Describe the relationship between cells, chromosomes, genes, and DNA.

Cells

Cells are the basic units of living organisms. Cells perform several important tasks including:

• providing structure


• extracting nutrients 


• producing energy


• reproducing genetic material

Cells in different parts of an organism may be specialized and perform unique functions. Cells also contain many specialized parts called organelles, which perform a variety of functions that help the cell accomplish its tasks.

Cells include a special structure called the nucleus. The nucleus of a cell contains chromosomes.

Chromosomes

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Cells

Cells are the basic units of living organisms. Cells perform several important tasks including:

• providing structure


• extracting nutrients 


• producing energy


• reproducing genetic material

Cells in different parts of an organism may be specialized and perform unique functions. Cells also contain many specialized parts called organelles, which perform a variety of functions that help the cell accomplish its tasks.

Cells include a special structure called the nucleus. The nucleus of a cell contains chromosomes.

Chromosomes

Most human cells contain twenty-three pairs of chromosomes (forty-six total chromosomes). One chromosome in each pair is inherited from each parent. 

Chromosomes are composed of protein and long strands of DNA.

DNA

DNA stands for deoxyribonucleic acid. DNA contains all of the instructions for creating an organism. These instructions are "coded" into the DNA molecule using four different nucleotide bases. Nucleotide bases are the basic structural units of DNA molecules. The four nucleotide bases are: adenine (A), cytosine (C), thymine (T), and guanine (G). 

Specific sequences of DNA nucleotide bases are called genes.

Genes

Genes are the basic units of heredity. The nucleotide sequence of a gene codes for the production of a specific protein. Proteins are composed of amino acids. Every three nucleotides along a gene sequence codes for a particular amino acid. Proteins are produced as amino acids are assembled in the order indicated by the nucleotide sequence of the gene.