Biological Molecules Practice Questions

Question: How does the structure of a nucleic acid compare to the structure of a protein? A.) Both are smaller subunits; nucleic acids make up nucleotides and proteins make up amino acids. B.) Both are larger compounds; nucleic acids are made of nucleotides while proteins are made of amino acids. C.) Nucleic acids are larger compounds made of amino acids, while proteins are smaller subunits that make up amino acids. D.) Nucleic acids are smaller subunits that make of ribosomes, while proteins are larger compounds made of amino acids.

Answer: B.) Both are larger compounds; nucleic acids are made of nucleotides while proteins are made of amino acids.

Question: Which organic molecule is paired with its function? A.) nucleic acid : to store energy B.) proteins : to provide insulation C.) lipids : to regulate metabolic processes D.) carbohydrate : to provide quick-release energy

Answer: D.) carbohydrate : to provide quick-release energy Explanation: carbohydrate : to provide quick-release energy nucleic acid : to store energy lipid : to regulate metabolic processes protein : to provide insulation

Question: Which best describes the difference between DNA and RNA? A.) DNA is an amino acid and RNA is a nucleic acid. B.) DNA contains phosphate and RNA contains potassium. C.) DNA has a nitrogenous base and RNA has a carbon base. D.) DNA contains deoxyribose sugar and RNA contains ribose sugar.

Answer: D.) DNA contains deoxyribose sugar and RNA contains ribose sugar. Explanation: DNA contains the sugar deoxyribose, while RNA contains the sugar ribose. The only difference between ribose and deoxyribose is that ribose has one more -OH group than deoxyribose, which has -H attached to the second (2') carbon in the ring. DNA is a double-stranded molecule, while RNA is a single-stranded molecule.

Question: Which best describes the importance of the carbohydrate cellulose to plant cells? A.) It lubricates cell organelles. B.) It provides enzymes for the cell. C.) It serves as a storage center for water and wastes. D.) It provides the main structural elements in the cell wall.

Answer: D.) It provides the main structural elements in the cell wall.

Question: Which substance makes up a large part of an animal cell? A.) lipids B.) water C.) sugars D.) proteins

Answer: A.) lipids

Question: Which is a least likely primary function of proteins? A.) to act as an organic catalyst B.) to supply short-term energy C.) to build and repair damaged cells D.) to defend against foreign invaders

Answer: B.) to supply short-term energy

Question: What differentiates one protein from another? A.) size of amino acids B.) color of amino acids C.) sequence of amino acids D.) chemical structure of amino acids

Answer: C.) sequence of amino acids

Question: Which is a building block for a lipid? A.) glycerol B.) nucleotide C.) amino acid D.) monosaccharide

Answer: A.) glycerol

Question: Which type of organic molecule should a person limit in order to lose weight? A.) Carbohydrates, because they store twice as much energy/gram. If they are not used, they will cause weight gain. B.) Lipids, because they store twice as much energy/gram. If they are not used, they will cause weight gain. C.) Carbohydrates, because they are nonpolar molecules and are insoluble in water. D.) Lipids, because they are nonpolar and soluble in water.

Answer: B.) Lipids, because they store twice as much energy/gram. If they are not used, they will cause weight gain. Explanation: Lipids, because they store twice as much energy/gram. If they are not used, they will cause weight gain.

Question: Which would best distinguish a nucleic acid from a carbohydrate? A.) presence of carbon B.) presence of adenine C.) presence of fatty acids D.) presence of amino acids

Answer: B.) presence of adenine

Question: Which is a function of lipids? A.) to supply cells with quick-release energy B.) to provide the body with insulation C.) to store genetic information D.) to regulate cell processes

Answer: B.) to provide the body with insulation Explanation: The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes.

Question: Why are proteins among the most diverse molecules? A.) They create nucleic acids. B.) They form muscle in animals. C.) Amino acids can link up in different combinations. D.) Amino acids are made up of more than 20 different proteins.

Answer: C.) Amino acids can link up in different combinations. Explanation: Protein functions are so diverse because of the many unique three-dimensional structures protein polymers form. Structural similarities among amino acids make protein synthesis a uniform and regulated process; however, each amino acid contains a unique structural component as well.

Question: Thermophiles are prokaryotes that live in water that is almost boiling. How must they be different from other organisms? A.) Their flagella beat in a fanning motion. B.) Their genetic material is RNA instead of DNA. C.) Their proteins do not denature at high temperatures. D.) They are able to maintain a cooler internal temperature.

Answer: C.) Their proteins do not denature at high temperatures.

Question: What must a yeast have to use the disaccharide, sucrose, as an energy source? A.) oxygen to use sucrose in aerobic respiration B.) an active electron transport chain to produce ATP C.) an enzyme that breaks down sucrose into monosaccharides D.) a lack of oxygen so that it can ferment sucrose to produce alcohol and carbon dioxide

Answer: C.) an enzyme that breaks down sucrose into monosaccharides

Question: Which best describes the relationship between DNA and proteins? A.) DNA contains nucleotides and codes to make amino acids, which in turn make proteins. B.) DNA and proteins have the same structure and function together to make carbohydrates. C.) DNA and proteins are nucleic acids that function together to maintain oxygen in the respiratory system. D.) DNA and proteins are made of polymers that function in controlling substances entering the cell membrane.

Answer: A.) DNA contains nucleotides and codes to make amino acids, which in turn make proteins. Explanation: 1.) Cells contain DNA that controls the production of proteins. 2.) DNA is composed of proteins that carry coded information for how cells function. 3.) Proteins are used to produce cells that link amino acids together into DNA.

Question: Which best describes starches and lipids? A.) Starches and lipids provide the cell with energy. B.) Starches and lipids are the trash cans of the cell. C.) Starches and lipids provide the cell with strength. D.) Starches and lipids are the primary materials of the cell components.

Answer: A.) Starches and lipids provide the cell with energy.

Question: Which is true about the structure of starch molecules and protein molecules? A.) Starches and proteins are both polymers. B.) Starches and proteins are both amino acids. C.) Starches and proteins are both built from simple sugars. D.) Starches and proteins are both built from nucleic acids.

Answer: A.) Starches and proteins are both polymers.

Question: Which is an example of a lipid? A.) fat B.) starch C.) glucose D.) hemoglobin

Answer: A.) fat Explanation: Examples of lipids include fats, oils, waxes, certain vitamins (such as A, D, E and K), hormones and most of the cell membrane that is not made up of protein. Lipids are not soluble in water as they are non-polar, but are thus soluble in non-polar solvents such as chloroform.

Question: Which biological molecule serves as an energy storage molecule? A.) lipids B.) proteins C.) nucleic acids D.) carbohydrates

Answer: A.) lipids Explanation: Adenosine 5'-triphosphate, or ATP, is the most abundant energy carrier molecule in cells. This molecule is made of a nitrogen base (adenine), a ribose sugar, and three phosphate groups. The word adenosine refers to the adenine plus the ribose sugar.

Question: If a person's arteries become clogged, he or she might have a stroke. What is the cause of these artery-clogging deposits? A.) lipids B.) proteins C.) nucleic acids D.) carbohydrates

Answer: A.) lipids Explanation: Ischemic stroke - (most common - 87% of cases) is caused by a blockage of an artery from a blood clot (thrombus) or from clogged blood vessels due to atherosclerosis (hardening of the arteries).

Question: Which organic molecules are used for long-term energy storage? A.) lipids B.) proteins C.) nucleic acids D.) carbohydrates

Answer: A.) lipids Explanation: Lipids are molecules that can be used for long-term energy storage. Also known as fats, lipids are organic compounds that are made of an arrangement.

Question: Which organic compound is correctly paired with its subunit? A.) nucleic acid and DNA B.) protein and amino acid C.) carbohydrate and glycerol D.) lipid and monosaccharide

Answer: A.) nucleic acid and DNA Explanation: nucleic acid and DNA protein and amino acid carbohydrate and monosaccharides lipid and glycerol

Question: What are the subunits of DNA and their function? A.) nucleotides that store information B.) monosaccharides that provide quick energy for the cell C.) lipids that store energy and provide insulation D.) proteins that provide the building blocks for the structural components of organisms

Answer: A.) nucleotides that store information Explanation: DNA is an example of a Nucleic Acid, which has a subunit of glycose and fatty acid chains.

Question: Which best describes the importance of carbohydrates to organisms? A.) Carbohydrates provide storage for water molecules. B.) Carbohydrates provide an immediate energy source. C.) Carbohydrates provide an additional source for amino acids. D.) Carbohydrates provide permanent storage for genetic information.

Answer: B.) Carbohydrates provide an immediate energy source. Explanation: Carbohydrates provide storage for water molecules. Carbohydrates provide an additional source for amino acids. Carbohydrates provide permanent storage for genetic information.

Question: Which elements combine to form carbohydrates? A.) Carbon, Nitrogen, and Oxygen B.) Carbon, Hydrogen, and Oxygen C.) Carbon, Potassium, and Calcium D.) Carbon, Calcium, and Hydrogen

Answer: B.) Carbon, Hydrogen, and Oxygen Explanation: Carbohydrates (carbo- = "carbon"; hydrate = "water") contain the elements carbon, hydrogen, and oxygen, and only those elements with a few exceptions. The ratio of carbon to hydrogen to oxygen in carbohydrate molecules is 1:2:1.

Question: Which best explains the function of the sequence of nucleotides? A.) It provides energy. B.) It carries genetic information. C.) It allows DNA to be successfully copied. D.) It determines the shape of the DNA molecule.

Answer: B.) It carries genetic information. Explanation: The nucleotide sequence is the most fundamental level of knowledge of a gene or genome. It is the blueprint that contains the instructions for building an organism, and no understanding of genetic function or evolution could be complete without obtaining.

Question: Which best describes a saturated fatty acid? A.) It is a liquid at room temperature. B.) It is a solid at room temperature. C.) It contains double bonds between carbon atoms. D.) It contains triple bonds between carbon atoms.

Answer: B.) It is a solid at room temperature. Explanation: A saturated fat is a type of fat in which the fatty acid chains have all or predominantly single bonds. Double bonds can react with hydrogen to form single bonds. They are called saturated because the second bond is broken and each half of the bond is attached to (saturated with) a hydrogen atom.

Question: Which best explains the process that occurs in order for energy to be derived from starch? A.) It must be dissolved in water. B.) It must be converted into glucose. C.) It must be combined with another polysaccharide. D.) It must be decomposed into carbon, hydrogen, and oxygen.

Answer: B.) It must be converted into glucose. Explanation: When you eat starchy food, special proteins called enzymes (which are also polymers) break starch down into glucose, so your body can burn it for energy. This starts happening in your mouth, there's an enzyme in your spit that starts to cut up the starch.

Question: Why are lipids important for the survival of animals? A.) Lipids carry genetic information in the form of RNA. B.) Lipids store energy and vitamins that animals need. C.) Lipids provide animals with quick energy for routine tasks. D.) Lipids contain amino acids necessary for protein synthesis.

Answer: B.) Lipids store energy and vitamins that animals need. Explanation: Lipids play an important role in storing energy. If an animal eats an excessive amount of energy it is able to store the energy for later use in fat molecules. Fat molecules can store a very high amount of energy for their size which is important for animals because of our mobile lifestyles.

Question: Which experiment could be conducted to determine if baked potato chips have less fat than fried potato chips? A.) Place potato chips in water and test the pH. B.) Place potato chips on a paper bag and test for oil spots. C.) Mix crushed potato chips with iodine to observe color change. D.) Mix crushed potato chips with Benedict's solution to observe color change.

Answer: B.) Place potato chips on a paper bag and test for oil spots. Explanation: With this method, you'd be able to see all the fat that will be showing on the paper bag.

Question: While trying to identify molecules and compounds within a cell, a scientist stumbles upon a nucleic acid that contains the nitrogenous base uracil, the sugar ribose, and is single-stranded. Which nucleic acid has this scientist most likely found? A.) DNA B.) RNA C.) amino acid D.) chromosome

Answer: B.) RNA Explanation: Uracil is one of four nitrogenous bases found in the RNA molecule (U replaces T; U=A, C=G). Both DNA and RNA are built with a sugar backbone, but whereas the sugar in DNA is called deoxyribose, the sugar in RNA is called simply ribose. Lastly, RNA is single-stranded, while DNA is double-stranded.

Question: What is a difference between saturated and unsaturated fats? A.) Saturated fats are liquid and unsaturated fats are solid. B.) Saturated fats are solid and unsaturated fats are liquid at room temperature. C.) Saturated fats are healthier for you than unsaturated fats. D.) Saturated fats contain double carbon bonds and unsaturated fats have single bonds.

Answer: B.) Saturated fats are solid and unsaturated fats are liquid at room temperature. Explanation: Unsaturated fats, which are liquid at room temperature, are different from saturated fats because they contain one or more double bonds and fewer hydrogen atoms on their carbon chains. Unsaturated fats come from plants and occur in the following kinds of foods: Olives.

Question: Which best describes lipids? A.) They are soluble in water. B.) They are insoluble in water. C.) They are all solids at room temperature. D.) They are are all liquids at room temperature.

Answer: B.) They are insoluble in water. Explanation: Lipid: Another word for "fat." A lipid is chemically defined as a substance that is insoluble in water and soluble in alcohol, ether, and chloroform. Lipids are an important component of living cells. Cholesterol and triglycerides are lipids.

Question: Which subunits make up the structure of all proteins? A.) glucose B.) amino acids C.) carbohydrates D.) phospholipids

Answer: B.) amino acids Explanation: In the case of proteins, those subunits are amino acids. Any amino acid features a central carbon atom that is connected to an amino group, a hydrogen atom, and a carboxyl group.

Question: Which organic molecule is described as high in fiber? A.) amino acid B.) cellulose C.) fatty acid D.) glucose

Answer: B.) cellulose Explanation: Cellulose is the main substance in the walls of plant cells, helping plants to remain stiff and upright. Humans cannot digest cellulose, but it is important in the diet as fibre. Fibre assists your digestive system - keeping food moving through the gut and pushing waste out of the body.

Question: What must organisms possess to make them radiation-resistant? A.) a protective coat of peptidoglycan B.) enzymes that repair damage to DNA C.) melanin, the pigment that darkens skin color D.) the ability to mutate into a radiation-resistant organism

Answer: B.) enzymes that repair damage to DNA

Question: Which is the best example of a monosaccharide, or simple sugar? A.) starch B.) glucose C.) cellulose D.) glycogen

Answer: B.) glucose Explanation: Examples of monosaccharides include glucose (dextrose), fructose (levulose), and galactose. Monosaccharides are the building blocks of disaccharides (such as sucrose and lactose) and polysaccharides (such as cellulose and starch) which are not fully sugar but a concentration of sugar aka concentrated sugar.

Question: Which organic molecule is paired with its basic building block? A.) carbohydrate : amino acids B.) nucleic acid : nucleotides C.) lipid : monosaccharides D.) protein : fatty acids

Answer: B.) nucleic acid : nucleotides Explanation: carbohydrate : monosaccharides (simple sugars) nucleic acid : nucleotides lipid : fatty acids protein : amino acids

Question: Which organic molecule serves as a catalyst? A.) lipid B.) protein C.) nucleic acids D.) carbohydrate

Answer: B.) protein Explanation: A fundamental task of proteins is to act as enzymes—catalysts that increase the rate of virtually all the chemical reactions within cells. Although RNAs are capable of catalyzing some reactions, most biological reactions are catalyzed by proteins.

Question: Which organic molecule would a long-distance runner most likely choose to eat before a race? A.) A protein, because it builds muscle mass. B.) A carbohydrate, because it gives quick energy. C.) A carbohydrate, because it stores and releases energy. D.) A protein, because it transports oxygen in the blood stream.

Answer: C.) A carbohydrate, because it stores and releases energy.

Question: What is most likely being shown?: T A C A C G A T G T G C A.) amino acids B.) chromosomes C.) DNA D.) RNA

Answer: C.) DNA

Question: Which best describes the role of hemoglobin in red blood cells? A.) It hydrates human body tissues. B.) It supplies support to human body tissues. C.) It transports oxygen to human body tissues. D.) It increases the rate of reactions in body tissues.

Answer: C.) It transports oxygen to human body tissues. Explanation: Hemoglobin is the protein inside red blood cells. It carries oxygen. Red blood cells also remove carbon dioxide from your body, transporting it to the lungs for you to exhale. Red blood cells are made in the bone marrow.

Question: What are the components of each nucleotide? A.) glucose, water, and cellulose B.) adenine, thymine, and cytosine C.) a phosphate group, a sugar molecule, and a nitrogen base D.) a phosphate group, a five-carbon sugar, and an amino acid

Answer: C.) a phosphate group, a sugar molecule, and a nitrogen base Explanation: A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). In RNA, the base uracil (U) takes the place of thymine.

Question: Which are the building blocks of most lipid molecules? A.) glucose and protein B.) glucose and fatty acids C.) fatty acids and glycerol D.) amino acids and glycerol

Answer: C.) fatty acids and glycerol Explanation: The building blocks of lipids are one glycerol molecule and at least one fatty acid, with a maximum of three fatty acids.

Question: Which is a carbohydrate consisting of a chain of monosaccharide molecules? A.) amino acid B.) enzyme C.) glycogen D.) hemoglobin

Answer: C.) glycogen Explanation: Sucrose (table sugar) is the most common disaccharide, which is composed of the monomers glucose and fructose. A polysaccharide is a long chain of monosaccharides linked by glycosidic bonds; the chain may be branched or unbranched and can contain many types of monosaccharides.

Question: Which organic molecules supply energy to cells? A.) carbohydrates and nucleic acids B.) proteins and nucleic acids C.) lipids and carbohydrates D.) lipids and nucleic acids

Answer: C.) lipids and carbohydrates Explanation: Carbohydrates --> quick energy/ cell wall structure Proteins --> regulate blood glucose- as a hormone or chemical messenger Lipids --> long term energy/ component in the cell membrane- to maintain fluidity Nucleic Acids --> genetic code/ protein synthesis

Question: Which organic compounds necessary for life are formed by a sugar bonded to a phosphate group and a nitrogenous base? A.) lipids B.) proteins C.) nucleic acids D.) carbohydrates

Answer: C.) nucleic acids Explanation: The nucleic acids are composed of smaller units called nucleotides. Each nucleotide contains a carbohydrate molecule (sugar), a phosphate group, and a nitrogen-containing molecule that, because of its properties, is a nitrogenous base. Living organisms have two important nucleic acids.

Question: Which is a least likely function of lipids in plants and animals? A.) to supply energy B.) to make up cell membranes C.) to transfer hereditary information D.) to provide insulation and protection

Answer: C.) to transfer hereditary information

Question: Which elements are present in all organic compounds? A.) Hydrogen and Oxygen B.) Nitrogen and Oxygen C.) Nitrogen and Carbon D.) Hydrogen and Carbon

Answer: D.) Hydrogen and Carbon

Question: Why are proteins important to the survival of animals? A.) Proteins provide the body with energy. B.) Proteins provide energy storage for cells. C.) Proteins provide genetic information to cells. D.) Proteins provide structural functions for the body.

Answer: D.) Proteins provide structural functions for the body. Explanation: Protein has several roles in the body, such as building and repairing muscles and other body tissues. It is needed to form new skin cells, grow hair, build muscle tissue, and more.

Question: What is the significance of nucleic acids for cells? A.) They generate energy for the cell. B.) They restrict what enters and leaves the cell. C.) They support and maintain the shape of the cell. D.) They provide all instructions for cellular activities.

Answer: D.) They provide all instructions for cellular activities. Explanation: Nucleic acid is an important class of macromolecules found in all cells and viruses. The functions of nucleic acids have to do with the storage and expression of genetic information. Deoxyribonucleic acid (DNA) encodes the information the cell needs to make proteins.

Question: Which best describes the importance of lipids to organisms? A.) They provide keratin in hair and outer layers of the skin. B.) They keep cellular organelles hydrated within an organism. C.) They provide storage for cellular waste within an organism. D.) They serve as cellular membrane components and as concentrated energy sources.

Answer: D.) They serve as cellular membrane components and as concentrated energy sources.

Question: Which best explains how DNA directs protein synthesis? A.) composition of the nucleotides B.) double-stranded spiral-helix shape C.) location of the deoxyribose molecule D.) arrangement of the nitrogenous bases

Answer: D.) arrangement of the nitrogenous bases Explanation: Thus, the synthesis of a protein is governed by the information in its DNA, with the help of messengers (mRNA) and translators (tRNA). In the nucleus, DNA is transcribed to RNA. The mRNA carries the message out of the nucleus to the ribosome in the cytoplasm where the tRNA helps translate the message to make a protein.

Question: A scientist examines the source of the carbon atoms found in a person's breath. Which food substances are most likely the source? A.) lipids B.) proteins C.) nucleic acids D.) carbohydrates

Answer: D.) carbohydrates

Question: Which organic molecule serves as the main source of energy for cells? A.) amino acids B.) starch C.) proteins D.) glucose

Answer: D.) glucose Explanation: Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen. Carbohydrates are the primary sources of energy for most organisms. The sugar glucose is the main source of energy for cells.

Question: Alpha-amylase, an enzyme present in saliva, breaks down starch. Which food does it help to digest? A.) milk B.) candy C.) steak D.) potato

Answer: D.) potato Explanation: milk- is a protein (enzymes, insulin, hemoglobin) candy- is a carbohydrate (glycogen, starch, cellulose) steak- is a protein (enzymes, insulin, hemoglobin) potato- is a carbohydrate (glycogen, starch, cellulose)

Question: What type of organic molecules are enzymes? A.) carbohydrates B.) lipids C.) nucleic acids D.) proteins

Answer: D.) proteins Explanation: Among the organic macromolecules, enzymes belong in the category of proteins. Proteins are distinct from carbohydrates, nucleic acids, and lipids in that a protein is made of amino acids. Amino acids link together into a chain that can fold into a three-dimensional shape.

Question: If nucleic acids code for proteins, which is a function of proteins? A.) to store hereditary information B.) to store energy for long-term use C.) to provide a quick supply of energy D.) to provide structure and transport materials in cells

Answer: D.) to provide structure and transport materials in cells Explanation: It helps repair and build your body's tissues, allows metabolic reactions to take place and coordinates bodily functions. In addition to providing your body with a structural framework, proteins also maintain proper pH and fluid balance.

Question: Which type of molecule do whales use for energy storage and insulation? A.) DNA B.) glucose C.) fat D.) starch

Answer: C.) fat Explanation: The answer is fat because, fat is an example of a lipid. The function of a lipid is that it stores long term energy.