DNA, RNA and Protein Synthesis Biology Chapter 10 Notes DNA, RNA and Protein Synthesis

10.1 and 10.2 – Discovery and Structure of DNA

Griffith - 1928 -

Avery – 1940s -

Chargaff - 1949

Hershey and Chase - 1952 Hershey and Chase – -

Watson and Crick (and Franklin) - 1953

Human Genome Project - 1990 Attempt to record a complete human genome (all of the A,T,C,G’s). Completed in 2001, but still being interpreted.

Dolly the Sheep -- 1999 The first cloned animal

Structure of DNA

Structure of DNA DNA is a double helix structure made up of 2 long chains of repeating nucleotides A nucleotide has 3 parts: - -(Adenine, Guanine, Cytosine or Thymine) The two chains of nucleotides are held together by __________that form between the nitrogenous bases

Structure of DNA Some of the bases have 2 rings -purines and some have 1 ring - pyrimidines _________: Adenine and Guanine (A and G) ____________: Cytosine and Thymine (C and T)

DNA is complementary – if you know one side, you know the other --Fill out the missing letters -- Show the H-bonds

FUN FACTS!! The human DNA code is made up of about 3 billion nucleotide pairs (6 billion bases total!!) If the total DNA in one person were laid in a straight line, it would stretch to the sun and back over 600 times (it's 93 million miles from here to the sun). Less than 2% of the DNA in your genome actually codes for proteins

Experiments showed that DNA is the hereditary factor that passes on traits Hershey and Chase Chargaff Watson and Crick Dolly the sheep

Used a photograph from Rosalind Franklin to determine the structure of DNA Hershey and Chase Chargaff Watson and Crick Dolly the sheep

How is the structure of DNA best described? Trapezoidal Double Helix Circular Triple Lutz

Always combines with Cytosine… Adenine Thymine Guanine None of the above

Holds the 2 strands of DNA together… Magic Covalent bonds between bases Hydrogen bonds between bases Ionic bonds between bases

What would the genetic code of the complementary DNA strand be What would the genetic code of the complementary DNA strand be? CGG ATA ACG GAC CGG ATA ACG GAC GCC TAT TGC CTG ATT GCG GTA ACT TGG CGC TAG CAG

Chapter 10.3 – DNA Replication During what phase of the cell cycle does DNA replication occur?

DNA Replication - Enzymes play a key role http://www.youtube.com/watch?v=Luw5_z8mIrI&feature=related

Steps of DNA Replication 1. The complementary strands ________ Helicases break H-bonds between the 2 strands Creates replication forks (Prokaryotes have 2, Eukaryotes have thousands at once) 2. Complementary nucleotides are added to each strand ___________“preps” the strand by adding a short segment of RNA ___________adds complementary nucleotides from 5’->3’ on the leading and lagging strands Gaps are filled in with the help of DNA ligase 3. Enzymes are released and 2 identical DNA molecules result

DNA Replication is a “semi-conservative” process

Replication in Prokaryotes -- Replication starts at one replication fork and works its way around the entire loop of DNA -- -

Replication in Eukaryotes Many replication forks occur at the same time (thousands!!!) on any given chromosome If only one formed per chromosome, would take 53 days to replicate the largest human chromosome!!!

DNA Errors in Replication Only 1 error occurs in about 1 billion nucleotides (enzymes correct most errors) Only mutations present in gametes (egg and sperm) can be passed on to offspring - Some beneficial : HIV resistance

When does Replication occur? G1 Phase S Phase G2 Phase Mitosis

What is the Y-shaped region that occurs when the DNA strands separate called? Template Helicase DNA Polymerase Replication Fork

Put the following enzymes in the order in which they are involved in the replication process RNA Primase – Helicase - DNA Polymerase - Ligase RNA Primase - DNA Polymerase - Helicase - Ligase Helicase – RNA Primase - DNA Polymerase – Ligase Helicase – DNA Polymerase - RNA Primase - Ligase

How can we remember the order of enzymes? Helicase RNA Primase DNA Polymerase Ligase “Helicopter Rides Don’t Last” ????

leading ; lagging lagging ; leading left ; right right ; left The ________ strand has nucleotides added continuously while the ________ strand has them added in segments called Okazaki fragments leading ; lagging lagging ; leading left ; right right ; left

Leading versus Lagging Strand http://nobelprize.org/educational/medicine/dna/a/replication/index.html

Nucleotides are always added in a ______ direction top to bottom bottom to top 5’  3’ 3’  5’

Can you meet the Replication Challenge????? http://nobelprize.org/educational/medicine/dna_double_helix/dnahelix.html

Chapter 10.4 – Protein Synthesis What are proteins? What are they made of? Where in the cell are they made? Today you will learn how they are made!!!

Protein Synthesis DNA contains the instructions for making proteins. The steps in the process are divided into 2 major stages: _____________ and _______________ DNA _________________, so it depends on RNA molecules to transmit the directions for making proteins.

THE MAIN IDEA SECTIONS 3 AND 4!

Structure of mRNA It is ___________ It has sugar and phosphate as it’s backbone – but the sugar is __________ The four nucleotides that attach to the sugars are Cytosine Guanine Adenine ________

There are 3 Types of RNA _________(messenger RNA) – carries instructions from the DNA in the nucleus out to the cytoplasm _______(ribosomal RNA) -- part of the structure of ribosomes ________(transfer RNA) -- transfers amino acids to the ribosomes to make proteins

Transcription  making RNA Transcribing the genetic material into an mRNA molecule http://www.youtube.com/watch?v=ztPkv7wc3yU&feature=related

Steps of Transcription ______________binds to a promoter (a sequence of nucleotides that initiates transcription), causing the DNA to unwind for that gene RNA polymerase adds complementary nucleotides to ___________(“sense strand”) of the DNA molecule The RNA polymerase releases the DNA and the new mRNA once it reaches the end of the gene __________= specific sequence of nucleotides) mRNA can now leave the ________ and take the genetic instructions into the ___________

Translation - Making Proteins Translation = translating the genetic instruction (genetic code) in the mRNA to make a ______ Every 3 adjacent nucleotides in an mRNA molecule is called a codon. Each codon in mRNA specifies a particular amino acid. Long strings of amino acids = a protein!!

Steps in Translation Initiation Elongation Termination -- The ribosome, mRNA and tRNA (carrying methionine) bind together Elongation The tRNA carrying the amino acid corresponding to the next mRNA codon travels to the ribosome A peptide bond forms between the methionine and the next amino acid The first tRNA detaches and leaves the methionine behind Elongation continues and the polypeptide chain grows longer Termination A stop codon is reached (it does not code for any amino acid and has no complementary anticodon) The ribosome releases the mRNA and the newly made protein

From DNA -> Protein http://www.youtube.com/watch?v=NJxobgkPEAo&feature=related

What’s are the Amino Acids? DNA sequence: TAC ACU CUU GGC AAC ATT mRNA codon: __________________________ tRNA anticodon: ___________________________ Amino acids: ___________________________