Inquiry into Life Chapter 6
A chemical reaction involves the breaking and making of ____ bonds. A) covalent B) ionic C) hydrogen D) enzymatic
a
ATP is NOT used for which of the following processes? A) diffusion of oxygen into cells B) synthesis of molecules C) active transport of molecules from one site to another D) conduction of nerve impulses E) muscle contraction
a
Each enzyme can speed up only one particular reaction. This specificity is due to the ______. A) shape of both the enzyme and the substrate B) lowering of the energy of activation C) pH of the surrounding medium D) temperature of the surrounding medium E) permanent binding of the enzyme-substrate complex
a
Oxidation refers to the _____________. A) loss of electrons and/or hydrogen atoms. B) loss of electrons and the gain of hydrogen atoms. C) gain of electrons and/or hydrogen atoms. D) gain of electrons and the loss of hydrogen atoms.
a
Energy is defined as the ability to do work. A) True B) False
True
Pepsin, an enzyme found in the stomach, acts best at a pH of about 2, but it is not active at a pH of 7. Why? A) The optimal pH helps to maintain the enzyme's globular structure. B) The optimal pH helps to maintain the substrate's globular structure. C) The optimal pH disrupts the normal interactions of the R groups within the protein molecule. D) A pH of 2 causes denaturation to occur but not at pH of 7.
a
The ______ is a place where the substrates fit onto the enzyme in such a way that they are oriented to react. A) active site B) inhibitory site C) enzyme-substrate complex D) metabolic pathway E) coenzyme
a
The ______ law of thermodynamics states that energy can neither be created nor destroyed. A) first B) second C) third D) fourth E) fifth
a
The average human male uses about 8,000 grams of ATP per hour. However, the body has on hand only 50 grams at any given time. This paradox can be explained by understanding that ______. A) ATP is recycled B) some cells use more ATP than other cells C) some organs use more ATP than other organs D) more ATP is broken down than synthesized E) more ATP is synthesized than broken down
a
The sum of all chemical reactions occurring inside a living cell is called ______. A) metabolism B) synthesis C) dehydration reaction D) hydrolysis E) thermodynamics
a
Which of the following statements is NOT correct? A) Chemicals and energy can cycle through living things. B) Energy can neither be created nor destroyed. C) One usable form of energy cannot be completely converted into another usable form. D) Metabolism is the sum of all chemical reactions occurring inside a living cell. E) Every reaction in a cell requires a specific enzyme.
a
______ inhibition is the normal way by which metabolic pathways are regulated in cells. A) Feedback B) Competitive C) Noncompetitive D) Psychological
a
A(An) ______ begins with a particular reactant, terminates with an end product, and has many minute steps in between. A) thermodynamic law B) metabolic pathway C) synthetic reaction D) hydrolytic reaction E) energy of activation
b
Cyanide is an inhibitor of the enzyme cytochrome oxidase, which is used to make ATP in mitochondria. Cyanide acts as a(an) _______. A) cofactor B) enzyme inhibitor C) denaturing agent D) substrate complex
b
Lactase is an enzyme that breaks down ______. A) lipids B) lactose C) maltose D) sucrose E) urea
b
Penicillin causes the death of bacteria by ______. A) blocking the active site of an enzyme unique to humans B) blocking the active site of an enzyme unique to bacteria C) denaturing the bacteria D) substituting a cofactor E) removing the substrate for an enzyme unique to bacteria
b
Study this metabolic pathway: E1 E2 E3 A → B → C → D Which of the following statements is NOT correct? A) A is the substrate for enzyme E1 and B is the product. B) A is the product for enzyme E1 and B is the substrate. C) Enzyme E2 can catalyze the substrate B but not substrates A, C, and D. D) B is the product formed by enzyme E1 but the substrate for enzyme E2. E) A is a reactant in the first reaction that forms the product B.
b
Too high or low a pH disrupts the hydrogen bonding and interactions between ______ of a protein and cause the enzyme to become denatured. A) amino acids B) R group side chains C) nucleic acids D) monosaccharides E) fatty acids
b
When muscles contract, chemical energy is converted to mechanical energy with the loss of heat. This is an example of the ______ law of thermodynamics. A) first B) second C) third D) fourth E) fifth
b
When the substrate binds to the enzyme, the active site undergoes a slight alteration to achieve the best fit. This is known as the ______ model. A) lock-and-key B) induced-fit C) deduced-fit D) reduced-fit E) fit-to-be-tied
b
Which organelle will convert solar energy into the energy of a carbohydrate? A) lysosome B) chloroplast C) Golgi apparatus D) mitochondria E) nucleolus
b
Within limits, the rate of enzymatic reaction doubles with every ______ C rise in temperature. A) 5° B) 10° C) 20° D) 30° E) 40°
b
A(An) ______ is generally a larger molecule that the body is incapable of synthesizing without the ingestion of a vitamin. A) ion B) cofactor C) coenzyme D) enzyme E) inhibitor
c
Energy of motion is referred to as __________ energy. A) potential B) heat or thermal C) kinetic D) electrical E) pure
c
The study of energy relationships and their exchanges is called ______. A) photosynthesis B) metabolism C) thermodynamics D) aerobic cellular respiration E) oxidation
c
What will form when ATP is initially broken down? A) just ADP B) just ADP + energy C) ADP + phosphate + energy D) AMP + phosphate + energy E) AMP + two phosphates + energy
c
Which of the following cell organelles convert one form of energy into another? A) ribosomes B) Golgi apparatus C) chloroplast D) lysosome E) endoplasmic reticulum
c
Which of the following comparisons is NOT correct? A) metabolism—sum of all chemical reactions occurring inside a living cell B) ATP—energy currency C) energy—constantly cycled back and forth through living things D) first law of thermodynamics—energy can neither be created nor destroyed E) enzyme—organic catalyst that speeds up a chemical reaction
c
Which of the following is NOT an enzyme? A) lipase B) urease C) maltose D) ribonuclease E) dehydrogenase
c
Which of the following molecules is the common energy currency of cells? A) glucose B) ADP C) ATP D) lipids E) amino acids
c
Which of the following statements about enzymes is NOT correct? A) Substrates fit onto the enzyme at the active site. B) No permanent change in the enzyme occurs when it combines with the substrate. C) Once the enzyme has combined with the substrate, the enzyme cannot be used again. D) Enzymes decrease the amount of heat needed by a cell for a chemical reaction to occur. E) Enzymes are named often for their substrates.
c
Which of the following statements is NOT correct about enzymes? A) Enzymes allow reactions to occur at moderate temperature. B) Enzymes bind with their substrates in such a way that the reaction can occur more readily. C) Enzymes raise the energy of activation for a reaction. D) Enzymes bring together particular molecules and cause them to react with one another. E) Enzymes can be used over and over again.
c
______ are organic dietary requirements needed in small amounts only. A) Cofactors B) Coenzymes C) Vitamins D) Minerals E) Enzymes
c
_______ is a measure of randomness or disorder. A) Metabolism B) Synthesis C) Entropy D) A coupled reaction E) Thermodynamics
c
A(An) ______ is any organic, nonprotein molecule that binds with an enzyme other than its substrate. A) reactant B) product C) inhibitor D) coenzyme
d
ATP is composed of ______. A) adenine, hexose sugar, three phosphate groups B) adenine, hexose sugar, two phosphate groups C) adenine, ribose sugar, two phosphate groups D) adenine, ribose sugar, three phosphate groups E) thymine, ribose sugar, three phosphate groups
d
In an enzymatic reaction, more product can be obtained if there is ______. A) enough substrate to fill all the active sites B) enough enzymes to fill all the active sites. C) higher than normal temperature and pH D) enough substrate to fill all the active sites and there are optimal pH and optimal temperature conditions
d
Sam, a biologist, was told by a friend that the electric power company was able to create electricity to be used in homes. Sam said that this was impossible because ______. A) energy can be created but not destroyed B) energy can be destroyed but not created C) energy can be created and destroyed D) energy cannot be created or destroyed but only converted from one form to another form E) energy cannot be created, destroyed, or converted from one form to another form
d
Which molecule is considered to be the energy currency of cells? A) glucose B) lipids C) proteins D) ATP E) oxygen
d
Which of the following may activate enzymes? A) Cleaving or removing part of the protein and the enzyme associating with another protein or cofactor B) Addition of phosphate groups C) Removal of phosphate groups D) All of these are correct
d
Which of the following statements about enzymes is NOT correct? A) Enzymes speed up a chemical reaction. B) The active site on the enzyme may undergo a slight change in shape when the substrate binds. C) Enzymes are very specific in their action. D) The presence of an enzyme will change the outcome of a reaction. E) Enzymes lower the energy of activation for a reaction to occur.
d
Which of the following statements is NOT correct about enzymes? A) Most enzymes are protein molecules. B) Every reaction in a cell requires a specific enzyme. C) Enzymes speed up a chemical reaction. D) Enzymes are often named for the products formed. E) Enzymes are absolutely necessary to the continued existence of a cell.
d
Which of the following statements is NOT correct for a metabolic pathway? A) One reaction leads to the next reaction. B) They begin with a particular reactant and terminate with an end product. C) One pathway may lead to other pathways if there are several molecules in common. D) Metabolic energy is captured more easily if it is released in large amounts rather than in small increments. E) Metabolic pathways are highly organized and structured.
d
Which of the following statements is NOT correct? A) Carbon dioxide given off by mitochondria is used by chloroplasts. B) Carbohydrates produced by chloroplasts may be used by mitochondria. C) Oxygen released by chloroplasts may be used by mitochondria. D) Carbon dioxide given off by chloroplasts may be used by mitochondria. E) Heat is released by reactions occurring in the chloroplast and mitochondria.
d
Which of the following statements is NOT correct? A) Catalase converts hydrogen peroxide into water and oxygen. B) Generally, enzyme activity increases as substrate concentration increases. C) Generally, enzyme activity decreases as substrate concentration decreases. D) The enzyme's rate of activity can increase even after all the active sites have been filled. E) A denatured enzyme cannot form an enzyme-substrate complex.
d
Which organelle converts energy stored in carbohydrates into ATP? A) lysosome B) Golgi apparatus C) chloroplast D) mitochondria E) nucleolus
d
Which statement is NOT correct in the cycling of ATP? A) Input of energy is required to produce ATP. B) Phosphate is added to ADP to make ATP. C) Mitochondria are the site of ATP synthesis. D) Because we need ATP for all cell energy needs, huge amounts of ATP are stored. E) About 7.3 kcal per mole of energy is released when ATP is hydrolized to ADP + P.
d
The amount of energy (e.g., heat) needed for a reaction to occur is called the ______. A) kinetic energy B) potential energy C) synthetic energy D) energy of deactivation E) energy of activation
e
The energy that is released from ATP when ATP is broken down comes from the ______. A) ribose sugar B) hexose sugar C) adenine nucleotide D) thymine nucleotide E) phosphate group
e
The letters ATP stand for ______. A) a structure within a cell B) any energy in a biological form C) adenosine monophosphate D) adenosine diphosphate E) adenosine triphosphate
e
The second law of thermodynamics says that ______. A) energy can be created but not destroyed B) energy can be created and destroyed C) energy can neither be created nor destroyed D) one usable form of energy can be completely converted into another usable form E) energy cannot be changed from one form to another without a loss of usuable energy
e
Which of the following enzymes will remove hydrogen atoms from its substrate? A) lipase B) urease C) maltose D) ribonuclease E) dehydrogenase
e
Which of the following is considered a vitamin? A) FAD B) NAD+ C) thiamine pyrophosphate D) coenzyme A (CoA) E) niacin
e
Which of the following is considered to be a coenzyme? A) magnesium ion B) riboflavin C) pantothenic acid D) niacin E) NAD+
e
A cell can take in energy from its surroundings without losing energy to its surroundings. A) True B) False
false
A cell must produce large quantities of each enzyme in order to survive. A) True B) False
false
All enzymes are proteins. A) True B) False
false
All organisms depend on organic nutrients as a source of energy. A) True B) False
false
An enzymatic reaction can bring about only synthesis, i.e., two smaller molecules joined to form a larger molecule. A) True B) False
false
Enzymes can only be denatured by high temperatures. A) True B) False
false
Glucose is the common energy currency for the syntheruesis of molecules. A) True B) False
false
In general, cellular respiration permits a flow of energy from the sun through all living things. A) True B) False
false
Until reaching a point where the enzyme is denatured, an increase in temperature will cause molecules to move faster, thereby decreasing the chance of the reactants colliding. A) True B) False
false
A denatured enzyme has lost its normal shape and therefore its ability to form an enzyme-substrate complex. A) True B) False
true
Adenosine, a component of ATP, is made up of the nitrogenous base adenine and the sugar ribose. A) True B) False
true
Energy cannot be created within a system. A) True B) False
true
Every reaction in a cell requires a specific enzyme. A) True B) False
true
Living systems continually take usable energy from the environment and eventually return it as heat. A) True B) False
true
The reactants in an enzymatic reaction are called the substrates for that enzyme. A) True B) False
true
There is a conversion of usable energy during cellular respiration and photosynthesis but eventually all ATP energy becomes heat. A) True B) False
true
