8.1 Study Guide Flashcards
The procedure and set up of the Griffith experiment?
Griffith gathered four healthy mice and injected them with different strains of bacteria. He researching pneumonia to see how it affected living organisms. He injected the first mouse with the smooth strain (virulent) bacteria, which caused the mouse to die. Griffith injected the second mouse with the rough strain (non-virulent) bacteria and it lived. He injected the third mouse with heat killed smooth strain bacteria and the mouse lived. Griffith injected the fourth mouse with a combination of the rough strain and heat killed smooth strain bacteria, and the mouse died. He called the process of one strain bacteria acquiring a factor from another bacteria transformation.
The procedure and set up of the Avery, MacLeod, and McCarty experiment?
These scientists created a solution with the heat killed smooth strain bacteria and the rough strain bacteria. They added the smooth strain cells,, spun them in a centrifuge, and then heat-killed them. Then they added the rough strain bacteria. Then, they removed the carbohydrates and lipids because they knew that these macromolecules were not responsible for the transformation. Next, they added the enzyme protease to the solution, which destroyed the protein, but the transformation still occurred. Then, they treated the solution with ribonuclease, which destroyed the RNA, but the transformation still occurred. However, when they treated the solution with deoxyribonuclease, which destroyed the DNA, the transformation did not occur. This proved that DNA was responsible for the transformation.
The procedure and set up of the Hershey and Chase experiment?
Phase 1: One batch of viruses was labeled with radioactive phosphorus which is incorporated in the DNA. Another batch of viruses was labeled with radioactive sulfur, which is incorporated into the protein coat.
Phase 2: The bacteria were infected with the viruses. The researchers were looking to identify if viral DNA or viral protein entered the host bacteria cell.
Phase 3: The cultures were blended and centrifuged to separate the viruses from the bacteria.
Phase 4: The bacteria infected with the DNA-marked viruses, contained radioactive phosphorus. The bacteria infected with Protein-marked viruses, contained no markers. This proved, that viruses use DNA as the genetic material.
What are the parts of a nucleotide?
Phosphate group, a carbohydrate molecule (deoxyribose), and a nitrogenous base.
What is the structure of a DNA molecule?
DNA contains four base pairs: Adenine, Thymine, Guanine, and Cytosine. Pyrimidine (1 ring) always pairs with purine (2 ring). Thymine pairs with Adenine. Cytosine pairs with Guanine. A sugar/phosphate backbone is created by covalent bonds holding the nucleotides together. Hydrogen bonds connect the base pairs to hold the two strands together. There are five carbons around the sugar in the nucleotide. Nucleotides are bonded from phosphate to sugar between carbons 3’ and 5’. The two strands in a DNA molecule are antiparallel, which means that they run in opposite directions. The 5’ end is connected to the phosphate and the 3’ end is connected to the sugar. The phosphates are on the outside of the a DNA molecule. DNA is composed of two strands. DNA strands form a double helix. The nucleotide bases (A, T, G, and C) pair in the middle like ladder rungs. A=T and C=G.
Similarities and differences between DNA and RNA?
Similarities: Both are made of nucleotides. Both have a pentose sugar. Both contain a phosphate, a sugar, and a base.
Both have a helix made of sugar phosphates. Both have hydrogen bonds between base pairs.
Differences:
DNA: Deoxyribose molecule, nitrogenous base: A, C, G, and T. Sugar has a hydrogen molecule. Double-helix. Stores genetic information.
RNA: Ribose molecule. Nitrogenous base: A, C, G, and U. Sugar has a hydroxyl group (OH). Single strand. The single strand folds over itself. Temporary carrier of information. Transfer RNA and ribosomes synthesis proteins.
Analyzing the Griffith experiment:
Griffith injected the mice with different strains of bacteria to see whether the mice lived or died. The mice lived when injected with the rough strain and the heat killed smooth strain bacteria. However, the mice died when injected with the smooth strain and the rough and heat killed smooth strain combination. This showed that something was transforming the rough strain and heat killed smooth strain combination into a virulent bacteria.
Analyzing the Avery, MacLeod, and the McCarty experiment:
When the enzyme destroyed the proteins, the transformation still occurred. When the enzyme destroyed the RNA, the transformation still occurred. When the enzyme destroyed the DNA, the transformation did not occur. This showed that DNA is responsible for the transformation. When DNA, was broken down, transformation did not occur. When the other molecules were broken down, the transformation still occurred. Scientists were still skeptical about this discovery because they thought that DNA was too simple and was far less complex than proteins.
Analyzing the Hershey and Chase experiment:
The viral DNA-markers were found in the host bacteria cell. Which showed that DNA allowed the radioactive phosphorus to enter the bacteria, transforming the cell. However, the viral protein markers were not found in the host bacteria cell. This showed that proteins did not allow the radioactive sulfur to enter the host bacteria cell.
Calculate the amount of the other three bases when given the % of one base in an organism’s DNA.
20% Adenine:
20% Thymine, 30% Guanine, 30% Cytosine
45% Cytosine:
45% Guanine, 5% Adenine, 5% Thymine
