Unit 2- CH 7 & 8 Terminology Flashcards
Alleles
each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
Chromosome
a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
Autosomal
that a specific gene is not on a sex chromosome and is a numbered chromosome.
Recessive
a trait that is expressed only when genotype is homozygous; a trait that tends to be masked by other inherited traits
Dominant
only one copy of the dominant allele is required to express the trait. The effect of the other allele (the recessive allele) is masked by the dominant allele.
nucleotides
the basic building block of nucleic acids (RNA and DNA)
codominance
both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype.
incomplete dominance
both alleles of a gene at a locus are partially expressed
chromatids
Essentially one half of a chromosome
genes
special stretch of DNA, a sequence of As Cs Ts and Gs that codes for something.
ribosomes
intercellular structure made of both RNA and protein-he runs the protein-in the cytoplasm
Homozygous
two identical versions of the same gene
Heterozygous
having two different alleles of a particular gene or genes.
genome
All of an organism’s DNA, in a haploid cell, measured in base pairs.
meiosis
a process where a single cell divides twice to produce four cells containing half the original amount of genetic information
mitosis
The process by which a single parent cell divides to make two new daughter cells. Each daughter cell receives a complete set of chromosomes from the parent cell.
Trisomy
is when an extra chromosome has been inherited
centromere
The middle joint of the chromosome, connecting the two arms.
Nucleosomes
a structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of histones.
Histones
any of a group of basic proteins found in chromatin.
phenotype
a characteristic determined by genes and the environment
Tetrasomy
a form of aneuploidy with the presence of four copies, instead of the normal two, of a particular chromosome.
Aneuploidy
The occurrence of one or more extra or missing chromosomes in a cell or organism.
polyploidy
the heritable condition of possessing more than two complete sets of chromosomes.
Chromatin
a mixture of DNA and proteins that form the chromosomes found in the cells of humans and other higher organisms.
