Bio 121 Ch 3 Exam

RNA polymerase complex can do which of the following?

All of these choices are correct. -release a finished RNA transcript from a DNA template -separate DNA strands -restore the original DNA strands -allow RNA-DNA hybrids to form

In which of the following cellular processes is RNA involved?

All of these choices are correct. -translation -splicing -transcription and translation -transcription

Which of the following is TRUE of DNA?

A purine always forms a complementary base pair with a pyrimidine.

Which of the following CORRECTLY describes the complementary base pairing of adenine in both DNA and RNA?

Adenine pairs with thymine in DNA and with uracil in RNA

A hydrogen atom is present on the 3′ carbon in the ribose of DNA nucleotides, whereas a hydroxyl group is present at the same position on RNA nucleotides.

False

Hydrogen bonds and phosphodiester bonds maintain the structure of DNA molecules, whereas only phosphodiester bonds are important for the structure of RNA molecules.

False

RNA is the primary long-term storage molecule for genetic information in eukaryotic cells

False

The DNA and RNA molecules in a cell are copied by replication before a cell divides.

False

The nitrogenous base thymine is present in DNA and RNA, while uracil is present only in RNA.

False

Which one of the following CORRECTLY lists the components necessary for eukaryotic transcription?

RNA polymerase, general transcription factors, DNA, and RNA nucleotides

DNA is usually a double-stranded molecule, and RNA is usually single-stranded

True

An intron is:

an RNA sequence that is removed during the processing of an RNA molecule in the nucleus.

An exon is:

part of an intact, mature mRNA that leaves the nucleus

In the spiral staircase analogy of DNA structure, each railing represents a _____ and each step represents a _____

sugar-phosphate backbone; pair of bases