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Chapter 1 and 2
Terms in this set (71)
The study of essential cellular macromolecules, including DNA, RNA, and proteins, and the biological pathways that link their biosynthesis.
Information required for cellular growth and metabolism, inherited from one generation of an organism to the next. Primarily imprinted within the sequences of nucleic acids, information may also be embedded within nucleic acid modifications and in the patterns of modification in certain proteins bound to nucleic acids; see epigenetic inheritance.
An increase in the rate of a chemical reaction caused by a substance that is not consumed by the reaction.
A process in which the population of a species changes over time. Genetic variation occurs in the populations due to mutation; competitive pressures in the environment lead to the natural selection of individuals whose genetic makeup gives them a reproductive advantage. Over time, the genetic makeup of the surviving population shifts, sometimes creating new species.
Describes an individual homozygous for a given trait or set of traits.
The parental generation in a genetic cross.
The offspring of a cross between genetically nonidentical individuals.
The first filial generation, the hybrid offspring in a genetic cross.
Describes the allele that determines the phenotype in a heterozygous individual. Compare recessive.
Describes an allele that manifests in a homozygous individual but is masked by the dominant allele in heterozygotes. Compare dominant.
The second filial generation, the offspring of crossing the F1 generation.
A chromosomal segment that codes for a single functional polypeptide chain or RNA molecule.
Having two sets of genetic information; describes a cell with two chromosomes of each type. Compare haploid.
A variant form of a gene at a specific locus.
The observable characteristics of an organism.
Having a single set of genetic information; describes a cell with one chromosome of each type. Compare diploid.
The genetic constitution of an organism, as distinct from its physical characteristics, or phenotype.
A matrix for displaying the genes involved in a cross and the possible combinations of alleles in the progeny. The gamete genotypes are written along the top and sides of the square; the possible combinations of alleles are shown in the matrix.
Having identical alleles at a specific genetic locus.
Having different alleles at a specific genetic locus.
law of segregation
In the formation of gametes there is an equal segregation of alleles. In other words, a haploid gamete contains one copy of each gene. Also known as Mendel's first law.
law of independent assortment
In the formation of gametes there is an independent assortment of alleles for different genes. Also known as Mendel's second law.
A condition in which alleles at a specific locus are neither dominant nor recessive, and the progeny express a phenotype intermediate between those of the two parents. Compare codominance.
Non-Mendelian behavior in which two alleles of a gene produce distinct functional products, neither of which is dominant to the other. Compare incomplete dominance.
Genes that are close together on a chromosome and the alleles of which therefore assort together during meiosis, in contradiction to Mendel's second law.
In diploid organisms, a pair of chromosomes, one inherited from each parent, that are of similar length, structure, and gene sequence. Also called homologs.
The study of cells and cellular structures.
The study of chromosomes and their role in heredity.
Membrane-bounded structure that is the smallest unit of life.
The theory proposed by Theodor Schwann in 1839 that cells are the basic units of all living things.
A single large DNA molecule and its associated proteins, containing many genes; stores and transmits genetic information.
The exterior membrane surrounding the cytoplasm of a cell. Also called the plasma membrane.
Membrane-bounded structures found in eukaryotic cells; contain enzymes and other components required for specialized cell functions.
The process by which cells replicate and divide. The bacterial cell cycle involves binary fission; the eukaryotic cell cycle has four phases, including mitosis.
The first gap phase of the eukaryotic cell cycle, in which the cell is diploid. G1, part of interphase, occurs before the S (synthesis) phase, in which the DNA is replicated.
The phase of the cell cycle during which the DNA is replicated. The S phase occurs between the G1 and G2 phases.
sister chromatid pair
Duplicate chromosomes, attached at the centromere, produced during the S phase of the eukaryotic cell cycle. Sister chromatids separate into individual chromosomes during anaphase of mitosis or anaphase II of meiosis, when the centromere divides.
A specialized site in a chromosome, serving as the attachment point for the mitotic or meiotic spindle.
The second gap phase of the eukaryotic cell cycle, in which the cell is tetraploid. G2, part of interphase, occurs between the S (synthesis) phase and the M (mitosis) phase.
The phase of the eukaryotic cell cycle during which mitosis, or cell division, occurs. The M phase follows the G2 phase and precedes the G1 phase.
In eukaryotic cells, the multistep process that results in the segregation of replicated cellular chromosomes and cell division.
An organelle that serves as the microtubule organizing center. Two centrosomes are responsible for the creation of the spindle apparatus that moves chromosomes to opposite poles of the cell during mitosis and meiosis.
The equatorial plane in a dividing cell along which chromosomes align during metaphase.
The final separation of daughter cells following mitosis.
A type of cell division in which diploid cells give rise to haploid cells destined to become gametes.
A structure formed in meiotic prophase I by the association of two homologous sister chromatid pairs.
A chromosome that determines the male or female sex of an organism. Compare autosome.
Any chromosome that is not a sex chromosome. Compare sex chromosome.
chromosome theory of inheritance
The hypothesis proposed by Walter Sutton in 1903 that genes are located on chromosomes.
The allele or phenotype that appears with the greatest frequency in a natural population of a species.
The failure of paired chromosomes or sister chromatids to segregate during mitotic or meiotic cell division.
The study of the structure and function of genes at the molecular level.
DNA (deoxyribonucleic acid)
A polynucleotide with a specific sequence of deoxyribonucleotide units covalently joined through 3',5'-phosphodiester bonds; serves as the carrier of genetic information.
Biologically occurring polynucleotides in which the nucleotide residues are linked in a specific sequence by phosphodiester bonds; DNA and RNA.
RNA (ribonucleic acid)
A polyribonucleotide of a specific sequence linked by successive 3',5'-phosphodiester bonds.
A nucleoside phosphorylated at one or more of its pentose hydroxyl groups.
A biomolecule, either protein or RNA, that catalyzes a specific chemical reaction. It does not affect the equilibrium of the catalyzed reaction; it enhances the rate of the reaction by providing a reaction path with lower activation energy.
A long chain of amino acids linked by peptide bonds; the molecular weight is generally less than 10,000. Also called a polypeptide.
Having a molecular surface with chemical groups arranged to interact specifically with chemical groups on another molecule. Because of complementarity, if the nucleotide sequence of one strand of a double-stranded nucleic acid is known, the sequence of the opposite strand can be deduced.
Two nucleotides in nucleic acid chains that are paired by hydrogen bonding of their bases; for example, A with T or U, and G with C.
The organizing principle of molecular biology: genetic information flows from DNA to RNA to protein. The pathways of information flow have been expanded to include RNA to DNA, and RNA to RNA, and are now established. They are no longer constituted dogma.
A macromolecular complex of rRNAs and r-proteins; the site of protein synthesis.
ribosomal RNA (rRNA)
A class of RNA molecules serving as components of ribosomes.
messenger RNA (mRNA)
A class of RNA molecules, each of which is complementary to one strand of DNA, that carry the genetic message from the chromosome to the ribosomes.
An enzyme that catalyzes the formation of RNA from ribonucleoside 5'-triphosphates, using a strand of DNA as a template. Some RNA polymerases, primarily in viruses, use RNA as a template and are called RNA-dependent RNA polymerases (RDRPs).
The enzymatic process whereby the genetic information contained in one strand of DNA is used to specify a complementary sequence of bases in an RNA strand.
transfer RNA (tRNA)
A class of RNA molecules (Mr 25,000 to 30,000), each of which combines covalently with a specific amino acid for use in protein synthesis.
The process in which the genetic information present in an mRNA molecule specifies the sequence of amino acids during protein synthesis.
An RNA molecule that is a functional end product, as distinct from messenger RNA (mRNA), which serves as a transient intermediary between DNA and a protein product it encodes.
A class of small RNA molecules (21 to 23 nucleotides after processing is complete) involved in gene silencing by inhibiting translation and/or promoting the degradation of particular mRNAs.
short interfering RNA (siRNA)
A short (~21 to 27 nucleotide) double-stranded RNA with 3' overhangs, created from exogenous double-stranded RNA by the endonuclease Dicer, that participates in the RNAi gene silencing pathway.
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