Chapter 3 -- Genetics and Heredity Flashcards
Genotype
Total genetic endowment inherited by an individual
Phenotype
Observable and measurable characteristics and traits of an individual; a product of the interaction of the genotype with the individual
Gene
Large segment of nucleotides within a chromosome that codes for the production of proteins and enzymes. These proteins and enzymes underlie traits and characteristics inherited from one generation to the next
Allele
Alternative form of a specific gene; provides a genetic basis for many individual differences
Gamete
Sperm cells in males, egg cells in females, normally containing only 23 chromosomes
Chromosome
Threadlike structure of DNA, located in the nucleus of cells, which forms a collection of genes. A human body cell normally contains forty-six chromosomes
Human Genome
Entire inventory of nucleotide base pairs that compose the genes and chromosomes of humans
DNA
Long, spiral staircase-like sequence of molecules created by nucleotides identified with the blueprint for for genetic inheritance
Karyotype
Pictorial representation of an individual’s chromosomes
Autosomes
One of 22 pairs of homologous chromosomes. The two members of each pair are similar in size, shape, and genetic function. The two sex chromosomes are excluded from this class
X Chromosome
Larger of the two sex chromosomes associated with genetic determination of sex. Normally females have two X chromosomes and males, only one.
Y Chromosome
Smaller of the two sex chromosomes associated with genetic determination of sex. Normally males have one Y chromosome and females, none
Homozygous
Genotype in which two alleles of a gene are identical, thus having the same effects on a trait
Heterozygous
Genotype in which two alleles of a gene are different. The effects on a trait will depend on how the two alleles interact.
Dominant Allele
Allele whose characteristics are reflected in the phenotype even when part of a heterozygous genotype. Its genetic characteristics tend to mask the characteristics of other alleles
Recessive Allele
Allele whose characteristics do not tend to be expressed when part of a heterozygous genotype. Its genetic characteristics tend to be masked by other alleles.
Polygenic
Phenotypic characteristic influenced by two or more genes
Epigenetics
The field of study concerned with how environmental factors interact with DNA and its transcription into mRNA to influence cell functioning and the phenotype
Williams Syndrome
Dominant genetic disorder involving the deletion of a set of genes, which results in affected individuals’ typically having a strong social orientation, good musical ability, and some unusual linguistic capabilities accompanied by intellectual impairment and severe deficits in numerical and spatial ability.
Sickle Cell Disease
Genetic blood disorder common in regions of Africa and other areas where malaria is found among descendants of the people of these regions. Abnormal blood cells carry insufficient oxygen.
Phenylketonuria
Recessive genetic disorder in which phenylalanine, an amino acid, fails to be metabolized. Unless dietary changes are made to reduce intake of phenylalanine, sever intellectual impairment occurs
Fragile X Syndrome
disorder associated with a pinched region of the X chromosome; a leading genetic cause of intellectual impairment in males
Down Syndrome/ Trisomy X
Disorder resulting from extra chromosomal material on pari number twenty one; associated with intellectual impairment and distinct physical features
Amniocentesis
method of sampling the fluid surrounding the developing fetus through insertion of a needle; used to diagnose fetal genetic and developmental disorders
