AP Bio - Genetics Vocab Flashcards

Alleles

alternative versions of a gene

Autosome

all the chromosomes that do not determine sex of individual

Barr Body

the silenced X chromosome - genes on this inactive X are not expressed

Carriers

females with an X chromosome with dominant allele and other X chromosome with a recessive allele that can pass a disorder to offspring

Character

distinct heritable feature that varies among individual members

Codominance

heterozygous individual - expression shows both phenotypes

Complete Dominance

heterozygous individual - the dominant alleles hides the recessive allele

Cross Pollination

fertilization between 2 different plants

Dihybrid Cross

punnett square for two genes

Diploid

2 sets of chromosomes

Dominant Lethal Alleles

lethal when alleles are present in just a single copy

Epistasis

One gene affects how another gene is expressed

Extranuclear Inheritance

traits are inherited from DNA found in the mitochondria and chloroplasts

F1 Generation

offspring of P generation - Only Dominant shows up here

F2 Generation

offspring of F1 generation (self pollination) - recessive shows up now

Gamete

Reproductive (sex) cells

Gene

basic unit of inheritance - segment on DNA that controls a trait

Gene Expressivity

degree to which the phenotype is expressed

Gene Penetrance

likelihood that an organism will actually express its inherited genotype

Genome

complete set of genes or genetic material present in a cell or organism

Genomic Imprinting

Variation in phenotype depending on if an allele is inherited from the male or female parent

Genotype

genetic makeup based of alleles inherited by parents

Haploid

1 set of chromosomes

Hemizygous

males only have one X chromosomes with an allele

Heterozygous

individual that has two different alleles

Homozygous

individual that has all the same alleles

Incomplete Dominance

heterozygous individual - expression is a blend of both phenotypes

Karyotype

picture of individuals chromosomes

Law of Independent Assortment

each pair of alleles lines up and separates independently (randomly) during gamete formation

Law of Segregation

Two alleles separate from each other during gamete formation

Locus

specific location of an allele on a chromosome

Monohybrid Cross

punnett square for one gene

Multiple Alleles

Genes with more than two alleles can have more than two phenotypes

P Generation

parents (usually true-breeding)

Phenotype

physical appearance or observable traits based of the genotype

Plasticity

Environmental factors influence gene expression

Pleitropy

one gene affects many traits

Polygenic

Many genes - one trait

Principle of Dominance

Recessive alleles will be masked by dominant alleles

Punnett Square

gives expected results which you can compare to observed results

Recessive Lethal Alleles

lethal when homozygous but not heterozygous

Self-Pollination

plant fertilizes itself - gives purebred traits

Sex Chromosome

chromosome that determine sex of individual

Sex-Linked

some genes are linked to the X or Y chromosomes instead of the autosomes

Somatic Cell

all the cells that make up the body

Test Cross

used to determine whether an organism with a dominant phenotype is either homozygous or heterozygous

Trait

each variant for a given character

X Inactivation

one of the two X chromosomes present in females is silenced

Zygote

fertilized egg