Biology Chapter 8 Vocab

Front 1

Heredity

Back 1

Biological inheritance; the transmission of characterisitics from parent to offspring through the gametes.

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Genetics

Back 2

Scientific study of heredity

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Sexual reproduction

Back 3

The fusion of gametes followed by meiosis and recombination at some point in the life cycle.

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Meiosis

Back 4

Process of nuclear division in which the chromosome number is reduced from the diploid to the haploid and segregation of the genes occurs; gametes or spores may be produced as a result of meiosis

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Diploid

Back 5

Having two sets of chromosomes; the 2n chromosome number is characteristic of the sporophyte generation

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Haploid

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Having only one set of chromosomes in contrast to diploid.

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Fertilization (also known as ___)

Back 7

Syngamy; fusion of two gamete nuclei to form a diploid zygote.

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Homologous chromosomes (also called ___)

Back 8

Homologs; chromosomes that associate in pairs in the first stage of meiosis; each member of the pair is derived from a different parent.

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Chromatin

Back 9

The deeply staining complex of DNA and proteins that forms eukaryotic chromosomes.

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Histones

Back 10

Group of five basic proteins associated with the chromosomes of all eukaryotic cells.

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Cytokinesis

Back 11

Division of the cytoplasm of a cell following nuclear division.

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Gamete

Back 12

A haploid reproductive cell; gametes fuse in pairs, forming zygotes, which are diploid.

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Synapsis

Back 13

The pairing of homologous chromosomes that occurs prior to the first meiotic division; (crossing-over occurs during synapsis)

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Bivalent

Back 14

Associated pairs of homologous chromosomes

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Crossing-over

Back 15

Results in chromatids that are complete but have a different representation of genes that they had originally.

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Chiasma (chiasmata)

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The X-shaped figure formed by the meeting of two nonsister chromatids of homologous chromosomes; the site of crossing-over.

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Genetic recombination

Back 17

Recombining the genetic material from the two parents

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Allele

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One of two or more alternative forms of the same gene.

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Locus

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same site on homologous chromosomes

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Monohybrid crosses

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Crosses between individuals that differ in a single trait (such as seed color)

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Genotype

Back 21

Genetic constitution, latent or expressed, of an organism, as constrasted with the phenotype; the sum total of all the genes present in an individual

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Homozygous

Back 22

Having identical alleles at the same locus on homologous chromosomes.

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Heterozygous

Back 23

Having two different alleles at teh same locus on homologous chromosomes.

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Principle of segregation

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Hereditary characteristics are determined by discrete factors (genes) that appear in pairs, one of the each pair being inherited from each parent.

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Principle of independent assortment

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Two alleles of a gene assort, or segregate, independently of the alleles of other genes.

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Linkage (also known as ___)

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Genetic; Tendency for certain genes to be inherited together owing to the fact that they are located on the same chromosome.

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Mutations

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Any change in the hereditary state of an organism.

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Mutagens

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An agent that increses the mutation rate.

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Duplication

Back 29

Same chromosome segment occurs twice.

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Plasmid

Back 30

Small circular molecules of DNA separate from the main chromosome.

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Transposons

Back 31

"Jumping genes"; DNA sequence that carries one or more genes and is flanked by sequences of bases that confer the ability to move from one DNA molecule to another; an element capable of transportion, which is the changing of a chromosomal location.

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Chromosome mutation

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Certain groups of plants involve the exchange of parts between two nonhomologous chromosomes to produce...(answer's title).

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Aneuploidy

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Chromosomal aberration in which the chromosome number differs from the normal chromosome number for the species by a small number

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Polypeptide

Back 34

Molecule composed of amino acids linked together by peptide bonds, not as complex as a protein.

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Multiple alleles

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Three or more alleles exist for a given gene.

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Epistasis

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One gene may interfere with or mask the effect of another' "Standing upon"

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Polygenic inheritance

Back 37

Combined effects of multiple genes.

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Continuous Variation

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Variation in traits to which a number of different genes contribute; the variation often exhibits a "normal" or bell-shaped distribution.

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Pleiotropy

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The capacity of a gene to affect more than one phenotypic characteristic.

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Cytoplasmic inheritance

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The inheritance of characteristics under the control of genes located in the cytoplasm (strictly speaking in the plastids and mitochondria).

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Maternal inheritance

Back 41

Inherited characteristics determined solely by the female partner

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Asexual Reproduction

Back 42

Any reproductive process, such as fission or budding, that does not involve the union of gametes.