Biology Chapter 8

Front 1

Cell Division

Back 1

When a cell undergoes reproduction.(2) the reproduction of a cell through duplication of the genome and division of the cytoplasm.

Front 2

Chromosomes

Back 2

The structures that contain most of the cells DNA.(2) A threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell and most visible during mitosis and meiosis;also, the main gene-carrying structure of a prokaryotic cell. A chromosome consists of one wery long piece of chromatin, a combination of DNA and protien.

Front 3

Asexual Reproduction

Back 3

The creation of genetically identical offspring by a single parent.

Front 4

Sexual Reproduction

Back 4

Requires fertilization of an egg by a sperm.

Front 5

Chromatin

Back 5

Fibers composed of roughly equal amounts of DNA and protein molecules.

Front 6

Sister Chromatids

Back 6

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.

Front 7

Centromere

Back 7

The region of a duplicated chromosome where two sister chromatids are joined.

Front 8

Cell Cycle

Back 8

An ordered sequence of events that extends from the time a cell is first formed from a dividing parent cell until it's own division into two cells.

Front 9

Interphase

Back 9

This is a time when a cell's metabolic activity is very high and the cell performs it's various functions within the organism.

Front 10

Miotic Phase

Back 10

The part of the cell cycle when the cell actually divides.

Front 11

Mitosis

Back 11

The nucleus and it's contents divide and are evenly distributed forming two daughter nuclei.

Front 12

Cytokinesis

Back 12

The cytoplasm is divided into two.

Front 13

Interphase

Back 13

The period of cell growth, when the cell synthesizes new molecules and organelles.

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Prophase

Back 14

Changes occur in both the nucleus and the cytoplasm

Front 15

Prometphase

Back 15

The nuclear envelope breaks into fragments and disappears

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Metaphase

Back 16

The miotic spindle is fully formed

Front 17

Anaphase

Back 17

When the two centromeres of each chromosome come apart.

Front 18

Telophase

Back 18

The cell elongation that started in the Anaphase continues

Front 19

Miotic Spindle

Back 19

A football shaped structure of microtubules that guides the separation of the two sets of daughter chromosomes.

Front 20

Centrosomes

Back 20

(1)Clouds of cytoplasmic material that in animal cells contain pairs of centrioles. (2) Material in the cytoplasm of a eukaryotic cell that gives rise to microtubules; important in mitosis and meiosis; also called the microtubule-organising center.

Front 21

Cell Cycle Control System

Back 21

A cyclically operation set of molecules in the cell that both triggers and coordinates key events in the cell cycle.

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Tumor

Back 22

An abnormally growing mass of body cells.

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Benign Tumor

Back 23

Abnormal cells that remain at the original site.

Front 24

Malignant Tumor

Back 24

An abnormal tissue mass that can spread into neighboring tissue and to other parts of the body.

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Metastasis

Back 25

The spread of cancer cells beyond their original site.

Front 26

Carcinomas

Back 26

Cancers that originate in the originate in the external or internal coverings of the body.

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Sarcomas

Back 27

Arise in tissues that support the body

Front 28

Leukemias and Lymphomas

Back 28

Cancers of blood-forming tissues, such as bone marrow, spleen, and lymph nodes.

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Somatic Cell

Back 29

A typical body cell that has 46 chromosomes.

Front 30

Homologous Chromosomes

Back 30

The two chromosomes that make up a matched pair in a diploid cell.

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Locus

Back 31

The particular site where a gene is found on a chromosome.

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Sex Chromosomes

Back 32

What determines an individuals sex.

Front 33

Autosomes

Back 33

The 22 remaining chromosomes foind in both males and females.

Front 34

Life Cycle

Back 34

The sequence of stages leading from the adults of one generation to the adults of the next.

Front 35

Diploid

Back 35

A cell containing two homologous sets of chromosomes.(2) In an organism that reproduces sexually, a cell containing two homologous sets of chromosomes, one set inherited from each parent; a 2n cell.

Front 36

Gametes

Back 36

Egg and sperm cells.

Front 37

Haploid

Back 37

A cell with a single chromosome set.(2) In the life cycle of an organism that reproduces sexually, a cell containing a single set of chromosomes; a n cell.

Front 38

Fertilization

Back 38

When a haploid cell from the father fuses with a haploid cell from the mother.

Front 39

Zygote

Back 39

A fertilized egg.

Front 40

Alleles

Back 40

The alternative versions of a gene

Front 41

Meiosis

Back 41

A type of cell division that produces haploid gametes in diploid organisms.

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Crossing over

Back 42

An exchange of corresponding segmentsbetween nonsister chromatids of homologous chromosomes,

Front 43

Chiasma

Back 43

The microscopially visible site where crossing over has occured between chromatids of homologous chromosomes during prophase I of meiosis.

Front 44

Tetrad

Back 44

A paired set of homologous chromosomes, each composed of two sister chromatids. Tetradsform during prophase I of meiosis,when crossing over may occur.

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Genetic recombination

Back 45

The production, by crossing over and/or independent assortment of chromosomes during meiosis, of offspring with allele combinations different from those in the parents. The term also may be used more specifically to mean the production by crossing over of eukaryotic or prokaryotic chromosomes with gene combinations different from those in the original chromosomes.

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Karotype

Back 46

A display of micrographs of the metaphase chrosomes of a cell, arranged by size and centromere position. Karotypes may be used to identify certain chromosomal abnormalities.

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Trisomy 21

Back 47

See Down syndrome

Front 48

Down Syndrome

Back 48

A human genetic disorder resulting from the presence of an extra chromosome 21; characterized by heart and respiratory defects and varying degrees of mental retardation.

Front 49

Nondisjunction

Back 49

An accident of meiosis or mitosis in which a pair of homologous chromosomes or a pair of sister chromatids fail to seperate at anaphase.

Front 50

Polypoid

Back 50

Am organism that has more than two complete sets of chromosomes as a result of an accident of cell division.

Front 51

Deletion

Back 51

The loss of one or more nucleotides from a gene by mutation; the loss of a fragment of a chromosome.

Front 52

Duplication

Back 52

Repetition of part of a chromosome resulting from fusion with a fragment from homologous chromosome; can result from an error in meiosis or from mutagenesis.

Front 53

Inversion

Back 53

A change in a chromosome resulting from reattachment of a chromosome fragment to the original chromosome, but in a reverse direction. Mutagens and errors during meiosis can cause inversions.

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Translocation

Back 54

(1) During protien synthesis,the movement of a tRNA molecule carrying a growing polypeptide chain from the A site to the P site on a ribosome.(The mRNA travels with it.) (2) A change in a chromosonoe resulting from a chromosomal fragment attaching to a nonhomologous chromosome; can occur as a result of an error in meiosis or from mutagenesis

Front 55

Mutagen

Back 55

A chemical or physical agent that interacts with DNA and causes a mutation.