Question

DNA polymerases are processed, which means that they remain tightly associated with the while moving rapidly and adding nucleotides to the growing daughter strand. Which piece of the machinery accounts for this characteristic? (a) helicase (b) sliding elamp (c) single-strand binding protein (d) primase RNA in cells differs from in that _____ (A) it contains the base uracil, which pairs with cytosine (b) it is single stranded and cannot form base pairs (c) it is single stranded and can fold up into a variety of structures (e) the sugar ribosome contains fewer oxygen atoms than does deoxyribose Which of the following statements is false? (a) A new RNA molecule can begin to be synthesized from a gene before the previous RNA synthesis is completed. (b) If two genes are to be expressed in a cell, these two genes can be transcribed with different (c) RNA polymerase is responsible for both unwinding the DNA helix and catalyzing the format phosphodiester bonds between nucleotides. Unlike DNA, RNA uses a uracil base and a deoxyribose sugar. The sigma subunit of bacterial RNA polymerase ____ (a) contains the catalytic activity of the polymerase (b) remains part of the polymerase thought transcription (c) recognizes promoter sites in the DNA (d) recognizes transcription termination sites in the DNA Operons _____ (a) are commonly found in eucaryotic cells (b) are transcribed by RNA polymerase II (c) contain a cluster of genes transcribed as a single mRNA (d) can only be regulated by gene activator proteins Which of the following is required for the secretion of neurotransmitters in responses to an action (a) neurotransmitter receptors (b) Na+ - K+ pumps voltage gated K + channels (d) voltage - gated Ca2+ channels

Answer 1

72. B

Clamps not only increase the processivity of these enzymes, but may also serve as an attachment point to coordinate the activities of enzymes required for a given process.

73. A

RNA is single stranded ribonucleotide which contain Urasil instead of Thymine (in DNA). This Urasil binds with Cytosine (as thymine does).It contain 5 carbon sugar ribonucleotide (DNA contains 5 Carbon sugar de-oxyribonucleotide).

74. D

RNA has ribonucleotide sugar..Rest all options are correct…

75. C

Sigma subunit of RNA polymerase in bacteria does the same function as general transcription factors do in Eukaryotes. It recognize the promoters of the genes in bacteria and recruit RNA polymerase on the initiator site.

76. C

Operon is the cluster of structural genes which are transcribed as single mRNA. Operons are found in bacteria (small genome size). They are absent in Eukaryotes.

Ex-Lac operon and trp operon in bacteria.

77. B

Na-K pump changes the polarization of the membrane which lead to the opening of Ca channels. Ca influx causes the fusion of neurotransmitter filled vesicles with the plasma membrane of telodendrites.