1) The functional unit of genetic information is the
A) nucleotide.
B) gene.
C) chromosome.
D) protein.
B) gene.
2) Which of the following statements is TRUE concerning mRNA?
A) mRNA has a very short half-life.
B) mRNA has complex secondary structure.
C) mRNA is catalytic.
D) mRNA is the product of translation.
A) mRNA has a very short half-life.
3) DNA-binding proteins interact predominantly within which portion of a double-stranded DNA helix?
A) major groove
B) minor groove
C) 3' end
D) supercoil
A) major groove
4) AT-rich DNA will denature/melt
A) at a higher temperature than GC-rich DNA.
B) at a lower temperature than GC-rich DNA.
C) usually at the same temperature as GC-rich DNA, with some minor variations.
D) in accordance with the animal or plant from which
B) at a lower temperature than GC-rich DNA.
5) Supercoiling is important for DNA structure, because
A) it holds together the antiparallel strands of DNA in the double helix.
B) it provides energy for transcription.
C) it condenses the DNA so that it can fit inside the cell.
D) it prevents RNA from
C) it condenses the DNA so that it can fit inside the cell.
6) Many pharmaceutical drugs specifically inhibit transcription in Bacteria but not Archaea or Eukarya. Why would drugs that inhibit transcription only affect Bacteria and not Archaea even though they are both prokaryotes?
A) Archaea and Eukarya have very
D) Archaea and Eukarya have very similar RNA polymerases that are different than bacterial RNA polymerases.
7) How are plasmids different than chromosomes?
A) Plasmids are always small, linear pieces of DNA.
B) Plasmids are composed of single-stranded DNA.
C) Plasmids contain genes that are NOT essential for cellular growth and replication.
D) Plasmids carry un
C) Plasmids contain genes that are NOT essential for cellular growth and replication.
8) Genes that encoded for polymerases, gyrases, ribosomal proteins, and other proteins essential to replication, transcription, and translation are present on
A) chromosomes.
B) plasmids.
C) chromosomes and plasmids.
D) neither chromosomes nor plasmids.
A) chromosomes.
9) The precursor of each new nucleotide in a strand of DNA is a
A) deoxynucleoside 5'-diphosphate.
B) deoxynucleoside 3'-diphosphate.
C) deoxynucleoside 5'-triphosphate.
D) deoxynucleoside 3'-triphosphate.
C) deoxynucleoside 5'-triphosphate.
10) DNA replication always proceeds in only one direction because the ________ of the incoming nucleotide is attached to the free ________ of the growing DNA strand.
A) 5'-phosphate / 3'-hydroxyl
B) 3'-phosphate / 5'-hydroxyl
C) 5'-deoxyribose / 3'-base
D
A) 5'-phosphate / 3'-hydroxyl
11) Which of the following is formed on the lagging strand during DNA synthesis?
A) DNA secondary structures
B) Okazaki fragments
C) RNA polymerase
D) replisomes
B) Okazaki fragments
12) The template for RNA polymerase is ________, and the new RNA chain is ________ to the template.
A) an independent RNA segment / parallel and identical
B) DNA / antiparallel and complementary
C) an independent RNA segment / antiparallel and complementa
B) DNA / antiparallel and complementary
13) In the process of transcription, promoters are specific sequences of ________ that are recognized by ________.
A) DNA / DNA polymerase
B) RNA / DNA polymerase
C) DNA / sigma factors
D) RNA / ribosomes
C) DNA / sigma factors
14) An example of correct nucleotide pairing is
A) T and U.
B) G and U.
C) A and T.
D) C and U.
B) G and U.
15) Stop codons are also called ________ codons.
A) nonsense
B) release factor
C) degeneracy
D) conversion
A) nonsense
16) Transfer RNA molecules
A) function to transfer ribonucleotides to RNA polymerase during transcription.
B) function to transfer the correct amino acids to the ribosome during translation.
C) contain codons that bind to ribosomes during translation.
D)
B) function to transfer the correct amino acids to the ribosome during translation.
17) tRNA is released from the ribosome at the ________ site.
A) P
B) A
C) R
D) E
D) E
18) Which statement is TRUE regarding protein synthesis?
A) Ribosomal proteins catalyze peptide bond formation in the growing polypeptide chain.
B) The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain.
C) Transfer RNAs catalyze p
B) The 23S rRNA catalyzes peptide bond formation in the growing polypeptide chain.
19) The Tat system is involved in
A) protein synthesis.
B) transcriptional initiation.
C) protein folding.
D) protein secretion.
D) protein secretion.
20) In all cells, genes are composed of
A) nucleic acids.
B) mRNA.
C) proteins.
D) chaperones.
A) nucleic acids.
21) Which of the following is an example of one codon?
A) CATT
B) GCCATT
C) CAG
D) CCGUAA
C) CAG
22) In all cells a gene encodes for
A) a protein (via mRNA).
B) a tRNA.
C) an rRNA.
D) a protein, tRNA, or rRNA depending on the specific gene.
D) a protein, tRNA, or rRNA depending on the specific gene.
23) Which of the following is NOT correct regarding DNA and RNA synthesis?
A) The overall direction of chain growth is from the 5' to 3' end.
B) Both processes require an RNA primer to begin.
C) The template strand is antiparallel to the newly synthesized
B) Both processes require an RNA primer to begin.
24) Termination of RNA synthesis is ultimately determined by
A) exhaustion of RNA polymerase activity.
B) special protein factors.
C) terminases.
D) specific nucleotide sequences on the template strand.
D) specific nucleotide sequences on the template strand.
25) GTP provides energy for
A) transcription.
B) translation.
C) DNA replication.
D) protein folding.
B) translation.
26) Transcription of chaperonins is greatly accelerated when a cell is stressed by
A) excessive osmotic pressure.
B) extremes in pH value.
C) lack of oxygen.
D) excessive heat.
D) excessive heat.
27) The flow of biological information begins with
A) DNA replication.
B) RNA transcription.
C) mRNA translation.
D) transcriptional regulation.
A) DNA replication.
28) DNA participates in protein synthesis through
A) cyclic messengers.
B) direct pairing with amino acids.
C) an RNA intermediate.
D) protein folding.
C) an RNA intermediate.
29) The two strands of the DNA double helix are held together by
A) 5' to 3' attraction.
B) hydrogen bonds between nucleotide bases.
C) codons.
D) peptide bonds between nucleotide bases.
B) hydrogen bonds between nucleotide bases.
30) In Bacteria, a chromosome can be distinguished from a plasmid, because a chromosome is a genetic element that
A) is circular.
B) is linear.
C) encodes for essential functional genes.
D) replicates via a bidirectional fork.
C) encodes for essential functional genes.
31) Transposable elements are
A) segments of DNA that move from one site to another.
B) transcribed genes.
C) segments of RNA that are involved in transposing DNA into proteins.
D) proteins that aid in the secretion of enzymes out of the cell.
A) segments of DNA that move from one site to another.
32) In complementary base pairing of DNA, adenine pairs with ________ (or ________ in RNA) and cytosine always pairs with ________.
A) guanine / uracil / thymine
B) uracil / thymine / guanine
C) thymine / guanine / uracil
D) thymine / uracil / guanine
D) thymine / uracil / guanine
33) The function of the DNA polymerase is to catalyze
A) the addition of deoxynucleotides.
B) the formation of RNA primers.
C) the addition of ribonucleotides.
D) hydrogen bonding between complementary base pairs.
A) the addition of deoxynucleotides.
34) DNA replication is started with a(n) ________, which, in most cases, in vivo is a short stretch of ________.
A) promoter / DNA
B) mRNA / RNA
C) primer / RNA
D) ribosome-binding sequence / DNA
C) primer / RNA
35) The function of RNA polymerase is to
A) catalyze the formation of phosphodiester bonds between deoxyribonucleotids.
B) catalyze the formation of phosphodiester bonds between ribonucleotides.
C) cleave mRNA to remove introns.
D) activate tRNAs.
B) catalyze the formation of phosphodiester bonds between ribonucleotides.
36) Polycistronic transcription units are common in
A) Archaea.
B) Bacteria.
C) Eukarya.
D) both Archaea and Bacteria.
D) both Archaea and Bacteria.
37) An operon is a useful genetic element, because it
A) encourages the binding of RNA polymerase.
B) allows coordinated expression of multiple related genes in prokaryotes.
C) translates DNA sequence into amino acid sequence.
D) encourages the binding of
B) allows coordinated expression of multiple related genes in prokaryotes.
38) Plasmids often encode for proteins
A) involved in translation.
B) required for cellular growth.
C) that confer resistance to antibiotics.
D) involved in DNA replication.
C) that confer resistance to antibiotics.
39) The codon on the ________ matches with the anticodon on the ________ to direct the addition of the correct amino acid to the growing polypeptide chain.
A) mRNA / tRNA
B) tRNA / mRNA
C) DNA / mRNA
D) tRNA / rRNA
A) mRNA / tRNA
40) The structure and function of a protein are determined by its ________ sequence.
A) nucleotide
B) amino acid
C) ribonucleotide
D) translocation
B) amino acid
41) You experimentally change the DNA sequence directly upstream of a start codon of an operon in E. coli to investigate the function of this region of DNA. Analysis reveals that after the change the same amount of mRNA is made from the operon, but there
A) The DNA sequence likely functions as a ribosome-binding site.
42) In ________ several ribosomes can simultaneously translate a single mRNA molecule in a complex called a(n) ________.
A) prokaryotes / polysome
B) eukaryotes / polysome
C) prokaryotes / initiation complex
D) eukaryotes / splicing complex
A) prokaryotes / polysome
43) You are studying a protein in Salmonella typhimurium that you believe is a toxin. Whenever you attempt to purify the protein from lysed cell cultures, you get two forms of the protein. One form is smaller than the other and is missing 15 amino acids f
C) the protein is secreted and folds outside of the cell.
44) Transcription in eukaryotes occurs in the
A) RNA polymerase.
B) endoplasmic reticulum.
C) cytoplasm.
D) nucleus.
D) nucleus.
45) During DNA replication Okazaki fragments are linked together by________, an enzyme that creates phosphodiester bonds between nicked fragments of DNA.
A) exopolymerase
B) DNA gyrase
C) topoisomerase
D) DNA ligase
D) DNA ligase
46) A triplet of bases on an mRNA molecule is known as a(n)
A) amino acid.
B) anticodon.
C) codon.
D) ribosome-binding sequence.
C) codon.
47) Each adenine-thymine base pair has ________ hydrogen bonds, while each guanine-cytosine base pair has ________ hydrogen bonds.
A) two / one
B) two / three
C) four / three
D) three / two
B) two / three
48) In DNA replication there are leading and lagging strands, because
A) DNA replication is conservative and a completely new DNA molecule must be made.
B) DNA replication is semiconservative and each strand is copied simultaneously in opposite directions
B) DNA replication is semiconservative and each strand is copied simultaneously in opposite directions.