What is the major difference between the lagging and leading strands during DNA replication ?
(1) On the leading strand, DNA synthesis occurs from 5' to 3', while DNA synthesis occurs from 3' to 5' on the lagging strand.
(2) DNA polymerase is able to continuously add new nucleotides on the leading strand while it must keep 'starting over' on the lagging strand.
(3) The lagging strand requires only a single primer while the leading strand requires many.
(4) Helicase opens the leading stran at a faster rate than the lagging strand.
A tRNA molecule must :
(1) have a base sequence identical to the codon in the mRNA
(2) be attached to a particular amino acid
(3) bind to the protein to determine its primary structure
(4) All of these
The inducer of lac operon is :
(1) Beta galactosidase
The creation of a DNA fingerprint would normally employ all the following techniques except :
(1) Southern blotting
(2) Use of restriction endonucleases
(3) Gel electrophoresis
(4) Western blotting
regulatory domains of most activators interact with
(1) the transcription factor complex
(2) RNA polymerase
(4) the DNA binding domain
DNA chemically is less reactive and structurally more stable than RNA. Therefore,
1. DNA has evolved from the RNA
2. RNA can directly code for proteins
3. DNA is the better genetic material than RNA
4. The protein synthesizing machinery has evolved around RNA
A transcription unit does not contain:
1. A promoter
2. The structural gene
3. A terminator
4. An operator
Regulation of lac operon by repressor is referred to as:
1. Inducible regulation
2. Repressible regulation
3. Negative regulation
4. Positive regulation
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
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.