SET 10 - Katie Crump PDF

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Katie Crump...

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SET 10 Hersey and chase expriement allowed researches to distinguish between DNA and protein as candidates for phage T2's generica material. Just as a test of your understanding of the experiment, imagine what the results would have been if the genetic material had been the protein? They would have found 65S label inside the bacteria after treatment with the blender. -Remember, Herhsey and Chase tagged the phosphorus, which is only in DNA, and sulfur which is only in protein. If the protein had been the genetic material passed on, the sulfur would have been INSIDe the bacteria after the bacteria took on the DNA.

Fraenkel-Conrat and Singer demonstrated ___ to be the genetic material of the tobacco mosaic virus (TMV). RNA -Fraenkel-Conrat and Singer separated protein and RNA fractions of two strains of TMV and reconsituted hybrid viruses, with the RNA of one strain and protein of another strain. When they were applied to tobacco plants, each hybrid virus produced the lasions characteristic of the virus that had donated the RNA part of the hybrid. Progny from the lesions had complete viruses (protein AND RNA) from the virus that donated the RNA.

Watson and Crick discovered the structure of the DNA molecule to be a double helix sugars and phosphate groups alternate to form the backbone of each helix

The nitrogenous bases in DNA and RNA are single ring pyrimidines and double ring purines

Avery, McCleod and McCarthy showed what to be the transforming principle? -DNA

Why did Avery, McCleod and McCarthy decide that DNA was the transforming principle?

-The bacteria that had no proteins and no RNA (because of the nucleases) still had bacteria that transformed from good bacteria to virulent bacteria. Bacteria can spontaneously take in DNA and assume that DNA properties. -however, when a DNAse was added, transformation stopped.

Hershey and Chase experiment showed that DNA is the genetic material of bacteriophage t2

Each nucleotide has polarity. what does this mean? it has a top and a bottom

All nucleotides in a given strand face the same direction. The nucleotides on the complementary strand all face the same direction too, which is opposite to the direction of the first strand. The two strands are: complementary and antiparallel -run in opposite direction, and are backwards copies of the other

What are hairpins in DNA or RNA? Hydrogen bonding occurs between complementary bases on the same strand. -unusual secondary structure, and disrupts double helix between two DNA strands -this structure is associated with disease in DNA -in RNA hairpins are more common and play an important role in the normal functioning of individual RNA molecules

Who proposed cell theory? Schleiden and Schwann

Griffith -introduced transformation principle, but did NOT know what caused the transformation

Griffith's transformation principle in detail -Griffith worked with an R strain (non virulent) and S strain (virulent) of streotpococcus pneumoniae -s strain had a coating of polysacharrides, allowing it to be less susceptible to antibodies and humans' immune systems -IIIS in particular was a very deadly strain -Griffith had four set ups -Set up 1: injected virulent into mice. As expected, mice died (control) and there were IIIs in the blood -Set up 2: injected non virulent into mice. AS expected, mice did NOT die - body was able to fight off. There were no bacteria in blood. (also control) -Set up 3: heat killed virulent bacteria in mice. None died, again no bacteria recovered. -Set up 4: Alive non virulent and heat killed virulen mixed together, injected into mouse. Mouse did die, and blood had the virulent bacteria. -HENCE the non virulent transformed into the virulent because the dead virulent were somehow passing on their traits! but griffith did NOT know what cause the transformation principle

How did the bacterium like the non virulent type tranform into the virulent, even though it was mixed with DEAD virulent bacteria? -when the virulent bacteria was heat killed, the DNA was not killed, it was left outside the bacteria, ready to be absorbed -the non virulent bacteria has the ability to take in a piece of dena from any species and sustitute a portion of it into its own circular dna. That dna then recombines, and it takes on new characteristics. -This is how the non virulent strand became virulent.

Griffith in picture

Did griffith ever find the identity of the transforming principle?

No avery, macleod and mccarty did it

Avery, MacLeod and McCarty -transofrming principle is DNA -in 1944, they took the last set up in griffith's experiment, and added RNA nuclease to 1, DNA nuclease to another one, and protease to a third. The endonucleauses would chop up the dna/rna/protein, rendering it useless and ideally unable to pass on genetic material. -the only one where transoformation DIDNT take place was with the DNAase =no DNA, no transformation!

Why was the s strain virulent versus the r strain? the s strain had a smooth coating of polysacharrides that allowed it to survive an attack from the nervous system. The R or rough strain did not, and that is way the body is able to fight it off.

Chargaff's rules G only pairs with C A only pairs with T or U he found a 1 to 1 ratio in the pairs

Hershey and Chase: in 1952, experiment with bacteriophage T2, part 1 -bacteriophage is 50% protein (shell) and 50% DNA -phage sinks into bacteria and releases their genetic material into host. remaining shell is ghost phages. -takes over bacteria and makes bacteria do what it wants.

Hershey and Chase: in 1952, experiment with bacteriophage T2, part 2 -they labelled DNA with radioactive phosphorus (P-32) which they could track. Phosphorus is only in DNA.

-they labelled S with S-35, also radioactive, and is only in protein. -they then infeted e.coli with radiolabeled phages -they then centrifuged and pelleted the material from the bacteriophage. -radioactivity P-32 was found in the supernatant (DNA) and not in the cell parts. -labelled protein stayed outside of the cell

What does H&Chae demonstrate? 1) DNA is what is sent to the cell as genetic inheritance 2) IF they had allowed the infection to proceed, they would have had some DNA labelled in progeny phages! 3) DNA is coding for phenotype of bacteria 4) what went into the cell was the dna 5) but what came out was entire phages (protein AND dna). Somehow the phenotype information was put in cell so cell could make it.

Watson and Crick used Franklin's method to get helical model of DNA Frankly created xray cyrstallography her crystal was very clean and pure, and it garnered information about the shape light goes through atom and bounces back shadow has a specific shape

Who proved that RNA could also be genetic material? Fraenkel-Conrat and Singer on tobacco mosaic virus

What was Fraenkel Conrat and Singer's epxperiment? -in TMV, they tried to see if RNA or protein produced lesions on plants. -from two strains of TMV, they diassociated with the virus -they made hybrid viruses from one strain and protein from the other

-for example RNA from A and protein from B and vice versa -they then infected plants with the hybrid strains -the lesions that came out on the tobacco were associated with the RNA and the protein on the viruses were also associated with the RNA

Did the progein in Fraenkel Conrat and singer's experiment have any effect on progeny? NO -progeny were the protein AND rna from the virus that donated the RNA.

What is the repeating unit of the DNA polymer nucleotides

what types of sugars are in nucleotides pentose sugar ribose and deoxyribose

difference between ribose and deoxyribose in the 2' carbon, deoxyribose has no oxygen (missing hydroxyl) -additonal O in ribose makes it more reactive

Where on the sugar is the phosphate attached to? The base? Phosphate is attached to the 5' sugar Base is attached to the 1' sugar

what is adenine?

what is guanine

what is cytosine

what is thymine

what is uracil

what is a nucleotide with adenosine called? -deoxyadenosine g'-monophosphate (dAMP)

What is a nucleotide with guanine called? -deoxyguanosine 5'-monophosphate (dGMP)

What is a nucleotide with thymine called? -Deoxythymadine 5'-monophosphate (dTMP)

What is a nucleotide with cytosine called? -deoxycytodine 5'-monophosphate (dCMP)

What are the pyramidines?

what are purines? What are the difference in purines?

How to tell the nucleotides apart Guanine - double ring, has one carbonyl and one amine Adenine - double ring, has no carbonyls, and one amine Cysotine - single ring, has one carbonyl and one amine Thymine - single ring, has two carbonyls, and one methyl uracil - single ring, has two caronyls and NO methyl

Why can thymine and uracil substitute for each other? They've got the same structure except thymine has a methyl, on the 5 carbon and uracil has CH on the 5 carbon, making the uracil more reactive and the DNA more repressed from expression.

The two strands in the double helix are both complementary and antiparallel -one strang is complementary and 5'-3' which hudrogen bonds with another strand that is 3'-5'

Each sugar molecule has polarity. What is the top and what is the bottom? -top of the sugar molecule is 5' end -bottom is 3' end -each nucleotide therefore has polarity and gives the wohle DNA strand polarity

What bonds are nucleotides linked with phosphodiester bonds -bond of strong covalent bonds between phosphate group and two 5 carbon pentoses over two ester bonds.

How are links of a strand made? -molecule is polar. -backbone of dna is composed of alternating sugar and phosphate molecules. -5' is connected to oxygen in phosphate which is then connected to 3' of another pentose sugar 5' to phosphate to 3'

When stacked, how do the bases create a helix? Each base is 36 degrees shifted than the other ten base pairs. All ten are needed to get around.

Where do proteins attach to DNA? -the minor groove -the major groove

What type of double helix does DNa form? -right handed helix -clockwise direction results in a motion away from you

What are the levels of DNA structure? primary - order and sequence of nucleotides which has the information content secondary - double helix - antiparralel and complementary -tertiary - higher level folding beyond double helix, such as z, B, A dna

What are the three tertiary structures od DNA A DNA is: -when solution is 75% water -the helix direction is right handed

-the overall shape is short and wide B DNA is: -when solution is 92% water -helix is still right handed -this is perfect for DNA, angle of rotation is 36 degrees -long and narrow Z DNA -shorter and wider -bases hide away from main axis of molecule for protction -this is in salt solutions -elongated and narrow -left handed helix direction -alternating purine and pyrmadine bases

Information transfer -DNA to DNA is DNA replication -DNA to RNA is Transcription -RNA to DNA is Translation

What is the central dogma of molecular biology? DNA to RNA to Protein -however sometimes there are exceptions such as reverse transcription (retroviruses) and RNA to RNA replication

What is a reverse transcription virus has rna then forces DNA to transcribe RNA and protein per its genetic information...