Honors Biology Vocab #2

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Trait

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a distinguishing characteristic or quality, especially of one's personal nature

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Gene

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the basic physical unit of heredity; a linear sequence of nucleotides along a segment of DNA that provides the coded instructions for synthesis of RNA, which, when translated into protein, leads to the expression of hereditary character.

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Allele

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any of several forms of a gene, usually arising through mutation, that are responsible for hereditary variation.

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Chromosome

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any of several threadlike bodies, consisting of chromatin, that carry the genes in a linear order: the human species has 23 pairs, designated 1 to 22 in order of decreasing size and X and Y for the female and male sex chromosomes respectively.

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Dominant

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the one of a pair of alternative alleles that masks the effect of the other when both are present in the same cell or organism.

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Recessive

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that one of a pair of alternative alleles whose effect is masked by the activity of the second when both are present in the same cell or organism.

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Heterozygous

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having dissimilar pairs of genes for any hereditary characteristic.

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Homozygous

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having identical pairs of genes for any given pair of hereditary characteristics.

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Genotype

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the genetic makeup of an organism or group of organisms with reference to a single trait, set of traits, or an entire complex of traits.

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Phenotype

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the appearance of an organism resulting from the interaction of the genotype and the environment

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Meiosis

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part of the process of gamete formation, consisting of chromosome conjugation and two cell divisions, in the course of which the diploid chromosome number becomes reduced to the haploid.

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Transcription

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The process by which mRNA is synthesized from a DNA template resulting in the transfer of genetic information from the DNA molecule to mRNA.

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Translation

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The process by which mRNA, tRNA, and ribosomes effect the production of a protein molecule from amino acids, the specificity of synthesis being controlled by the base sequences of the mRNA.

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mRNA

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RNA, synthesized from a DNA template during transcription, that mediates the transfer of genetic information from the cell nucleus to ribosomes in the cytoplasm, where it serves as a template for protein synthesis. Also called messenger RNA .

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tRNA

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a small RNA molecule, consisting of a strand of nucleotides folded into a clover-leaf shape, that picks up an unattached amino acid within the cell cytoplasm and conveys it to the ribosome for protein synthesis.

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rRNA

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a type of RNA, distinguished by its length and abundance, functioning in protein synthesis as a component of ribosomes.

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Nucleotide

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any of a group of molecules that, when linked together, form the building blocks of DNA or RNA: composed of a phosphate group, the bases adenine, cytosine, guanine, and thymine, and a pentose sugar, in RNA the thymine base being replaced by uracil.

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Codon

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a triplet of adjacent nucleotides in the messenger RNA chain that codes for a specific amino acid in the synthesis of a protein molecule.

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Anticodon

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a sequence of three nucleotides in a region of transfer RNA that recognizes a complementary coding triplet of nucleotides in messenger RNA during translation by the ribosomes in protein biosynthesis.

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Gamete

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a mature sexual reproductive cell, as a sperm or egg, that unites with another cell to form a new organism.

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Zygote

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the cell produced by the union of two gametes, before it undergoes cleavage.