Identify structure and purpose of carbohydrates, lipids, proteins, and nucleic acids - AP Biology
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Hemoglobin is an example of a __________.
Hemoglobin is an example of a __________.
Hemoglobin is the protein in red blood cells that binds and transports oxygen to the body tissues. It contains an iron core, and each hemoglobin molecule can bind up to four oxygen molecules.
Hemoglobin is the protein in red blood cells that binds and transports oxygen to the body tissues. It contains an iron core, and each hemoglobin molecule can bind up to four oxygen molecules.
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A(n) __________ fat contains no double bonds in the fatty acid chain.
A(n) __________ fat contains no double bonds in the fatty acid chain.
A saturated fat contains no double bonds in its fatty acid chain. Just remember that saturated means the fat is saturated with hydrogens. Double bonds eliminate two hydrogen atoms per occurrence, and are present in unsaturated fats.
A saturated fat contains no double bonds in its fatty acid chain. Just remember that saturated means the fat is saturated with hydrogens. Double bonds eliminate two hydrogen atoms per occurrence, and are present in unsaturated fats.
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Which of the following statements about enzymes is false?
Which of the following statements about enzymes is false?
Enzymes are not changed or consumed by the reactions they catalyze, but can be altered by environmental conditions. They work in three-dimensional active sites to bind specific substrates and lower the activation of certain reactions, subsequently increasing the reaction rate. Reaction rate can be further increased when enzymes react with cofactors or coenzymes, but decreased when enzymes are blocked from their specified active sites by competitive inhibitors.
Enzymes are not changed or consumed by the reactions they catalyze, but can be altered by environmental conditions. They work in three-dimensional active sites to bind specific substrates and lower the activation of certain reactions, subsequently increasing the reaction rate. Reaction rate can be further increased when enzymes react with cofactors or coenzymes, but decreased when enzymes are blocked from their specified active sites by competitive inhibitors.
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Which of the following types of molecules has the most energy available per unit of carbon?
Which of the following types of molecules has the most energy available per unit of carbon?
Fats have an incredibly high potential to produce a lot of energy when broken down. This is because they are very saturated, which means they have a lot of bonded hydrogens. They also have a lot of carbon-carbon bonds, which have a lot of potential energy stored. When you break down a fat, especially one that has fourteen or more carbons in the chain, you release the energy from every carbon-carbon and carbon-hydrogen bond.
Comparing this to a sugar, alcohol, or protein (amino acids make up proteins), we can see that there aren't as many of these bonds to break. Proteins, in fact, require a lot of energy to break down because they have to be converted into other forms first.
Fats have an incredibly high potential to produce a lot of energy when broken down. This is because they are very saturated, which means they have a lot of bonded hydrogens. They also have a lot of carbon-carbon bonds, which have a lot of potential energy stored. When you break down a fat, especially one that has fourteen or more carbons in the chain, you release the energy from every carbon-carbon and carbon-hydrogen bond.
Comparing this to a sugar, alcohol, or protein (amino acids make up proteins), we can see that there aren't as many of these bonds to break. Proteins, in fact, require a lot of energy to break down because they have to be converted into other forms first.
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Phospholipids are amphipathic. This means that a phospholipid is __________.
Phospholipids are amphipathic. This means that a phospholipid is __________.
Amphipathic molecules have both a polar and nonpolar region. This amphipathic quality allows phospholipids to create the plasma membrane in eukaryotic cells. The polar region is the phosphate head, which interacts with the aqueous cytosol and extracellular environment. The nonpolar region is the fatty acid tail, which is sequestered in the bilayer of the membrane and helps reduce the permeability to certain molecules.
Amphipathic molecules have both a polar and nonpolar region. This amphipathic quality allows phospholipids to create the plasma membrane in eukaryotic cells. The polar region is the phosphate head, which interacts with the aqueous cytosol and extracellular environment. The nonpolar region is the fatty acid tail, which is sequestered in the bilayer of the membrane and helps reduce the permeability to certain molecules.
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The monomers of all biological macromolecules are combined by which type of bond?
The monomers of all biological macromolecules are combined by which type of bond?
Macromolecules, such as proteins, nucleic acids, and polysaccharides, are composed of monomers. Each polymer is made from at least two smaller monomers. Protein monomers are amino acids, nucleic acid monomers are nucleotides, and polysaccharide monomers are monosaccharides. In order to form polymers, the monomers must form covalent bonds with one another.
For proteins, these covalent bonds are peptide bonds, and for saccharides they are glycosidic linkages.
Macromolecules, such as proteins, nucleic acids, and polysaccharides, are composed of monomers. Each polymer is made from at least two smaller monomers. Protein monomers are amino acids, nucleic acid monomers are nucleotides, and polysaccharide monomers are monosaccharides. In order to form polymers, the monomers must form covalent bonds with one another.
For proteins, these covalent bonds are peptide bonds, and for saccharides they are glycosidic linkages.
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How many fatty acid chains are contained in a typical molecule of "body fat?"
How many fatty acid chains are contained in a typical molecule of "body fat?"
Body fat, also known as triglycerides or triacylglycerols have three fatty acid chains. These hydrocarbon tails are hydrophobic, and they are each attached to the glycerol head, which is hydrophilic via ester linkages. Adipose tissue is a type of connective tissue that plays a structural and protective role, provides stored energy, and helps regulate body temperature.
Body fat, also known as triglycerides or triacylglycerols have three fatty acid chains. These hydrocarbon tails are hydrophobic, and they are each attached to the glycerol head, which is hydrophilic via ester linkages. Adipose tissue is a type of connective tissue that plays a structural and protective role, provides stored energy, and helps regulate body temperature.
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Which of the following is not found in nucleotides?
Which of the following is not found in nucleotides?
Nucleotides are the monomers that make up nucleic acids. They are composed of a five-carbon sugar, a nitrogenous base, and a phosphate group. In building the polymer nucleic acid chain, the sugar and phosphate of one nucleotide align with those of another to build the phosphate-sugar backbone, while the nitrogenous bases will form hydrogen bonds across the helix to link two chains of nucleotides together. Phosphate groups carry negative charge; this gives the cell nucleus an overall negative charge and can be used to generate electrochemical gradients across the nuclear membrane.
Carboxylic acids are found in amino acids, and are not present in nucleic acids.
Nucleotides are the monomers that make up nucleic acids. They are composed of a five-carbon sugar, a nitrogenous base, and a phosphate group. In building the polymer nucleic acid chain, the sugar and phosphate of one nucleotide align with those of another to build the phosphate-sugar backbone, while the nitrogenous bases will form hydrogen bonds across the helix to link two chains of nucleotides together. Phosphate groups carry negative charge; this gives the cell nucleus an overall negative charge and can be used to generate electrochemical gradients across the nuclear membrane.
Carboxylic acids are found in amino acids, and are not present in nucleic acids.
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Cholesterol is soluble in organic solvents such as chloroform, but is insoluble in water. Based on this information, to which class of macromolecule does cholesterol belong?
Cholesterol is soluble in organic solvents such as chloroform, but is insoluble in water. Based on this information, to which class of macromolecule does cholesterol belong?
Water is a very polar substance that will not interact well with nonpolar macromolecules. Enzymes (proteins), oligosaccharides (carbohydrates), and nucleic acids all contain polar regions that make them soluble in aqueous environments. Lipids, however, are hydrocarbons and generally lack a polar region. Lipids would not be soluble in water, but would be soluble in nonpolar organic solvents, like chloroform. We can conclude that cholesterol is a lipid.
Water is a very polar substance that will not interact well with nonpolar macromolecules. Enzymes (proteins), oligosaccharides (carbohydrates), and nucleic acids all contain polar regions that make them soluble in aqueous environments. Lipids, however, are hydrocarbons and generally lack a polar region. Lipids would not be soluble in water, but would be soluble in nonpolar organic solvents, like chloroform. We can conclude that cholesterol is a lipid.
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Which of the following choices is a correct statement about DNA?
Which of the following choices is a correct statement about DNA?
Chargaff found that in double-stranded DNA, the number of guanine bases should be equal to the number of cytosine bases, and the number of adenine bases should equal the number of thymine bases. These rules proved to be important pieces of evidence for the idea of complementarity, the theory that each DNA base pairs only with a specific other base on its opposite strand.
According to Chargaff's rules, the statement regarding guanine and cytosine bases is correct. The two other statements that are similarly worded are not correct because they do not compare the frequencies of two bases that are complementary to each other (adenine will not bind cytosine and guanine will not bind thymine). Finally, guanine-cytosine bonds are more stable than adenine-thymine bonds.
Chargaff found that in double-stranded DNA, the number of guanine bases should be equal to the number of cytosine bases, and the number of adenine bases should equal the number of thymine bases. These rules proved to be important pieces of evidence for the idea of complementarity, the theory that each DNA base pairs only with a specific other base on its opposite strand.
According to Chargaff's rules, the statement regarding guanine and cytosine bases is correct. The two other statements that are similarly worded are not correct because they do not compare the frequencies of two bases that are complementary to each other (adenine will not bind cytosine and guanine will not bind thymine). Finally, guanine-cytosine bonds are more stable than adenine-thymine bonds.
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Pharmaceutical researchers are often interested in blocking particular receptor proteins on cell surfaces. What chemical property of a molecule would be most important for it to bind a receptor active site?
Pharmaceutical researchers are often interested in blocking particular receptor proteins on cell surfaces. What chemical property of a molecule would be most important for it to bind a receptor active site?
To block a receptor protein, a molecule must structurally resemble the natural ligand. The active sites of proteins are highly specific, and will only bind certain molecules. The chemical formula, electrons, and bonding in the molecule can all influence small regions of the molecule's structure, but the overall shape must ultimately match the active site of the target protein.
To block a receptor protein, a molecule must structurally resemble the natural ligand. The active sites of proteins are highly specific, and will only bind certain molecules. The chemical formula, electrons, and bonding in the molecule can all influence small regions of the molecule's structure, but the overall shape must ultimately match the active site of the target protein.
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What event would activate a G protein?
What event would activate a G protein?
G proteins are second messengers involved in cell signaling and propagation or effects within the cell. G protein receptors in the plasma membrane bind to extracellular ligands, causing them to recruit G proteins. Inactive G proteins carry ADP. Once they bind to G protein receptors in the membrane, this GDP molecule is removed, and a GTP molecule is substituted to activate the G protein.
The activated G protein then binds another protein and hydrolyzes GTP to GDP to activate this protein and stimulate cellular effects.
G proteins are second messengers involved in cell signaling and propagation or effects within the cell. G protein receptors in the plasma membrane bind to extracellular ligands, causing them to recruit G proteins. Inactive G proteins carry ADP. Once they bind to G protein receptors in the membrane, this GDP molecule is removed, and a GTP molecule is substituted to activate the G protein.
The activated G protein then binds another protein and hydrolyzes GTP to GDP to activate this protein and stimulate cellular effects.
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What are the main components of a triglyceride?
What are the main components of a triglyceride?
Triglycerides are made up of a glycerol backbone and three fatty acids. They are commonly used to store energy within cells.
A polar head group, a glycerol backbone, and three fatty acids very nearly describes a phospholipid (phospholipids only have two fatty acids). The other answers are not compounds that are readily observed in cells.
Triglycerides are made up of a glycerol backbone and three fatty acids. They are commonly used to store energy within cells.
A polar head group, a glycerol backbone, and three fatty acids very nearly describes a phospholipid (phospholipids only have two fatty acids). The other answers are not compounds that are readily observed in cells.
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What are the components of the DNA backbone?
What are the components of the DNA backbone?
The backbone of DNA is made up of deoxyribose sugars linked to phosphate groups. These units are joined by phosphodiester bonds into chains. Nitrogenous bases are bound to the sugars of these groups and join DNA strands together by hydrogen bonds with their complementary base pairs.
Amino acids are the building blocks of proteins, and are not found in DNA. Alpha-linked glucose residues describe a type of polysaccharide, namely glycogen. Glycerol and fatty acids describe a type of lipid known as a triglyceride. Triglycerides and glycogen are primarily used in energy storage.
The backbone of DNA is made up of deoxyribose sugars linked to phosphate groups. These units are joined by phosphodiester bonds into chains. Nitrogenous bases are bound to the sugars of these groups and join DNA strands together by hydrogen bonds with their complementary base pairs.
Amino acids are the building blocks of proteins, and are not found in DNA. Alpha-linked glucose residues describe a type of polysaccharide, namely glycogen. Glycerol and fatty acids describe a type of lipid known as a triglyceride. Triglycerides and glycogen are primarily used in energy storage.
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How is protein primary structure formed?
How is protein primary structure formed?
Peptide bonds form between the amine group of one amino acid and the carboxylic acid of another via a covalent linkage. The formation of a polypeptide chain from amino acid residues constitutes the protein primary structure.
Secondary structure is formed by hydrogen bonding between the amino and carboxyl backbone units of the polypeptide. Tertiary structure is formed by disulfide covalent bonds, hydrophobic interactions, and R-group hydrogen bonding. Quaternary structure is the joining of multiple polypeptide subunits.
Peptide bonds form between the amine group of one amino acid and the carboxylic acid of another via a covalent linkage. The formation of a polypeptide chain from amino acid residues constitutes the protein primary structure.
Secondary structure is formed by hydrogen bonding between the amino and carboxyl backbone units of the polypeptide. Tertiary structure is formed by disulfide covalent bonds, hydrophobic interactions, and R-group hydrogen bonding. Quaternary structure is the joining of multiple polypeptide subunits.
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Where are lipids most commonly found in cells?
Where are lipids most commonly found in cells?
Lipids are primarily found in membranes. This includes both the plasma membrane and membranes surrounding particular organelles. Lipids are very useful in membranes because their nonpolar nature helps them act as a barrier between the cell and the outside environment.
Lipids are primarily found in membranes. This includes both the plasma membrane and membranes surrounding particular organelles. Lipids are very useful in membranes because their nonpolar nature helps them act as a barrier between the cell and the outside environment.
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What would happen to a group of lipids in a polar solvent?
What would happen to a group of lipids in a polar solvent?
Lipids are composed of hydrocarbon chains and are very nonpolar. Polar solvents interact well with polar solutes, but do not solvate nonpolar solutes. When lipids are placed in a polar solvent, they will group together to minimize surface contact with the solvent. These droplets of lipids, or micelles, act like containers for the lipid, keeping them grouped together instead of being distributed through the solvent.
The lipids do not precipitate as they are not necessarily in a solid form. Even lipids in the liquid state can form micelles.
Lipids are composed of hydrocarbon chains and are very nonpolar. Polar solvents interact well with polar solutes, but do not solvate nonpolar solutes. When lipids are placed in a polar solvent, they will group together to minimize surface contact with the solvent. These droplets of lipids, or micelles, act like containers for the lipid, keeping them grouped together instead of being distributed through the solvent.
The lipids do not precipitate as they are not necessarily in a solid form. Even lipids in the liquid state can form micelles.
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Amino acids are most closely related to which macromolecule?
Amino acids are most closely related to which macromolecule?
An amino acid is the monomer unit of the polymer known as a polypeptide. Polypeptide chains form the primary structure of proteins.
A monosaccharide is the simplest unit of a carbohydrate; a monosaccharide dimer is a disaccharide. Triglycerides are a simple form of lipid and nucleic acids are primarily composed of nucleotide monomers.
An amino acid is the monomer unit of the polymer known as a polypeptide. Polypeptide chains form the primary structure of proteins.
A monosaccharide is the simplest unit of a carbohydrate; a monosaccharide dimer is a disaccharide. Triglycerides are a simple form of lipid and nucleic acids are primarily composed of nucleotide monomers.
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The DNA and amino acid sequences of two organisms belonging to the same species were analyzed. It was revealed that there was more variability between their DNA sequences, as compared to their amino acid sequences. What is one possible explanation for the reduced variability of the amino acid sequence?
The DNA and amino acid sequences of two organisms belonging to the same species were analyzed. It was revealed that there was more variability between their DNA sequences, as compared to their amino acid sequences. What is one possible explanation for the reduced variability of the amino acid sequence?
An amino acid may be represented by multiple different codon sequences of base pairs of DNA. This codon degeneracy is what allows for the greater variability of DNA as compared to amino acid sequences.
For example, a DNA sequence may show variability without affecting the variability of the coded amino acids.
Organism 1 DNA: 5'-AAAGCAGGC-3' // Organism 2 DNA: 5'-AAGGCTGGT-3' // Differences: 3
Organism 1 RNA: 3'-UUU-CGU-CCG-5' // Organism 2 RNA: 3'-UUC-CGA-CCA-5' // Differences: 3
Organisms 1 Amino Acids: Phe-Arg-Pro // Organism 2 Amino Acids: Phe-Arg-Pro // Differences: 0
An amino acid may be represented by multiple different codon sequences of base pairs of DNA. This codon degeneracy is what allows for the greater variability of DNA as compared to amino acid sequences.
For example, a DNA sequence may show variability without affecting the variability of the coded amino acids.
Organism 1 DNA: 5'-AAAGCAGGC-3' // Organism 2 DNA: 5'-AAGGCTGGT-3' // Differences: 3
Organism 1 RNA: 3'-UUU-CGU-CCG-5' // Organism 2 RNA: 3'-UUC-CGA-CCA-5' // Differences: 3
Organisms 1 Amino Acids: Phe-Arg-Pro // Organism 2 Amino Acids: Phe-Arg-Pro // Differences: 0
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A lipid with three fatty acids linked to glycerol is a __________.
A lipid with three fatty acids linked to glycerol is a __________.
A fat is a lipid with three fatty chains linked by an ester linkage to glycerol.
A fat is a lipid with three fatty chains linked by an ester linkage to glycerol.
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