Molecular Genetics, Mitosis, Genetics


monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base


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 pairs with

Uracil, Thymine

Guanine pairs with


Cytosine pairs with


Thymine pairs with


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


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


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


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


sequence of DNA that codes for a protein and thus determines a trait


one of the alternative forms of a gene that governs a characteristic


having two different alleles for a trait


having two identical alleles for a trait


Trait that will show up in an organism's phenotype if gene is present


trait that will only appear in the phenotype if organism inherits two of them; covered up by the dominant gene


process of combining egg and sperm to create a zygote


genetic makeup of an organism


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


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)


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


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.


a diagram that shows the occurrence of a genetic trait in several generations of a family