What is Genetics The study of Heredity Heredity

What is Genetics? • The study of Heredity • Heredity is the passing of genetic information from one generation to the next

Genes • Each cell nucleus contains DNA (hereditary information) in the form of chromosomes

Genes are located on these chromosomes, and each gene carries a piece of coded information Each cell in your body has over 6 feet of chromosomes tightly coiled inside!

The Human Genome • A genome is all of the genes possessed by an organism • The human genome consists of over 100, 000 genes • Each gene has at least 10, 000 nucleotide pairs

DNA • DNA resembles a twisted ladder called a double helix. • It is made up of subunits called nucleotides. • Each subunit or nucleotide contains 3 chemical parts: • A sugar, a phosphate, and a nitrogenous base (ATCG)

Base Pairs • The four bases found in DNA are Thymine (T) , Adenine (A), Cytosine (C), and Guanine (G) • A always bonds with T and G always bonds with C • Remember: AT Garden City • Bases are joined by weak hydrogen bonds

DNA Base Pairing Animation

Match up the Base Pairs A G C T T G T C A • • • T C G A A C A G T

DNA Replication • When DNA needs to copy itself, the hydrogen bonds between bases “unzip” and the DNA separates into 2 single strands. • Each single strand serves as a template or pattern • Using the base pair rule, 2 new double strands form which are identical to the original double strand

RNA • RNA is similar to DNA except: 1. m. RNA is always single stranded 2. The sugar is ribose instead of deoxyribose 3. RNA contains Uracil (U) instead of Thymine (T) • Therefore, every time m. RNA copies DNA, the A in DNA bonds to a U in m. RNA instead of a T

Protein Synthesis • DNA codes for your protein • Proteins are made by the Ribosomes • Proteins include enzymes, antibodies, hormones, hair, muscle, etc. • The process of protein synthesis involves 2 steps: • Transcription and Translation

1. Transcription • The process of passing genetic information from DNA to RNA • Takes place in the Nucleus • A molecule of DNA “unzips” and one side acts as a template for producing m. RNA • m. RNA (messenger RNA) copies the DNA code and carries it to the ribosomes

2. Translation • Takes place in the Cytoplasm at the Ribosomes and involves m. RNA and t. RNA (transfer RNA) • Every strand of m. RNA now contains the genetic code called CODONS (groups of 3 bases) Ex: AUG

• Every CODON codes for a specific Amino Acid • t. RNA translates codons into amino acids (AA) and carries the AA to the ribosomes • The ribosomes use the Amino Acids to make Proteins!

Review of Terms: 3 Nitrogen Bases CODONS (A, U, C, G (RNA) PROTEINS Amino Acids

Codons • How does RNA know when a protein code is done? • Each codon codes for a specific Amino Acid • There are codons that signal “start” and “stop” • Ex: m. RNA “start” codon is AUG • There are 3 “stop” codons: UAG, UAA, UGA

Central Dogma Transcription Translation DNA RNA PROTEIN A-T A-U Amino G-C Acids