AP Biology Vocabulary & Roots: Ch. 12
1. actin- A globular protein that links into chains, two of which twist helically about each other,
forming microfilaments (actin filaments) in muscle and other kinds of cells.
2. anaphase-The fourth stage of mitosis, in which the chromatids of each chromosome have
separated and the daughter chromosomes are moving to the poles of the cell.
3. anchorage dependence-The requirement that a cell must be attached to a substratum in order to
divide.
4. aster-A radial array of short microtubules that extends from each centrosome toward the plasma
membrane in an animal cell undergoing mitosis.
5. Bacteria-One of two prokaryotic domains, the other being Archaea.
6. benign tumor-A mass of abnormal cells that remains at the site of its origin.
7. binary fission-A method of asexual reproduction by “division in half.” In prokaryotes, binary
fission does not involve mitosis; but in single-celled eukaryotes that undergo binary fission, mitosis
is part of the process.
8. cell cycle-An ordered sequence of events in the life of a cell, from its origin in the division of a
parent cell until its own division into two; the eukaryotic cell cycle is composed of interphase
(including G1, S, and G2 subphases) and M phase (including mitosis and cytokinesis).
9. cell cycle control system-A cyclically operating set of molecules in the eukaryotic cell that both
triggers and coordinates key events in the cell cycle.
10. cell division-The reproduction of cells.
11. cell plate-A double membrane across the midline of a dividing plant cell, between which the
new cell wall forms during cytokinesis.
12. centromere-The specialized region of the chromosome where two sister chromatids are most
closely attached.
13. centrosome-Structure present in the cytoplasm of animal cells, important during cell division;
functions as a microtubule-organizing center. A centrosome has two centrioles.
14. checkpoint-A control point in the cell cycle where stop and go-ahead signals can regulate the
cycle.
15. chromatin-The complex of DNA and proteins that makes up a eukaryotic chromosome. When
the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers
that are not visible with a light microscope.
16. chromosome-A cellular structure carrying genetic material, found in the nucleus of eukaryotic
cells. Each chromosome consists of one very long DNA molecule and associated proteins. (A
bacterial chromosome usually consists of a single circular DNA molecule and associated proteins. It
is found in the nucleoid region, which is not membrane bounded.) See also chromatin.
17. cleavage-(1) The process of cytokinesis in animal cells, characterized by pinching of the plasma
membrane. (2) The succession of rapid cell divisions without significant growth during early
embryonic development that converts the zygote to a ball of cells.
18. cleavage furrow-The first sign of cleavage in an animal cell; a shallow groove in the cell
surface near the old metaphase plate.
19. cyclin-A cellular protein that occurs in a cyclically fluctuating concentration and that plays an
important role in regulating the cell cycle.
20. cyclin-dependent kinase (Cdk)-A protein kinase that is active only when attached to a
particular cyclin.
21. cytokinesis-The division of the cytoplasm to form two separate daughter cells immediately after
mitosis, meiosis I, or meiosis II.
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22. density-dependent inhibition-The phenomenon observed in normal animal cells that causes
them to stop dividing when they come into contact with one another.
23. Down syndrome-A human genetic disease caused by the presence of an extra chromosome 21;
characterized by mental retardation and heart and respiratory defects.
24. G0 phase-A nondividing state occupied by cells that have left the cell cycle.
25. G1 phase-The first gap, or growth phase, of the cell cycle, consisting of the portion of
interphase before DNA synthesis begins.
26. G2 phase-The second gap, or growth phase, of the cell cycle, consisting of the portion of
interphase after DNA synthesis occurs.
27. gamete-A haploid reproductive cell, such as an egg or sperm. Gametes unite during sexual
reproduction to produce a diploid zygote.
28. genome-The genetic material of an organism or virus; the complete complement of an
organism’s or virus’s genes along with its noncoding nucleic acid sequences.
29. growth factor-(1) A protein that must be present in the extracellular environment (culture
medium or animal body) for the growth and normal development of certain types of cells. (2) A
local regulator that acts on nearby cells to stimulate cell proliferation and differentiation.
30. interphase-The period in the cell cycle when the cell is not dividing. During interphase, cellular
metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase.
Interphase accounts for 90% of the cell cycle.
31. kinetochore-A structure of proteins attached to the centromere that links each sister chromatid
to the mitotic spindle.
32. malignant tumor-A cancerous tumor that is invasive enough to impair the functions of one or
more organs.
33. metaphase-The third stage of mitosis, in which the spindle is complete and the chromosomes,
attached to microtubules at their kinetochores, are all aligned at the metaphase plate.
34. metaphase plate-An imaginary plane midway between the two poles of a cell in metaphase on
which the centromeres of all the duplicated chromosomes are located.
35. metastasis-The spread of cancer cells to locations distant from their original site.
36. 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 allocating replicated chromosomes equally to each of the daughter nuclei.
37. mitotic (M) phase-The phase of the cell cycle that includes mitosis and cytokinesis.
38. mitotic spindle-An assemblage of microtubules and associated proteins that is involved in the
movements of chromosomes during mitosis.
39. origin of replication-Site where the replication of a DNA molecule begins, consisting of a
specific sequence of nucleotides.
40. prometaphase-The second stage of mitosis, in which discrete chromosomes consisting of
identical sister chromatids appear, the nuclear envelope fragments, and the spindle microtubules
attach to the kinetochores of the chromosomes.
41. prophase-The first stage of mitosis, in which the chromatin condenses, the mitotic spindle
begins to form, and the nucleolus disappears, but the nucleus remains intact.
42. S phase-The synthesis phase of the cell cycle; the portion of interphase during which DNA is
replicated.
43. sister chromatid-Either of two copies of a duplicated chromosome attached to each other by
proteins at the centromere and, sometimes, along the arms. While joined, two sister chromatids
make up one chromosome; chromatids are eventually separated during mitosis or meiosis II.
44. somatic cell-Any cell in a multicellular organism except a sperm or egg.
45. telophase-The fifth and final stage of mitosis, in which daughter nuclei are forming and
cytokinesis has typically begun.
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46. transformation-(1) The conversion of a normal animal cell to a cancerous cell.
Word Roots
ana- = up, throughout, again (anaphase: the mitotic stage in which the chromatids of each
chromosome have separated and the daughter chromosomes are moving to the poles of the cell)
bi- = two (binary fission: a type of cell division in which a cell divides in half)
centro- = the center; -mere = a part (centromere: the narrow "waist" of a condensed chromosome)
chroma- = colored (chromatin: DNA and the various associated proteins that form eukaryotic
chromosomes)
cyclo- = a circle (cyclin: a regulatory protein whose concentration fluctuates cyclically)
cyto- = cell; -kinet = move (cytokinesis: division of the cytoplasm)
gamet- = a wife or husband (gamete: a haploid egg or sperm cell)
gen- = produce (genome: a cell's endowment of DNA)
inter- = between (interphase: time when a cell metabolizes and performs its various functions)
mal- = bad or evil (malignant tumor: a cancerous tumor that is invasive enough to impair functions
of one or more organs)
meio- = less (meiosis: a variation of cell division that yields daughter cells with half as many
chromosomes as the parent cell)
meta- = between (metaphase: the mitotic stage in which the chromosomes are aligned in the middle
of the cell, at the metaphase plate)
mito- = a thread (mitosis: the division of the nucleus)
pro- = before (prophase: the first mitotic stage in which the chromatin is condensing)
soma- = body (centrosome: a nonmembranous organelle that functions throughout the cell cycle to
organize the cell's microtubules)
telos- = an end (telophase: the final stage of mitosis in which daughter nuclei are forming and
cytokinesis has typically begun)
trans- = across; -form shape (transformation: the process that converts a normal cell into a cancer
cell)
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