Biology Terms Chapter 11-12

Front 1

cell cycle

Back 1

A series of events from the time a cell forms until its cytoplasm divides.

Front 2

interphase

Back 2

In a eukaryotic cell cycle, the interval between mitotic divisions when a cell enlarges, roughly doubles the number of its cytoplasmic components, and replicates its DNA.

Front 3

mitosis

Back 3

Nuclear division mechanism that maintains the chromosome number. Basis of body growth and tissue repair in multicelled eukaryotes; also asexual reproduction in some plants, animals, fungi, and protists.

Front 4

asexual reproduction

Back 4

Reproductive mode by which offspring arise from a single parent only.

Front 5

homologous chromosomes

Back 5

Chromosomes with the same length, shape, and set of genes.

Front 6

prophase

Back 6

First stage of mitosis during which chromosomes condense and become attached to a newly forming spindle.

Front 7

spindle

Back 7

Dynamically assembled and disassembled network of microtubules that moves chromosomes during nuclear division.

Front 8

metaphase

Back 8

Second stage of mitosis at which the cell's chromosomes are aligned midway between the poles of the spindle.

Front 9

anaphase

Back 9

Third stage of mitosis during which sister chromatids separate and move to opposite spindle poles.

Front 10

telophase

Back 10

Final stage of mitosis during which chromosomes arrive at the spindle poles and decondense, and new nuclei form.

Front 11

cytokinesis

Back 11

Cytoplasmic division.

Front 12

cleavage furrow

Back 12

In a dividing animal cell, the indentation where cytoplasmic division will occur.

Front 13

cell plate

Back 13

After nuclear division in a plant cell, a disk-shaped structure that forms a cross wall between the two new nuclei.

Front 14

telomere

Back 14

Noncoding, repetitive DNA sequence at the end of chromosomes; protects the coding sequences from degradation.

Front 15

sexual reproduction

Back 15

Reproductive mode by which offspring arise from two parents and inherit genes from both.

Front 16

meiosis

Back 16

Nuclear division process that halves the chromosome number. Basis of sexual reproduction.

Front 17

somatic

Back 17

Relating to the body.

Front 18

alleles

Back 18

Forms of a gene with slightly different DNA sequences; may encode slightly different versions of the gene's product.

Front 19

gametes

Back 19

Mature, haploid reproductive cell; e.g., an egg or a sperm

Front 20

germ cells

Back 20

Immature reproductive cell that gives rise to haploid gametes when it divides

Front 21

haploid

Back 21

Having one of each type of chromosome characteristic of the species.

Front 22

zygote

Back 22

Diploid cell formed by fusion of the two gametes; the first cell of a new individual.

Front 23

crossing over

Back 23

Process in which homologous chromosomes exchange corresponding segments during prophase I of meiosis.

Front 24

sporophyte

Back 24

Diploid, spore-producing stage of a plant life cycle.

Front 25

gametophyte

Back 25

A haploid, multicelled body in which gametes form during the life cycle of land plants and some algae.

Front 26

sperm

Back 26

Mature male gamete.

Front 27

egg

Back 27

Mature female gamete, or ovum.