BIS11 exam2

If 27 percent of the bases in a double-stranded DNA molecule are A, which of the following must be true? Its bases must be 27 percent T. Its bases must be 27 percent C. Its bases must be 23 percent G. Both a and b are true. Both a and c are true.

Both a and c are true.

Refer to the figure. Which letter represents the leading strand? A B C D E

C

Suppose the DNA of a gene contains five regions—A, B, C, D, and E, in that order. Regions A, B, and D are located in introns, while regions C and E are located in exons. What is the order of the regions in the mature mRNA that was transcribed from that sequence? CE ABD BAD ABDCE ABCDE

CE

Nucleotides in RNA are connected to one another in the polynucleotide chain by _______ bonds between _______. hydrogen; a sugar and a phosphate group covalent; two phosphates covalent; two sugars hydrogen; two phosphate groups covalent; a sugar and a phosphate group

Covalent; a sugar and a phosohate group

Refer to the figure, which illustrates the chemical structure of DNA. Which label corresponds to a 3ʹ end? A B C D E

D

The molecules that function to replicate DNA in the cell are DNA nucleoside triphosphates. DNA polymerases. nucleoside polymerases. DNases. ribonucleases.

DNA polymerases

Which molecular model describes the structure of the DNA molecule? Single-stranded and antiparallel Double-stranded and antiparallel Single-stranded and parallel Double-stranded and parallel Triple-stranded and parallel

Double-stranded and antiparallel

Would you predict that mutations in the first letter or the third letter of a codon would have a greater likelihood of changing the protein structure? First Third

First

If the following synthetic RNA were added to a test tube containing all the components necessary for protein translation to occur, what would the amino acid sequence be? 5'-AUAUAUAUAUAU-3' Polyphenylalanine Isoleucine-tyrosine-isoleucine-tyrosine Isoleucine-isoleucine-isoleucine-isoleucine Tyrosine-tyrosine-tyrosine-tyrosine Asparagine-asparagine-asparagine-asparagine

Isoleucine-tyrosine-isoleucine-tyrosine

Which statement about RNA is false? Transfer RNA functions in translation. Ribosomal RNA functions in translation. RNAs are produced by transcription. Messenger RNAs are produced on ribosomes. DNA codes for mRNA, tRNA, and rRNA.

Messenger RNAs are produced on ribosomes.

What is attached to the 5ʹ carbon of deoxyribose in DNA? Adenine Phosphate Guanine Thymine Uracil

Phosphate

If pyrimidines could bind to other pyrimidines, and purines could bind to other purines, what would be the effect on the DNA double helix? The width of the double helix would vary rather than being fixed. The phosphodiester bonds would be unable to form. There would be a reduced requirement for phosphates in nucleotides. The two strands would no longer be antiparallel. The sugar would have to be ribose instead of deoxyribose.

The width of the double helix would vary rather than being fixed.

Which is an example of a nucleotide?

base + ribose sugar + nitrogenous base

Aside from using T instead of U, the template strand of DNA is ____________ to the mRNA sequence. identical in sequence identical in sequence but antiparallel complementary and parallel complementary and antiparallel in a random order and complementary

complementary and antiparallel

In DNA, bonding of A with T and bonding of C with G are examples of complementary base pairing. a dehydration reaction. a reduction reaction. a hydrophobic interaction. a purine-purine interaction.

complementary base pairing.

The characteristic of DNA that allows it to make an exact copy of itself is its sugar-phosphate backbone. complementary base pairing. phosphodiester bonding of the helices. twisting of the molecule to form an α helix. use of a primer.

complementary base pairing.

Stop codons on mRNA bind with tRNAs to stop translation. code for a specific "stop" amino acid. have no complementary tRNA to bind with. All of the above None of the above

have no complementary tRNA to bind with.

The "central dogma of molecular biology" states that information flow between DNA, RNA, and protein is reversible. information flow in a cell is unidirectional, from protein to DNA. information flow in a cell is unidirectional, from DNA to protein. the DNA sequence of a gene can be predicted if we know the amino acid sequence of the protein it encodes. the genetic code is ambiguous but not degenerate.

information flow in a cell is unidirectional, from DNA to protein.

Consider the typical multicellular eukaryote. In comparison with the DNA made in DNA replication, transcribed mRNAs are made in _______ copies, are _______ error prone, and last _______. more; more; longer more; more; a shorter time more; less; a shorter time fewer; more; longer fewer; less; longer

more; more; a shorter time

Compared with DNA replication, transcription is _______ error prone because of differences in _______. more; the number of copies made more; the proofreading system more; excision repair less; the number of copies made less; the proofreading system

more; the proofreading system

In eukaryotic cells, each chromosome has _______ origin(s) of replication. Each origin generates _____ replication forks. one; two two; one multiple; one multiple; two multiple; many

multiple; two

The stop codons code for no amino acid. methionine. glycine. halt enzyme. DNA binding protein.

no amino acid.

Exons are spliced out and removed from the original transcript. spliced together into mRNA from the original transcript. spliced to introns to form the final transcript. much larger than introns. larger than the original coding region.

spliced together into mRNA from the original transcript

Aside from using T instead of U, the coding strand of DNA is _______ to the mRNA. identical in sequence identical in sequence but antiparallel complementary and parallel complementary and antiparallel in a random order and complementary

identical in sequence

How is it possible for single-stranded RNA to fold into complex shapes? Phosphodiester linkages form between the phosphate and the sugar ribose. Internal base pairings occur—adenine with uracil, and cytosine with guanine. Uracil's methyl group binds to adenine, coiling the molecule. The single strand "twists" around itself. The RNA binds to proteins, creating a conformation (three-dimensional shape).

Internal base pairings occur—adenine with uracil, and cytosine with guanine.

DNA differs from RNA in that RNA contains thymine whereas DNA contains uracil. DNA has a phosphate attached to the 5'-Carbon while RNA does not only DNA is present in the cell nucleus. RNA contains pentose sugar residues whereas DNA contains hexose sugar residues. only DNA has an equal number of purines and pyrimidines.

only DNA has an equal number of purines and pyrimidines.

Complementary base pairing occurs due to covalent bonds between bases. pairing of a purine with a pyrimidine. hydrophobic interactions. hydrogen bonds between sugar residues. pairing of two purines or two pyrimidines.

pairing of a purine with a pyrimidine.

A codon is _______ nucleotides long, and there are _______ different possible codons in total. 2; 16 2; 64 3; 16 3; 64 4; 64

3; 64

Match the terms on the left with the definition on the right for the lists below: A. Translation 1 - copying RNA into RNA B. Replication 2 - copying DNA into DNA C. Transcription 3 - copying DNA into protein 4 - copying RNA into protein 5 - copying protein into RNA 6 - copying DNA into RNA A-3, B-1, C-6 A-6, B-2, C-4 A-4, B-2, C-6 A-4, B-6, C-2

A-4, B-2, C-6

The enzyme that unwinds the DNA prior to replication is called DNA polymerase III. DNA ligase. single-stranded DNA binding protein. primase. helicase.

helicase

Imagine that a novel life-form is found deep within Earth's crust. Although its DNA is composed of the same four nucleotides as other life-forms, its codons are four bases in length. This organism could therefore be composed of _______ different amino acids. 4 16 64 128 256

256

What is the nucleotide sequence of the complementary strand of the following DNA molecule: 5'-AATGCGA-3'? 3'-TTACGCT-5' 5'-AATGCGA-3' 3'- GGCATAG-5' 5'-CCGTTAT-3' 3'-AGCGTAA-5'

3'-TTACGCT-5'

The bases from DNA isolated from a newly discovered single-stranded virus are found to be 32 percent A, 18 percent C, 18 percent G, and 32 percent T. During replication, this DNA forms a complementary strand. The bases of the complementary DNA would be _______ percent A, _______ percent C, _______ percent G, and _______ percent T. 32; 17; 32; 19 19; 32; 17; 32 17; 32; 32; 19 25; 25; 25; 25 32; 18; 18; 32

32; 18; 18; 32

Suppose the 5ʹ-to-3ʹ coding strand of DNA is GTCTATGCATTA. What is the sequence of the template strand DNA that would be used for transcription? 5ʹ-GTCTATGCATTA-3ʹ 5ʹ-CAGATACGTAAT-3ʹ 3ʹ-GTCTATGCATTA-5ʹ 3ʹ-CAGATACGTAAT-5ʹ 5ʹ-GUCUAUGCAUUA-3ʹ

3ʹ-CAGATACGTAAT-5ʹ

If a sequence in one strand of DNA is 5ʹ-AGCTGCTGA-3ʹ, what is the sequence in the complementary strand? 5ʹ-AGCTGCTGA-3ʹ 3ʹ-AGCTGCTGA-5ʹ 5ʹ-TCGACGACT-3ʹ 3ʹ-TCGATGACT-5ʹ 3ʹ-TCGACGACT-5ʹ

3ʹ-TCGACGACT-5ʹ

What is the sequence of the complementary strand of RNA made from this DNA template sequence? 5ʹ-AGC TTC GCT GAA GCT CGG-3ʹ (Note: The spaces between the nucleotides have been inserted in order to make the sequence easier to read.) 5ʹ-UCG AAG CGA CUU CGA GCC-5ʹ 3ʹ-UCG AAG CGA CUU CGA GCC-5ʹ 3ʹ-TCG AAG CGA CTT CGA GCC-5ʹ 5ʹ-GGC TCG AAG TCG CTT CGA-5ʹ 5ʹ-TCG AAG CGA CTT CGA GCC-3ʹ

3ʹ-UCG AAG CGA CUU CGA GCC-5ʹ

An mRNA has the sequence 5'-AUGAAAUCCUAG-3'. What is the template DNA strand for this sequence? 5'-TACTTTAGGATC-3' 5'-ATGAAATCCTAG-3' 5'-GATCCTAAAGTA-3' 5'-TACAAATCCTAG-3' 5'-CTAGGATTTCAT-3'

5'-CTAGGATTTCAT-3'

Translation of messenger RNA into protein occurs in mRNA in a _______ direction, and the protein is built from _______ terminus to _______ terminus. 3'-to-5'; N; C 5'-to-3'; N; C 3'-to-5'; C; N 5'-to-3'; C; N 3'-to-5'; C; C

5'-to-3'; N; C

The anticodon 3ʹ-UAC-5ʹ will bind to which of the following codons? 5ʹ-ATC-3ʹ 5ʹ-AUC-3ʹ 5ʹ-AUG-3ʹ 5ʹ-TAG-3ʹ 3ʹ-AUG-5ʹ

5ʹ-AUG-3ʹ

Refer to the figure, which illustrates the chemical structure of DNA. Which two labeled structures participate in a phosphodiester bond? A and B B and D C and D C and E A and E

A and B

_______ is not required for transcription. A DNA template A primer Ribonucleoside triphosphate RNA polymerase Helicase activity

A primer

The promoter is __________ A short RNA primer used to initiate synthesis of a new RNA transcript. A DNA sequence that establishes where replication will initiate. An RNA polymerase subunit that speeds up the rate of nucleotide polymerization. A short DNA sequence near the beginning of a transcription unit where RNA polymerase binds to begin transcription. a DNA sequence near the end of a transcription unit that controls termination of transcription

A short DNA sequence near the beginning of a transcription unit where RNA polymerase binds to begin transcription.

Suppose the DNA of a gene contains five regions—A, B, C, D, and E, in that order. Regions A, B, and D are located in introns, while regions C and E are located in exons. What is the order of the regions in the pre-mRNA transcribed from that sequence? CE ABD BAD ABDCE ABCDE

ABCDE

Refer to the figure. Which arrow points to the location of the anticodon site of this tRNA molecule? A B C D None of the arrows

B

Suppose you obtain four different samples of nucleic acids. You analyze the nitrogenous base composition of each one and get the results in the table below (the numbers indicate percentage of each nitrogenous base in the samples). Which of these nucleic acids is/are single-stranded RNA? A B C D Both C and D

Both C and D

Which statement about the flow of genetic information is true? Proteins encode information that is used to produce other proteins of the same amino acid sequence. RNA encodes information that is transcribed into DNA, and DNA encodes information that is translated into proteins. Proteins encode information that can be translated into RNA, and RNA encodes information that can be transcribed into DNA. DNA encodes information that is transcribed into RNA, and RNA encodes information that is translated into proteins. DNA encodes information that is translated directly to proteins, without any intermediaries.

DNA encodes information that is transcribed into RNA, and RNA encodes information that is translated into proteins.

Which statement about DNA or RNA is true? DNA is completely replicated but only partially transcribed. DNA is partially replicated but completely transcribed. RNA is completely replicated but only partially translated. DNA is completely replicated and completely translated. DNA is partially replicated but completely translated.

DNA is completely replicated but only partially transcribed.

The bases of nucleic acids are purines or pyrimidines. Which statement contrasting purines and pyrimidines is true? Purines include the bases cytosine and thymine, whereas pyrimidines include the bases adenine and guanine. Pyrimidines are found in RNA, whereas purines are found in DNA. Purines are double-ring structures, whereas pyrimidines are single-ring structures. Purines have only single bonds in their structure, whereas pyrimidines have both single and double bonds in their structure. Purines consist of hydrogen, carbon, oxygen, and nitrogen, whereas pyrimidines have phosphorus, hydrogen, carbon, oxygen, and nitrogen.

Purines are double-ring structures, whereas pyrimidines are single-ring structures.

DNA is composed of two strands, only one of which is typically used as a template for RNA synthesis. By what mechanism is the correct strand chosen? The promoter acts to direct the RNA polymerase to initiate polymerization in the correct direction. Only one strand has a start codon. Both strands are tried, and the one that works is remembered. An initiation factor informs the system about which strand to use. The strand chosen randomly.

The promoter acts to direct the RNA polymerase to initiate polymerization in the correct direction.

Which statement about bidirectional replication at an origin is NOT TRUE? The activity of DNA ligase is required to complete DNA synthesis on both template strands of the helix. The length of the replication bubble increases as replication proceeds. The DNA strand that is "leading" at one replication fork is the lagging strand at the opposite fork. There are two DNA polymerases at each replication fork; each polymerase is copying one template strand of the original DNA helix. There are two "leading" strands at one replication fork and two "lagging" strands at the other fork.

There are two "leading" strands at one replication fork and two "lagging" strands at the other fork.

Which statement about Okazaki fragments is TRUE? They occur because DNA polymerase polymerizes nucleotides in only one direction along a strand of DNA. They are synthesized by primase to act as a primer that initiates DNA replication. They are synthesized on the leading strand at a replication fork It they did not exist, bases would pair with their complementary bases. They reduce the mutation rate during DNA replication.

They occur because DNA polymerase polymerizes nucleotides in only one direction along a strand of DNA.

Humans share the same genetic code with just other vertebrates. just other multicellular animals. just other multicellular animals and plants. just other eukaryotes. all living organisms, with a few exceptions.

all living organisms, with a few exceptions.

tRNAs are "charged" by mRNAs. amino acids. tRNA polymerases. proteases. aminoacyl-tRNA synthetases.

aminoacyl-tRNA synthetases

In the process of transcription, a DNA molecule is synthesized from an RNA template. ribonucleoside triphosphates are assembled into an RNA molecule in the absence of a template. an RNA molecule is synthesized from a DNA template. a protein is synthesized with the use of information from a messenger RNA. a single-stranded DNA molecule is replicated.

an RNA molecule is synthesized from a DNA template.

You are least likely to see introns in a(n) plant genome. insect genome. mammalian genome. bacterial genome. yeast genome.

bacterial genome.

In eukaryotic cells, translation occurs in the _______ and transcription occurs _______. nucleus; in the nucleus nucleus; in the cytoplasm cytoplasm; in the nucleus nucleus; outside of the cell cytoplasm; outside of the cell

cytoplasm; in the nucleus

The guanosine triphosphate (GTP) cap that is added to the 5ʹ end of primary mRNA contains all the coding and noncoding sequences of the DNA template. provides the mRNA molecule with a poly A tail. helps transfer amino acids to the ribosomes. forms hydrogen bonds with the polymerase. facilitates the binding of mRNA to ribosomes.

facilitates the binding of mRNA to ribosomes

The enzyme DNA ligase is required continuously during DNA replication in order for fragments of the leading strand to be joined together. fragments of the lagging strand to be joined together. the parental strands to be joined back together. 3ʹ-deoxynucleoside triphosphates to be converted to 5ʹ-deoxynucleoside triphosphates. the complex of proteins that work together at the replication fork to remain attached together.

fragments of the lagging strand to be joined together

Single-stranded RNA can fold back on itself, creating three-dimensional structures such as tRNA. The folds are stabilized by _______ bonds. hydrogen ionic phosphodiester peptide glycosidic

hydrogen

The nitrogenous bases of the two complementary strands in the DNA double helix are held together by van der Waals forces. covalent bonds. hydrogen bonds. covalent and hydrogen bonds. van der Waals forces and covalent bonds.

hydrogen bonds

During replication, the new DNA strand is synthesized in the 3ʹ-to-5ʹ direction. in the 5ʹ-to-3ʹ direction. in both the 3ʹ-to-5ʹ and 5ʹ-to-3ʹ directions from the replication fork. from one end to the other, in the 3ʹ-to-5ʹ or the 5ʹ-to-3ʹ direction. None of the above

in the 5ʹ-to-3ʹ direction

The poly A tail added to pre-mRNA is coded for by DNA. increases mRNA stability. reduces mRNA stability. is attached to its 5ʹ end. counteracts the effect of the GTP-cap.

increases mRNA stability

Refer to the figure at the beginning of these questions, which shows the standard genetic code. If an anticodon is 3′-GAG-5′, then the associated amino acid is aspartic acid. glutamic acid. histidine. leucine. threonine.

leucine

Nucleic acids and proteins are both polymers made of a set of monomers. Complete the following analogy: _______ are to nucleotides as side chains (R groups) are to amino acids. ribose/deoxyribose sugars phosphate ions nitrogenous bases nucleosides hydroxyl groups

nitrogenous bases

Ribosomes are a collection of _______ that are needed for _______. small proteins; translation proteins and rRNAs; translation proteins and tRNAs; transcription proteins and mRNAs; translation mRNAs and tRNAs; translation

proteins and rRNAs; translation

According to the principle of complementary base pairing, purines always pair with deoxyribose sugars. uracil. pyrimidines. adenine. guanine.

pyrimidines

The strands that make up DNA are antiparallel, meaning that one strand is positively charged, and the other is negatively charged. the base pairings create unequal spacing between the two DNA strands. the 5ʹ-to-3ʹ direction of one strand is opposite to the 5ʹ-to-3ʹ direction of the other strand. the twisting of the DNA molecule has shifted the two strands. purines bond with purines, and pyrimidines bond with pyrimidines.

the 5ʹ-to-3ʹ direction of one strand is opposite to the 5ʹ-to-3ʹ direction of the other strand.

During DNA replication one template strand must be degraded to allow the other strand to be copied. the template strands must separate so that both can be copied. the template strands come back together after the passage of the replication fork. origins of replication always give rise to single replication forks. two replication forks diverge from each origin, but one always lags behind the other.

the template strands must separate so that both can be copied

DNA utilizes the bases guanine, cytosine, thymine, and adenine. In RNA, _______ is replaced by _______. adenine; arginine thymine; uracil cytosine; uracil cytosine; arginine cytosine; thymine

thymine; uracil