Genetics

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!

Human Genome

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 Structure

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, - phosphate - nitrogen base (A-T, G-C)

Base Pairs The four bases found in DNA are Thymine (T) , Adenine (A), Cytosine (C), and Guanine (G) A - T and G - C Remember: AT Garbage Can Bases are joined by weak hydrogen bonds

DNA Base Pairing Animation

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

DNA Replication

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

Protein Synthesis

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

Transcription

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 mRNA mRNA (messenger RNA) copies the DNA code and carries it to the ribosomes

Translation

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

Every CODON codes for a specific Amino Acid tRNA 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 (A,U,C,G (RNA) CODONS 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: mRNA “start” codon is AUG There are 3 “stop” codons: UAG, UAA, UGA

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