Bio vocab unit 5

Alleles

An alternative version of a gene

Carrier

An individual who is heterozygous for a recessively inherited disorder and who therefore does not show symptoms of that disorder

Codon

A three-nucleotide sequence in mRna that specifies a particular amino acid or polypeptide termination signal; basic unit of the genetic code

Codominant

Expressing two different alleles of a gene in a heterozygote

Dihybrid cross

A mating of individuals differing at two genetic loci

DNA

Deoxyribonucleic acid; The genetic material that organisms inherit from their parents

Dominant Allele

In a heterozygote, the allele that determines the phenotype with respect to a particular gene

Exons

In eukaryotes, a coding portion of a gene

F1 Generation

The offspring of two parental individuals (stands for first filial)

F2 Generation

The offspring of the F1 generation (stands for second filial)

Genetics

The scientific study of heredity

Genotype

The genetic makeup of an organism

Heredity

The transmission of traits from one generation to the next

Heterozygous

Having two different alleles for a given gene

Homozygous

Having two identical alleles for a given gene

Hybrid

The offspring of parents of two different species or of two different varieties of one species

Incomplete Dominance

A type of inheritance in which the phenotype of a heterozygote is intermediate between the phenotypes of the two types of homozygotes

Introns

In eukaryotes, a nonexpressed portion of a gene that is excised from the RNA transcript

Law of independent assortment

A general rule of inheritance, first proposed by Gregor Mendel, that states that when gametes form during meiosis, each pair of alleles for a particular character segregate independently of each other pair

Law of segregation

A general rule of inheritance, first proposed by Gregor Mendel, that states that the two alleles in a pair segregate into different gametes during meiosis

Linked genes

Genes located close enough together on a chromosome that they are usually inherited together

Locus

The particular site where a gene is found on a chromosome

Messenger RNA (mRNA)

The type of ribonucleic acid that encodes genetic information from DNA and conveys it to ribosomes, where the information is translated into amino acid sequences

Monohybrid Cross

A mating of individuals differing at one genetic locus

Mutagen

A chemical or physical agent that interacts with DNA and causes a mutation

Mutation

A change in the nucleotide sequence of DNA; a major source of genetic diversity

Nucleotide

An organic monomer consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group (building blocks of nucleic acids)

Pedigree

A family tree representing the occurrence of heritable traits in parents and offspring across a number of generations

P generation

The parent individuals from which offspring are derived in studies of inheritance. P stands for parental

Phenotype

The expressed traits of an organism

Pleiotropy

The control of more that one phenotypic character by a single gene

Polygenic inheritance

The additive effect of two or more genes on a single phenotypic characteristic

Punnett Square

A diagram used in the study of inheritance to show the results of random fertilization

Recessive Allele

In Heterozygotes, the allele that has no noticeable effect on the phenotype

sex-linked gene

A gene located on a sex chromosome

Trait

A variant of a character found within a population, such as purple flowers in pea plants

Transcription

The synthesis of RNA on a DNA Template

Translation

The synthesis of a polypeptide using the genetic information encoded in an mRNA Molecule