Chapter 4 Nucleic Acids
(d) 5' end to the 3' end
By convention, nucleotide sequences are always written from the _____. (a) 3' end to the 5' end (b) amino terminus to the carboxyl terminus (c) sugar end to the phosphate end (d) 5' end to the 3' end
(c) Only antiparallel strands create the geometry that allows complementary base pairs to form via hydrogen bonding.
Complementary base pairing is possible only if two DNA strands align in antiparallel—instead of parallel—fashion. Which statement best explains why? (a) Only antiparallel strands contain the nitrogenous bases necessary to form complementary base pairs. (b) Only antiparallel strands contain unusual backbone atoms which allow complementary base pairing (c) Only antiparallel strands create the geometry that allows complementary base pairs to form via hydrogen bonding. (d) Only antiparallel strands create the geometry that allows complementary base pairs to form via van der Waals interactions.
(d) These numbers tell us there are ten rungs, or steps, on the DNA "ladder" for every turn of the helix.
Franklin and Wilkins analyzed DNA by bombarding DNA crystals with X-rays. Their analysis yielded two numbers that sparked interest, 3.4 nm and 0.34 nm. What is the significance of these numbers? (a) The width of a DNA molecule is 3.4 nm, whereas the width of a nucleotide monomer is 0.34 m. (b) The 10 to 1 ratio signifies that DNA molecules are ten times longer than they are wide. (c) It turned out to be just a coincidence. (d) These numbers tell us there are ten rungs, or steps, on the DNA "ladder" for every turn of the helix. (e) DNA molecules are 3.4 nm long and 0.34 nm wide.
(a) In DNA and RNA, a phosphodiester linkage connects the 3' carbon of one nucleotide and the 5' carbon of another.
How are nucleotides linked together to form a polynucleotide chain? (a) In DNA and RNA, a phosphodiester linkage connects the 3' carbon of one nucleotide and the 5' carbon of another. (b) In DNA but not RNA, a phosphodiester linkage connects the 3' carbon of one nucleotide and the 5' carbon of another. (c) In RNA but not DNA, a phosphodiester linkage connects the 2' carbon of one nucleotide and the 5' carbon of another. (d) In DNA and RNA, a peptide bond connects the 3' carbon of one nucleotide and the 5' carbon of another.
(b) 40
If a DNA sample were composed of 10% thymine, what would be the percentage of guanine? (a) 80 (b) 40 (c) 10 (d) 20 (e) It is impossible to tell from the information given
(e) 5'TGCAAT3'
If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence _____. (a) 5'TAACGT3' (b) 5'UGCAAU3' (c) 3'UAACGU5' (d) 5'UAACGU3' (e) 5'TGCAAT3'
(a) hydrogen bonds
In a DNA double helix, what kind of chemical bonds form between the complementary nitrogenous bases? (a) hydrogen bonds (b) phosphodiester bonds (c) polar covalent bonds (d) nitrogen bonds
(a) nitrogenous bases
In a nucleic acid polymer, the bonds that help to hold regions of double-strandedness together occur between what parts of the nucleotide monomers? (a) nitrogenous bases (b) sugars and phosphates (c) sugars (d) nitrogenous bases and phosphates
(b) function in the synthesis of proteins
One of the primary functions of RNA molecules is to _____. (a) transmit genetic information to offspring (b) function in the synthesis of proteins (c) act as a pattern or blueprint to form DNA (d) form the genes of higher organisms (e) make a copy of itself, thus ensuring genetic continuity
(a) UAGC
Starting at the 5' end, what is the base sequence of the RNA strand shown in Figure 4.3? (a) UAGC (b) UGAC (c) TAGC (d) CGAU
(d) phosphate, hydroxyl
The condensation reaction that forms nucleic acid polymers occurs between a _____ group on one nucleotide and a _____ group on a second nucleotide. (a) nitrogenous base, sugar (b) carbon, carbon (c) nitrogenous base, nitrogenous base (d) phosphate, hydroxyl
(c) A-T and G-C
What are the complementary base pairs that form in DNA? (a) A-T and G-U (b) A-G and T-C (c) A-T and G-C (d) A-U and G-C
(b) a sugar, a phosphate group and a nitrogenous base
What are the components of a nucleotide? (a) a sugar, a sulfate group and a purine (b) a sugar, a phosphate group and a nitrogenous base (c) a sugar, an amino acid and a nitrogenous base (d) a sugar, a sulfate group and a pyrimidine
(b) the sequence of deoxyribonucleotides
What determines the primary structure of a DNA molecule? (a) complementary base pairing and the formation of hairpins (b) the sequence of deoxyribonucleotides (c) the sugar-phosphate backbone (d) the sequence of ribonucleotides
(c) their phosphate groups
What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed? (a) their sugar groups (b) their nitrogenous bases (c) their phosphate groups (d) their methyl groups
(d) complementary pairing of the nitrogenous bases
What is the structural feature that allows DNA to replicate? (a) three-component structure of the nucleotides (b) disulfide bonding (bridging) of the two helixes (c) twisting of the molecule to form an α-helix (d) complementary pairing of the nitrogenous bases (e) sugar-phosphate backbone
(b) the sugar and the base
What is/are the variable structure(s) of a nucleotide? (a) the base (b) the sugar and the base (c) the phosphate group (d) the sugar
(a) a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
When nucleotides polymerize to form a nucleic acid _____. (a) a covalent bond forms between the sugar of one nucleotide and the phosphate of a second (b) hydrogen bonds form between the bases of two nucleotides (c) covalent bonds form between the bases of two nucleotides (d) a hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second
(e) guanine and adenine
Which of the following are purine nitrogenous bases? (a) thymine and uracil (b) adenine and thymine (c) cytosine and guanine (d) uracil and cytosine (e) guanine and adenine
(e) cytosine and uracil
Which of the following are pyrimidine nitrogenous bases? (a) thymine and guanine (b) adenine and thymine (c) ribose and deoxyribose (d) guanine and adenine (e) cytosine and uracil
(d) double antiparallel helical strands
Which of the following best describes DNA's secondary structure? (a) double parallel helical strands (b) beta-pleated sheet (c) turn-loop-turn (d) double antiparallel helical strands
(a) purines is always the same as pyrimidines
Which of the following did Watson and Crick already know when they were trying to determine the structure of DNA? The number of _____. (a) purines is always the same as pyrimidines (b) cytosines is always the same as adenines (c) guanines is always the same as thymines (d) purines is always larger than the number of pyrimidines (e) pyrimidines is always larger than purines
(b) 5'-ATGC-3' with 5'-GCAT-3'
Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA? (a) 5'-purine-pyrimidine-purine-pyrimidine-3' with 3'-purine-pyrimidine-purine-pyrimidine-5' (b) 5'-ATGC-3' with 5'-GCAT-3' (c) 5'-AGCT-3' with 5'-TCGA-3' (d) 5'-GCGC-3' with 5'-TATA-3' (e) All of these pairs are correct.
(c) Ribonucleotides have a hydroxyl group bonded to their 2' carbon; deoxyribonucleotides have an H at the same location.
Which statement accurately summarizes a difference between ribonucleotides and deoxyribonucleotides? (a) Ribonucleotides contain only purines; deoxyribonucleotides contain only pyrimidines. (b) In ribonucleotides, the sugar is a pentose; deoxyribonucleotides have a hexose. (c) Ribonucleotides have a hydroxyl group bonded to their 2' carbon; deoxyribonucleotides have an H at the same location. (d) Ribonucleotides have a hydroxyl group bonded to their 3' carbon; deoxyribonucleotides have an H at the same location.
(d) Base pairing allows production of identical daughter molecules.
Which statement concerning the DNA double helix is correct? (a) Bases on one strand pair with the same base on the opposite strand. (b) Base pairing restricts the variety of genetic information DNA can contain. (c) Base pairing is the only stabilizing force. (d) Base pairing allows production of identical daughter molecules.
