DNA & GENES What is DNA? DNA (deoxyribonucleic acid) is a nucleic acid It is composed of smaller units called nucleotides These are: A, T, C, and G Shapedouble helix DNA DNA Nucleotides Complimentary Base Pairing AAA TCC GCT AAT CCG GGG TTT AGG CGA TTA GGC CCC Try another! GCA TTA CCG AGA CCC TAA CGT AAT GGC TCT GGG ATT The Double Helix Who discovered the Double Helix? In 1953, James Watson and Francis Crick published an article on what DNA looked like. Made of tow chains of nucleotides held together by nitrogen bases. DOUBLE HELIX. Hydrogen Bonds How the nitrogen bases bond What is DNA Replication? The DNA in chromosomes is copied. Enzymes break Hydrogen bonds Add matching nucleotides 2 identical molecules made, each with 1 new, 1 old strand Chromosome What is a GENE? A sequence of DNA (nucleotides) that codes for a protein Proteins = traits! What is Protein Synthesis? The process of making proteins from DNA instructions What is mRNA? mRNA is similar to DNA Only one strand Uses a U instead of a T It brings the instructions from DNA in the nucleus to the cytoplasm. Example: DNA = AAT GGC CAT mRNA=UUA CCG GUA What is Transcription? First part = TRANSCRIPTION Enzymes separates DNA strand and reads the letters (nucleotides) RNA copy of DNA is made A molecule called mRNA is made Transcription What is Translation? mRNA moves out of the nucleus and finds a ribosome The information in the mRNA (nitrogen bases) is changed into a sequence of amino acids in protein. Where and what happens during tranlation? Ribosome uses instructions on mRNA to build one protein Translation Once at the ribosome, transfer RNA (tRNA) brings amino acids Translation tRNA drops off correct amino acid and adds it to the growing chain What is tRNA? Is the supplier RNA It delivers amino acids to the ribosome to be assembled into a protein. tRNA Uses the same letters as mRNA; Us instead of Ts. Uuracil instead of thymine How does mRNA and tRNA work in translation? Each 3-letter chunk of mRNA is called a CODON (CUA) Codons match the 3-letter chunk of tRNA called an ANTI- CODON (GAU) How are codons and anti-codons coded? Use a table to determine which amino acids are connected Translation There are about 20 different amino acids What is rRNA? Binds to the mRNA and uses the instructions to assemble the amino acids in the correct order. Which are then transferred to the ribosomes by tRNA. What are mutations? Any change that occurs in the DNA sequence. 2 types Point mutation Frameshift mutation What is a point mutation? A change in a single base pair of DNA. A has become a C (pt. mutation) What is frameshift mutation? Where a single base is added or deleted from DNA. What causes mutations? Caused by a mutagen. Any agent that can cause a change in DNA. Radiation Cosmic rays Ultraviolet light Nuclear radiation Alcohol Mutagens Copyright Information All images displayed in this presentation are the property of their respective owners, and no copyright infringement is intended. Images displayed in this presentation are being used under the "Fair Use" guidelines for educators for educational purposes only. Please contact if you are the owner of a posted image and would like for its use to be discontinued.