Nucleic Acids and Protein Synthesis

Nucleic Acids DNA DNA Deoxyribonucleic Acid Deoxyribonucleic Acid RNA RNA Ribonucleic Acid Ribonucleic Acid

DNA Double stranded helix Double stranded helix Never leaves the nucleus Never leaves the nucleus Watson, Crick, Wilkins won Nobel Prize in 1962 Watson, Crick, Wilkins won Nobel Prize in 1962 Franklin died in 1958 never recognized Franklin died in 1958 never recognized

DNA

Nucleotide Building Blocks of nucleic acids are NUCLEOTIDES! Building Blocks of nucleic acids are NUCLEOTIDES! Phospate group Phospate group Sugar molecule (deoyribose) Sugar molecule (deoyribose) Nitrogenous bases Nitrogenous bases

Nitrogenous Bases of DNA

How do the N-Bases pair up? A-T (2 bonds) A-T (2 bonds) G-C (3 bonds) G-C (3 bonds)

How Does DNA Replicate? 1. double helix unwinds 1. double helix unwinds 2. Each chain serves as a template for new nucleoide chain 2. Each chain serves as a template for new nucleoide chain 3. point at which 2 chains separate is called the REPLICATION FORK. 3. point at which 2 chains separate is called the REPLICATION FORK. 4. HELICASE = the enzyme that separates the chains (breaks H bonds) 4. HELICASE = the enzyme that separates the chains (breaks H bonds) 5. DNA POLYMERASE moves along the chains and helps assemble new nucelotides forming new chains (3’ to 5’ ONLY) 5. DNA POLYMERASE moves along the chains and helps assemble new nucelotides forming new chains (3’ to 5’ ONLY) DNA LIGASE – ligates 5’ to 3’ (DNA polymerase brings the nucleotides) DNA LIGASE – ligates 5’ to 3’ (DNA polymerase brings the nucleotides)

DNA replication continue… The 3’ sugar has an –OH GROUP The 3’ sugar has an –OH GROUP The 5’ sugar has a PHOSPHATE GROUP The 5’ sugar has a PHOSPHATE GROUP LEADING STRAND – formed from 3’-5’ LEADING STRAND – formed from 3’-5’ LAGGING STRAND – formed from 5’- 3’ with the help of DNA LIGASE! LAGGING STRAND – formed from 5’- 3’ with the help of DNA LIGASE! OKAZAKI FRAGMENTS – fragments that will be ligated together OKAZAKI FRAGMENTS – fragments that will be ligated together

Can you see how DNA is making an exact copy of itself! *

This a little more difficult Can you figure out the diagram? Can you figure out the diagram?

Simplest Illustration of DNA replication…

What is a mutation ?? A CHANGE in the nucleotide sequence at even ONE location!! A CHANGE in the nucleotide sequence at even ONE location!!

RNA RIBONUCLEIC ACID SINGLE STRANDED SINGLE STRANDED RESPONSIBLE FOR BRINGING THE GENETIC INFO. FROM THE NUCLEUS TO THE CYTOSOL! RESPONSIBLE FOR BRINGING THE GENETIC INFO. FROM THE NUCLEUS TO THE CYTOSOL!

RNA Nucleotide Phosphate group Phosphate group Sugar molecule (ribose) Sugar molecule (ribose) Nitrogenous bases Nitrogenous bases Adenine – URACIL Adenine – URACIL Cytosine - guanine Cytosine - guanine

3 Kinds of RNA mRNA – (messenger) brings info from DNA in nucleus to cytosol in eukaryotic cells (uncoiled) mRNA – (messenger) brings info from DNA in nucleus to cytosol in eukaryotic cells (uncoiled) tRNA –(transfer) brings amino acids to mRNA for translation (hairpin shape) tRNA –(transfer) brings amino acids to mRNA for translation (hairpin shape) rRNA –(ribosomal) most abundant, rRNA makes up the ribosomes where proteins are made (globular) rRNA –(ribosomal) most abundant, rRNA makes up the ribosomes where proteins are made (globular)

TRANSCRIPTION!! DNA  RNA 1.RNA polymerase-initiates transcription by binding to region on DNA called PROMOTER (causes DNA to separate) 1.RNA polymerase-initiates transcription by binding to region on DNA called PROMOTER (causes DNA to separate) 2. only ONE of the DNA chains will be used for transcription it’s call the TEMPLATE 2. only ONE of the DNA chains will be used for transcription it’s call the TEMPLATE 3. RNA POLYMERASE – attached to first DNA nucleotide of template chain – then begins adding complementary RNA nucleotides 3. RNA POLYMERASE – attached to first DNA nucleotide of template chain – then begins adding complementary RNA nucleotides

Cont. Transcription 4. transcription continues until RNA polymerase reaches a TERMINATION SIGNAL on the DNA 4. transcription continues until RNA polymerase reaches a TERMINATION SIGNAL on the DNA 5. RNA polymerase releases both the DNA mol. And newly formed RNA mol. Are transcribed in this way (all three!!!) 5. RNA polymerase releases both the DNA mol. And newly formed RNA mol. Are transcribed in this way (all three!!!)

RNA *

RNA replications

Protein Synthesis PROTEINS CARRY OUT THE GENETIC INSTRUCTIONS ENCODED IN AN ORGANISM’S DNA!!!! PROTEINS CARRY OUT THE GENETIC INSTRUCTIONS ENCODED IN AN ORGANISM’S DNA!!!!

TRANSLATION The process of assembling from info. Encoded in a mRNA! 1. mRNA leaves nucleus 1. mRNA leaves nucleus 2. mRNA migrates to ribosome in cytosol for protein synthesis 2. mRNA migrates to ribosome in cytosol for protein synthesis 3.amino acids floating in cytosol are transported to ribosomes by tRNA mole 3.amino acids floating in cytosol are transported to ribosomes by tRNA mole 4. peptide bonds join the amino acids to make polypeptide chain 4. peptide bonds join the amino acids to make polypeptide chain

Vocabulary! 1. GENETIC CODE: correlation between a nucleotide sequence and an amino acid sequence 1. GENETIC CODE: correlation between a nucleotide sequence and an amino acid sequence 2. CODON 3 mRNA nucleotides, codes for a specific amino acid (64) 2. CODON 3 mRNA nucleotides, codes for a specific amino acid (64) 3. START CODON (AUG) & a.a. methionine 3. START CODON (AUG) & a.a. methionine 4. STOP CODON (UAA, UAG, UGA) 4. STOP CODON (UAA, UAG, UGA) 5. ANTICODON – 3 tRNA nucleotides carrying a specific amino acid! 5. ANTICODON – 3 tRNA nucleotides carrying a specific amino acid!

Protein Synthesis *

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THE SUMMARY!