Anth203 Chapter 3 Vocabulary

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prokaryotes

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Single-celled organisms with no nuclear membranes or organelles and with their genetic material as a single strand in the cytoplasm

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eukaryotes

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Multicelled organisms that have a membrane-bound nucleus containing both the genetic material and specialized organelles

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nucleus

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A membrane-bound structure in eukaryotic cells that contains the genetic material

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cytoplasm

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The jelly-like substance inside the cell membrane that surrounds the nucleus and in which the organelles are suspended

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somatic cells

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Diploid cells that form the organs, tissues, and other parts of an organism's body

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gametes

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Sexual reproductive cells, ova and sperm, that have a haploid number of chromosomes and that can unite with a gamete of the opposite type to form a new organism

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genome

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The complete set of genetic information- chromosomal and mitochrondrial DNA- for an organism or species that represents all the inheritable traits

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homoplasmic

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Refers to nuclear DNA, which is identical in the nucleus of each cell type (except red blood cells)

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mitochondria

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Energy-producing (ATP) organelles in eukaryotic cells; they possess their own independent DNA

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adenosine triphosphate (ATP)

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An important cellular molecule, created by the mitochrondria and carrying the energy necessary for cellular functions

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matriline

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DNA, such as mitochondrial DNA, whose inheritance can be traced from mother to daughter or to son

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heteroplasmic

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Refers to a mixture of more than one type of organellar DNA, such as mitochondrial DNA, within a cell or a single organism's body, usually due to the mutation of the DNA in some organelles but not in others

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replication

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The process of copying nuclear DNA prior to cell division, so that each new daughter cell receives a complete complement of DNA

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mitosis

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The process of cellular and nuclear divison that creates two identical diploid daughter cells

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meiosis

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The production of gametes through one DNA replication and two cell (and nuclear) divisions, creating four haploid gametic cells

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free-floating nucleotides

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Nucleotide (the basic building block of DNA and RNA) that is present in the nucleus and is used during DNA replication and mRNA synthesis

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homologous

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Refers to each set of paired chromosomes in the genome

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autosomes

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All chromosomes, except the sex chromosomes, that occur in pairs in all somatic cells (not the gametes).

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karyotype

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The characteristics of the chromosomes for an individual organism or a species, such as number, size, and type; typically presented as a photograph of a person's chromosomes that have been arranged in homologous pairs and put in numerical order by size

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sex chromosomes

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The pair of chromosomes that determine an organism's biological sex

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genomics

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The branch of genetics that studies species' genomes

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patriline

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DNA whose inheritance can be traced from father to son via the Y chromosome

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paleogenetics

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The application of genetics to the past, especially in anthropology and paleontology; the study of genetics in past organisms

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polymerase chain reaction (PCR)

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A technique that amplifies a small sample of DNA into a larger amount that can be used for various genetic tests

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diploid cell

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A cell that has a full complement of paired chromosomes

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haploid cell

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A cell that has a single set of unpaired chromosomes; half of the number of chromosomes as a diploid cell

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crossing-over

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The process by which homologous chromosomes partially wrap around each other and exchange genetic information during meiosis

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recombination

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The exchange of genetic material between homologous chromosomes, resulting from a cross-over event

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haplotypes

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A group of alleles that tend to be inherited as unit due to their closely spaced loci on a single chromosome

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haplotypes

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A large set of haplotypes, such as the Y-chromosome or mitochondrial DNA, that may be used to define a population

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translocations

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Rearrangements of chromosomes due to the insertion of genetic material from one chromosome to another

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nondisjunctions

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Refers to the failure of the chromosomes to properly segregate during meiosis, creating some gametes with abnormal numbers of chromosomes

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monosomy

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Refers to the condition in which only one of a specific pair of chromosomes is present in a cell's nucleus

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trisomy

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Refers to the condition in which an additional chromosome exists with the homologous pair

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law of independent assortment

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Mendel's second law, which asserts that the inheritance of one trait does not affect the inheritance of other traits

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linkage

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Refers to the inheritance, as a unit, of individual genes closely located on a chromosome; an exception to the law of independent assortment

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amino acids

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Organic molecules combined in a specific sequence by the ribosomes to form a protein

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essential amino acids

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Those amino acids that cannot be synthesized in the body; they must be supplied by the diet

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structural proteins

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Proteins that form an organism's physical attributes

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regulatory proteins

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Proteins involved in the expression of control genes

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transcription

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The first step of protein synthesis, involving the creation of mRNA based on the DNA template

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translation

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The second step of protein synthesis, involving the transfer of amino acids by tRNA to the ribosomes, which are then added to the protein chain

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ribonucleic acid (RNA)

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A single-stranded molecule involved in protein synthesis, consisting of a phosphate, ribose sugar, and one of four nitrogen bases

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uracil

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One of four nitrogen nases that make up RNA; it pairs with adenine

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messenger RNA (mRNA)

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The molecules that are responsible for making a chemical copy of a gene needed for a specific protein, that is, for the transcription phase of protein synthesis

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ribosomes

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The organelles attached to the surface of endoplasmic reticulum, located in the cytoplasm of a cell; they are the site of protein synthesis

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ribosomal RNA (rRNA)

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A fundamental structural component of a ribsome

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polypeptide

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Also known as a protein, a chain of amino acids held together by multiple peptide bonds

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coding DNA

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Sequences of a gene's DNA (also known as exons) that are coded to produce a specific protein and are transcribed and translated during protein synthesis

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noncoding DNA

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Sequences of a gene's DNA (also known as introns) that are not coded to produce specific proteins and are excised before protein synthesis

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strucutral genes

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Genes coded to produce particular products, such as an enzyme or hormone, rather than for regulatory proteins

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regulatory genes

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Those genes that determine when structural genes and other regulatory genes are turned on and off for protein synthesis

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homeotic (Hox) genes

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Responsible for differentiating the specific segments of the body, such as the head, tail, and limbs, during embryological development.

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locus

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The location on a chromosome of a specific gene

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polymorphism

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Refers to the presence of two or more alleles at a locus and where the frequency of the alleles is greate than 1% in the population

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law of segregation

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Mendel's first law, which asserts that the two alleles for any given gene (or trait) are inherited, one from each parent; during gamete production, only one of the two alleles will be present in each ovum or sperm

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antigens

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Specific proteins proteins, on the surface of cells, that stimulate the immune system's antibody production

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antibodies

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Molecules that form as part of the primary immune response to the presence of foreign substances; they attach to the foreign antigens

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microsatellites

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Refers to sequences of repeated base pairs of DNA, usually no more than two to six; if repeated excessively, they are often associated with neurological disorders, such as Huntington's chorea; also called "short tandem repeats" (STRs)

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homozygous

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Refers to the condition in which a pair of alleles at a single locus on homologous chromosomes are the same

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heterozygous

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Refers to the condition in which a pair of alleles at a single locus on homologous chromosomes are different

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codominance

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Refers to two different alleles that are equally dominant; both are fully expressed in a heterozygote's phenotype

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polygenic

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Refers to one phenotypic triat that is affected by two or more genes

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epigenetic

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Refers to hertiable changes but without alteration in the genome

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heritability

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The proportion of phenotypic variation in a population that is due to genetic variation across individuals rather than variation in the environmental conditions experienced by individuals

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zygote

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The cell that results from a sperm's fertilization of an ovum

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triplets

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Sequences of three nitrogen bases each in DNA, known as codons in mRNA

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thymine

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One of four nitrogen bases that make up DNA; its pairs with adenine

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Single nucleotide polymorphisms (SNP)

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Variations in the DNA sequence due to the change of a single nitrogen base

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adenine

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One of four nitrogen bases that make up DNA and RNA; it pairs with thymine in DNA molecules and uracil in RNA molecules

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anticodons

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Sequences of three nitrogen bases carried by tRNA; they match up with the complementary mRNA codons, and each designates a specific amino acid during protein synthesis

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autosomes

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All chromosomes, except the sex chromosomes, that occur in pairs all somatic cells (not the gametes)

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codons

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The sequence of three nitrogen bases carried by mRNA that are coded to produce specific amino acids in protein synthesis

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complementary bases

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The predictable pairing of nitrogen bases in the structure of DNA and RNA, such that adenine and thymine always pair together (adenine and uracil in RNA) and cytosine and guanine pair together

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guanine

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One of four nitrogen bases that make up DNA and RNA; it pairs with cytosine

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haplogroups

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A large set of haplotypes, such as the Y-chromosome or mitochondrial DNA, that may be used to define a population

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haplotypes

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A group of alleles that tend to be inherited as a unit due to their closely spaced loci on a single chromosome

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cytosine

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One of four nitrogen bases that make up DNA and RNA; it pairs with guanine