DNA to Proteins PDF

DNA & RNA WHAT IS IT? DNA = Makes up genes for all living things. What are genes?? Blueprints for us!! Genes are parts of DNA that code for particular traits or proteins. DNA Deoxyribonucleic Acid (DNA) Dee-oxy-ribo + nuke-lay-ick +Acid DNA DO Now: What is DNA? What is i...

DNA & RNA WHAT IS IT? DNA = Makes up genes for all living things. What are genes?? Blueprints for us!! Genes are parts of DNA that code for particular traits or proteins. DNA Deoxyribonucleic Acid (DNA) Dee-oxy-ribo + nuke-lay-ick +Acid DNA DO Now: What is DNA? What is it used for? Why do we need it? DNA Structure “Double Helix” shape DNA is made up of Nucleotides Nucleotides are the basic units of DNA Recognize the similarities between the terms: Nucleotide Deoxyribonucleic acid nucleus. Structure of a nucleotide A nucleotide is made of 3 components: - A Phosphate - A Nitrogen Base - A Sugar The sugar in DNA is deoxyribose. (Deoxyribonucleic acid) DNA NITROGEN BASES Four bases are: Thymine Adenine Cytosine Guanine Base pairing The Bases pair up with bases on another strand A group of 3 bases is called a “codon.” Codons code for amino acids. The Rule:  Adenine (A) always pairs with Thymine (T)  Cytosine (C) always pairs with Guanine (G) James Watson (L) and Francis Crick (R), and the model they built of the structure of DNA X-ray diffraction photograph of the DNA double helix Review of DNA  What is the general  What is each nucleotide structure of DNA? made of? ◦ Double Helix ◦ Sugar (Deoxyribose)  What composes the ◦ Phosphate DNA “backbone” or side ◦ Nitrogen Base pieces?  What are the bases? ◦ Deoxyribose (sugar) ◦ Adanine, Thyamine, & Phosphate Cytosine, Guanine  What is the name of the  What bases pair with 3-part unit of DNA each other? called? ◦ A+T ◦ Nucleotide ◦ C+G  What is a Codon? ◦ A group of 3 bases (codes for an amino acid) RNA What is RNA? Ribonucleic Acid Structure Created from DNA replication Single-strand Uracil base instead of Thyamine base Ribonucleic acid Uses ribose instead of deoxyribose What is RNA used for? Protein Synthesis  Types: mRNA & tRNA “Messenger” RNA is used to send messages from DNA to be used elsewhere (e.g. create proteins for hormones, repair cells, help the immune system, etc.) “Transfer” RNA uses “anticodons” to put amino acids in the correct order of mRNA codons Protein Synthesis using RNA? Protein Synthesis = Making proteins Examples include: Hormones, Enzymes, Cell parts, Immune response, etc. Two steps are involved: Transcription & Translation DNA REPLICATION (in the nucleus)  DNA Replication First an enzyme DNA topoisomerase untangles the coils Next: Enzymes called “Helicase” “unzip” the DNA molecule exposing both strands nitrogenous bases. The DNA is separated into two strands. DNA Replication Then: (enzyme) DNA polymerase pairs the bases A-T and G-C. DNA Polymerase checks work and corrects mistakes …. Nucleotides are paired DNA ligase (enzyme) follows behind and bonds the nucleotides together. Two strands of DNA are created. DNA Replication The process is fast and accurate an error occurs in only about one of a billion nucleotides. DNA replication occurs before a cell divides, ensuring that the cells in a multicellular organism all carry the same genetic information. It is also the mechanism for producing the DNA copies that offspring inherit from parents during reproduction. DNA replication The resulting double-stranded DNA molecules are identical; proofreading and error- checking mechanisms exist CENTRAL DOGMA transcription DNA translation RNA Proteins 3 different RNA molecules involved in protein synthesis: mRNA (messenger RNA) rRNA (ribosomal RNA tRNA (transfer RNA) PROTEIN SYTNESIS 1 step: Transcription occurs in the nucleus 2 step: Translation occurs in the cytoplasm  1st step Transcription: DNA  RNA Transcription occurs in the nucleus First: DNA unwinds in a section Next: mRNA (messenger RNA) is formed by base pairing with the parent strand of DNA. This begins transcription. Then: mRNA carries the message about what type of protein to make from the DNA in the nucleus to the ribosome  Transcription Once mRNA is formed, enzymes in the nucleus remove the Introns (noncoding message) and leave the Exons (good message)  The Genetic Code Each 3 consecutive bases on the mRNA is a code word, CODON, that specifies an amino acid. The genetic code consists of 64 codons, but only 61 code amino acids. Three codons act as signal to stop the process One codon, AUG, codes for methionine, and is also the Start signal for translation.  2nd step Translation: RNA  Protein Translation: synthesizing a code from amino acids, according to the sequences of the nucleotides in mRNA. Occurs at the ribosome, in cytoplasm of cell Ribosomal RNA, rRNA, is needed for protein synthesis – helps mRNA bind to the ribosome tRNA, brings specific amino acids to the ribosome to be assembled as proteins.  Translation Ribosomes are the sites of ______________  Transfer RNA (tRNA) Transport molecule that carries specific amino acid to a ribosome Each tRNA recognizes the correct codon on the mRNA molecule Translation  Steps in Translation 1. mRNA leaves the nucleus and migrates to ribosome 2. mRNA binds to small ribosomal subunit 3. tRNA brings an amino acid to the ribosome, where anticodon on the tRNA binds to the codon of the mRNA 4. The amino acid bonds to its adjoining amino acid to form a growing polypeptide molecule 5. The tRNA without the amino acid is released from the ribosome 6. Other tRNA’s bring amino acids to the ribosome to complete the protein molecule Protein translation Protein synthesis Occurs in the cytoplasm of the cell Summary:  Important Both DNA and RNA have a direction: one end is the 3’ the other is the 5’ end. Thus, codons are read in one direction only. Also, note there is redundancy in the genetic code: the different sequences can specify for the same amino acid. Example: _______________= Leucine