back 17

synthesis of a new DNA double helix prior to mitosis and meiosis in eukaryotic cells and during prokaryotic fission in prokaryotic cells

Front 18

histone

Back 18

protein molecule responsible for packing chromatin

Front 19

interphase

Back 19

stages of the cell cycle (G1, S, G2) during which growth and DNA synthesis occur when the nucleus is not actively dividing

Front 20

kinase

Back 20

enzyme that activates another enzyme by adding a phosphate group

Front 21

metaphase

Back 21

mitotic phase during which chromosomes are aligned at the spindle equator

Front 22

metastasis

Back 22

spread of cancer from the place of origiin throughout the body; caused by the ability of cancer cells to migrate and invade tissues

Front 23

mitosis

Back 23

process in which a parent nucleus produces two daughter nuclei, each having the same number and kinds of chromosomes as the parent nucleus

Front 24

nucleosome

Back 24

in the nucleus of a eukaryotic cell, a unit composed of DNA wound around a core of 8 histone proteins, giving the appearance of a string of beads

Front 25

prophase

Back 25

mitotic phase during which chromatin condenses so that chromosomes appear; chromosomes are scattered

Front 26

signal

Back 26

molecule that stimulates or inhibits an event in the cell cycle

Front 27

sister chromatid

Back 27

1 of 2 genetically identical chromosomal units that are the result of DNA replication and are attached to each other at the centromere

Front 28

somatic cell

Back 28

body cell; exlcudes cells that undergo meiosis and become sperm or egg

Front 29

spindle

Back 29

microtubule structure that brings about chromosomal movement during nuclear division

Front 30

spindle equator

Back 30

disk formed during metaphase in which all of a cell's chromosomes lie in a single plane at right angles to the spindle fibers

Front 31

telomere

Back 31

long, repeating DNA sequence at the ends of chromosomes; functions like a cap and keeps chromosomes from fusing with each other

Front 32

telophase

Back 32

mitotic phase during which daughter cells are located at each pole

Front 33

tumor

Back 33

cells derived from a single mutated cell that has repeatedly undergone cell division; benign tumors remain at the site of origin, while malignant tumors metastasize