Ap Bio Chapters 12-14 For The Final Exam

Front 1

genome

Back 1

the complete complement of an organism's genes

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centromere

Back 2

The centralized region joining two sister chromatids.

Front 3

chromatin

Back 3

The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, it exists as a mass of very long, thin fibers that are not visible with a light microscope.

Front 4

chromosome

Back 4

A threadlike, gene-carrying structure found in the nucleus. Each one consists of one very long DNA molecule and associated proteins.

Front 5

chromosome theory of inheritance

Back 5

A basic principle in biology stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns.

Front 6

cleavage furrow

Back 6

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

Front 7

gametes

Back 7

A haploid cell such as an egg or sperm. They unite during sexual reproduction to produce a diploid zygote.

Front 8

cytokinesis

Back 8

The division of the cytoplasm to form two separate daughter cells immediately after mitosis.

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M phase

Back 9

The mitotic phase of the cell cycle, which includes mitosis and cytokinesis.

Front 10

meiosis

Back 10

A two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell.

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meiosis I

Back 11

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

Front 12

meiosis II

Back 12

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

Front 13

metaphase

Back 13

The third subphase of mitosis, in which the spindle is complete and the chromosomes, attached to microtubules at their kinetochores, are all aligned at the metaphase plate.

Front 14

metaphase plate

Back 14

An imaginary plane during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles.

Front 15

Mitosis

Back 15

A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. It conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei.

Front 16

heredity

Back 16

The transmission of traits from one generation to the next.

Front 17

genetics

Back 17

The scientific study of heredity and hereditary variation.

Front 18

gene

Back 18

A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA, in some viruses).

Front 19

locus

Back 19

plural, loci) A particular place along the length of a certain chromosome where a given gene is located.

Front 20

asexual reproduction

Back 20

A type of reproduction involving only one parent that produces genetically identical offspring by budding or by the division of a single cell or the entire organism into two or more parts.

Front 21

sexual reproduction

Back 21

A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited from the gametes of the two parents.

Front 22

diploid cell

Back 22

A cell containing two sets of chromosomes (2n), one set inherited from each parent.

Front 23

haploid

Back 23

A cell containing only one set of chromosomes (n).

Front 24

M phase

Back 24

The mitotic phase of the cell cycle, which includes mitosis and cytokinesis.

Front 25

meiosis

Back 25

A two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell.

Front 26

meiosis I

Back 26

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

Front 27

meiosis II

Back 27

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

Front 28

metaphase

Back 28

The third subphase of mitosis, in which the spindle is complete and the chromosomes, attached to microtubules at their kinetochores, are all aligned at the metaphase plate.

Front 29

metaphase plate

Back 29

An imaginary plane during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles.

Front 30

Mitosis

Back 30

A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. It conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei.

Front 31

aneuploidy

Back 31

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

Front 32

barr body

Back 32

A dense object lying along the inside of the nuclear envelope in female mammalian cells, representing an inactivated X chromosome.

Front 33

chromosome theory of inheritance

Back 33

A basic principle in biology stating that genes are located on chromosomes and that the behavior of chromosomes during meiosis accounts for inheritance patterns.

Front 34

cytological maps

Back 34

Charts of chromosomes that locate genes with respect to chromosomal features.

Front 35

deletion

Back 35

A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene

Front 36

Down syndrome

Back 36

A human genetic disease resulting from having an extra chromosome 21, characterized by mental retardation and heart and respiratory defects.

Front 37

Duchenne muscular dystrophy

Back 37

A human genetic disease caused by a sex-linked recessive allele; characterized by progressive weakening and a loss of muscle tissue.

Front 38

duplication

Back 38

An aberration in chromosome structure resulting from an error in meiosis or mutagens; duplication of a portion of a chromosome resulting from fusion with a fragment from a homologous chromosome.

Front 39

fragile X syndrome

Back 39

A hereditary mental disorder, partially explained by genomic imprinting and the addition of nucleotides to a triplet repeat near the end of an X chromosome.

Front 40

genetic map

Back 40

An ordered list of genetic loci (genes or other genetic markers) along a chromosome.

Front 41

genetic recombination

Back 41

The general term for the production of offspring with new combinations of traits inherited from the two parents.

Front 42

genomic imprinting

Back 42

The parental effect on gene expression whereby identical alleles have different effects on offspring, depending on whether they arrive in the zygote via the ovum or via the sperm.

Front 43

hemophilia

Back 43

A human genetic disease caused by a sex-linked recessive allele, characterized by excessive bleeding following injury.

Front 44

inversion

Back 44

An aberration in chromosome structure resulting from an error in meiosis or from mutagens; specifically, reattachment of a chromosomal fragment to the chromosome from which the fragment originated, but in a reverse orientation.

Front 45

linkage map

Back 45

A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes. The greater the frequency of recombination between two genetic markers, the farther apart they are assumed to be. See also genetic map.

Front 46

linked genes

Back 46

Genes that are located on the same chromosome.

Front 47

map units

Back 47

A measurement of the distance between genes; one map unit is equivalent to a 1 percent recombination frequency.

Front 48

monosomic

Back 48

A chromosomal condition in which a particular cell has only one copy of a chromosome, instead of the normal two; the cell is said to be monosomic for that chromosome.

Front 49

mosaic

Back 49

A pattern of development in which an organism consists of two sets of cells that differ according to which X chromosome is inactivated.

Front 50

nondisjunction

Back 50

An accident of meiosis or mitosis, in which the members of a pair of homologous chromosomes or sister chromatids fail to move apart properly.

Front 51

parental types

Back 51

Offspring with a phenotype that matches one of the parental phenotypes.

Front 52

recombinant

Back 52

An offspring whose phenotype differs from that of the parents.

Front 53

sex-linked gene

Back 53

A gene located on a sex chromosome.

Front 54

translocation

Back 54

An aberration in chromosome structure resulting from an error in meiosis or from mutagens; specifically, attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport via phloem of food in a plan

Front 55

trisomic

Back 55

A chromosomal condition in which a particular cell has an extra copy of one chromosome, instead of the normal two; the cell is said to be trisomic for that chromosome.

Front 56

wild type

Back 56

An individual with the normal phenotype.

Front 57

alternation of generations

Back 57

A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants.

Front 58

autosome

Back 58

A chromosome that is not directly involved in determining sex, as opposed to a sex chromosome.

Front 59

chiasmata

Back 59

The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis.

Front 60

crossing over

Back 60

The reciprocal exchange of genetic material between nonsister chromatids during synapsis of meiosis I.

Front 61

fertilization

Back 61

The union of haploid gametes to produce a diploid zygote.

Front 62

gamete

Back 62

A haploid cell such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.

Front 63

gametophyte

Back 63

The multicellular haploid form in organisms undergoing alternation of generations that mitotically produces haploid gametes that unite and grow into the sporophyte generation.

Front 64

homologous chromosomes

Back 64

Chromosome pairs of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organism's father, the other from the mother.

Front 65

karyotype

Back 65

A method of organizing the chromosomes of a cell in relation to number, size, and type.

Front 66

life cycle

Back 66

The generation-to-generation sequence of stages in the reproductive history of an organism.

Front 67

meiosis

Back 67

A two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell.

Front 68

meiosis I

Back 68

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

Front 69

meiosis II

Back 69

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

Front 70

recombinant chromosomes

Back 70

Chromosomes created when crossing over combines the DNA from two parents into a single chromosome.

Front 71

sex chromosomes

Back 71

One of the pair of chromosomes responsible for determining the sex of an individual.

Front 72

somatic cell

Back 72

Any cell in a multicellular organism except a sperm or egg cell.

Front 73

spore

Back 73

In the life cycle of a plant or alga undergoing alternation of generations, a meiotically produced haploid cell that divides mitotically, generating a multicellular individual, the gametophyte, without fusing with another cell.

Front 74

synapsis

Back 74

The pairing of replicated homologous chromosomes during prophase I of meiosis.

Front 75

sporophyte

Back 75

The multicellular diploid form in organisms undergoing alternation of generations that results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generation.

Front 76

syngamy

Back 76

The process of cellular union during fertilization.

Front 77

tetrad

Back 77

A paired set of homologous chromosomes, each composed of two sister chromatids. Tetrads form during prophase I of meiosis.

Front 78

variation

Back 78

Differences between members of the same species.

Front 79

zygote

Back 79

The diploid product of the union of haploid gametes in conception; a fertilized egg.

Front 80

MPF (M-phase-promoting factor)

Back 80

A protein complex required for a cell to progress from late interphase to mitosis; the active form consists of cyclin and cdc2, a protein kinase.

Front 81

cyclin

Back 81

A regulatory protein whose concentration fluctuates cyclically.

Front 82

cyclin-dependent kinase (Cdk)

Back 82

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

Front 83

G0phase

Back 83

A nondividing state in which a cell has left the cell cycle.

Front 84

G1 phase

Back 84

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

Front 85

G2 phase

Back 85

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

Front 86

density-dependent inhibition

Back 86

The phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another.

Front 87

anchorage dependence

Back 87

The requirement that to divide, a cell must be attached to the substratum.

Front 88

checkpoint

Back 88

A critical control point in the cell cycle where stop and go-ahead signals can regulate the cycle.

Front 89

codominance

Back 89

A phenotypic situation in which the two alleles affect the phenotype in separate, distinguishable ways.

Front 90

complete dominance

Back 90

A type of inheritance in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable.

Front 91

epistasis

Back 91

A phenomenon in which one gene alters the expression of another gene that is independently inherited.

Front 92

pleiotropy

Back 92

The ability of a single gene to have multiple effects.

Front 93

polygenic inheritance

Back 93

An additive effect of two or more gene loci on a single phenotypic character.

Front 94

incomplete dominance

Back 94

A type of inheritance in which F1 hybrids have an appearance that is intermediate between the phenotypes of the parental varieties.

Front 95

chorionic villus sampling (CVS)

Back 95

A technique for diagnosing genetic and congenital defects in a fetus by removing and analyzing a small sample of the fetal portion of the placenta.

Front 96

amniocentesis

Back 96

A technique for determining genetic abnormalities in a fetus by the presence of certain chemicals or defective fetal cells in the amniotic fluid, obtained by aspiration from a needle inserted into the uterus.