Today’s Bellwork: Use pages 196 – 199 of Modern Bio text to complete the Skills Worksheet “DNA Structure” You may work in SMALL groups (3-4) Turn in for a grade! You have 10 minutes……….. When you turn in, get today’s notes outline (two pages front and back.

Today’s Bellwork Sit in groups of 3 or 4. DO NOT MOVE CHAIRS! Each group has a picture or diagram. On a square of paper, write a detailed description of your picture or diagram (use as many Unit 5 terms as possible). Each group will quickly show their diagram/picture and read their description. Put all of your names on the back of the SQUARE paper with your description. Turn in for a grade!

Announcements Bring signed letter for 100 in gradebook (formative) Vocabulary Quiz Retake for everyone – Wed. Jan. 13 (A)/Thurs. Jan. 14 (B) Unit 5 TEST Fri. Jan 15(A)/Tues. Jan 19(B) School Holiday Monday, Jan. 18

UNIT 5: MOLECULAR GENETICS DNA, RNA, PROTEINS

I. BUILDING BLOCK OF DNA

B. Three parts are a phosphate group, sugar, and nitrogen base. A. A NUCLEOTIDE = THE BUILDING BLOCK OF RNA AND DNA

Purines Pyrimidines AdenineGuanineCytosineThymine Phosphate group Deoxyribose C. Two categories of bases

THE 4 BASES FIT INTO ONE OF TWO CATEGORIES: 1. PURINE---LARGER (ADENINE & GUANINE) 2. PYRIMIDINE---SMALLER (CYTOSINE & THYMINE)

DNA Structure= String of nucleotides (sugar, phosphate, base) *Adenine *Thymine *Guanine *Cytosine purines - adenine, guanine pyrimidines - cytosine, thymine

D. The DNA Molecule The DNA sides are made of alternating sugar and phosphate groups The rungs(steps) are made of the nitrogen bases Hydrogen bonds hold the bases together

WHEN THE NUCLEOTIDES “CLICK” TOGETHER LIKE LEGOS, THE RNA OR DNA MOLECULE IS FORMED

Practice Questions: Where does DNA contain its genetic information? A.In its hydrogen bond B. In its deoxyribose sugar C. In its nucleotide sequence D. In its phosphate group

Practice Questions: What do the sequence of nucleotide bases determine? A.The kind of DNA made B. The kind of protein made C. The chromosomes that will be passed on D. The amino acids that will be made

Practice Questions: Which of the following is true about the relationship among DNA, genes and chromosomes? A.Chromosomes and proteins make up genes, and genes make up DNA. B. Chromosomes are made up of DNA and protein. Genes are sections of DNA on a chromosome. C. Genes and proteins are made up of DNA. The sequence of genes and proteins make up a chromosome. D. Proteins make up chromosomes and DNA. DNA and chromosomes make up genes.

II. The History of the Study of DNA Know what Griffith, Avery and Hershey and Chase contributed (see crossword puzzle)

D. ERWIN CHARGAFF & CHARGAFF’S RULES DISCOVERED THAT THE AMOUNT OF ADENINE WAS EQUAL TO THE AMOUNT OF THYMINE A=T DISCOVERED THAT THE AMOUNT OF GUANINE WAS EQUAL TO THE AMOUNT OF CYTOSINE G=C

E. ROSALIND FRANKLIN X-RAY DIFFRACTION DISCOVERED THAT DNA WAS 2 STRANDS WOUND AROUND EACH OTHER (SPIRAL SHAPE)

F. WATSON & CRICK BUILT THE PRESENT DAY MODEL OF DNA SAID HYDROGEN BONDS HOLD BASES TOGETHER AND FORM BETWEEN CERTAIN BASES—A & T AND G & C EXPLAINS CHARGAFF’S RULES---FOR EVERY A THERE IS A T AND FOR EVERY G THERE IS A C.

Francis Crick and James Watson (1953) Twisted Double Helix Hydrogen Bonds are the “ glue ” that keeps the two strands together Each strand of the helix is a chain of nucleotides What holds the strands together?

CE ow_he_discovered_dna?language=en#t One of the world’s greatest discoveries

Group Reflection: As a group, come up with one statement that reflects your thoughts about James Watson and the discovery of the structure of DNA.

III. The Structure of DNA

Always Together….Great Couple DENINEDENINE HYMINEHYMINE UANINEUANINE YTOSINEYTOSINE A & TG & C A. Chargaff’s Rule = complimentary bases in equal numbers

Hydrogen bonds Nucleotide Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G) B. The Structure of DNA

How is DNA organized in a chromosome? Remember Chromatin?? DNA tightly coiled around proteins forming Chromatin which pack together to form thick fibers. What exactly is chromatin? ONE nucleus of ONE human cell = more than 1 meter of DNA!!!

C. D N A In PROKARYOTES FOUND IN NUCLEAR AREA CIRCULAR LESS DNA ONE REPLICATION POINT In EUKARYOTES FOUND IN THE NUCLEUS LINEAR MORE DNA REPLICATION STARTS AT MANY PLACES AT ONCE

Chromosome E. coli bacterium Bases on the chromosome Prokaryotic Chromosome Structure Section 12-2

Chromosome Structure of Eukaryotes Chromosome Supercoils Coils Nucleosome Histones DNA double helix

IV. How can DNA use its double-stranded structure to its advantage for replication???

“Something Old…Something New”

A. DNA Replication – process in which a cell duplicates its DNA When does this occur in the cell cycle? B. Steps of Replication 1) Enzymes un-twist and unzip the molecule (break H bonds between base pairs). 2) Each strand serves as a template (something “ OLD ” ) 3) Free nitrogen bases form bonds and make complementary strands (Something “ NEW ” ) 4) DNA Polymerase bonds the nucleotides and proofreads the molecule

Figure 12–11 DNA Replication Growth Replication fork DNA polymerase New strand Original strand DNA polymerase Nitrogenous bases Replication fork Original strand New strand

C. Results of DNA Replication This occurs during interphase of the cell life cycle and before mitosis. Results in 2 DNA molecules identical to each other Each new DNA molecule has one original strand and one new (replicated) strand. This is called semi-conservative replication.

Replication Wsuc Wsuc

Practice Questions: How is the shape of DNA usually described? A. Double helix B. Twisted sister C. Flattened ladder D. Twisted spiral

Practice Questions: Which of the following is NOT true about DNA replication? A.It occurs during interphase B. The new DNA is identical to the original DNA C. It is semi-conservative D. The sequence of the nucleotides is changed

Practice Questions: What would be the DNA compliment to the following section of DNA: GCCTTA A.CGGUUT B. CGGAAT C. ATTCCG D. TAAGGC

Reflection: As a group, write one statement that describes the role the structure of DNA plays in its ability to replicate itself.

V. DNA vs RNA Work together to complete the graphic organizer in your notes comparing and contrasting DNA and RNA

DNA vs. RNA DNA – also a long chain of nucleotides (5- carbon sugar, phosphate group, nitrogenous base); double stranded and twisted RNA Differences: 1. RNA sugar = ribose, instead of deoxyribose 2. RNA – usually single-stranded 3. RNA has uracil to replace thymine (so U binds with A) “Always United & Great Couple”

HOW ARE PROTEINS MADE? BYJOINING TOGETHER LONG CHAINS OF AMINO ACIDS AMINO ACID---AMINO ACID=DIPEPTIDE AA, AA, AA, AA, AA,AA, = POLYPEPTIDE A POLYPEPTIDE IS A L O N G CHAIN OF AMINO ACIDS (A PROTEIN!)

RNA is in charge of assembling Amino Acids into Proteins

VI. From DNA(Gene) to Protein rRNA - ribosomal RNA - location of protein synthesis uses tRNA to make proteins The players: DNA - sequences of nitrogen bases forms the genetic code mRNA - messenger RNA - makes a copy of the DNA in the nucleus and brings it to the rRNA tRNA - transfer RNA - reads the mRNA and brings specific amino acids to the rRNA

B. Step 1: Transcription = recording the message Occurs in nucleus New mRNA strand forms from one of DNA strands (creating the message) Remember Always Together (A and T) and Great Couple (C and G) when DNA is replicating and Always United (A and U) and Great Couple (G and C) during translation and transcription. WHY???? Let’s Practice…

Transcription Practice 1. Replicate the DNA strand below. 2. Then, transcribe the replicated strand into mRNA ATTATCGCGTAATGCTAATAGC TAATAGCGCATTACGATTATCG Original DNA AUUAUCGCGUAAUGCUAAUAGC mRNA transcript Replicated DNA

RNA DNA RNA polymerase Figure 12–14 Transcription Adenine (DNA and RNA) Cystosine (DNA and RNA) Guanine(DNA and RNA) Thymine (DNA only) Uracil (RNA only)

C. Step 2: Editing of mRNA Introns are removed – non coding regions of the DNA molecule Exons remain – sequences that will be expressed

D. Step 3: Translation = Protein Synthesis Occurs at ribosome tRNA reads mRNA which has message from genetic code (DNA) Genetic code is read 3 letters at a time, so each word is 3 bases long

Every 3 letters is a CODON Each codon codes for a specific amino acid. What does an Amino Acid do again?Helps make proteins! We need codons for Protein Synthesis (Translation) They are like directions to make proteins Every set of directions tells you where to START and where to STOP We too have these, we call them the “start and stop codons”

Codons to remember… START is always:  AUG STOP is always:  UAA  UAG  UGA

Translation Explained tRNA UAC mRNA AUGCGCAUAACGCAU Start Codon methionine

Alternate sequence: There are 20 different amino acids to be coded for. There are 64 possible codons. Start codon Stop codon

Figure 12–17 The Genetic Code

Translation Practice Make a polypeptide (chain of amino acids) chain from the mRNA molecule AUGAUCGCGUAUUGCUACUAG - mRNA methionine-isoleucine-alanine-tyrosine-cysteine-tyrosine STOP

Protein Synthesis – Transcribing and Translating the DNA Code to Make Protein

Figure 12–18 Translation Section 12-3

Figure 12–18 Translation (continued) Section 12-3

Practice Questions: How is RNA similar to DNA? A.They both contain ribose sugar B. They both contain uracil C. They are both single strands D. They both contain nucleotides

Practice Questions: Which process copies instructions from DNA onto mRNA? A.transcription B. translation C. duplication D. replication

Practice Questions: Which process interprets the information from mRNA as an amino acid? A.transcription B. translation C. duplication D. replication

Practice Questions: What is a codon? A.A type of RNA that copies instructions from DNA B. A sequence of three bases that codes for a protein C. A portion of DNA that codes for proteins D. A sequence of three bases that codes for an amino acid

Practice Questions: What is the end result of translation? A.It produces duplicate copy of mRNA B. It produces duplicate copy of original DNA C. It forms a polypeptide chain D. It forms rRNA

Practice Questions: Why does the information in DNA have to be copied onto RNA? A.DNA is unable to leave the nucleus B. DNA doesn’t contain uracil C. There are three different types of RNA D. RNA contains ribose

Practice Questions: What is the purpose of mRNA? A.It attaches to the ribosomes B. It carries the code from DNA to the area outside the nucleus. C. It forms the anticodons D. It carries amino acids to the ribosomes

Reflection: As a group, come up with a student’s way to describe replication, transcription and translation. Imagine you have to explain this to a little brother or sister….or to an alien on earth for the first time …how would you use normal, every day language to describe these processes.

VII. The Nucleotide Sequence and Mutations

A. Mutations - changes in the DNA sequence Gene mutation- changes in a single gene Point Mutations - substitution of one nucleotide for another Frame Shift Mutations - shifting of the genetic code due to insertion or deletion of nucleotide Chromosomal mutation changes in the entire chromosome (containing many genes)

Deletion Duplication Inversion Translocation Figure 12–20 Chromosomal Mutations

B. Mutation Analogy THE FAT CAT ATE THE RAT substitution THE FAT CAT ATE THE CAT * The letter “C” was substituted for the “R” insertionTHE FAT CAT ATE THE RAT THC EFA TCA TAT ETH ERA T *Because the “C” was added, all other letters shifted down, thereby changing the amino acids that are made. C DeletionTHE FT CAT ATE THE RAT THE FTC ATA TET HER AT *Again, the amino acids will change b/c the “F” was removed A

Mutation Practice What will the new amino acid be if the 5th nucleotide is substituted with an adenine? AUGA CGCGUAUUGCUACUAG - mRNAU What will the new amino acid sequence be if a guanine is inserted between the 9th and 10th nucleotide ? ASPARAGINE G GUA = VALINE

When a mutation occurs… If the amino acid sequence is stopped early (a STOP codon is reached) = Nonsense If the amino acid sequence continues but the wrong amino acids are coded for = Missense

VIII. Putting it all together A. Replication. What would be the complimentary strand replicated/copied during DNA replication?) TACTACACCGTATAACAGGGCCTAGCAACT Original DNA Template ATGATGTGGCATATTGTCCCGGATCGTTGA Replicated DNA

B. Transcription – what would be the mRNA “code” for the following DNA strand? DNA - TACTACACCGTATAACAGGGCCTAGCAACT mRNA - AUGAUGUGGCAUAUUGUCCCGGAUCGUUGA C. Translation – what amino acids does this mRNA code for? amino acid sequence methionine-methionine-tryptophan-histidine- isoleucine-valine-proline-aspartic acid-arginine-stop

Alternate sequence: There are 20 different amino acids to be coded for. There are 64 possible codons. Start codon Stop codon

IX.

Transcription and Translation: Crash Course Style….

Protein Synthesis Skills Worksheet

Putting it All Together Replication, Transcription, Translation Flip Chart

Vocabulary Quiz and Open Notes Quiz Complete the Vocab Quiz. You do not get extra time!! Turn in. Get the 5 Question Open Notes Quiz Turn in!

x.html Online Hands On Activities: Replication of DNA Transcription and Translation