unit 2

DNA

The molecule that carries genetic information for the development and function of organisms; stands for deoxyribonucleic acid.

Chromosome

A subunit (or molecule) of DNA located in the nucleus of a cell, often appearing as an 'I' in its condensed form.

Duplicated Chromosome

Two connected subunits of DNA in the nucleus that are duplicates of each other, often appearing as an 'X'.

Chromosome Pairs

Two unconnected subunits of DNA that contain the same genes but are not identical; one is inherited from each parent.

Diploid

An individual with two versions (i.e., pairs) of each chromosome.

Nucleotides

The four nucleotides in DNA—Adenine (A), Cytosine (C), Guanine (G), and Thymine (T)—that collectively form a sequence in DNA.

Gene

A segment of DNA on a chromosome that provides information for making molecules like mRNA and proteins.

Allele

A version of a gene that differs from another version of the same gene based on nucleotide sequence.

Homozygous

A diploid individual with identical alleles for a given gene.

Heterozygous

A diploid individual with different alleles for a given gene.

Chromosome Copies

Two connected subunits of DNA that are copies of each other, with identical sequences and genes.

Genotype

The genetic constitution of an organism, often indicated by specific sequences in the DNA.

Phenotype

The observable physical or biochemical characteristics of an organism, influenced by genotype.

Coding DNA

The region of a gene that is responsible for coding a protein.

Noncoding DNA

The part of DNA that does not encode proteins but influences the regulation and amount of transcription.

Gene Regulatory Switches

Segments of the gene that control when and how much a gene is transcribed.