BSC2010 - Chapter 16 Vocabulary

cell division

Process by which a cell divides into two new daughter cells

cell cycle

The regular sequence of growth and division that cells undergo

karyotype

A picture of all the chromosomes in a cell arranged in pairs

sister chromatids

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

sex chromosomes

Chromosomes that determine the sex of an individual

autosomes

Any chromosome that is not a sex chromosome

diploid

2 sets of chromosomes

haploid

having a single set of unpaired chromosomes

homologs

Members of a pair of chromosomes

interphase

period of the cell cycle between cell divisions

G1 phase

The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

G2 phase

The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

M phase

mitosis and cytokinesis

mitosis

part of eukaryotic cell division during which the cell nucleus divides

cytokinesis

division of the cytoplasm

cyclins

proteins that regulate the cell cycle

cyclin-dependent kinases (Cdks)

A protein kinase that is active only when attached to a particular cyclin.

checkpoints

3 points where regulatory proteins (enzymes) determine if cell is ready to proceed in cell cycle

asexual reproduction

Process by which a single parent reproduces by itself

centromere

Region of a chromosome where the two sister chromatids attach

kinetochore

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

mitotic spindle

a structure made of microtubules that controls chromosome movement during mitosis

Kinetochore Spindle Fibers

attach to kinetochores on the surface of centromeres and pull chromosomes

polar spindle fibers

spindle fibers that extend beyond midpoint of cell

push cell poles apart

astral spindle fibers

spindle fibers that grow toward plasma membrane

prophase

Chromosomes become visible, nuclear envelop dissolves, spindle forms

prometaphase

The second stage of mitosis, in which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the chromosomes.

metaphase

Chromosomes line up in the middle of the cell

metaphase plate

An imaginary structure located at a plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located.

anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

telophase

the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.

cleavage furrow

The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.

cell plate

In a plant cell, midline of dividing cells. Becomes the cell wall eventually.

meiosis

Cell division that produces reproductive cells in sexually reproducing organisms

bivalent or tetrad

homologous replicated chromosomes that are joined together during prophase I and metaphase I of meiosis

synapsis

Pairing of homologous chromosomes

crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

meiosis I

The first division of a two-stage process of cell division in sexually reproducing organisms that results in cells with half the number of chromosome sets as the original cell.

meiosis II

the second phase of meiosis consisting of chromatids separating, along with the two diploid cells splitting in two

sexual reproduction

A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents

metacentric

centromere in middle

submetacentric

centromere slightly off center

acrocentric

centromere close to end

telocentric

centromere at end

deletion

A change to a chromosome in which a fragment of the chromosome is removed.

duplication

change to a chromosome in which part of the chromosome is repeated

inversion

change to a chromosome in which genes are in reverse order

translocation

Change to a chromosome in which a fragment of one chromosome attaches to a nonhomologous chromosome.

euploid

normal number of chromosomes

polyploid

condition in which an organism has extra sets of chromosomes

triploid

A chromosomal mutation where an organism has three sets of chromosomes (3n) instead of two (2n)

aneuploidy

A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number.

nondisjunction

Error in meiosis in which homologous chromosomes fail to separate.

Trisomy

a condition in which an extra copy of a chromosome is present in the cell nuclei, causing developmental abnormalities.

Monosomy

Chromosomal abnormality consisting of the absence of one chromosome from the normal diploid number