Question 1

Figure 7-52 shows an mRNA molecule.   
Figure 7-52
Is the mRNA shown prokaryotic or eukaryotic? Explain your answer.

Accepted Answer

The mRNA is prokaryotic.It contains codi

Question 2

An extraterrestrial organism (ET) is discovered whose basic cell biology seems pretty much the same as that of terrestrial organisms except that it uses a different genetic code to translate RNA into protein.You set out to break the code by translation experiments using RNAs of known sequence and cell-free extracts of ET cells to supply the necessary protein-synthesizing machinery.In experiments using the RNAs below, the following results were obtained when the 20 possible amino acids were added either singly or in different combinations of two or three:
RNA 1: 5′-GCGCGCGCGCGCGCGCGCGCGCGCGCGC-3′
RNA 2: 5′-GCCGCCGCCGCCGCCGCCGCCGCCGCCGCC-3′
Using RNA 1, a polypeptide was produced only if alanine and valine were added to the reaction mixture.Using RNA 2, a polypeptide was produced only if leucine and serine and cysteine were added to the reaction mixture.Assuming that protein synthesis can start anywhere on the template, that the ET genetic code is nonoverlapping and linear, and that each codon is the same length (like the terrestrial triplet code), how many nucleotides does an ET codon contain?

Accepted Answer

A) 2 
B) 3 
C) 4 
D) 5 
A) 2 
B) 3 
C) 4 
D) 5

Question 3

Which of the following might decrease the transcription of only one specific gene in a bacterial cell?

Accepted Answer

A) a decrease in the amount of sigma factor 
B) a decrease in the amount of RNA polymerase 
C) a mutation that introduced a stop codon into the DNA that precedes the gene's coding sequence 
D) a mutation that introduced extensive sequence changes into the DNA that precedes the gene's transcription start site 
A) a decrease in the amount of sigma factor 
B) a decrease in the amount of RNA polymerase 
C) a mutation that introduced a stop codon into the DNA that precedes the gene's coding sequence 
D) a mutation that introduced extensive sequence changes into the DNA that precedes the gene's transcription start site

Question 4

Which of the following statements is FALSE?

Accepted Answer

A) RNA polymerase can start making a new RNA molecule without a primer; DNA polymerase cannot. 
B) RNA polymerase does not proofread its work; DNA polymerase does. 
C) RNA polymerase catalyzes the linkage of ribonucleotides while DNA polymerase catalyzes the linkage of deoxyribonucleotides. 
D) RNA polymerase adds bases in a 3′-to-5′ direction; DNA polymerase adds bases in a 5′-to-3′ direction. 
A) RNA polymerase can start making a new RNA molecule without a primer; DNA polymerase cannot. 
B) RNA polymerase does not proofread its work; DNA polymerase does. 
C) RNA polymerase catalyzes the linkage of ribonucleotides while DNA polymerase catalyzes the linkage of deoxyribonucleotides. 
D) RNA polymerase adds bases in a 3′-to-5′ direction; DNA polymerase adds bases in a 5′-to-3′ direction.

Question 5

Which of the following methods is not used by cells to regulate the amount of a protein in the cell?

Accepted Answer

A) Genes can be transcribed into mRNA with different efficiencies. 
B) Many ribosomes can bind to a single mRNA molecule. 
C) Proteins can be tagged with ubiquitin, marking them for degradation. 
D) Nuclear pore complexes can regulate the speed at which newly synthesized proteins are exported from the nucleus into the cytoplasm. 
A) Genes can be transcribed into mRNA with different efficiencies. 
B) Many ribosomes can bind to a single mRNA molecule. 
C) Proteins can be tagged with ubiquitin, marking them for degradation. 
D) Nuclear pore complexes can regulate the speed at which newly synthesized proteins are exported from the nucleus into the cytoplasm.

Question 6

When using a repeating trinucleotide sequence (such as 5′-AAC-3′) in a cell-free translation system, you will obtain

Accepted Answer

A) three different types of peptides, each made up of a single amino acid. 
B) peptides made up of three different amino acids in random order. 
C) peptides made up of three different amino acids, each alternating with each other in a repetitive fashion. 
D) polyasparagine, as the codon for asparagine is AAC. 
A) three different types of peptides, each made up of a single amino acid. 
B) peptides made up of three different amino acids in random order. 
C) peptides made up of three different amino acids, each alternating with each other in a repetitive fashion. 
D) polyasparagine, as the codon for asparagine is AAC.

Question 7

Transcription is similar to DNA replication in that

Accepted Answer

A) an RNA transcript is synthesized discontinuously and the pieces are then joined together. 
B) it uses the same enzyme as that used to synthesize RNA primers during DNA replication. 
C) the newly synthesized RNA remains paired to the template DNA. 
D) nucleotide polymerization occurs only in the 5′-to-3′ direction. 
A) an RNA transcript is synthesized discontinuously and the pieces are then joined together. 
B) it uses the same enzyme as that used to synthesize RNA primers during DNA replication. 
C) the newly synthesized RNA remains paired to the template DNA. 
D) nucleotide polymerization occurs only in the 5′-to-3′ direction.

Question 8

According to current thinking, the minimum requirement for life to have originated on Earth was the formation of a

Accepted Answer

A) molecule that could provide a template for the production of a complementary molecule. 
B) double-stranded DNA helix. 
C) molecule that could direct protein synthesis. 
D) molecule that could catalyze its own replication. 
A) molecule that could provide a template for the production of a complementary molecule. 
B) double-stranded DNA helix. 
C) molecule that could direct protein synthesis. 
D) molecule that could catalyze its own replication.

Question 9

A poison added to an in vitro translation mixture containing mRNA molecules with the sequence 5′-AUGAAAAAAAAAAAAUAA-3′ has the following effect: the only product made is a Met-Lys dipeptide that remains attached to the ribosome.What is the most likely way in which the poison acts to inhibit protein synthesis?

Accepted Answer

A) It inhibits peptidyl transferase activity. 
B) It inhibits movement of the small subunit relative to the large subunit. 
C) It inhibits release factor. 
D) It mimics release factor. 
A) It inhibits peptidyl transferase activity. 
B) It inhibits movement of the small subunit relative to the large subunit. 
C) It inhibits release factor. 
D) It mimics release factor.

Question 10

Which of the following statements about RNA splicing is FALSE?

Accepted Answer

A) Conventional introns are not found in bacterial genes. 
B) For a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene. 
C) Small RNA molecules in the nucleus perform the splicing reactions necessary for the removal of introns. 
D) Splicing occurs after the 5′ cap has been added to the end of the primary transcript. 
A) Conventional introns are not found in bacterial genes. 
B) For a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene. 
C) Small RNA molecules in the nucleus perform the splicing reactions necessary for the removal of introns. 
D) Splicing occurs after the 5′ cap has been added to the end of the primary transcript.

Question 11

In a diploid organism, the DNA encoding one of the tRNAs for the amino acid tyrosine is mutated such that the sequence of the anticodon is now 5′-CTA-3′ instead of 5′-GTA-3′.What kind of aberration in protein synthesis will this tRNA cause? Explain your answer. $\text { The Genetic Code }$
\(\begin{array}{|l|l|l|l|l|}
\hline & \text { U } & \text { C } & \text { A } & \text { G } \
\hline &\text { UUU Phe (F) } & \text { UCU Ser (S) } & \text { UAU Tyr (Y) } & \text { UGU Cys (C) } \
&\text { UUC - } & \text { UCC - } & \text { UAC - } & \text { UGC - } \
 \text { U } &\text { UUA Leu (L) } & \text { UCA -- } & \text { UAA Stop } & \text { UGA Stop } \
&\text { UUG - } & \text { UCG - } & \text { UAG Stop } & \text { UGG Trp (W) } \
\hline &\text { CUU Leu (L) } & \text { CCU Pro (P) } & \text { CAU His (H) } & \text { CGU Arg (R) } \
&\text { CUC - } & \text { CCC - } & \text { CAC - } & \text { CGC - } \
 \text { C}&\text { CUA - } & \text { CCA - } & \text { CAA Gin (Q) } & \text { CGA - } \
&\text { CUG }- & \text { CCG }- & \text { CAG }- & \text { CGG }- \
\hline &\text { AUU Ile (I) } & \text { ACU Thr (T) } & \text { AAU Asn (N) } & \text { AGU Ser (S) } \
&\text { AUC - } & \text { ACC - } & \text { AAC - } & \text { AGC - } \
 \text { A}&\text { AUA - } & \text { ACA - } & \text { AAA Lys (K) } & \text { AGA Arg (R) } \
&\text { AUG Met (M) } & \text { ACG - } & \text { AAG - } & \text { AGG - } \
\hline &\text { GUU Val (V) } & \text { GCU Ala (A) } & \text { GAU Asp (D) } & \text { GGU Gly (G) } \
&\text { GUC - } & \text { GCC - } & \text { GAC - } & \text { GGC - } \
 \text { G}&\text { GUA - } & \text { GCA - } & \text { GAA Glu (E) } & \text { GGA - } \
&\text { GUG - } & \text { GCG - } & \text { GAG - } & \text { GGG - } \
\hline
\end{array}\) 
Table 7-29

Accepted Answer

If the DNA sequence specifying the antic

Question 12

Below is the sequence from the 3? end of an mRNA.
5?-CCGUUACCAGGCCUCAUUAUUGGUAACGGAAAAAAAAAAAAAA-3? $\text { The Genetic Code }$
\(\begin{array}{|l|l|l|l|l|}
\hline & \text { U } & \text { C } & \text { A } & \text { G } \
\hline &\text { UUU Phe (F) } & \text { UCU Ser (S) } & \text { UAU Tyr (Y) } & \text { UGU Cys (C) } \
&\text { UUC - } & \text { UCC - } & \text { UAC - } & \text { UGC - } \
 \text { U } &\text { UUA Leu (L) } & \text { UCA -- } & \text { UAA Stop } & \text { UGA Stop } \
&\text { UUG - } & \text { UCG - } & \text { UAG Stop } & \text { UGG Trp (W) } \
\hline &\text { CUU Leu (L) } & \text { CCU Pro (P) } & \text { CAU His (H) } & \text { CGU Arg (R) } \
&\text { CUC - } & \text { CCC - } & \text { CAC - } & \text { CGC - } \
 \text { C}&\text { CUA - } & \text { CCA - } & \text { CAA Gin (Q) } & \text { CGA - } \
&\text { CUG }- & \text { CCG }- & \text { CAG }- & \text { CGG }- \
\hline &\text { AUU Ile (I) } & \text { ACU Thr (T) } & \text { AAU Asn (N) } & \text { AGU Ser (S) } \
&\text { AUC - } & \text { ACC - } & \text { AAC - } & \text { AGC - } \
 \text { A}&\text { AUA - } & \text { ACA - } & \text { AAA Lys (K) } & \text { AGA Arg (R) } \
&\text { AUG Met (M) } & \text { ACG - } & \text { AAG - } & \text { AGG - } \
\hline &\text { GUU Val (V) } & \text { GCU Ala (A) } & \text { GAU Asp (D) } & \text { GGU Gly (G) } \
&\text { GUC - } & \text { GCC - } & \text { GAC - } & \text { GGC - } \
 \text { G}&\text { GUA - } & \text { GCA - } & \text { GAA Glu (E) } & \text { GGA - } \
&\text { GUG - } & \text { GCG - } & \text { GAG - } & \text { GGG - } \
\hline
\end{array}\)
Table 7-29
If you were told that this sequence contains the stop codon for the protein encoded by this mRNA, what is the anticodon on the tRNA in the P site of the ribosome when release factor binds to the A site?

Accepted Answer

A) 5?-CCA-3? 
B) 5?-CCG-3? 
C) 5?-UGG-3? 
D) 5?-UUA-3? 
A) 5?-CCA-3? 
B) 5?-CCG-3? 
C) 5?-UGG-3? 
D) 5?-UUA-3?

Question 13

RNA in cells differs from DNA in that

Accepted Answer

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. 
D) the sugar ribose contains fewer oxygen atoms than does deoxyribose. 
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. 
D) the sugar ribose contains fewer oxygen atoms than does deoxyribose.

Question 14

Which of the following statements is TRUE?

Accepted Answer

A) Ribosomes are large RNA structures composed solely of rRNA. 
B) Ribosomes are synthesized entirely in the cytoplasm. 
C) rRNA contains the catalytic activity that joins amino acids together. 
D) A ribosome binds one tRNA at a time. 
A) Ribosomes are large RNA structures composed solely of rRNA. 
B) Ribosomes are synthesized entirely in the cytoplasm. 
C) rRNA contains the catalytic activity that joins amino acids together. 
D) A ribosome binds one tRNA at a time.

Question 15

Figure 7-3 shows a ribose sugar.The part of the ribose sugar where a new ribonucleotide will attach in an RNA molecule is pointed to by arrow   Figure 7-3

Accepted Answer

A) 1. 
B) 3. 
C) 4. 
D) 5. 
A) 1. 
B) 3. 
C) 4. 
D) 5.

Question 16

Figure 7-3 shows a ribose sugar.The part of the ribose sugar that is different from the deoxyribose sugar used in DNA is pointed to by arrow   Figure 7-3

Accepted Answer

A) 1. 
B) 4. 
C) 5. 
D) 6. 
A) 1. 
B) 4. 
C) 5. 
D) 6.

Question 17

Figure 7-75A shows the stage in translation when an incoming aminoacyl-tRNA has bound to the A site on the ribosome.Using the components shown in Figure 7-75A as a guide, show on Figures 7-75B and 7-75C what happens in the next two stages to complete the addition of the new amino acid to the growing polypeptide chain. (A)

(B)

(C)

Figure 7-75

Accepted Answer

See Figure

Question 18

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; use each word or phrase only once.
$\begin{array}{lll}
\text { A } & \text { medium } & \text { protein } \
\text { central } & \text { P } & \text { RNA } \
\text { DNA } & \text { peptidyl transferase } & \text { small } \
\text { E } & \text { polymerase } & \text { T } \
\text { large } & \text { proteasome } & \text { ubiquitin }
\end{array}$

Once an mRNA is produced, its message can be decoded on ribosomes.The ribosome is composed of two subunits: the __________ subunit, which catalyzes the formation of the peptide bonds that link the amino acids together into a polypeptide chain, and the __________ subunit, which matches the tRNAs to the codons of the mRNA.During the chain elongation process of translating an mRNA into protein, the growing polypeptide chain attached to a tRNA is bound to the __________ site of the ribosome.An incoming aminoacyl-tRNA carrying the next amino acid in the chain will bind to the __________ site by forming base pairs with the exposed codon in the mRNA.The __________ enzyme catalyzes the formation of a new peptide bond between the growing polypeptide chain and the newly arriving amino acid.The end of a protein-coding message is signaled by the presence of a stop codon, which binds the __________ called release factor.Eventually, most proteins will be degraded by a large complex of proteolytic enzymes called the __________.

Accepted Answer

Once an mRNA is produced, its message ca

Question 19

You have a piece of DNA that includes the following sequence:
5′-ATAGGCATTCGATCCGGATAGCAT-3′
3′-TATCCGTAAGCTAGGCCTATCGTA-5′
Which of the following RNA molecules could be transcribed from this piece of DNA?

Accepted Answer

A) 5′-UAUCCGUAAGCUAGGCCUAUGCUA-3′ 
B) 5′-AUAGGCAUUCGAUCCGGAUAGCAU-3′ 
C) 5′-UACGAUAGGCCUAGCUUACGGAUA-3′ 
D) none of these answers are correct. 
A) 5′-UAUCCGUAAGCUAGGCCUAUGCUA-3′ 
B) 5′-AUAGGCAUUCGAUCCGGAUAGCAU-3′ 
C) 5′-UACGAUAGGCCUAGCUUACGGAUA-3′ 
D) none of these answers are correct.

Question 20

Consider two genes that are next to each other on a chromosome, as arranged in Figure 7-1.   Figure 7-1
Which of the following statements is TRUE?

Accepted Answer

A) The two genes must be transcribed into RNA using the same strand of DNA. 
B) If gene A is transcribed in a cell, gene B cannot be transcribed. 
C) Gene A and gene B can be transcribed at different rates, producing different amounts of RNA within the same cell. 
D) If gene A is transcribed in a cell, gene B must be transcribed. 
A) The two genes must be transcribed into RNA using the same strand of DNA. 
B) If gene A is transcribed in a cell, gene B cannot be transcribed. 
C) Gene A and gene B can be transcribed at different rates, producing different amounts of RNA within the same cell. 
D) If gene A is transcribed in a cell, gene B must be transcribed.

Figure 7-52 shows an mRNA molecule. Figure 7-52 Is the mRNA shown prokaryotic or eukaryotic? Explain your answer.

Which of the following might decrease the transcription of only one specific gene in a bacterial cell?

Which of the following statements is FALSE?

Which of the following methods is not used by cells to regulate the amount of a protein in the cell?

When using a repeating trinucleotide sequence (such as 5′-AAC-3′) in a cell-free translation system, you will obtain

Transcription is similar to DNA replication in that

According to current thinking, the minimum requirement for life to have originated on Earth was the formation of a

Which of the following statements about RNA splicing is FALSE?

RNA in cells differs from DNA in that

Which of the following statements is TRUE?

Figure 7-3 shows a ribose sugar.The part of the ribose sugar where a new ribonucleotide will attach in an RNA molecule is pointed to by arrow Figure 7-3

Figure 7-3 shows a ribose sugar.The part of the ribose sugar that is different from the deoxyribose sugar used in DNA is pointed to by arrow Figure 7-3

You have a piece of DNA that includes the following sequence: 5′-ATAGGCATTCGATCCGGATAGCAT-3′ 3′-TATCCGTAAGCTAGGCCTATCGTA-5′ Which of the following RNA molecules could be transcribed from this piece of DNA?

Consider two genes that are next to each other on a chromosome, as arranged in Figure 7-1. Figure 7-1 Which of the following statements is TRUE?

Cells: The Fundamental Units of Life

Chemical Components of Cells

Energy, Catalysis, and Biosynthesis

Protein Structure and Function

DNA and Chromosomes

DNA Replication and Repair

Control of Gene Expression

How Genes and Genomes Evolve

Analyzing the Structure and Function of Genes

Membrane Structure

Transport Across Cell Membranes

How Cells Obtain Energy From Food

Energy Generation in Mitochondria and Chloroplasts

Intracellular Compartments and Protein Transport

Cell Signaling

Cytoskeleton

The Cell-Division Cycle

Sexual Reproduction and the Power of Genetics

Cell Communities: Tissues, Stem Cells, and Cancer

Filters

Exam 7: From DNA to Protein

Figure 7-52 shows an mRNA molecule. Figure 7-52 Is the mRNA shown prokaryotic or eukaryotic? Explain your answer.

Which of the following might decrease the transcription of only one specific gene in a bacterial cell?

Which of the following statements is FALSE?

Which of the following methods is not used by cells to regulate the amount of a protein in the cell?

When using a repeating trinucleotide sequence (such as 5′-AAC-3′) in a cell-free translation system, you will obtain

Transcription is similar to DNA replication in that

According to current thinking, the minimum requirement for life to have originated on Earth was the formation of a

Which of the following statements about RNA splicing is FALSE?

RNA in cells differs from DNA in that

Which of the following statements is TRUE?

Figure 7-3 shows a ribose sugar.The part of the ribose sugar where a new ribonucleotide will attach in an RNA molecule is pointed to by arrow Figure 7-3

Figure 7-3 shows a ribose sugar.The part of the ribose sugar that is different from the deoxyribose sugar used in DNA is pointed to by arrow Figure 7-3

You have a piece of DNA that includes the following sequence: 5′-ATAGGCATTCGATCCGGATAGCAT-3′ 3′-TATCCGTAAGCTAGGCCTATCGTA-5′ Which of the following RNA molecules could be transcribed from this piece of DNA?

Consider two genes that are next to each other on a chromosome, as arranged in Figure 7-1. Figure 7-1 Which of the following statements is TRUE?

Cells: The Fundamental Units of Life

Chemical Components of Cells

Energy, Catalysis, and Biosynthesis

Protein Structure and Function

DNA and Chromosomes

DNA Replication and Repair

Control of Gene Expression

How Genes and Genomes Evolve

Analyzing the Structure and Function of Genes

Membrane Structure

Transport Across Cell Membranes

How Cells Obtain Energy From Food

Energy Generation in Mitochondria and Chloroplasts

Intracellular Compartments and Protein Transport

Cell Signaling

Cytoskeleton

The Cell-Division Cycle

Sexual Reproduction and the Power of Genetics

Cell Communities: Tissues, Stem Cells, and Cancer

Filters