What radioactive isotope was used in Meselson and Stahl experiment to prove the semi-conservative mode of DNA replication?
1. | 35S | 2. | 32P |
3. | 15N | 4. | None |
Under conditions where methionine must be the first amino acid, what protein would be coded for by the following mRNA?
5'-CCUCAUAUGCGCCAUUAUAAGUGACACACA-3'
1. | pro his met arg his tyrlyscys his thr |
2. | met arg his tyrlyscys his thr |
3. | met arg his tyrlys |
4. | met pro his met arg his tyrlyscys his thr |
Which of the following is likely if there is a mutation in the lacY gene of the lac operon in E.coli?
1. | The lac genes would be expressed efficiently only in the absence of lactose. |
2. | The lac genes would be expressed efficiently until the lactose supply in the cell is exhausted. |
3. | The lac genes would be expressed continuously. |
4. | Expression of the lac genes would cease immediately. |
The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that:
1. | The nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose. |
2. | The nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups. |
3. | ATP contains three high-energy bonds; the nucleoside triphosphates have two. |
4. | ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells. |
Which of the following pairs of codons encode the same amino acid?
1. | AUG and AUC | 2. | UAA and UAC |
3. | GUA and GUG | 4. | UAG and UAC |
Griffith wanted to make a vaccine to prevent pneumonia. He injected heat-killed S-strain bacteria into the mice for this purpose. How can a killed bacteria help in making a vaccine?
1. | The heat-killed bacteria is a more potent toxin than the live one. |
2. | Protein denaturation due to heat changes the proteins of the bacterium. |
3. | Molecules from the cell surface are still intact and can provoke an immune response. |
4. | DNA molecules can transform other strains of bacteria. |
Griffith's experiment discovered bacterial transformation which in his experiment means:
1. | A mutation in the R strain made them virulent. |
2. | A mutation in the S strain made them non-virulent. |
3. | A rough strain passed genetic information to a smooth strain. |
4. | A smooth strain passed genetic information to a rough strain. |
Avery, MacLeod, and McCarty used DNase in their experiment because:
1. | It enabled them to isolate pure DNA samples. |
2. | It enabled them to isolate pure protein samples. |
3. | This allowed them to demonstrate that removing the DNA prevents transformation. |
4. | It made sure that RNA will always be present when they attempted to transform the R strain. |
What key observation regarding Garrod'sinborn of metabolism leads to a landmark discovery in molecular biology?
1. | Identification of a defective gene in individuals with alkaptonuria. |
2. | Identification of a defective gene in parents of alkaptonuria patients. |
3. | Identification of a defective enzyme in individuals with alkaptonuria. |
4. | Identification of the inheritance pattern of alkaptonuria as autosomal recessive. |
T2 bacteriophage was used by Hershey and Chase to conclusively prove that DNA and not protein is the genetic material because:
1. | It makes capsomeres with the help of its genes. |
2. | It injects its genetic material into a bacterial cell. |
3. | It can undergo either the lytic or lysogenic life cycle |
4. | It enters the bacterial cell to cause infection. |