unit 3 list 2 Flashcards
allele
One of two or more versions of a genetic sequence at a particular region on a chromosome
centromere
structure in a chromosome that holds together the two chromatids
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
DNA or RNA sequence of three nucleotides (a trinucleotide) that forms a unit of genomic
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
the cells that are formed after cell division
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
the insertion or deletion of nucleotide bases in numbers that are not multiples of three
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
refers to the instructions contained in a gene that tell a cell how to make a specific protein
genetic variation
the presence of differences in sequences of genes between individual organisms of a species
haploid
the presence of a single set of chromosomes in an organism’s cells
homologous chromosome
pairs of chromosomes in a diploid organism that have similar genes, although not necessarily identical
independent assortment
how different genes independently separate from one another when reproductive cells develop
insertion
a type of mutation that involves the addition of one or more nucleotides into a segment of DNA
meiosis
a type of cell division in sexually reproducing organisms that reduces the number of chromosomes in gametes
meiosis I
a type of cell division unique to germ cells
meiosis 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
is a change in the DNA sequence of an organism
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
something thought of as an overhanging shelter
point mutation
occurs in a genome when a single base pair is added, deleted or changed
replication
double-stranded DNA molecule is copied into two, identical DNA
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
