Bio Exam Ch 3

Proteins are constructed using how many different amino acids? 4 20 100 1,000 More than 5,000

20

How many hydrogen bonds exist between a G-C base pair? 1 3 2 4

3

Explain how a saturated fat is structurally different from an unsaturated fat.

A saturated fat has three fatty acids that are saturated with hydrogens, and the tails are able to be straight and packed closely together. Unsaturated fats are not fully saturated with hydrogens and contain bonds that cause bends or kinks in the fatty acid chains, so they cannot pack tightly together.

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? Dehydration reactions occur only in animals, and hydrolysis reactions occur only in plants. Hydrolysis creates polysaccharides, and dehydration creates monosaccharides. Dehydration reactions assemble polymers, and hydrolysis breaks them down. Hydrolysis creates monomers, and dehydration reactions destroy them. Dehydration reactions can occur only after hydrolysis.

Dehydration reactions assemble polymers, and hydrolysis breaks them down.

Your friend is trying to learn about how to kill bacteria. She reads that preservatives such as citric acid are added to foods because the acidic environment kills bacteria by denaturing their proteins. She thinks this sounds like a lot of scientific jargon and asks you what it means. How can you explain it in simpler terms? Denaturing refers to the fact that the bacterial cells divide too quickly and die. Denaturing their proteins means that the proteins in bacteria are converted into carbohydrates. The acid causes the cells to swell and burst open, also known as denaturation. Denaturing means that the proteins of the bacteria lose their structure and can't function, so the bacteria die.

Denaturing means that the proteins of the bacteria lose their structure and can't function, so the bacteria die.

Phospholipids have hydrophilic tail regions and hydrophobic head regions. True False

False

When 1 gram of each of these food sources is consumed, which yields the greatest amount of energy in calories? Glucose Polypeptide Fat Sucrose Phenylalanine

Fat

Carbon provides a backbone for a variety of biological molecules. Carbon can typically form ________ covalent bonds.

Four

Which of the following reactions is an example of dehydration synthesis? Glycogen → glucose subunits Fat → fatty acids + glycerol Glucose + galactose → lactose Cellulose → glucose Peptide → alanine + glycine

Glucose + galactose → lactose

In humans, dental cavities form when Streptococcus mutans bacteria in the mouth hydrolyze sucrose. Which of the following is (are) the products of this reaction? Glycogen Starch Glucose and galactose Glucose and fructose

Glucose and fructose

Where is glycogen stored in vertebrate animals? Brain and kidneys Pancreas and blood Liver and muscles Fat cells Teeth and bones

Liver and muscles

The fat substitute Olestra contains a sucrose backbone with six to eight fatty acids attached. How is this different from a naturally occurring fat? Naturally occurring fats contain a glycerol, two fatty acids, and a phosphate group. Naturally occurring fats contain a sucrose backbone and three fatty acid chains. Naturally occurring fats contain a glycerol and three fatty acids. It isn't; Olestra and natural fats have the same structure, just different tastes.

Naturally occurring fats contain a glycerol and three fatty acids.

Which of the following biological molecules are composed of monomer units containing a sugar, a phosphate group, and a nitrogen-containing base? Carbohydrates Proteins Lipids Nucleic acids

Nucleic acids

Which of these biological molecules contain genetic information? Lipids Nucleic acids Proteins Carbohydrates

Nucleic acids

Many biological molecules are formed by the joining of monomer units in a(n) ________ reaction (removal of water); the reverse process is called ________.

dehydration synthesis; hydrolysis

The carbohydrate in DNA is deoxyribose. cellulose. phosphate. ribose. glucose.

deoxyribose.

What are the two main functions of carbohydrates in a living system? Give an example of each.

energy storage (glucose, starch, glycogen) and structural support (chitin, cellulose)

The specific function of a protein is determined by the number of peptide bonds it contains. hydrophilic head attached to the hydrophobic tail. number of disulfide bonds. fatty acids that are joined together in the polypeptide. exact sequence of amino acids.

exact sequence of amino acids.

All of the following lipids or lipid components are hydrophobic EXCEPT fatty acid tails. waxes. saturated fats. unsaturated fats. fatty acid heads.

fatty acid heads.

All of the following are polysaccharides EXCEPT chitin. glucose. starch. glycogen.

glucose.

A denatured protein differs from a normal protein because it does not contain amino acids. is composed of nucleotides. has lost its usual secondary and tertiary structures. contains many disulfide bonds.

has lost its usual secondary and tertiary structures.

Complex, three-dimensional, tertiary structures of proteins result from disulfide bonds. hydrogen and disulfide bonds. ionic bonds. hydrogen bonds. ionic and hydrogen bonds

hydrogen and disulfide bonds.

If digestion is ________, then building polymers from monomers is ________. dehydration synthesis; hydrolysis hydrolysis; dehydration synthesis inorganic; organic organic; inorganic

hydrolysis; dehydration synthesis

Cell membranes are an example of a lipid bilayer. In this lipid bilayer, both the outside of the cell and the inside of the cell are ________ in nature. polar watery hydrophilic hydrophobic charged

hydrophilic

Lactose is a disaccharide of glucose and galactose, and its digestion requires the actions of the enzyme lactase. If lactose is eaten as part of the diet but is not digested by lactase, this sugar is then metabolized by bacteria in the intestine, leading to the symptoms of lactose intolerance. Lactose intolerance, therefore, results from a(n) inability of the body to produce lactose. lack of hydrolysis of lactose. low blood lactose level. lack of dehydration synthesis of lactose.

lack of hydrolysis of lactose.

HDL and LDL are different types of cholesterol found in the blood. These compounds are proteins. nucleic acids. lipids. carbohydrates.

lipids

Prions are known to cause herpes. sickle cell anemia. mad cow disease. the common cold.

mad cow disease.

Triglycerides are polymers of amino acids. hydrophilic. a main component of cellular membranes. always composed of carbon rings. made from glycerol and fatty acids.

made from glycerol and fatty acids.

Keratin and silk are examples of ________, whereas glucose and maltose are examples of ________. nucleic acids; lipids proteins; lipids proteins; carbohydrates carbohydrates; proteins

proteins; carbohydrates

RNA differs from DNA in that RNA contains the sugar ________.

ribose

DNA carries genetic information in its phosphate groups. tertiary structure. sequence of bases. sugar groups. helical form.

sequence of bases.

Cholesterol, testosterone, and estrogen are examples of nucleic acids. steroids. waxes. proteins. fatty acids.

steroids.

The "backbone" of a nucleic acid molecule is made of sugar and phosphate groups. amino acids. lipids. NAD+ and FAD. ATP molecules.

sugar and phosphate groups.

Fats and oils are made of three amino acids and one glycerol. one glycogen and two phospholipids. three glycerols and three fatty acids. two fatty acids and one carboxyl acid. three fatty acids and one glycerol.

three fatty acids and one glycerol.

Maltose is made from two peptides. glucose and fructose. glucose and galactose. two glucose molecules.

two glucose molecules.

Fatty acids that contain double-bonded carbon atoms are called ________.

unsaturated

You are telling your friend that organic molecules are all made up of carbon backbones with hydrogens. She doesn't understand how there can be so many different organic molecules if they all are made up of the same basic components. You explain that organic molecules vary because they possess different functional groups. are different because of the different types of hydrogen bonds that form. actually all have the same structure but differ in the number of electrons. vary because they possess different isotopes of carbon.

vary because they possess different functional groups.

Large biological molecules are synthesized by removing peptides. oxygen. carbon. water. covalent bonds.

water.

Which of the following best explains the molecular complexity of living organisms? The large number of different monomers allows for the construction of many polymers. A small number of monomers can be assembled into large polymers with many different combinations/sequences. Although there are not many biological molecules in cells, each one has many different functions. Each organism has its own unique set of monomers for use in constructing polymers. Condensation reactions can create different polymers because they can combine virtually any molecules in the cell.

A small number of monomers can be assembled into large polymers with many different combinations/sequences.

Which nucleotide molecule functions as an energy carrier in the cell?

ATP

Which of the following can serve as an energy source and as structural support in plant cells? Nucleic acids Lipids Carbohydrates Proteins

Carbohydrates

Which of the following categories includes monosaccharide monomers? Carbohydrates Proteins Nucleic acids Lipids

Carbohydrates

What are the four major types of biological molecules?

Carbohydrates, lipids, proteins, and nucleic acids.

Which of the following is NOT an organic molecule? Lipid Carbon monoxide Nucleic acid Monosaccharide Protein

Carbon monoxide

A peptide bond forms between which of these functional groups? Phosphate and hydroxyl Amino and aldehyde Carboxyl and aldehyde Hydroxyl and carboxyl Carboxyl and amino

Carboxyl and amino

What do carbohydrates, lipids, and proteins have in common? Covalent bonding holds these molecules together. All are important enzymes that function within the cell. All are inorganic molecules. Polymers of these organic molecules form monomers via dehydration synthesis reactions.

Covalent bonding holds these molecules together.

Why can cows break down cellulose into glucose subunits, but humans cannot?

Cows lack the ability to break down cellulose, but they have special microbes in their digestive tracts that break down cellulose for them; humans do not.

What are some of the similarities and differences between DNA and RNA?

DNA uses the nucleotides A-T-G-C, and RNA uses the nucleotides A-U-G-C. DNA uses a deoxyribose sugar, and RNA uses a ribose sugar. DNA is usually double-stranded, and RNA is usually single-stranded.

When the level of glucose in your blood is high, your body is able to store excess glucose in the liver by forming glycogen. When blood glucose levels fall, this stored glucose can be released. Based on this information, which of the following is TRUE? Glycogen is a highly branched functional group that forms a larger glucose polymer. Glycogen is a polysaccharide formed by joining excess monosaccharides of glucose. Glucose is not an organic molecule, but glycogen is an organic molecule. Glucose is a polysaccharide that can join to form the monosaccharide glycogen.

Glycogen is a polysaccharide formed by joining excess monosaccharides of glucose.

What maintains the secondary structure of a protein? Hydrogen bonds Peptide bonds Ionic bonds Disulfide bonds

Hydrogen bonds

What type of chemical reaction results in the breakdown of organic polymers into their respective subunits? Oxidation Hydrolysis Condensation Ionization

Hydrolysis

Suppose you have discovered a new virus and have isolated its nucleic acids. What feature could you look for to determine whether the nucleic acids of this virus are RNA or DNA? If it is DNA, the virus will not contain proteins. If is RNA, it will contain deoxyribose. If it is RNA, it will contain ribose. If it is RNA, there will be no adenine.

If it is RNA, it will contain ribose.

Which of the following is an example of a protein? Keratin Cellulose Estrogen ATP

Keratin

Which of these is NOT a nucleic acid or nucleotide? RNA DNA ATP LDL

LDL

Which molecule is a disaccharide? Glucose Water Lactose Fructose

Lactose

Lard is a solid fat at room temperature. What does this tell you about the triglycerides in lard? The fats in lard are mostly phospholipids. Lard is composed of saturated fats. The fats in lard are not organic molecules. Lard is composed of unsaturated fats.

Lard is composed of saturated fats.

Imagine that you have isolated a mysterious liquid from a sample of food. You add the liquid to a beaker of water and shake vigorously. After a few minutes, the water and the other liquid separate into two layers. To which class of biological molecules does the unknown liquid most likely belong? Nucleic acids Proteins Carbohydrates Lipids

Lipids

Which of the following biological molecules possess large nonpolar regions, making them insoluble in water? Nucleic acids Proteins Carbohydrates Lipids

Lipids

Which of the following groups is crucial to the structure and function of the sex hormones estrogen and testosterone? Nucleic acids Carbohydrates Proteins Lipids

Lipids

Why is it an advantage for animals that migrate long distances to store energy as lipids rather than carbohydrates?

Lipids (fats) store more than twice as much energy as carbohydrates.

Which of the following is insoluble in water? Salt Sucrose DNA Olive oil Amino acids

Olive oil

Which type of lipid is most important in biological membranes? Fat Phospholipid Oil Wax Steroid

Phospholipid

Which of the following refers to the amino acid sequence of proteins? Primary Secondary Tertiary Quaternary

Primary

Scientists consider prions to be "puzzling" proteins. Which of the following is TRUE about prions? Prions are infectious proteins that cannot be denatured by any amount of heat. Prions are proteins that are denatured more easily than most proteins. Prions are proteins that cause nearby proteins to change shape and become infectious. Prions are noninfectious proteins.

Prions are proteins that cause nearby proteins to change shape and become infectious.

Which of the following correctly matches an organic polymer with its monomers, respectively? Lipid; steroids Protein; amino acids DNA; ATP Carbohydrate; polysaccharides Hydrocarbon; monosaccharides

Protein; amino acids

Which of the following biological molecules are composed of amino acid subunits? Nucleic acids Proteins Carbohydrates Lipids

Proteins

Which of the following may possess primary, secondary, tertiary, and quaternary structures? Proteins Nucleic acids Lipids Carbohydrates

Proteins

Your classmate is trying to keep all the facts about biological molecules straight. He asks you to explain how amino acids and proteins are related. What do you tell him? Proteins are a portion of an amino acid. Amino acids are formed by joining together many proteins. Proteins are made up of chains of amino acids. Proteins are chains of carbohydrates, and amino acids are a type of lipid.

Proteins are made up of chains of amino acids.

The four polypeptides that are joined together to make functional hemoglobin represent which level of protein organization? Secondary structure Quaternary structure Tertiary structure Primary structure

Quaternary structure

The bonding of two amino acid molecules to form a larger molecule requires which of the following? Both removal of a water molecule and formation of a hydrogen bond Addition of a water molecule Removal of a water molecule Formation of a hydrogen bond Formation of a glycosidic bond

Removal of a water molecule

Describe the differences between saturated and unsaturated fatty acids. Which is most likely to be solid at room temperature? Why?

Saturated fats have only single C-C bonds, whereas unsaturated fats have at least one double C-C bond. The saturated fatty acids are most likely to be solid at room temperature because the fatty acid chains can be packed together more tightly.

Which of the following provides long-term energy storage for plants? Glucose Starch Glycogen ATP Cellulose

Starch

Dehydration synthesis involves the removal of a hydrogen ion and a hydroxyl ion. What happens next? The hydrogen and hydroxyl ions combine to form water. The hydrogen ion becomes an isotope. A polysaccharide is released from a monosaccharide. A large polymer is split apart into small monomers.

The hydrogen and hydroxyl ions combine to form water.

You have curly hair, and your brother has straight hair. Describe how the proteins of your curly hair are different from the proteins of his straight hair.

The keratin proteins in your curly hair have disulfide bonds in certain locations that cause the keratin to have bends or curls. The disulfide bonds in your brother's straight hair are in locations that don't cause bends in the keratin, so there are no curls.

Soap and detergent molecules have a long, hydrophobic tail and a polar, hydrophilic head. They are sometimes referred to as bridge molecules because they allow oils and fats to be suspended and dissolved in water (which they otherwise would not be able to do). Imagine that you are using soap to wash away dirt that is being held against your skin in an oily film. In this scenario, how are the soap, dirt/oil, and water arranged at the molecular level? The soap is converted into a lipid that binds to the dirt/oil while repelling the water. Water and dirt/oil form covalent bonds inside a small droplet that has a soap-based outer membrane. The soap molecules encase the dirt/oil within a small droplet that has a hydrophobic exterior and a hydrophilic interior. The soap molecules encase the dirt/oil within a small droplet that has a hydrophilic exterior and a hydrophobic interior.

The soap molecules encase the dirt/oil within a small droplet that has a hydrophilic exterior and a hydrophobic interior.

Soap and detergent molecules have a long, hydrophobic tail and a polar, hydrophilic head. They are sometimes referred to as bridge molecules because they allow oils and fats to be suspended and dissolved in water (which they otherwise would not be able to do). Imagine that you are using soap to wash away dirt that is being held against your skin in an oily film. In this scenario, what is the most likely procedure beer makers use to produce alcohol from starchy grains? The starch is broken down into mono- and/or disaccharides by hydrolysis before use. The starch is converted into a polymer of many glucose molecules before being used. The starch is converted into glycogen, which is easier for the yeast to digest. Water is used to break the bonds between glucose subunits in the starch, in a form of dehydration synthesis.

The starch is broken down into mono- and/or disaccharides by hydrolysis before use.

Which of the following is TRUE about waxes? They are unsaturated and most similar to proteins. They are saturated fats and are solid at normal outdoor temperatures. They are a type of complex carbohydrate. They are an important food source, and most animals have enzymes for breaking them down.

They are saturated fats and are solid at normal outdoor temperatures.

Which of the following statements about lipids is incorrect? They are short chains of polar hydrocarbons. They are hydrophobic and water insoluble. They are large chains of nonpolar hydrocarbons. They are used for energy storage. They are primary component of cell membranes.

They are short chains of polar hydrocarbons.

What property of phospholipids makes them important in cell membranes? They are part of DNA. They are an important energy carrier molecule. They have a polar end and a nonpolar end. They are found only in animals. They contain nucleic acids.

They have a polar end and a nonpolar end.

How do two amino acids, such as lysine and methionine, differ from each other?

They have different functional (or "R") groups.

Functional groups determine the characteristics and chemical reactivity of organic molecules. True False

True

Which type of molecule is most abundant in a typical cell? Carbohydrate Lipid Protein Nucleic acids Water

Water

New government regulations require that foods containing trans fats be labeled appropriately. A trans fat is formed when food manufacturers turn liquid oils into solid fats by adding hydrogen to vegetable oils. This hydrogenation process produces a solid fat because adding the hydrogen allows fats to form tertiary and quaternary structures. causes a phospholipid to form. forms a wax molecule. allows the fatty acid chains to pack together more tightly.

allows the fatty acid chains to pack together more tightly.

In dehydration synthesis, the atoms that make up a water molecule come from carbohydrates. oxygen. enzymes. both of the reactants. only one of the reactants.

both of the reactants.

Hydrolysis may be correctly described as the removal of water from a polymer. heating of a compound in order to drive off its excess water and to concentrate its volume. constant removal of hydrogen atoms from a carbohydrate. breaking of a compound into its subunits by using water to break the bond between monomers.

breaking of a compound into its subunits by using water to break the bond between monomers.

Two categories of organic compounds typically provide energy for living systems. Representatives of these two classes are carbohydrates and lipids. proteins and nucleic acids. carbohydrates and proteins. lipids and proteins. carbohydrates and nucleic acids.

carbohydrates and proteins.

An example of a structural polysaccharide is glucose. starch. cellulose. maltose. glycogen.

cellulose

The fiber in your diet is actually protein. starch. ATP. glycogen. cellulose.

cellulose.

As shown in this figure, the top triglyceride (a) has ________, whereas the bottom triglyceride (b) has ________. double bonds and is unsaturated; no double and/or triple bonds and is saturated no double bonds and is unsaturated; double and/or triple bonds and is saturated double bonds and is saturated; no double and/or triple bonds and is unsaturated no double bonds and is saturated; double and/or triple bonds and is unsaturated

no double bonds and is saturated; double and/or triple bonds and is unsaturated

Adenosine triphosphate (ATP) is an example of a(n) lipid. carbohydrate. inorganic molecule. nucleotide. protein.

nucleotide

Important biological molecules that have a carbon backbone bonded to hydrogen atoms are considered to be ________.

organic molecules

Proteins are formed by joining amino acids together into a polymer. A ________ bond joins the amino end of one amino acid with the carboxyl end of another.

peptide

A nucleotide is made of a phosphate, protein, and nitrogenous base. phosphate, sugar, and nitrogenous base. phospholipid, sugar, and nitrogenous base. phospholipid, sugar, and protein.

phosphate, sugar, and nitrogenous base.

Chitin is an example of a monomer. nucleic acid. peptide. triglyceride. polysaccharide.

polysaccharide.

As shown in this figure, the valine and lysine in this protein are linked by covalent bonds within the ________ structure, whereas the hydrogen bonds hold together molecules within the helical ________ structure. secondary; tertiary primary; tertiary tertiary; quaternary secondary; quaternary primary; secondary

primary; secondary

Enzymes are specialized ________ that catalyze chemical reactions within the body. lipids proteins nucleic acids carbohydrates

proteins

The group of biological molecules that are most diverse in function is carbohydrates. lipids. nucleic acids. proteins.

proteins.