DNA

• DNA stands for deoxyribonucleic acid and is one of the two types of nucleic acids
• The main function of DNA is to store an organism's genetic information
• DNA directs the synthesis of proteins, which control traits
• DNA is found in the cell nucleus, mitochondria, and chloroplasts (plants only)
• DNA is made up of repeating monomers called nucleotides
• In its un-condensed form, DNA is called chromatin
• Chromosomes are the condensed form of DNA and are typically visible during cell division
• To coil into chromosomes, DNA must wrap around proteins called histones
• Humans have 23 pairs of chromosomes
• A nucleotide is a repeating subunit of a nucleic acid and is made up of a phosphate group, a 5-carbon sugar (deoxyribose in DNA), and one of four nitrogenous bases: Adenine, Cytosine, Guanine, Thymine
• The double helix structure of DNA consists of rails made of deoxyribose and phosphate groups held by covalent bonds, and rungs made of base pairs held by hydrogen bonds
• Adenine bonds with Thymine, and Cytosine bonds with Guanine in DNA
• DNA replication is the process by which DNA copies itself before cell division
• DNA replication is semiconservative, with each new molecule containing one parent strand and one new complementary strand
• New strands can only be synthesized in the 5' to 3' direction during DNA replication
• Mutations are changes in the original sequence of base pairs in DNA
• Point mutations are changes in a single nucleotide base and can be substitutions, insertions, or deletions
• RNA is used to make proteins and contains adenine, guanine, cytosine, and uracil bases
• Protein synthesis involves DNA, mRNA, and proteins, with transcription occurring in the nucleus and translation at a ribosome in the cytoplasm
• During translation, tRNA molecules with anticodons complementary to mRNA codons bring the correct amino acids to the ribosome to form a protein