DNA Structure, Function, Replication, and Heredity Vocabulary

Comprehensive set of vocabulary flashcards covering DNA structure, cellular forms, replication, protein synthesis, meiosis, heredity laws, and Mendelian inheritance patterns from Biology Lessons 1 and 2.

DNA (Deoxyribonucleic Acid)

A double-helix shaped macromolecule that holds all the key genetic information necessary for living things to exist.

Nucleotide

The repeating subunit component of DNA, consisting of a phosphate group, a sugar, and a nitrogenous base.

Nitrogenous Base

A nitrogen-containing component of a nucleotide; in DNA, these are Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).

Base-Pair Rule

The complementary rule stating that Adenine (A) always binds with Thymine (T), and Guanine (G) always binds with Cytosine (C).

Chromatin

The form of DNA present during Interphase that is wrapped around proteins and condensed enough to fit inside the cell nucleus.

Chromosome

The most condensed form of DNA, present during Mitosis or Meiosis to efficiently move DNA during cell division.

Histones

Proteins that function to condense DNA inside the cell.

Nucleosome

A structural unit of DNA wrapped around histone proteins.

Karyotype

A photograph of all the chromosomes in a cell.

Autosome

Any of the first 22 pairs of body chromosomes in humans.

Sex Chromosomes

The X or Y chromosomes that make up the 23rd pair of chromosomes in humans.

Genome

The complete set of DNA that accounts for all of an organism's life processes.

Ploidy

Refers to how many sets of the same chromosome a cell contains.

Diploid

Refers to a cell having 2 sets of chromosomes ($2n = 46$ in regular human somatic body cells).

Haploid

Refers to a cell having 1 set of chromosomes ($n = 23$ in human gametes/sex cells).

Homologous Chromosomes

Chromosomes that are of the same type (same length, height, width, and carrying the same genes) but originate from different parents.

Gene

A section of DNA that codes for a specific trait passed on to offspring.

Allele

A different form of the same gene.

Sister Chromatids

Identical copies of a single replicated chromosome connected together.

Proteins

Chemicals that facilitate cellular processes and express physical traits in an organism.

Semi-Conservative Replication

The mechanism of DNA replication during cell division where each strand of parental DNA serves as a template to produce two new double-stranded DNA molecules.

Transcription

The process in protein synthesis where a segment of DNA coding for a protein is copied to produce a single strand of RNA.

Translation

The process in protein synthesis where information from mRNA is used at ribosomes to build a physical protein.

Heredity

Refers to the patterns and mechanisms of traits that are passed on from one generation to the next.

Law of Segregation

The genetic principle stating that every resulting gamete carries only 1 allele for each trait.

Crossing Over

A process during Prophase I of meiosis where homologous chromosomes exchange sections of DNA to contribute to genetic diversity.

Independent Assortment

A process at the beginning of Metaphase I of meiosis where pairs of homologous chromosomes line up randomly along the center of the cell.

Genotype

The specific combination of alleles that an individual possesses for a given gene.

Phenotype

The physical outcome or visual expression of a specific trait.

Homozygous

A genotype that contains only one type of allele for a given trait.

Heterozygous

A genotype that contains two different alleles for a given trait.

True-Breeding

Organisms or plants guaranteed to be homozygous for their expressed trait.

First Generation ($F_1$)

The resulting offspring produced from the breeding of two true-breeding parents.

Second Generation ($F_2$)

The resulting offspring produced from the self-fertilization or breeding of first-generation ($F_1$) parents.