Unit 3 List 2 DNA & Heredity Flashcards
Centromere
structure in a chromosome that holds together the two chromatids
Allele
one of two or more versions of DNA sequence (a single base or a segment of bases) at a given genomic location.
Chromatid
one of the two identical halves of a chromosome that has been replicated in preparation for cell division
Chromosome
A structure found inside the nucleus of a cell.
Codon
a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis
Crossing Over
the exchange of DNA between paired homologous chromosomes (one from each parent) that occurs during the development of egg and sperm cells (meiosis)
Daughter Cell
Either of the two cells formed when a cell undergoes cell division by mitosis
Deletion
A type of genetic change that involves the absence of a segment of DNA.
Diploid
the presence of two complete sets of chromosomes in an organism’s cells, with each parent contributing a chromosome to each pair.
DNA
the molecule that carries genetic information for the development and functioning of an organism
Fertilization
the union of two gametes
Frameshift
a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read
Gamete
a reproductive cell of an animal or plant
Gene
The basic unit of heredity passed from parent to child
Gene Mutation
a change to a gene’s DNA sequence to produce something different
Genetic Code
a set of rules defining how the four-letter code of DNA is translated into the 20-letter code of amino acids
Genetic Variation
the presence of differences in sequences of genes between individual organisms of a species
Haploid
a cell that contains a single set of chromosomes
Homologous Chromosome
pairs of chromosomes in a diploid organism that have similar genes, although not necessarily identical
Independent Assortment
a genetic principle that states that the alleles of two genes will segregate into daughter cells independent of one another
Insertion
A type of genetic change that involves the addition of a segment of DNA
Meiosis
a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells
Meiosis I
a type of cell division unique to germ cells
Meosis II
a mitotic division of each of the haploid cells produced in meiosis I
Monosomy
the condition in which only one chromosome from a pair is present in cells rather than the two copies usually found in diploid cells
Mutagen
a chemical or physical agent capable of inducing changes in DNA called mutations
Mutation
Any change in the DNA sequence of a cell
Nondisjunction
the failure of the chromosomes to separate, which produces daughter cells with abnormal numbers of chromosomes
Offspring
the young creation of living organisms, produced either by sexual or asexual reproduction
Parent Cell
A cell that is the source of other cells, as a cell that divides to produce two or more daughter cells, or a stem cell that is a progenitor of other cells or is the first in a line of developing cells
Point Mutation
A genetic alteration caused by the substitution of a single nucleotide for another nucleotide
Replication
the process by which the genome’s DNA is copied in cells
Sexual Reproduction
the production of new organisms by the combination of genetic information of two individuals of different sexes
Somatic Cell
the cells in the body other than sperm and egg cells
Substitution
a type of mutation in which one nucleotide is replaced by a different nucleotide
Trisomy
The presence of an extra chromosome in some or all of the body’s cells
Trait
a specific characteristic of an individual
