Nucleic Acids Quiz

PDF page 135: Only certain types of base pairing are allowed. For example, a certain purine can only pair with a certain pyrimidine. This means A can pair with T, and G can pair with C, as shown in Figure 3.35. This is known as the base complementary rule. In other words, the DNA strands are complementary to each other. If the sequence of one strand is AATTGGCC, the complementary strand would have the sequence TTAACCGG. During DNA replication, each strand is copied, resulting in a daughter DNA double helix containing one parental DNA strand and a newly synthesized strand.

PDF page 132: addition to carbon, hydrogen, oxygen, and nitrogen. Conserved through evolution in all organisms, nucleic acids store and transmit hereditary information. As will be explored in more detail in Chapters 14-17, DNA contains the instructions for the synthesis of proteins by dictating the sequences of amino acids in polypeptides through processes known as transcription and translation. Nucleic acids are made up of nucleotides; in turn, each nucleotide consists of a pentose sugar (deoxyribose in DNA and ribose in RNA), a nitrogenous base (adenine, cytosine, guanine, and thymine or uracil), and a phosphate group. DNA carries the genetic blueprint of the cell that is passed from parent to offspring via cell division. DNA has a double-helical structure with the two strands running in opposite directions (antiparallel), connected by hydrogen bonds and complementary to each other. In DNA, purines pair with pyrimidines: adenine pairs with thymine (A-T), and cytosine pairs with guanine (C-G). In RNA, uracil replaces thymine to pair with adenine (U-A). RNA also differs from DNA in that it is single-stranded and has many forms, such as messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA) that all participate in the synthesis of proteins. MicroRNAs (miRNAs) regulate the use of mRNA. The flow of genetic information is usually DNA → RNA → protein, also known as the Central Dogma of Life. Information presented and the examples highlighted in the section support concepts and Learning Objectives outlined in

PDF page 132: addition to carbon, hydrogen, oxygen, and nitrogen. Conserved through evolution in all organisms, nucleic acids store and transmit hereditary information. As will be explored in more detail in Chapters 14-17, DNA contains the instructions for the synthesis of proteins by dictating the sequences of amino acids in polypeptides through processes known as transcription and translation. Nucleic acids are made up of nucleotides; in turn, each nucleotide consists of a pentose sugar (deoxyribose in DNA and ribose in RNA), a nitrogenous base (adenine, cytosine, guanine, and thymine or uracil), and a phosphate group. DNA carries the genetic blueprint of the cell that is passed from parent to offspring via cell division. DNA has a double-helical structure with the two strands running in opposite directions (antiparallel), connected by hydrogen bonds and complementary to each other. In DNA, purines pair with pyrimidines: adenine pairs with thymine (A-T), and cytosine pairs with guanine (C-G). In RNA, uracil replaces thymine to pair with adenine (U-A). RNA also differs from DNA in that it is single-stranded and has many forms, such as messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA) that all participate in the synthesis of proteins. MicroRNAs (miRNAs) regulate the use of mRNA. The flow of genetic information is usually DNA → RNA → protein, also known as the Central Dogma of Life. Information presented and the examples highlighted in the section support concepts and Learning Objectives outlined in

PDF page 134: The nitrogenous bases, important components of nucleotides, are organic molecules and are so named because they contain carbon and nitrogen. They are bases because they contain an amino group that has the potential of binding an extra hydrogen, thus decreasing the hydrogen ion concentration in its environment, making it more basic. Each nucleotide in DNA contains one of four possible nitrogenous bases: adenine (A), guanine (G) cytosine (C), and thymine (T). Adenine and guanine are classified as purines. The primary structure of a purine is two carbon-nitrogen rings. Cytosine, thymine, and uracil are classified as pyrimidines which have a single carbon-nitrogen ring as their primary structure (Figure 3.33). Each of these basic carbon-nitrogen rings has different functional groups attached to it. In molecular biology shorthand, the nitrogenous bases are simply known by their symbols A, T, G, C, and U. DNA contains A, T, G, and C whereas RNA contains A, U, G, and C. The pentose sugar in DNA is deoxyribose, and in RNA, the sugar is ribose (Figure 3.33). The difference between the sugars is the presence of the hydroxyl group on the second carbon of the ribose and hydrogen on the second carbon of the deoxyribose. The carbon atoms of the sugar molecule are numbered as 1′, 2′, 3′, 4′, and 5′ (1′ is read as “one prime”). The phosphate residue is attached to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′–3′ phosphodiester linkage. The phosphodiester linkage is not formed by simple dehydration reaction like the other linkages connecting monomers in macromolecules: its formation involves the

PDF page 134: phosphate groups. Carbon residues in the pentose are numbered 1′ through 5′ (the prime distinguishes these residues from those in the base, which are numbered without using a prime notation). The base is attached to the 1′ position of the ribose, and the phosphate is attached to the 5′ position. When a polynucleotide is formed, the 5′ phosphate of the incoming nucleotide attaches to the 3′ hydroxyl group at the end of the growing chain. Two types of pentose are found in nucleotides, deoxyribose (found in DNA) and ribose (found in RNA). Deoxyribose is similar in structure to ribose, but it has an H instead of an OH at the 2′ position. Bases can be divided into two categories: purines and pyrimidines. Purines have a double ring structure, and pyrimidines have a single ring.

PDF page 137: DNA RNA Function Carries genetic information Involved in protein synthesis Location Remains in the nucleus Leaves the nucleus Structure Double helix Usually single-stranded Sugar Deoxyribose Ribose Pyrimidines Cytosine, thymine Cytosine, uracil Purines Adenine, guanine Adenine, guanine

PDF page 134: phosphate groups. Carbon residues in the pentose are numbered 1′ through 5′ (the prime distinguishes these residues from those in the base, which are numbered without using a prime notation). The base is attached to the 1′ position of the ribose, and the phosphate is attached to the 5′ position. When a polynucleotide is formed, the 5′ phosphate of the incoming nucleotide attaches to the 3′ hydroxyl group at the end of the growing chain. Two types of pentose are found in nucleotides, deoxyribose (found in DNA) and ribose (found in RNA). Deoxyribose is similar in structure to ribose, but it has an H instead of an OH at the 2′ position. Bases can be divided into two categories: purines and pyrimidines. Purines have a double ring structure, and pyrimidines have a single ring.

PDF page 134: The nitrogenous bases, important components of nucleotides, are organic molecules and are so named because they contain carbon and nitrogen. They are bases because they contain an amino group that has the potential of binding an extra hydrogen, thus decreasing the hydrogen ion concentration in its environment, making it more basic. Each nucleotide in DNA contains one of four possible nitrogenous bases: adenine (A), guanine (G) cytosine (C), and thymine (T). Adenine and guanine are classified as purines. The primary structure of a purine is two carbon-nitrogen rings. Cytosine, thymine, and uracil are classified as pyrimidines which have a single carbon-nitrogen ring as their primary structure (Figure 3.33). Each of these basic carbon-nitrogen rings has different functional groups attached to it. In molecular biology shorthand, the nitrogenous bases are simply known by their symbols A, T, G, C, and U. DNA contains A, T, G, and C whereas RNA contains A, U, G, and C. The pentose sugar in DNA is deoxyribose, and in RNA, the sugar is ribose (Figure 3.33). The difference between the sugars is the presence of the hydroxyl group on the second carbon of the ribose and hydrogen on the second carbon of the deoxyribose. The carbon atoms of the sugar molecule are numbered as 1′, 2′, 3′, 4′, and 5′ (1′ is read as “one prime”). The phosphate residue is attached to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′–3′ phosphodiester linkage. The phosphodiester linkage is not formed by simple dehydration reaction like the other linkages connecting monomers in macromolecules: its formation involves the

PDF page 134: The nitrogenous bases, important components of nucleotides, are organic molecules and are so named because they contain carbon and nitrogen. They are bases because they contain an amino group that has the potential of binding an extra hydrogen, thus decreasing the hydrogen ion concentration in its environment, making it more basic. Each nucleotide in DNA contains one of four possible nitrogenous bases: adenine (A), guanine (G) cytosine (C), and thymine (T). Adenine and guanine are classified as purines. The primary structure of a purine is two carbon-nitrogen rings. Cytosine, thymine, and uracil are classified as pyrimidines which have a single carbon-nitrogen ring as their primary structure (Figure 3.33). Each of these basic carbon-nitrogen rings has different functional groups attached to it. In molecular biology shorthand, the nitrogenous bases are simply known by their symbols A, T, G, C, and U. DNA contains A, T, G, and C whereas RNA contains A, U, G, and C. The pentose sugar in DNA is deoxyribose, and in RNA, the sugar is ribose (Figure 3.33). The difference between the sugars is the presence of the hydroxyl group on the second carbon of the ribose and hydrogen on the second carbon of the deoxyribose. The carbon atoms of the sugar molecule are numbered as 1′, 2′, 3′, 4′, and 5′ (1′ is read as “one prime”). The phosphate residue is attached to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′–3′ phosphodiester linkage. The phosphodiester linkage is not formed by simple dehydration reaction like the other linkages connecting monomers in macromolecules: its formation involves the

PDF page 137: DNA RNA Function Carries genetic information Involved in protein synthesis Location Remains in the nucleus Leaves the nucleus Structure Double helix Usually single-stranded Sugar Deoxyribose Ribose Pyrimidines Cytosine, thymine Cytosine, uracil Purines Adenine, guanine Adenine, guanine

PDF page 134: The nitrogenous bases, important components of nucleotides, are organic molecules and are so named because they contain carbon and nitrogen. They are bases because they contain an amino group that has the potential of binding an extra hydrogen, thus decreasing the hydrogen ion concentration in its environment, making it more basic. Each nucleotide in DNA contains one of four possible nitrogenous bases: adenine (A), guanine (G) cytosine (C), and thymine (T). Adenine and guanine are classified as purines. The primary structure of a purine is two carbon-nitrogen rings. Cytosine, thymine, and uracil are classified as pyrimidines which have a single carbon-nitrogen ring as their primary structure (Figure 3.33). Each of these basic carbon-nitrogen rings has different functional groups attached to it. In molecular biology shorthand, the nitrogenous bases are simply known by their symbols A, T, G, C, and U. DNA contains A, T, G, and C whereas RNA contains A, U, G, and C. The pentose sugar in DNA is deoxyribose, and in RNA, the sugar is ribose (Figure 3.33). The difference between the sugars is the presence of the hydroxyl group on the second carbon of the ribose and hydrogen on the second carbon of the deoxyribose. The carbon atoms of the sugar molecule are numbered as 1′, 2′, 3′, 4′, and 5′ (1′ is read as “one prime”). The phosphate residue is attached to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms a 5′–3′ phosphodiester linkage. The phosphodiester linkage is not formed by simple dehydration reaction like the other linkages connecting monomers in macromolecules: its formation involves the

PDF page 139: peptide bond bond formed between two amino acids by a dehydration reaction phosphodiester linkage covalent chemical bond that holds together the polynucleotide chains, with a phosphate group

PDF page 135: DNA has a double-helix structure (Figure 3.34). The sugar and phosphate lie on the outside of the helix, forming the backbone of the DNA. The nitrogenous bases are stacked in the interior, like the steps of a staircase, in pairs; the pairs are bound to each other by hydrogen bonds. Every base pair in the double helix is separated from the next base pair by 0.34 nm. The two strands of the helix run in opposite directions, meaning that the 5′ carbon end of one strand will face the 3′ carbon end of its matching strand. (This is referred to as antiparallel orientation and is important to DNA replication and in many nucleic acid interactions.)

PDF page 137: DNA RNA Function Carries genetic information Involved in protein synthesis Location Remains in the nucleus Leaves the nucleus Structure Double helix Usually single-stranded Sugar Deoxyribose Ribose Pyrimidines Cytosine, thymine Cytosine, uracil Purines Adenine, guanine Adenine, guanine

PDF page 135: DNA has a double-helix structure (Figure 3.34). The sugar and phosphate lie on the outside of the helix, forming the backbone of the DNA. The nitrogenous bases are stacked in the interior, like the steps of a staircase, in pairs; the pairs are bound to each other by hydrogen bonds. Every base pair in the double helix is separated from the next base pair by 0.34 nm. The two strands of the helix run in opposite directions, meaning that the 5′ carbon end of one strand will face the 3′ carbon end of its matching strand. (This is referred to as antiparallel orientation and is important to DNA replication and in many nucleic acid interactions.)

PDF page 135: DNA has a double-helix structure (Figure 3.34). The sugar and phosphate lie on the outside of the helix, forming the backbone of the DNA. The nitrogenous bases are stacked in the interior, like the steps of a staircase, in pairs; the pairs are bound to each other by hydrogen bonds. Every base pair in the double helix is separated from the next base pair by 0.34 nm. The two strands of the helix run in opposite directions, meaning that the 5′ carbon end of one strand will face the 3′ carbon end of its matching strand. (This is referred to as antiparallel orientation and is important to DNA replication and in many nucleic acid interactions.)

PDF page 135: the outside, and the bases are on the inside. Each base from one strand interacts via hydrogen bonding with a base from the opposing strand. (credit: Jerome Walker/Dennis Myts)

PDF page 135: DNA has a double-helix structure (Figure 3.34). The sugar and phosphate lie on the outside of the helix, forming the backbone of the DNA. The nitrogenous bases are stacked in the interior, like the steps of a staircase, in pairs; the pairs are bound to each other by hydrogen bonds. Every base pair in the double helix is separated from the next base pair by 0.34 nm. The two strands of the helix run in opposite directions, meaning that the 5′ carbon end of one strand will face the 3′ carbon end of its matching strand. (This is referred to as antiparallel orientation and is important to DNA replication and in many nucleic acid interactions.)

PDF page 132: addition to carbon, hydrogen, oxygen, and nitrogen. Conserved through evolution in all organisms, nucleic acids store and transmit hereditary information. As will be explored in more detail in Chapters 14-17, DNA contains the instructions for the synthesis of proteins by dictating the sequences of amino acids in polypeptides through processes known as transcription and translation. Nucleic acids are made up of nucleotides; in turn, each nucleotide consists of a pentose sugar (deoxyribose in DNA and ribose in RNA), a nitrogenous base (adenine, cytosine, guanine, and thymine or uracil), and a phosphate group. DNA carries the genetic blueprint of the cell that is passed from parent to offspring via cell division. DNA has a double-helical structure with the two strands running in opposite directions (antiparallel), connected by hydrogen bonds and complementary to each other. In DNA, purines pair with pyrimidines: adenine pairs with thymine (A-T), and cytosine pairs with guanine (C-G). In RNA, uracil replaces thymine to pair with adenine (U-A). RNA also differs from DNA in that it is single-stranded and has many forms, such as messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA) that all participate in the synthesis of proteins. MicroRNAs (miRNAs) regulate the use of mRNA. The flow of genetic information is usually DNA → RNA → protein, also known as the Central Dogma of Life. Information presented and the examples highlighted in the section support concepts and Learning Objectives outlined in

PDF page 135: Only certain types of base pairing are allowed. For example, a certain purine can only pair with a certain pyrimidine. This means A can pair with T, and G can pair with C, as shown in Figure 3.35. This is known as the base complementary rule. In other words, the DNA strands are complementary to each other. If the sequence of one strand is AATTGGCC, the complementary strand would have the sequence TTAACCGG. During DNA replication, each strand is copied, resulting in a daughter DNA double helix containing one parental DNA strand and a newly synthesized strand.

PDF page 137: The mRNA is read in sets of three bases known as codons. Each codon codes for a single amino acid. In this way, the mRNA is read and the protein product is made. Ribosomal RNA (rRNA) is a major constituent of ribosomes on which the mRNA binds. The rRNA ensures the proper alignment of the mRNA and the ribosomes; the rRNA of the ribosome also has an enzymatic activity (peptidyl transferase) and catalyzes the formation of the peptide bonds between two aligned amino acids. Transfer RNA (tRNA) is one of the smallest of the four types of RNA, usually 70–90 nucleotides long. It carries the correct amino acid to the site of protein synthesis. It is the base pairing between the tRNA and mRNA that allows for the correct amino acid to be inserted in the polypeptide chain. microRNAs are the smallest RNA molecules and their role involves the regulation of gene expression by interfering with the expression of certain mRNA messages. Table 3.2 summarizes features of DNA and RNA.