Question 1

The mechanical changes that ribosomes undergo are driven by energy from ______.

Accepted Answer

A) GTP hydrolysis 
B) ATP hydrolysis 
C) ADP hydrolysis 
D) an electrochemical gradient 
E) a concentration gradient 
A) GTP hydrolysis 
B) ATP hydrolysis 
C) ADP hydrolysis 
D) an electrochemical gradient 
E) a concentration gradient

Question 2

The reverse reaction of nucleic acid synthesis almost never happens.What prevents it?

Accepted Answer

A) The enzyme does not work in reverse. 
B) Polynucleotides are too stable to depolymerize. 
C) H bonds holding the strands together are too strong. 
D) Nucleic acid synthesis is coupled to the highly exergonic pyrophosphate hydrolysis. 
E) There is a large uptake of free energy. 
A) The enzyme does not work in reverse. 
B) Polynucleotides are too stable to depolymerize. 
C) H bonds holding the strands together are too strong. 
D) Nucleic acid synthesis is coupled to the highly exergonic pyrophosphate hydrolysis. 
E) There is a large uptake of free energy.

Question 3

What is the name of the nucleotide sequence that helps the 30S ribosomal subunit find the initiation codon on bacterial mRNAs?

Accepted Answer

A) the Watson-Crick sequence 
B) the Hershey-Chase sequence 
C) the Hatch-Slack sequence 
D) the Shine-Dalgarno sequence 
E) the Franklin sequence 
A) the Watson-Crick sequence 
B) the Hershey-Chase sequence 
C) the Hatch-Slack sequence 
D) the Shine-Dalgarno sequence 
E) the Franklin sequence

Question 4

Once bound to the promoter,RNA polymerase ________.

Accepted Answer

A) breaks the DNA chain in the start site region 
B) melts the two DNA strands in the start site region 
C) degrades the two DNA strands in the start site region 
D) melts the two DNA strands in the termination site region 
E) chemically alters the DNA template 
A) breaks the DNA chain in the start site region 
B) melts the two DNA strands in the start site region 
C) degrades the two DNA strands in the start site region 
D) melts the two DNA strands in the termination site region 
E) chemically alters the DNA template

Question 5

How would you describe the half-lives of rRNAs and tRNAs?

Accepted Answer

A) days or weeks long 
B) minutes long 
C) seconds long 
D) hours long 
E) years long 
A) days or weeks long 
B) minutes long 
C) seconds long 
D) hours long 
E) years long

Question 6

The enzyme in eukaryotes that is responsible for the synthesis of RNA from a DNA template is called _______.

Accepted Answer

A) DNA-dependent DNA polymerase 
B) DNA-dependent RNA polymerase 
C) RNA-dependent RNA polymerase 
D) RNA-dependent DNA polymerase 
E) ribonuclease 
A) DNA-dependent DNA polymerase 
B) DNA-dependent RNA polymerase 
C) RNA-dependent RNA polymerase 
D) RNA-dependent DNA polymerase 
E) ribonuclease

Question 7

Why does the isoleucyl-tRNA synthetase use two types of proofreading mechanisms to ensure its accurate aminoacylation?

Accepted Answer

A) It is not a very precise enzyme. 
B) It is a very big enzyme. 
C) Isoleucine is very hard to distinguish from valine,since they differ only by a single methylene group. 
D) Isoleucine is very difficult to distinguish from glycine. 
E) Isoleucine can spontaneously turn into phenylalanine. 
A) It is not a very precise enzyme. 
B) It is a very big enzyme. 
C) Isoleucine is very hard to distinguish from valine,since they differ only by a single methylene group. 
D) Isoleucine is very difficult to distinguish from glycine. 
E) Isoleucine can spontaneously turn into phenylalanine.

Question 8

The naked regions seen on the DNA fiber between transcriptional units are called ________.

Accepted Answer

A) spacelies 
B) nontranscribed spacers 
C) nontranslated spacers 
D) untranslated spacers 
E) naked genes 
A) spacelies 
B) nontranscribed spacers 
C) nontranslated spacers 
D) untranslated spacers 
E) naked genes

Question 9

While RNA polymerase is a processive enzyme that remains attached to the DNA over long stretches of template,it must be associated _______ enough so that it can move from nucleotide to nucleotide along the template.

Accepted Answer

A) tightly 
B) loosely 
C) angularly 
D) rapidly 
E) linearly 
A) tightly 
B) loosely 
C) angularly 
D) rapidly 
E) linearly

Question 10

Which bacterial initiation factor facilitates attachment of the 30S subunit to the mRNA and may prevent the aminoacyl-tRNA from entering the wrong site on the ribosome?

Accepted Answer

A) IF2 
B) IF1 
C) IF3 
D) eIF2 
E) IF4 
A) IF2 
B) IF1 
C) IF3 
D) eIF2 
E) IF4

Question 11

You have set up a cell-free transcription system in a test tube.By mixing DNA,RNA polymerase,sigma factors,ribonucleotides and other essential substances,you are able to make mRNAs identical to those made under a variety of conditions in the cells from which these components were isolated.What would happen if you were able to remove the sigma factor first added to the tube and replace it with another sigma factor?

Accepted Answer

Since sigma factors often can

Question 12

Before the genetic code was actually known,Francis Crick predicted that it was degenerate.What piece of evidence led him to make this prediction?

Accepted Answer

A) All proteins looked the same. 
B) All proteins were made of amino acids. 
C) He noted that the base composition of the DNAs of various bacteria varied greatly while the amino acid composition of their proteins varied very little overall. 
D) He noted that the base composition of the DNAs of various bacteria varied little while the amino acid composition of their proteins varied greatly overall. 
E) The code was non-overlapping. 
A) All proteins looked the same. 
B) All proteins were made of amino acids. 
C) He noted that the base composition of the DNAs of various bacteria varied greatly while the amino acid composition of their proteins varied very little overall. 
D) He noted that the base composition of the DNAs of various bacteria varied little while the amino acid composition of their proteins varied greatly overall. 
E) The code was non-overlapping.

Question 13

What did Archibald Garrod call diseases like alcaptonuria?

Accepted Answer

A) deadly diseases 
B) inborn errors of transcription 
C) homogentisms 
D) errors 
E) inborn errors of metabolism 
A) deadly diseases 
B) inborn errors of transcription 
C) homogentisms 
D) errors 
E) inborn errors of metabolism

Question 14

What are the differences between piRNAs on the one hand and si/miRNAs on the other hand?

Accepted Answer

A) piRNAs are longer than si/miRNAs. 
B) The majority of mammalian piRNAs can be mapped to a small number of huge genomic loci,unlike si/mi RNAs. 
C) The formation of piRNAs does not involve the formation of dsRNA precursors,unlike si/mi RNAs. 
D) Formation of piRNAs does not involve cleavage by Dicer ribonuclease,but instead it depends on the endonuclease activity of the PIWI protein acting on a long,single stranded primary transcript. 
E) All of these are correct. 
A) piRNAs are longer than si/miRNAs. 
B) The majority of mammalian piRNAs can be mapped to a small number of huge genomic loci,unlike si/mi RNAs. 
C) The formation of piRNAs does not involve the formation of dsRNA precursors,unlike si/mi RNAs. 
D) Formation of piRNAs does not involve cleavage by Dicer ribonuclease,but instead it depends on the endonuclease activity of the PIWI protein acting on a long,single stranded primary transcript. 
E) All of these are correct.

Question 15

How do the unusual bases of the loops in tRNA influence tRNA structure?

Accepted Answer

A) They disrupt H bond formation in the loop regions causing the loops to form. 
B) They bind to proteins that hold the loops open. 
C) They disrupt hydrophobic interactions in the loop regions causing the loops to form. 
D) They prevent van der Waals interactions which prevents loop formation. 
E) They disrupt H bond formation which causes complementary pairing in the stem regions. 
A) They disrupt H bond formation in the loop regions causing the loops to form. 
B) They bind to proteins that hold the loops open. 
C) They disrupt hydrophobic interactions in the loop regions causing the loops to form. 
D) They prevent van der Waals interactions which prevents loop formation. 
E) They disrupt H bond formation which causes complementary pairing in the stem regions.

Question 16

A space probe brings back a new life form.It is carbon-based and its genetic material is similar to Earth DNA except that it uses 6 different nucleotide bases instead of 4.Its proteins are also similar to those on Earth,but there are 28 amino acids instead of 20.You hypothesize about the genetic code for this organism.How many "letters" would you propose in each codon of the genetic code for this organism? The code should be unambiguous and may be degenerate.

Accepted Answer

Since there are 36 possible co

Question 17

Which of the following is not required for protein synthesis?

Accepted Answer

A) All of the various tRNAs with their attached amino acids 
B) Ribosomes 
C) mRNA 
D) anions 
E) GTP 
A) All of the various tRNAs with their attached amino acids 
B) Ribosomes 
C) mRNA 
D) anions 
E) GTP

Question 18

What percentage of cellular RNA is rRNA?

Accepted Answer

A) less than 20% 
B) more than 90% 
C) more than 80% 
D) exactly 75% 
E) 36.5% 
A) less than 20% 
B) more than 90% 
C) more than 80% 
D) exactly 75% 
E) 36.5%

Question 19

What is responsible for synthesizing hnRNAs?

Accepted Answer

A) RNA polymerase I 
B) RNA polymerase II 
C) RNA polymerase III 
D) reverse transcriptase 
E) general transcription factors 
A) RNA polymerase I 
B) RNA polymerase II 
C) RNA polymerase III 
D) reverse transcriptase 
E) general transcription factors

Question 20

Which codon below usually serves as the initiation codon?

Accepted Answer

A) 5'-AUG-3' 
B) 5'-GUG-3' 
C) 3'-AUG-5' 
D) 3'-GUG-3' 
E) 3'-UAC-5' 
A) 5'-AUG-3' 
B) 5'-GUG-3' 
C) 3'-AUG-5' 
D) 3'-GUG-3' 
E) 3'-UAC-5'

The mechanical changes that ribosomes undergo are driven by energy from ______.

The reverse reaction of nucleic acid synthesis almost never happens.What prevents it?

What is the name of the nucleotide sequence that helps the 30S ribosomal subunit find the initiation codon on bacterial mRNAs?

Once bound to the promoter,RNA polymerase ________.

How would you describe the half-lives of rRNAs and tRNAs?

The enzyme in eukaryotes that is responsible for the synthesis of RNA from a DNA template is called _______.

Why does the isoleucyl-tRNA synthetase use two types of proofreading mechanisms to ensure its accurate aminoacylation?

The naked regions seen on the DNA fiber between transcriptional units are called ________.

While RNA polymerase is a processive enzyme that remains attached to the DNA over long stretches of template,it must be associated _______ enough so that it can move from nucleotide to nucleotide along the template.

Which bacterial initiation factor facilitates attachment of the 30S subunit to the mRNA and may prevent the aminoacyl-tRNA from entering the wrong site on the ribosome?

Before the genetic code was actually known,Francis Crick predicted that it was degenerate.What piece of evidence led him to make this prediction?

What did Archibald Garrod call diseases like alcaptonuria?

What are the differences between piRNAs on the one hand and si/miRNAs on the other hand?

How do the unusual bases of the loops in tRNA influence tRNA structure?

Which of the following is not required for protein synthesis?

What percentage of cellular RNA is rRNA?

What is responsible for synthesizing hnRNAs?

Which codon below usually serves as the initiation codon?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics, Enzymes, and Metabolism

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, Function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cell Signaling and Signal Transduction: Communication Between Cells

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters

Exam 11: Gene Expression: From Transcription to Translation

The mechanical changes that ribosomes undergo are driven by energy from ______.

The reverse reaction of nucleic acid synthesis almost never happens.What prevents it?

What is the name of the nucleotide sequence that helps the 30S ribosomal subunit find the initiation codon on bacterial mRNAs?

Once bound to the promoter,RNA polymerase ________.

How would you describe the half-lives of rRNAs and tRNAs?

The enzyme in eukaryotes that is responsible for the synthesis of RNA from a DNA template is called _______.

Why does the isoleucyl-tRNA synthetase use two types of proofreading mechanisms to ensure its accurate aminoacylation?

The naked regions seen on the DNA fiber between transcriptional units are called ________.

While RNA polymerase is a processive enzyme that remains attached to the DNA over long stretches of template,it must be associated _______ enough so that it can move from nucleotide to nucleotide along the template.

Which bacterial initiation factor facilitates attachment of the 30S subunit to the mRNA and may prevent the aminoacyl-tRNA from entering the wrong site on the ribosome?

Before the genetic code was actually known,Francis Crick predicted that it was degenerate.What piece of evidence led him to make this prediction?

What did Archibald Garrod call diseases like alcaptonuria?

What are the differences between piRNAs on the one hand and si/miRNAs on the other hand?

How do the unusual bases of the loops in tRNA influence tRNA structure?

Which of the following is not required for protein synthesis?

What percentage of cellular RNA is rRNA?

What is responsible for synthesizing hnRNAs?

Which codon below usually serves as the initiation codon?

Introduction to the Study of Cell and Molecular Biology

The Chemical Basis of Life

Bioenergetics, Enzymes, and Metabolism

The Structure and Function of the Plasma Membrane

Aerobic Respiration and the Mitochondrion

Photosynthesis and the Chloroplast

Interactions Between Cells and Their Environment

Cytoplasmic Membrane Systems: Structure, Function, and Membrane Trafficking

The Cytoskeleton and Cell Motility

The Nature of the Gene and the Genome

Control of Gene Expression

Dna Replication and Repair

Cellular Reproduction

Cell Signaling and Signal Transduction: Communication Between Cells

Cancer

The Immune Response

Techniques in Cell and Molecular Biology

Filters