Module+Three+Review

[] [] This picture above shows Hershey and Chase (say that 5 times fast). I would like you to use the links above and your text and your workbook to get ready to talk about this experiment. Draw a diagram and explain the experimental procedure.

What were the key results of the Hershey Chase Experiment? -That DNA is the genetic material. That DNA, not protein contains the genes. Protien is not transferred to the cell, therefore DNA not proteins are the hereditary information being transferred.

What did these results tell scientists about the nature of the genetic material? -That Genes are DNA. That something other then protiens are being transferred from the bacteriphage to the cell. That protiens are not the transforming principle.

Know the other scientists and their work leading up to Watson and Crick: Miescher 1868, discovered acidic compound isolated from bandages (nuclein) Griffith 1928, discovered inheritance of traits summarized in his "transforming principle". Avery/McCarty discovered that DNA is the transforming principle. Franklin 1953, showed physical structure of DNA using Xrays Chargaff, discovered that the nucleotides are complimentary in DNA, that the amount of Adenine is equal to that of Thymine/Uracil and Cytosine is equal Guanine. 2. Replication Bubble. [] This is a picture of a bubble of replication. You should be able to draw something like this. Also be able to label and above (3’, 5’, lagging strand, leading strand, direction DNA polymerase reads, and helicase. Also, add where DNA Ligase would work and the origin of replication.

3. How did Watson and Crick figure out the exact configuration of the base pairing on the DNA double helix? Remember our discussion in class. 1. Hydrogen bonds between bases allows for easy unzipping, rezipping; 2. A=T, G=C according to Chargaff’s rules; 3. Purine must hook up with pyrimidine to keep the constant diameter of the double helix; 4. 2 bonds between A-T, 3 H-bonds between G-C.

I like the question in your workbook pg. 12: Give two reasons why in DNA replication, the nucleotides T always pairs with A and Cytosine always pairs with Guanine. -The amount of Adenine always equals the amount of Thymine and the amount of Cytosine always equals the amount of Guanine. -The double helix is a certain diameter apart always, and the measurements for the A, T and G, C will always be the same and create a double helix.

4. Describe 4 differences between the structures of a DNA and RNA molecule. (see page 5 in your workbook). -DNA is formed from nucleotides, RNA is formed by ribonucleotides. -DNA is double stranded, RNA is single stranded. -DNA has sugar deoxyribose, and RNA has sugar ribose. -DNA : Adenine,Thymine, Guanine, Cytosine. RNA: Uracil, Adenine, Guanine, Cytosine. -DNA: stays in nucleus while RNA leaves and enters the cytoplasm

5. List the enzymes used in DNA replication and the enzymes used in Transcription/Translation. Tell the role of each enzyme and tell which direction they may proceed? Either direction or one way only. Helicase Seperates the two strands of polynucleotides (DNA) creating a gap. Moves in both directions Primase--> attach to parent DNA strand in the center of the helicase gap on the lagging end to prepare the strand for replication. Allows DNA polymerase to read lagging strand. Reads strand in the 3' to 5' direction only but grows in the 5' to 3' direction to allow the DNA polymerase to copy in the correct direction. RNA Polymerase> The workhourse in Transcription in the Elongation stage, this enzyme types the mRNA strand, making a nucleic acid single stranded chain using the pyridimine Uracil instead of Thymine in the 5' to 3' direction. DNA polymerase> The workhorse typwriter which builds the daughter strand by taking nucleotides and matching them to the parent strand readin the parent strand in the 3' to 5' direction (directionally dependant) Ligase--> Seals gaps on the lagging strand of DNA created by Okazaki fragments, creates covalent bonds between sugar and phosphate groups forming DNA backbone, NOT directionally dependent.

6. Know the changes that a newly transcribed RNA molecule undergo before export from the nucleus as a fully functioning mRNA. (Cap, Tail, splicing) Draw the changes here and explain.

Functional Group added to 5' end of mRNA, protects "start" instructions

Ribonucleotide added to 3' end of strand (poly A tail), combines with protiens and coils, influences how long mRNA strand will function.

Introns are removed (sections of a gene not needed for a specifically coded protien like disk defragmenter)

Exons are spliced together forming final version of mRNA strand

7. Please study your workbook. Read it over and over and try to make up some questions of your own. 8. Please know everything on the **Review Key Concepts Page** (24 of your workbook). Would you be able to fill this out from memory?

I may just Xerox a couple of pages of your workbook and have you fill them out to see that you have used your workbook and KNOW the workbook on the exam.

Practice drug problems: [] Don’t forget, this exam also has some questions from Chapters 2&3 (arrgh!!!) so don’t forget to review these.

[] [] This picture above shows Hershey and Chase (say that 5 times fast). I would like you to use the links above and your text and your workbook to get ready to talk about this experiment. Draw a diagram and explain the experimental procedure.

What were the key results of the Hershey Chase Experiment?

What did these results tell scientists about the nature of the genetic material?

Know the other scientists and their work leading up to Watson and Crick: Miescher Griffith Avery/McCarty Franklin 2. Replication Bubble. [] This is a picture of a bubble of replication. You should be able to draw something like this. Also be able to label and above (3’, 5’, lagging strand, leading strand, direction DNA polymerase reads, and helicase. Also, add where DNA Ligase would work and the origin of replication.

3. How did Watson and Crick figure out the exact configuration of the base pairing on the DNA double helix? Remember our discussion in class. 1. Hydrogen bonds between bases allows for easy unzipping, rezipping; 2. A=T, G=C according to Chargaff’s rules; 3. Purine must hook up with pyrimidine to keep the constant diameter of the double helix; 4. 2 bonds between A-T, 3 H-bonds between G-C.

I like the question in your workbook pg. 12: Give two reasons why in DNA replication, the nucleotides T always pairs with A and Cytosine always pairs with Guanine.

4. Describe 4 differences between the structures of a DNA and RNA molecule. (see page 5 in your workbook).

5. List the enzymes used in DNA replication and the enzymes used in Transcription/Translation. Tell the role of each enzyme and tell which direction they may proceed? Either direction or one way only.

6. Know the changes that a newly transcribed RNA molecule undergo before export from the nucleus as a fully functioning mRNA. (Cap, Tail, splicing) Draw the changes here and explain.

7. Please study your workbook. Read it over and over and try to make up some questions of your own. 8. Please know everything on the **Review Key Concepts Page** (24 of your workbook). Would you be able to fill this out from memory?

I may just Xerox a couple of pages of your workbook and have you fill them out to see that you have used your workbook and KNOW the workbook on the exam.

Practice drug problems: [] Don’t forget, this exam also has some questions from Chapters 2&3 (arrgh!!!) so don’t forget to review these.