Q. No.In DNA replication, the Okazaki fragments on the lagging strand are joined together by:
1. DNA ligase
2. DNA polymerase
3. Primase
4. Helicase
Which scientists first gave experimental evidence that DNA is the genetic material?
| 1. | Avery, MacLeod , and McCarty who repeated the transformation experiments of Griffith, and chemically characterized the transforming principle. |
| 2. | Garrod, who postulated that Alcaptonuria, or black urine disease, was due to a defective enzyme. |
| 3. | Beadle and Tatum, who used a mutational and biochemical analysis of the bread mold Neurospora to extablish a direct link between genes and enzymes. |
| 4. | Meselson and Stahl who showed that DNA is replicated semiconservatively. |
Fredrick Griffith accidentally discovered transformation when attempting to develop a vaccine for pneumonia. He injected mice with samples from S-strain (virulent) and/or R-strain (nonvirulent) pneumococci bacteria (Sterptococcus pneumoniae). Which of the following results is NOT consistent with Griffith's experiments?
1. injected S-strain; mouse dies.
2. injected R-strain; mouse lives.
3. injected heat-killed S-strain; mouse lives.
4. injected mixture of heat-killed S-strain and live R-strain; mouse lives.
A transcription unit does not contain:
1. A promoter
2. The structural gene
3. A terminator
4. An operator
Genetic information in a DNA molecule is coded in the:
1. Sequence of nucleotides
2. Base pairings
3. Proportion of each base present
4. The turning pattern of the helix
In general, bacterial genes are regulated at the time of:
1. Transcription
2. Post transcription
3. Translation
4. Post translation
Regulation of lac operon by repressor is referred to as:
1. Inducible regulation
2. Repressible regulation
3. Negative regulation
4. Positive regulation
The function of the rho protein is
1. to help terminate translation
2. to help RNA polymerase bind to the DNA
3. to help RNA polymerase find a promoter
4. to help terminate transcription
The enzyme that catalyzes the peptide bonding in prokaryotes is located in the:
1. Leader region of the mRNA
2. Central part of tRNA
3. Smaller subunit of the ribosome
4. Larger subunit of the ribosome
A synthetic mRNA of repeating sequence 5'-CACACACACACACACAC... is used for a cell-free protein synthesizing system like the one used used by Nirenberg. If we assume that protein synthesis can begin without the need for an initiator codon, what product or products would you expect to occur after protein synthesis?
1. one protein, consisting of a single amino acid
2. three proteins, each consisting of a different, single amino acid
3. two proteins, each with an alternating sequence of two different amino acids
4. one protein, with an alternating sequence of two different amino acids
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