nucleotide
monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base
mRNA
messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome
Nitrogen bases
Adenine, Thymine, Guanine, Cytosine
Uracil pairs with
Adenine
Adenine pairs with
Uracil, Thymine
Guanine pairs with
Cytosine
Cytosine pairs with
Guanine
Thymine pairs with
Adenine
double helix
two strands of nucleotides wound about each other; structure of DNA
base substitution mutation
one nucleotide is substituted for another; could be harmless if same amino acid is made; usually harmful
base insertion mutation
a nucleotide is removed from the sequence or a nucleotide is added; changes entire sequence of proteins and has largest effect
tetrad
formed when homologous chromosomes come together
crossing over
the exchange of genetic material between two homologous chromosomes
somatic cell
new body cells in a multicellular organism
zygote
result of fertilization, fertilized egg
homologous chromosomes
chromosomes that have the same sequence of genes, that have the same structured, and that pair during meisosis
daughter cells
The cells that are produced as a result of mitosis. These cells are identical to each other, and also to the original parent cell.
single rod chromosome
detached sister chromatids
double rod chromosome
DNA attached to a duplicated stand, consists of sister chromatid
mitosis
creates new cells for growth and development, replication and division of the contents of the nucleus
independent assortment of chromosomes
tetrads align randomly during metaphase
genes
sequence of DNA that codes for a protein and thus determines a trait
allele
one of the alternative forms of a gene that governs a characteristic
heterozygous
having two different alleles for a trait
homozygous
having two identical alleles for a trait
dominant
Trait that will show up in an organism's phenotype if gene is present
recessive
trait that will only appear in the phenotype if organism inherits two of them; covered up by the dominant gene
fertilization
process of combining egg and sperm to create a zygote
genotype
genetic makeup of an organism
phenotype
The physical traits that appear in an individual as a result of its gentic make up.
punnet square
A chart that shows all the possible combinations of alleles that can result from a genetic cross
F1 generation
the first offspring from a cross of two varieties in the parental (P) generation
P generation
Parental generation, the first two individuals that mate in a genetic cross
F2 generation
offspring of the F1 generation
codominance
a cross between organisms with two different phenotypes, produces offspring with a new phenotype (doesn't follow alternate forms, all genes have dominant and recessive alleles)
incomplete
a cross between organisms with two different phenotypes that produce a third blending of the parents(doesn't follow two alternate forms, dominant and recessive allele)
multiple alleles and codominance
More than two alleles that share dominance completely
sex-linked
An inheritance pattern in which traits are controlled by genes located on the X chromosome.
Gregor Mendel
Father of genetics. Experimented with pea plants and discovered law of dominance, ind. assortment, and segregation.
Gregor Mendel's hypotheses
1. Genes have alternate forms.
2. An allele is either dominant or recessive.
3. For each inherited trait, an orgasm has 2 alleles.
4. A gamete (egg or sperm) has only one allele for a gene.
pedigree
a diagram that shows the occurrence of a genetic trait in several generations of a family