A.P. Biology Chapter 5 (Macromolecules)

DNA is double stranded because it consists of two strands of nucleotides that are twisted together to form a double helix structure. Each strand is made up of a sequence of nucleotides, which are the building blocks of DNA. The two strands are connected by hydrogen bonds between complementary nucleotide bases (adenine with thymine, and guanine with cytosine). This double-stranded structure allows DNA to replicate and transmit genetic information accurately during cell division and protein synthesis.

A double helix refers to a twisted ladder-like structure of DNA. DNA consists of two strands that are twisted around each other in a helical shape, forming a double helix. This structure is essential for the stability and replication of DNA molecules. The term "double helix" accurately describes the shape and structure of DNA.

Carbohydrates are organic compounds that consist of sugars, starches, and fibers. They are one of the three macronutrients required by the body for energy production. Carbohydrates can be found in various foods such as grains, fruits, vegetables, and dairy products. They provide the body with a quick source of energy and play a crucial role in maintaining proper brain function. Additionally, carbohydrates are important for digestion and are essential for the synthesis of certain molecules in the body.

Lipids are organic molecules that include fats, oils, and other similar substances. They are characterized by their insolubility in water and their solubility in organic solvents. Lipids serve as a source of energy, insulation, and protection for organs. They also play a crucial role in the structure and function of cell membranes. Therefore, the correct answer is "Fats, oils, etc..." as lipids encompass these substances.

A monomer refers to a single unit of macromolecules. Macromolecules, such as proteins, nucleic acids, and carbohydrates, are composed of repeating units called monomers. These monomers join together through chemical bonds to form larger, more complex structures. Therefore, the correct answer is "A single unit of macromolecules."

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Proteins can be denatured by various methods, including intense heat, pH change, and changing the salt concentration. Intense heat disrupts the weak bonds and interactions within the protein structure, causing it to unfold and lose its functional shape. pH change alters the charges on the protein molecules, affecting their interactions and leading to denaturation. Changing the salt concentration can disrupt the ionic interactions and hydrogen bonds within the protein, causing it to unfold. Therefore, all of the mentioned methods can denature a protein.

The given question is asking for the complement of C. In DNA, the complement of C is G. This means that when C is present in a DNA sequence, G will be its corresponding base pair.

Saturated fats are straight because they consist of single bonds between carbon atoms in their fatty acid chains. This straight structure allows saturated fats to pack tightly together, resulting in a solid or semi-solid state at room temperature. In contrast, unsaturated fats have double bonds between carbon atoms, causing a bend or kink in their fatty acid chains. This bent structure prevents unsaturated fats from packing tightly together, resulting in a liquid state at room temperature.

RNA is single-stranded because it consists of a single strand of nucleotides. Unlike DNA, which is double-stranded, RNA does not form a double helix structure. This single-stranded nature of RNA allows it to fold into various shapes and perform different functions in the cell, such as coding for proteins or acting as an enzyme.

Saturated fats are solid at room temperature. This is because their molecular structure lacks double bonds, making them tightly packed and solid. In contrast, unsaturated fats have double bonds, which create kinks in their structure and keep them in a liquid state at room temperature. Therefore, the quality of being solid at room temperature is characteristic of saturated fats.

The monomer of carbs is a monosaccharide. Carbohydrates are made up of repeating units of monosaccharides, which are simple sugars such as glucose, fructose, and galactose. These monosaccharides can be joined together through glycosidic bonds to form larger carbohydrates like disaccharides (e.g. sucrose, lactose) and polysaccharides (e.g. starch, cellulose). Therefore, monosaccharides are the building blocks or monomers of carbohydrates.

A disaccharide is a type of carbohydrate made up of two monosaccharide units joined together through a glycosidic bond. It is considered a polymer of a carbohydrate because it is composed of repeating units (monosaccharides) linked together. Other options like phospholipid, DNA, and secondary structure are not polymers of carbohydrates. Phospholipids are a type of lipid, DNA is a nucleic acid, and secondary structure refers to the folding pattern of proteins.

Unsaturated fats are bent. Unsaturated fats have double bonds in their carbon chains, causing a kink or bend in the molecule. This double bond creates a rigid structure, preventing the fatty acid chains from packing tightly together. As a result, unsaturated fats are usually liquid at room temperature. On the other hand, saturated fats have single bonds in their carbon chains, allowing the fatty acid chains to pack tightly together and form a straight structure. Saturated fats are typically solid at room temperature.

To make a nucleotide, three components are required: a sugar, a nitrogenous base, and a phosphate group. The sugar provides the backbone for the nucleotide, the nitrogenous base determines the type of nucleotide (adenine, thymine, cytosine, or guanine), and the phosphate group links the nucleotides together to form a nucleic acid chain. The other options listed in the question (ATP, RNA, DNA, AMP, ADP, ATP) are not the correct components needed to make a nucleotide.

Unsaturated fats are liquid at room temperature. This is because they have double bonds in their carbon chain, which cause the molecules to have a kink or bend. This kink prevents the molecules from packing tightly together, resulting in a liquid state. In contrast, saturated fats do not have double bonds and have a straight carbon chain, allowing them to pack tightly together and be solid at room temperature.

A diglyceride is a molecule composed of one glycerol molecule and two fatty acid molecules. Glycerol is a three-carbon alcohol, and fatty acids are long hydrocarbon chains with a carboxyl group at one end. When the glycerol molecule forms ester bonds with two fatty acid molecules, a diglyceride is formed. This molecule is commonly found in biological systems and is an important component of lipids, which are essential for energy storage and cell membrane structure.

A polymer is a large molecule made up of repeating subunits called monomers. These monomers join together to form a long chain, resulting in a macromolecule. Therefore, the correct answer is "Multiple units of macromolecules."

A monoglyceride is formed by the esterification of one molecule of glycerol with one molecule of fatty acid. This reaction results in the formation of a single ester bond between the glycerol and fatty acid, producing a monoglyceride. Monoglycerides are commonly found in food as emulsifiers and are also important intermediates in lipid metabolism.

Uricil is used in RNA. RNA, or ribonucleic acid, is a type of nucleic acid that is essential for the coding, decoding, regulation, and expression of genes. It is made up of nucleotides, which consist of a sugar molecule, a phosphate group, and a nitrogenous base. One of the four nitrogenous bases found in RNA is uracil (not uricil), which pairs with adenine during RNA synthesis. Uricil is not used in DNA, which instead uses thymine as one of its nitrogenous bases.

A triglyceride is composed of one glycerol molecule and three fatty acid molecules. Glycerol is a type of alcohol with three hydroxyl groups, and fatty acids are long chains of carbon and hydrogen atoms with a carboxyl group at one end. When these components combine, they form a triglyceride molecule, which is a type of lipid and serves as a major source of energy in the body.

Proteins are made up of long chains of amino acids, which are the monomers of proteins. Amino acids are organic compounds that contain an amino group (-NH2) and a carboxyl group (-COOH). They are the building blocks of proteins and are linked together through peptide bonds to form polypeptide chains. Therefore, the correct answer is amino acid.

Nucleic acids are composed of repeating units called nucleotides. A nucleotide consists of a sugar molecule (either ribose or deoxyribose), a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, guanine, or uracil). These nucleotides join together through phosphodiester bonds to form the backbone of DNA and RNA strands. Therefore, the correct answer is nucleotide.

Antiparallel refers to the orientation of the two strands in a DNA molecule. In antiparallel strands, one strand runs in the 5' to 3' direction, while the other runs in the opposite direction, from 3' to 5'. This arrangement allows for complementary base pairing between the strands, with adenine (A) pairing with thymine (T) and guanine (G) pairing with cytosine (C). This antiparallel arrangement is essential for DNA replication and transcription processes.

To form a polymer from a monomer, the process of dehydration synthesis is used. This involves removing a water molecule from between two monomers, which forms a covalent bond between them. This reaction allows the monomers to join together and create a larger molecule, known as a polymer. Therefore, the correct answer is "Remove water."

The correct answer is CH2O. This is because the ratio of carbohydrate chemical formulas is typically represented as CH2O, meaning that for every carbon atom, there are two hydrogen atoms and one oxygen atom. This ratio is consistent across most carbohydrates.

Cellulose is a complex carbohydrate that makes up the structural component of plant cell walls. It provides strength and rigidity to the cell, allowing plants to maintain their shape and withstand external pressures. Cellulose is not used in fungi and arthropod exoskeletons, animal skeletons, or cell membranes. Therefore, the correct answer is that cellulose is used for plant cell walls.

The non-polar/hydrophobic part of a phospholipid is the lipid part. Phospholipids consist of a hydrophilic phosphate head and two hydrophobic lipid tails. The lipid part is composed of fatty acid chains, which are non-polar and repel water. This hydrophobic region is responsible for the phospholipid bilayer's structure, as it forms a barrier that prevents water-soluble molecules from freely crossing the membrane.

The tails of a phospholipid are composed of fatty acids. Phospholipids are a type of lipid molecule that make up the cell membrane. They consist of a hydrophilic (water-loving) head made up of glycerol and phosphate, and hydrophobic (water-repelling) tails made up of fatty acids. The fatty acid tails are responsible for the phospholipid's ability to form a bilayer in the cell membrane, with the hydrophilic heads facing outward towards the watery environment and the hydrophobic tails facing inward, away from the water.

Pyrimidine and Purine are the two types of nitrogenous bases. Nitrogenous bases are the building blocks of nucleotides, which in turn make up DNA and RNA. Pyrimidine bases include cytosine, thymine, and uracil, while purine bases include adenine and guanine. These bases pair up to form the rungs of the DNA ladder, with pyrimidines always pairing with purines. Therefore, Pyrimidine and Purine is the correct answer.

The polar/hydrophilic part of a phospholipid is the phosphate part. This is because the phosphate group contains a negatively charged oxygen atom, making it attracted to water molecules and allowing it to interact with the aqueous environment. The lipid part of the phospholipid, on the other hand, is hydrophobic and repels water. Therefore, the correct answer is the phosphate part.

Fat serves multiple functions in the body. It stores energy in the form of adipose tissue, which can be used as fuel when needed. Additionally, fat acts as an insulator, helping to regulate body temperature and protect organs from extreme temperatures. It also provides insulation against electrical impulses in the nervous system. Furthermore, fat acts as a cushion, absorbing shock and protecting vital organs from injury. Therefore, all of the given options accurately describe what fat does in the body.

When water is added to a polymer, it undergoes a process called hydrolysis. During hydrolysis, water molecules break the bonds between the monomers in the polymer chain, resulting in the formation of individual monomer units. This process is commonly used in the digestion of complex carbohydrates in our bodies, where enzymes break down polymers like starch into monosaccharides by adding water molecules. Therefore, adding water to a polymer is the correct way to break it down into its monomer units.

A triglyceride is a type of fat molecule that is composed of three fatty acids attached to a glycerol molecule. It is the main form of fat storage in the body and is found in foods such as oils, butter, and animal fats. Therefore, "fat" is another name for a triglyceride.

The head of a phospholipid is composed of glycerol and phosphate. Phospholipids are a type of lipid molecule that make up the cell membrane. They have a hydrophilic (water-loving) head made up of glycerol and phosphate, which is attracted to water. This head region is polar and interacts with the aqueous environment inside and outside of the cell. The fatty acid tails, on the other hand, are hydrophobic (water-hating) and make up the nonpolar tail region of the phospholipid.

Amino acids are organic compounds that are the building blocks of proteins. They are made up of an amino group (-NH2) and a carboxyl group (-COOH) attached to a central carbon atom. The amino group contains nitrogen, while the carboxyl group contains carbon, oxygen, and hydrogen. These two functional groups give amino acids their unique properties and allow them to form peptide bonds with other amino acids, creating protein chains. Therefore, the correct answer is "Amino + Carboxyl."

A glycosidic linkage is the bond that holds two monosaccharides together. It is a type of covalent bond formed between the hydroxyl group of one monosaccharide and the anomeric carbon of another monosaccharide. This linkage is important in the formation of disaccharides, such as sucrose and lactose, as well as polysaccharides, such as starch and cellulose. Glycosidic linkages are crucial for the structural integrity and function of carbohydrates in living organisms.

When glucose and fructose combine, they form sucrose. Sucrose is a disaccharide composed of one glucose molecule and one fructose molecule. It is commonly found in table sugar and is a common sweetener used in food and beverages.

Lipids are made with glycerol and fatty acids. Glycerol is a three-carbon alcohol molecule, while fatty acids are long hydrocarbon chains with a carboxyl group at one end. These two molecules combine through a dehydration reaction, where the hydroxyl group of glycerol reacts with the carboxyl group of the fatty acid, forming an ester bond. This process is called esterification and results in the formation of a lipid molecule, such as a triglyceride. Lipids play important roles in storing energy, insulating the body, and acting as structural components of cell membranes.

Phospholipids are a type of lipid molecule that make up the cell membrane. They have a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails, which arrange themselves in a bilayer to form the cell membrane. This structure provides a barrier that separates the inside of the cell from its external environment, controlling the movement of substances in and out of the cell. Therefore, phospholipids play a crucial role in making up cell membranes.

Starch is a storage polysaccharide that is made up of many glucose molecules. It is a complex carbohydrate that serves as a major energy source in many organisms. As a polysaccharide, starch is composed of long chains of glucose units, making it a combination of many glucose molecules. Therefore, the correct answer is both option B and C.

Cell membranes are made of a phospholipid bilayer. Phospholipids have a hydrophilic (water-loving) head and a hydrophobic (water-repelling) tail. In the bilayer arrangement, the hydrophilic heads face outward towards the watery environment both inside and outside the cell, while the hydrophobic tails face inward, creating a barrier that separates the cell's internal contents from the external environment. This structure allows the cell membrane to regulate the movement of substances in and out of the cell, maintaining cellular homeostasis.

Primary proteins are held together by peptide bonds. Peptide bonds are formed between the amino group of one amino acid and the carboxyl group of another amino acid. This bond forms a chain of amino acids, known as a polypeptide chain, which is the primary structure of a protein. Hydrogen bonds, disulfide bridges, and covalent bonds are also important for the overall structure and stability of proteins, but they are not specifically responsible for holding the primary structure together.

Cytosine is one of the four nucleotide bases found in DNA and RNA, making it used in both. It pairs with guanine in DNA and RNA to form the base pairs that make up the genetic code. Therefore, it is essential for the structure and function of both DNA and RNA molecules.

A dehydration/condensation reaction refers to the process of removing water molecules from a substance. In the context of polymers and monomers, it is the mechanism by which monomers combine to form polymers. This reaction involves the removal of a water molecule as a byproduct, resulting in the formation of a covalent bond between the monomers. Therefore, options B and D, which state "The removal of water" and "How to get from a monomer to a polymer," respectively, correctly describe a dehydration/condensation reaction.

The correct answer is "Beta is zig zag, alpha is looped." This is because beta-pleated sheets are formed by hydrogen bonding between adjacent strands of the polypeptide chain, resulting in a sheet-like structure with a zig zag pattern. On the other hand, alpha-helices are formed by a coiled structure in which the polypeptide chain twists into a helical shape, giving it a looped appearance.

Thymine is used in DNA. It is one of the four nucleotide bases found in DNA, along with adenine, guanine, and cytosine. Thymine pairs with adenine through hydrogen bonding, forming one of the base pairs in the DNA double helix structure. RNA, on the other hand, uses uracil instead of thymine. Therefore, thymine is specifically used in DNA.

Glucose and galactose combine to form lactose. Lactose is a disaccharide sugar found in milk and dairy products. It is composed of one molecule of glucose and one molecule of galactose, linked together by a beta-1,4-glycosidic bond. Lactose is an important source of energy for infants and is broken down by the enzyme lactase in the small intestine to be absorbed into the bloodstream.

Chitin is a structural polysaccharide that is primarily found in the cell walls of fungi and the exoskeletons of arthropods. It provides strength and rigidity to these organisms, allowing them to maintain their shape and protect their internal structures. Chitin is not used in animal skeletons, plant cell walls, or cell membranes.

Hydrolysis refers to the chemical reaction that involves the addition of water to break down a compound into its smaller components. In the context of polymers, hydrolysis is the process of breaking down a polymer into its monomer units by adding water. Therefore, options A and C, which state that hydrolysis is the addition of water and how to get from a polymer to a monomer, respectively, are both correct explanations for hydrolysis.