AP BIO VOCAB (help version)

trait

one of two or more detectable varients in a genetic character

heredity

the transmission of traits from one generation to the next

genetics

the scientific study of heredity and heredity variation

purebred/homozygous

having two identical alleles for a gene (encoding a character)

gene

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

allele

any of the alternative versions of a gene that may produce distinguishable phenotypic efforts

dominant allele

an allele that is fully expressed in the phenotype of a heterozygote

recessive allele

an allele whose phenotypic effects not observed in a heterozygote

hybrid/heterozygous

offspring that results from the making of individuals from two different species or from two true-breeding varients of the same species; having two different alleles for a given gene

Punnett square

a diagram used in the study of inheritance to show the predicted genotypic results of random fertilization in genetic crosses between individuals of known genotype

phenotype

the observable physical and physiological traits of an organism, which are determined by its genetic makeup

genotype

the gentic makeup, or set of alleles, of an organism

codominance

the situation in which the phenotype of both allleles are exhibited in the heterozygote became both alleles affect the phenotype in a separate, distinguishable ways

sperm

the male gamete

egg

the female gamete

meiosis

a modified type of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication; it results in cells with half the numbers of chromosome sets as the original cell

mutation

a change in the nucleotide sequence of an organism’s DNA of in the DNA or RNA of a virus

multiple alleles

different versions of genes, different options

carrier

in genetics, an individual who is heterozygous at a given genetic locus for a recessively inherited disorder; the hertozygote is generating phenotypically normal for the disorder but can pass on the recessive allele to offspring

pedigree

a diagran of a family tree with conventional symbols, showing the occurance of heritable character to parents and offspring over multiple generations

karyotype

a display of the chromosome pairs of a cell arranged by size and shape

gene expression

the process by which information encoded in DNA directs the synthesis of proteins or, in some cases, RNAs that are not translated into proteins and instead function as RNAs

Law of Independent Assortment

Mendel’s second law, stating that each pair of alleles, segregates, or a sorts, independently of each other pair during gamete formation; applies when genes for two characters are located on different parts of homologous chromosomes or when they are far enough apart on the same chromosome to behave as though they are on different chromosomes

Law of Segregation

Mendel’s first law, stating that the two alleles in a pair segregate (separate from each other) into different gametes during gamete formation

Nondisjunction

an error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other