Unit 2 Biology Test
Which of the following is an important, life-sustaining property of water? - expansion upon freezing - versatility as a solvent - ability to moderate temperature - cohesive behavior - contraction upon freezing
- expansion upon freezing - versatility as a solvent - ability to moderate temperature - cohesive behavior
Which of the following is true about nucleic acids? I. Nucleic acids always consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups. II. Both DNA, which stores genetic information and encodes protein sequences, and RNA, which is involved in the direct production of proteins, are nucleic acids. III. Nucleic acids are usually insoluble in water and are used for long term energy storage. IV. Glucose, cellulose, and starch are examples of nucleic acids found in most cells. A. I and II only B. I, III, and IV only C. I, II, III, and IV D. II only
A. I and II only
All living things contain carbon. Which of the following statements are true about carbon atoms? I. Each carbon atom can form single bonds with up to four other carbon atoms. II. Each carbon atom can form double bonds with up to two other carbon atoms. III. Carbon atoms can join together to form chains or rings. IV. A single molecule of some compounds can contain thousands of carbon atoms. A. I, II, III, and IV B. I, II, and III only C. I and III only D. II and III only
A. I, II, III, and IV
Enzymes are catalysts. This means that they are able to speed up chemical reactions. Which of the following statements is also true of enzyme catalysts? A. They are not used up by reactions. B. They must be continuously replaced after each catalyzed reaction. C. They increase the energy that must be absorbed by reactions. D. They increase the energy that is released by reactions.
A. They are not used up by reactions.
The human body contains approximately 70% water by weight. Water is found inside and outside of cells, and it is able to carry nutrients into and around cells in addition to carrying wastes away from cells. Why is water able to do this? A. Water is able to dissolve many substances. B. Water is very acidic. C. Water is an ionic solution. D. Water is a nonpolar covalent compound.
A. Water is able to dissolve many substances.
Glucose is a carbohydrate that is made by plants and used by both plants and animals to produce energy. Which of the molecules pictured is glucose? W. X. Y. Z. A. Y B. X C. Z D. W
A. Y
Lipids, also called fats or oils, can be found in cell membranes. Which of the molecules shown below is a lipid? W. X. Y. Z. A. Y B. X C. Z D. W
A. Y
Suppose that enzyme X catalyzes a reaction that involves the breakdown of a molecule. The product of this reaction is an amino acid. What molecule is the enzyme breaking down? A. a protein B. a mineral C. a carbohydrate D. a lipid
A. a protein
The above graph shows how temperature affects the rate of a reaction that uses the catalase enzyme. At what temperatures, approximately, is the enzyme denatured? A. between 60°C and 100°C B. between 27°C and 37°C C. between 37°C and 60°C D. between 0°C and 27°C
A. between 60°C and 100°C
Sugars such as glucose, fructose, and ribose are examples of _______. A. carbohydrates B. nucleic acids C. proteins D. lipids
A. carbohydrates
Carbohydrates are composed of which three elements? A. carbon, hydrogen, and oxygen B. oxygen, hydrogen, and nitrogen C. oxygen, sulfur, and phosphorus D. carbon, nitrogen, and phosphorus
A. carbon, hydrogen, and oxygen
Proteins serve a variety of functions in living organisms. Which of the following protein-containing substances plays only a structural role? A. hair B. muscles C. hormones D. antibodies
A. hair
What type of molecule is shown above? A. protein B. lipid C. nucleic acid D. disaccharide
A. protein
Any factor that changes the shape of an enzyme can affect the enzyme's activity. Which of the following two factors affect an enzyme's operation the most? A. temperature and pH B. amount of light and temperature C. amount of light and pressure D. blood glucose level and pH
A. temperature and pH
Carbohydrates, such as glucose, are excellent sources of immediate energy for living organisms. More complex carbohydrates, such as glycogen and starch, can also be used for the long term storage of energy. However, carbohydrates play other vital roles, too. Which of the following describes another common use for carbohydrates? A. Collagen is a major component in cartilage and tendons. B. Cellulose is used as a structural component in plant cell walls. C. Enzymes help speed up metabolic reactions. D. Keratin provides support in hair, nails, feathers, hooves, and some animal shells.
B. Cellulose is used as a structural component in plant cell walls.
Water is important to plant cells because it is used as one of the reactants in the process of photosynthesis. What is another reason why water is important to plant cells? A. Water signals plant DNA to start transcription and translation. B. Water helps to maintain turgidity in plant cells. C. Water is a major structural component found in plant cell walls. D. Water can be used as a substitute for glucose in times of distress.
B. Water helps to maintain turgidity in plant cells.
Organic macromolecules called _______ are insoluble in water, are often found in biological membranes and other waterproof coverings, and have the ability to store energy for extended periods of time. A. proteins B. lipids C. carbohydrates D. nucleic acids
B. lipids
Polymers of the carbohydrate monomer glucose are used as the major form of energy storage for many plants. What are these glucose polymers called? A. maltose B. starch C. table sugar D. glycogen
B. starch
Suppose that the temperature in the ecosystem below dips below freezing. What would happen to the fish swimming in the lake? A. The fish would move more rapidly to increase their body temperature. B. Ice would form on the surface of the lake and insulate the fish. C. The fish would die because the lake would freeze solid. D. Ice would only form on the bottom of the lake, so the fish would be okay.
B. Ice would form on the surface of the lake and insulate the fish.
Hydrogen peroxide is a substance that is produced as a byproduct of many cell processes. However, hydrogen peroxide is toxic to cells. In fact, if cells are unable to break down hydrogen peroxide, they become poisoned and die. The chemical reaction for the breakdown of hydrogen peroxide is shown below. What role does catalase play in this reaction? A. Catalase in an enzyme that slows down the reaction. B. Catalase is a reactant that gets used up in the reaction. C. Catalase is an enzyme that speeds up the reaction. D. Catalase is a product that is created during the reaction.
C. Catalase is an enzyme that speeds up the reaction.
All cells in multicellular organisms contain thousands of different kinds of enzymes that are specialized to catalyze different chemical reactions. Given this information, which of the following is most likely to be true? A. All cells do not contain the same types of enzymes. B. All cells contain exactly the same number of enzymes. C. All cells do not contain enzymes. D. All cells contain exactly the same types of enzymes.
A. All cells do not contain the same types of enzymes.
Water is the most abundant molecule found in living organisms. Most mammals, in fact, are approximately 70% water by weight. About two-thirds of this water is present inside cells. The other one-third is present outside cells (e.g., in blood plasma or other body fluids). Why is water so important to cells? A. Almost all the chemical reactions in life processes occur in solutions with water. B. The main structural component found in plasma membranes and cell walls is water. C. Water determines which proteins are translated from the cellular DNA. D. Water is stored in the cells to be used when the organism gets thirsty.
A. Almost all the chemical reactions in life processes occur in solutions with water.
The above graph shows how temperature affects the rate of a reaction that uses the catalase enzyme. What trend is shown by the graph? A. Between zero and twenty-seven degrees Celsius, the rate of the reaction increases as the temperature increases. B. Between zero and twenty-seven degrees Celsius, the rate of the reaction decreases as the temperature increases. C. Between sixty and one hundred degrees Celsius, the rate of the reaction decreases as the temperature increases. D. Between thirty-seven and sixty degrees Celsius, the rate of the reaction increases as the temperature increases.
A. Between zero and twenty-seven degrees Celsius, the rate of the reaction increases as the temperature increases.
Which of the following are examples of nucleic acids? A. DNA and RNA B. glucose and starch C. saturated fats and unsaturated fats D. collagen and keratin
A. DNA and RNA
Which of the following describes the role that enzymes play in the process of metabolism? A. Enzymes increase the rate of the chemical reactions carried out during metabolism. B. Enzymes provide the chemical energy that is broken down and released during metabolism. C. Enzymes store the chemical energy that is used to construct nucleic acids during metabolism. D. Enzymes carry the genetic instructions required for a cell to initiate metabolism.
A. Enzymes increase the rate of the chemical reactions carried out during metabolism.
Examine the diagram of the enzyme below: How does the structure of this enzyme help with its function? A. The enzyme's shape complements the substrate's shape, so it only catalyzes specific reactions. B. The enzyme's active site is amorphous and can change its shape to fit any substrate. C. Since the enzyme's shape matches the substrate's shape, it catalyzes only reverse reactions. D. Since the enzyme is larger than the substrate, catalytic reactions can occur within the enzyme itself.
A. The enzyme's shape complements the substrate's shape, so it only catalyzes specific reactions.
Pepsin is produced by cells lining the stomach. It catalyzes reactions needed to digest certain proteins. After leaving the stomach, food enters the small intestine. The pH of the small intestine is around 7. What would most likely happen to pepsin enzymes that traveled with the food from the stomach to the small intestines? A. The pepsin would become inactive. B. The pepsin would continue to digest proteins in the small intestine. C. The pepsin would turn into the enzyme arginase. D. The pepsin would begin to digest carbohydrates
A. The pepsin would become inactive.
The characteristics of all organisms and viruses are determined by the instructions carried in _______. A. sugar bases B. phosphoric acids C. nucleic acids D. hydrogen bonds
C. nucleic acids
Nucleic acids are one of the four major macromolecules. The main functions of nucleic acids are to A. carry genetic material and create structures inside the cell. B. aid in development, the immune system, and blood clotting. C. store and transport energy and structural components in the cell. D. act as enzymes, cell signals, and structural support for the cell.
A. carry genetic material and create structures inside the cell.
DNA molecules store genetic information and allow for self-replicating life. Molecules of DNA can be long and very complex. They always consist of smaller molecules that are made up of nitrogenous bases, phosphate groups, and 5-carbon sugars. DNA is an example of a complex _______. A. organic molecule B. protein structure C. carbohydrate polymer D. inorganic molecule
A. organic molecule
Monosaccharides are the simplest form of carbohydrates. They can be combined to form more complex carbohydrates known as polysaccharides, which are typically used for long term energy storage within a cell. Based on the information above, it can be concluded that A. simple organic molecules can be organized into much longer, more complex molecules. B. complex organic molecules can only be formed by the polymerization of inorganic molecules. C. simple organic molecules are not necessary for the life processes of an organism. D. complex organic molecules cannot contain more than one carbon atom.
A. simple organic molecules can be organized into much longer, more complex molecules.
Carbon atoms have four electrons in their outer shell. This means that a single carbon atom can form up to _______ bonds with other atoms. A. four B. eight C. two D. six
A. Four
Proteins are used for many structural functions such as in the actin and myosin in muscle or as a part of the cytoskeleton scaffolding that maintains cell shape. What other main function do proteins serve? A. as enzymes to control the rate of reactions and regulate cellular activity B. as waterproof membranes to regulate the transport of molecules in and out of the cell C. as cellulose to form the major structural component of plant cell walls D. as coding for genotypic expression and phenotypic traits
A. as enzymes to control the rate of reactions and regulate cellular activity
All living organisms contain carbon atoms. Which of the following is an important characteristic of carbon? A. Carbon atoms can bond with any other atom, but they cannot form bonds with other carbon atoms. B. Carbon atoms can bond with many other kinds of atoms to form very stable molecules. C. Carbon atoms are very stable and do not easily form bonds with other atoms. D. Carbon atoms are highly reactive and form unstable bonds with any available atom.
B. Carbon atoms can bond with many other kinds of atoms to form very stable molecules.
Which of the following enzymes serve as catalysts in metabolism? I. amylase II. lactase III. pepsin IV. polymerase A. I, II, III, and IV B. I, II, and III only C. IV only D. I and II only
B. I, II, and III only
Examine the diagram below. If the black line represents a reaction without an enzyme and the red line represents the same reaction with the addition of an enzyme, what can be said of the relationship between the use of an enzyme and the energy of the reaction? A. Less energy is released by a reaction with an enzyme. B. More energy is absorbed by reactions without an enzyme. C. Less energy is released by a reaction without an enzyme. D. More energy is absorbed by a reaction with an enzyme.
B. More energy is absorbed by reactions without an enzyme.
Lactase is an enzyme that breaks down the complex carbohydrate lactose into glucose and galactose, which can be absorbed by the bloodstream and carried to the body's cells. Lactose is found primarily in dairy products. What would most likely happen to a person who had a shortage of lactase? A. The person would not be able to digest any carbohydrates. B. The person would be unable to fully digest dairy products. C. The person would develop an allergy for dairy products. D. The person's pancreas would not be able to regulate the body's blood glucose level.
B. The person would be unable to fully digest dairy products.
A biochemist is attempting to replicate a chemical reaction that commonly takes place in cells. During the chemical reaction, starch is broken down into glucose. What will most likely happen if the biochemist adds an enzyme to the reactants? A. The reaction will stop. B. The reaction will speed up. C. The reaction will slow down. D. The reaction will take place at a higher temperature.
B. The reaction will speed up.
Water has a high specific heat, which means that it requires a great deal of heat to change its temperature. Which of the following helps support life on Earth and is a result of water's high specific heat? A. In freezing temperatures, ice rises to the top of lakes and provides an insulating layer that keeps the rest of the water from freezing. B. The water that covers over 70% of the Earth's surface stabilizes the weather and climate of the Earth. C. Water droplets tend to clump together in drops instead of spreading out in a thin film, allowing it to move through the roots of plants and through blood vessels in the human body. D. Water is part of a continuous cycle in which liquid water falls to the Earth's surface, is evaporated back into the atmosphere, and condenses into clouds that produce precipitation.
B. The water that covers over 70% of the Earth's surface stabilizes the weather and climate of the Earth.
Proteins are used for many structural functions such as in the actin and myosin in muscle or as a part of the cytoskeleton scaffolding that maintains cell shape. What other main function do proteins serve? A. as coding for genotypic expression and phenotypic traits B. as enzymes to control the rate of reactions and regulate cellular activity C. as waterproof membranes to regulate the transport of molecules in and out of the cell D. as cellulose to form the major structural component of plant cell walls
B. as enzymes to control the rate of reactions and regulate cellular activity
The above graph shows how temperature affects the rate of a reaction that uses the catalase enzyme. At what temperatures, approximately, is the enzyme the most effective? A. between 0°C and 27°C B. between 27°C and 37°C C. between 37°C and 60°C D. between 60°C and 100°C
B. between 27°C and 37°
Atoms of what element form the backbone of large, complex molecules such as sugars and fats? A. oxygen B. carbon C. sulfur D. sodium
B. carbon
Atoms of what element form the backbone of large, complex molecules such as sugars and fats? A. sodium B. carbon C. oxygen D. sulfur
B. carbon
Nucleic acids are one of the four major macromolecules. The main functions of nucleic acids are to A. aid in development, the immune system, and blood clotting. B. carry genetic material and create structures inside the cell. C. act as enzymes, cell signals, and structural support for the cell. D. store and transport energy and structural components in the cell.
B. carry genetic material and create structures inside the cell.
Proteins serve many functions within cells. They aid in cellular transport within the cell. They assist with the transport of substances across the cell membrane. They form enzymes that are involved in many cellular processes, and so on. However, proteins do not function properly unless they are immersed in water. This is because water A. reacts with proteins to form new complexes. B. helps to maintain the structure, flexibility, and motion of proteins. C. serves as a catalyst for metabolic reactions involving proteins. D. determines the amino acid sequences found in proteins.
B. helps to maintain the structure, flexibility, and motion of proteins.
In order to change from a solid to a liquid or a liquid to a gas, water must absorb a large amount of heat energy. Water can absorb a large amount of energy while producing only small changes in temperature because water has a A. low specific heat. B. high specific heat. C. low particle density. D. high particle density.
B. high specific heat.
A student is given a small amount of unknown tan-colored liquid substance. This unknown liquid is placed into a glass of water and mixed. Despite mixing, the tan liquid remains separated from the water and collects as a large droplet at the top. Which of the macromolecule groups is this liquid MOST likely to be a member of? A. proteins B. lipids C. carbohydrates D. nucleic acids
B. lipids
Proteins serve a variety of functions in living organisms. Which of the following protein-containing substances plays a role in movement? A. hormones B. muscles C. hair D. antibodies
B. muscles
Each enzyme produced by the body is A. immature—meaning it cannot catalyze a reaction until many years later. B. specific—meaning it is only able to catalyze a reaction with a certain molecule. C. incomplete—meaning it requires other parts before it is able to bind to a molecule. D. open—meaning it is able to catalyze a reaction with any molecule.
B. specific—meaning it is only able to catalyze a reaction with a certain molecule.
Nucleic acids, proteins, and other large biological molecules are known as polymers because A. they are the base units used in the formation of plastics. B. they contain many small, repeating subunits bonded together. C. they all contain only ionic bonds. D. they all have the capability of functioning as enzymes.
B. they contain many small, repeating subunits bonded together.
Lipids are organic macromolecules that serve a variety of purposes. What is the most important role of lipids? A. to build muscles B. to store energy C. to oxygenate blood D. to metabolize sugar
B. to store energy
An enzyme is a biomolecule that increases the rate of a chemical reaction. Which of the following is true about enzymes? I. Enzymes are not consumed during a chemical reaction. II. Enzymes are specific to particular molecules. III. Enzymes increase the energy produced by a chemical reaction. A. I and III only B. I and II only C. II only D. I, II, and III
B. I and II only
Catalase is an enzyme that is found in all living tissues. Cells need catalase in order to function properly. Which of the following statements can be inferred using the above information? A. Cells can function equally as well at all temperatures because enzymes are effective at all temperatures. B. Cells only function within a specific pH range because enzymes only function within a specific pH range. C. Cells only function within a specific temperature range because enzymes only function within a specific temperature range. D. Cells can function equally as well at all pH's because enzymes are effective at all pH's.
C. Cells only function within a specific temperature range because enzymes only function within a specific temperature range.
Examine the following chemical reaction, which is catalyzed by the enzyme catalase: What molecule is catalase breaking down in this reaction? A. H2O B. O2 C. H2O2 D. There are no molecules in this reaction.
C. H2O2
When cellular respiration occurs within a cell, carbon dioxide is formed as a waste product. The carbon dioxide is transported out of the cell and absorbed by the blood stream. There, the carbon dioxide undergoes a chemical reaction and forms carbonic acid within the blood. When the carbonic acid reaches the capillaries in the lungs, the enzyme carbonic anhydrase helps reverse the reaction, and the carbonic acid is converted back to carbon dioxide and water. Which of the following would most likely happen if a person's body stopped producing carbonic anhydrase? A. The blood's volume would increase until a hemorrhage occurred. B. The person's breathing rate would slow down. C. The blood's acidity would increase and become toxic. D. The person would begin exhaling carbonic acid instead of carbon dioxide
C. The blood's acidity would increase and become toxic.
Examine the diagram of the enzyme catalase below: How does the structure of this enzyme help with its function? A. The enzyme's substrate is a mirror image of the enzyme, thus allowing it to reverse any reactions initiated by the enzyme. B. The enzyme is much larger than its substrate, thus allowing the catalyzed chemical reaction to take place inside the enzyme. C. The enzyme's shape fits its substrate's shape, thus allowing the enzyme to catalyze the appropriate reaction. D. The enzyme's active site can change shape in order to match any substrates in need of a catalyst.
C. The enzyme's shape fits its substrate's shape, thus allowing the enzyme to catalyze the appropriate reaction.
Many of the biochemical reactions that occur within your cells are catalyzed by enzymes. Which of the following statements is true about most enzyme-assisted reactions? A. They can take place at any temperature or pH. B. They can take place only within a ribosome. C. They occur more quickly than reactions without enzymes. D. Enzymes are quickly used up during the reactions.
C. They occur more quickly than reactions without enzymes.
Homeostasis is the ability of an organism to maintain a relatively stable internal environment. How would an organism's homeostasis be affected if it was not able to produce enzymes? A. Without enzymes, biochemical reactions would cease completely. B. Without enzymes, the temperature inside cells would increase rapidly. C. Without enzymes, chemical reactions would not occur quickly enough to sustain life. D. Without enzymes, ribosomes would break down proteins, rather than build them.
C. Without enzymes, chemical reactions would not occur quickly enough to sustain life.
Proteins serve a variety of functions in living organisms. Which of the following protein-containing substances plays a role in defense? A. muscles B. hair C. antibodies D. hormones
C. antibodies
A polymer is a large molecule that forms when smaller molecules known as monomers bond covalently in a repeating pattern. There are many biological polymers such as nucleic acids, proteins, and starches. What are the monomer units that make up starches? A. amino acids B. fatty acids C. glucose D. nucleotides
C. glucose
Proteins serve a variety of functions in living organisms. Which of the following protein-containing substances plays a role in the regulation of cell functions? A. muscles B. hair C. hormones D. antibodies
C. hormones
To which of the following could this complex best be compared? A. dime and penny B. shoe and sock C. lock and key D. salt and pepper
C. lock and key
A polymer is a large molecule that forms when smaller molecules known as monomers bond covalently in a repeating pattern. There are many biological polymers such as nucleic acids, proteins, and starches. What are the monomer units that make up nucleic acids? A. fatty acids B. amino acids C. nucleotides D. glucose
C. nucleotides
Nitrogen atoms are part of the structure of some organic molecules, such as all amino acids and some modified carbohydrates. What other organic molecules contain nitrogen? A. starch B. fatty acids C. nucleotides D. cellulose
C. nucleotides
Lakes and oceans are able to stabilize air and land temperatures because A. the temperature of water changes significantly instead of the temperature of the air and land. B. the salt in the water bodies is able to absorb large amounts of heat. C. water is able to absorb large amounts of heat without significantly changing its temperature. D. the water is able to release large amounts of heat into the air when necessary.
C. water is able to absorb large amounts of heat without significantly changing its temperature.
The darker parts occur on the cooler parts of the cat's body because the enzyme that catalyzes the formation of the dark pigment is more active when cool. This example shows that enzymes are affected by . A. pH B. concentration C. temperature D. all of these
C. temperature
Which of the following best describes a carbohydrate? A. Carbohydrates are composed of amino acid monomers and are involved in cell signaling, cell transport, immune responses, and the cell cycle. B. Carbohydrates always consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups and are used to store genetic information. C. Carbohydrates are organic macromolecules that are insoluble in water and have the ability to store energy for extended periods of time. D. Carbohydrates are organic macromolecules that are made up of carbon, hydrogen, and oxygen atoms and are used for energy storage or as structural molecules.
D. Carbohydrates are organic macromolecules that are made up of carbon, hydrogen, and oxygen atoms and are used for energy storage or as structural molecules.
The graph below shows the relationship between pH and three different digestive enzymes. Which of the following conclusions can be drawn from this graph? A. Enzymes are only able to operate in acidic environments. B. Digestive enzymes are most active in an environment with a pH of 7. C. Enzymes operate most efficiently within a certain range of temperatures. D. Each enzyme operates best within a certain pH range.
D. Each enzyme operates best within a certain pH range.
Which of the following is true about protein molecules? A. Protein molecules have many functions in the body, including the storage of genetic information. B. The sequence of amino acids that make up a protein molecule do not affect its function. C. Protein molecules are made up of strands of DNA joined together by amino acid sequences. D. The shape and folded structure of a protein molecule are important in determining its function.
D. The shape and folded structure of a protein molecule are important in determining its function.
Pepsin is found in the stomach. Salivary amylase is found in the mouth. And arginase is found in the liver. What does the graph indicate about the relative acidity of these three locations? A. The stomach is more acidic than the liver, which is more acidic than the mouth. B. The liver is more acidic than the mouth, which is more acidic than the stomach. C. The mouth is more acidic than the stomach, which is more acidic than the liver. D. The stomach is more acidic than the mouth, which is more acidic than the liver.
D. The stomach is more acidic than the mouth, which is more acidic than the liver.
Tobin perfomed an experiment in which he mixed varying amounts of enzyme with an excess amount of a certain molecule. He measured the rate of each reaction and recorded his data in the table below. Enzyme Concentration (millimoles) Reaction Rate (micromoles/minute) 0 0 100 0.05 200 0.10 300 0.15 400 0.20 500 0.25 What can Tobin conclude about the relationship between the enzyme concentration and the reaction rate in the presence of excess molecules? A. The experiment is invalid because it was performed in the presence of excess molecules. B. There is an inverse relationship; as the enzyme concentration increases, the reaction rate decreases. C. There is no relationship between the enzyme concentration and the reaction rate. D. There is a direct relationship; as the enzyme concentration increases, the rate of reaction increases.
D. There is a direct relationship; as the enzyme concentration increases, the rate of reaction increases.
From the information given, what can be inferred about cells that have salivary amylase? A. They function best at a high pH. B. They function equally well regardless of the pH level. C. They function best at a low pH. D. They do not function well at a pH that is too high or too low.
D. They do not function well at a pH that is too high or too low.
What role do ATP and NADH play in living cells? A. They also store and transfer information. B. They provide structural support to cell membranes. C. They are involved in cell-to-cell signaling. D. They store and transfer energy.
D. They store and transfer energy.
Nucleic acids are biological polymers that are comprised of nucleotide monomers covalently bonded together. The picture above shows two monomer units of a nucleic acid chain. What are the components that make up each nucleotide monomer? A. glucose, a phosphate group, and a nitrogenous base B. a five-carbon sugar, a phosphate group, and an amino acid C. glucose, a phophate group, and an amino acid D. a five-carbon sugar, a phosphate group, and a nitrogenous base
D. a five-carbon sugar, a phosphate group, and a nitrogenous base
A large carbohydrate molecule is composed of several subunits, such as glucose. An example of a large carbohydrate molecule is _______. A. starch B. glycogen C. cellulose D. all of these
D. all of these
In which of the following are lipids found? A. in some vitamins and steroids B. in saturated and unsaturated fats C. in biological membranes D. all of these
D. all of these
Which of the following can affect the function of a cell? A. high temperature B. low temperature C. high acidity D. all of these
D. all of these
A polymer is a large molecule that forms when smaller molecules known as monomers bond covalently in a repeating pattern. There are many biological polymers such as nucleic acids, proteins, and starches. What are the monomer units that make up proteins? A. glucose B. nucleotides C. fatty acids D. amino acids
D. amino acids
Cellular processes are carried out by many different types of molecules, mostly proteins. The function of each protein molecule depends on its shape which, in turn, is determined by the protein's specific sequence of _______. A. nucleotides B. triglycerides C. monosaccharides D. amino acids
D. amino acids
Protein molecules are composed of long chains of _______. A. DNA B. ribosomes C. RNA D. amino acids
D. amino acids
A _______ is a kind of lipid that can store energy for a long period of time. These lipids are made up of long chains of carbon and oxygen atoms bonded to a backbone structure. A. protein B. carbohydrate C. nucleic acid D. fat
D. fat
The molecule pictured below is a __________. A. amino acid B. lipid C. carbohydrate D. nucleic acid
D. nucleic acid
The human body can properly function only within a certain temperature range. This tendency toward maintaining a stable internal environment is known as homeostasis. Which of the following substances is most important for maintaining a stable thermal environment within the human body? A. glucose B. insulin C. marrow D. water
D. water
Proteins can perform many different functions in living cells. One major function—acting as a catalyst for chemical reactions—can also be performed by what other kind of organic molecule? A. cholesterol B. glycogen C. phospholipids D. RNA
D. RNA
A reaction that is catalyzed by an enzyme usually absorbs less energy and is faster than normal reactions. Which of the reactions was most likely catalyzed by an enzyme? A. Reaction A B. Reaction D C. Reaction C D. Reaction B
D. Reaction B
Carbohydrates are biological molecules that contain carbon, hydrogen, and oxygen. Polysaccharides are biological polymers because they contain repeating patterns of monomer subunits. Amylose is a polysaccharide that serves as one of two components in starches. Glycogen is also a polysaccharide used to store energy in animal cells. How does the structure of amylose compare to the structure of glycogen? A. They contain different monomer subunits and they are arranged differently. B. They contain the same monomer subunits and they are arranged in the same pattern. C. They contain different monomer subunits but they are arranged in the same pattern. D. They contain the same monomer subunits but they are arranged differently.
D. They contain the same monomer subunits but they are arranged differently.
In most animal cells, a complex network of proteins provides which of the following? A. organization B. movement C. shape D. all of these
D. all of these
In which of the following are lipids found? A. in biological membranes B. in some vitamins and steroids C. in saturated and unsaturated fats D. all of these
D. all of these
An enzyme is a biomolecule that increases the rate of a chemical reaction. An enzyme is a kind of _______. A. inhibitor B. translator C. ribosome D. catalyst
D. catalyst
Hydrogen peroxide is a substance that is produced as a byproduct of many cell processes. However, hydrogen peroxide is toxic to cells. In fact, if cells are unable to break down hydrogen peroxide, they become poisoned and die. Catalase is an enzyme that is found in all living tissues. This enzyme speeds up the reaction that breaks down hydrogen peroxide into less harmful substances. What substances are formed as a result of this reaction? A. hydrogen peroxide and oxygen B. hydrogen peroxide and water C. water and ozone D. water and oxygen
D. water and oxygen
The freezing point of water is 0°C, and the boiling point is 100°C. This range of temperatures can be found naturally on the Earth, which means that A. water makes up less than 30% of the Earth's surface. B. water has a very low specific heat. C. water cannot move through the roots of plants. D. water can exist in all three states on Earth.
D. water can exist in all three states on Earth.
A water molecule, shown below, is composed of two hydrogen atoms and one oxygen atom arranged in a bent shape. Since oxygen is significantly more electronegative than hydrogen, oxygen atoms have a much stronger attraction to shared electrons than hydrogen atoms have. This unequal sharing of electrons and bent shape results in a polar molecule. The oxygen end of the molecule has a slightly negative charge while the hydrogen ends of the molecule have a slightly positive charge. The composition and polar covalent nature of water allow water molecules to form_________with_________.
Hydrogen Bonds with other water molecules.
