Biology Chapter 8 Vocab Flashcards
Anaphase
The fourth stage of mitosis, beginning when sister chromatids
separate from each other and ending when a complete set of
daughter chromosomes arrives at each of the two poles of the cell.
Asexual reproduction
The creation of genetically identical offspring
by a single parent, without the participation of sperm and egg.
Autosome
A chromosome not directly involved in determining the sex
of an organism; in mammals, for example, any chromosome other
than X or Y.
Benign tumor
An abnormal mass of cells that remains at its original
site in the body.
Binary fission
A means of asexual reproduction in which a parent
organism, often a single cell, divides into two genetically identical
individuals of about equal size.
Cancer
A disease characterized by the presence of malignant tumors
(rapidly growing and spreading masses of abnormal body cells) in the
body.
Cell cycle
An ordered sequence of events (including interphase and
the mitotic phase) that extends from the time a eukaryotic cell is
first formed from a dividing parent cell until its own division into
two cells.
Cell plate
A double membrane across the midline of a dividing plant
cell, between which the new cell wall forms during cytokinesis.
Centromere
The region of a duplicated chromosome
where two sister chromatids are joined (often appearing as a narrow
“waist”) and where spindle microtubules attach during mitosis and
meiosis. The centromere divides at the onset of anaphase during
mitosis and anaphase II during meiosis.
Clone
As a verb, to produce genetically identical copies of a cell, organism,
or DNA molecule. As a noun, the collection of cells, organisms,
or molecules resulting from cloning; colloquially, a single organism
that is genetically identical to another because it arose from the cloning
of a somatic cell.
Crossing over
The exchange of segments between chromatids of
homologous chromosomes during synapsis in prophase I of meiosis;
also, the exchange of segments between DNA molecules in
prokaryotes.
Cytokinesis
The division of the cytoplasm to form
two separate daughter cells. Cytokinesis usually occurs in conjunction
with telophase of mitosis. Mitosis and cytokinesis make up the
mitotic (M) phase of the cell cycle.
Diploid
In an organism that reproduces sexually, a cell containing two
homologous sets of chromosomes, one set inherited from each parent;
a 2n cell.
Duplication
Repetition of part of a chromosome resulting from fusion
with a fragment from a homologous chromosome; can result from an
error in meiosis or from mutagenesis.
Gamete
A sex cell; a haploid egg or sperm. The union of two
gametes of opposite sex (fertilization) produces a zygote.
Haploid
In the life cycle of an organism that reproduces sexually, a cell
containing a single set of chromosomes; an n cell.
Homologous chromosomes
The two chromosomes
that make up a matched pair in a diploid cell. Homologous
chromosomes are of the same length, centromere position, and
staining pattern and possess genes for the same characters at corresponding
loci. One homologous chromosome is inherited from the
organism’s father, the other from the mother
Interphase
The period in the eukaryotic cell cycle when the cell is not
actually dividing. Interphase constitutes the majority of the time
spent in the cell cycle
Karyotype
A display of micrographs of the metaphase
chromosomes of a cell, arranged by size and centromere position.
Karyotypes may be used to identify certain chromosomal
abnormalities.
Locus
The particular site where a gene is found on a chromosome.
Homologous chromosomes have corresponding gene loci.
Malignant tumor
An abnormal tissue mass that can spread into
neighboring tissue and to other parts of the body; a cancerous tumor.
Meiosis
In a sexually reproducing organism, the division
of a single diploid nucleus into four haploid daughter nuclei. Meiosis
and cytokinesis produce haploid gametes from diploid cells in the
reproductive organs of the parents.
Metaphase
The third stage of mitosis, during which all
the cell’s duplicated chromosomes are lined up at an imaginary plane
equidistant between the poles of the mitotic spindle.
Mitosis
The division of a single nucleus into two genetically
identical nuclei. Mitosis and cytokinesis make up the mitotic
(M) phase of the cell cycle.
Mitotic spindle
A football-shaped structure formed of microtubules
and associated proteins that is involved in the movement of chromosomes
during mitosis and meiosis.
Prophase
The first stage of mitosis, during which the chromatin
condenses to form structures (sister chromatids) visible with a light
microscope and the mitotic spindle begins to form, but the nucleus is
still intact.
Sex chromosome
A chromosome that determines whether an individual
is male or female.
Sister Chromatid
One of the two identical parts of a
duplicated chromosome in a eukaryotic cell. Prior to mitosis, sister
chromatids remain attached to each another at the centromere.
Somatic cell
Any cell in a multicellular organism except a
sperm or egg cell or a cell that develops into a sperm or egg.
Telophase
The fifth and final stage of mitosis, during which daughter
nuclei form at the two poles of a cell. Telophase usually occurs
together with cytokinesis.
Zygote
The diploid fertilized egg, which results from the union
of a sperm cell nucleus and an egg cell nucleus.
