Human Physiology Ch. 4

Transcription occurs in/on the __________ of the cell.

nucleus

After coming off a ribosome, several things can happen to the newly synthesized protein. Name three.

1. folded into various three-dimensional shapes 2. create cross-links between different regions of its amino acid chain 3. be cleaved into fragments 4. attach other molecules or groups 5. assemble with other amino acids into polymeric protein

What is the potential yield of ATP molecules for each FADH2 molecule entering the electron transport system?

1.5

For each NADH molecule that moves through the electron transport system, what is the potential yield of ATP molecules?

2.5

What are the five ways that cells regulate flow of molecules through their metabolic pathways?

: 1. by controlling the enzyme concentration 2. by producing allosteric and covalent modulators 3. by using two different enzymes to catalyze reversible reaction 4. by isolating enzymes within intracellular organelles 5. by maintaining an optimum ratio of ATP to ADP

Define substrate and product. Are these definitions relative or absolute, and why?

: Substrates are chemicals that bind to the enzyme and become altered (bonds formed and/or broken), producing a product. A product is the result of enzyme action on substrates. These terms are relative because chemical reactions are reversible. Example: if two monomers bind to the enzyme and form a dimer, the monomers are the substrates and the dimer is the product. If instead the dimer binds to the enzyme and splits to form two monomers, the monomers are the products and the dimer is the substrate.

Question 177 - too complicated to put here

??

Explain what a concentration gradient is and how it assists a cell in doing its work.

A concentration gradient is a difference in concentration of a particular molecule between the cytosol of a cell and the interstitial fluid. A concentration gradient establishes potential energy because of the tendency of molecules to diffuse from areas of high to areas of low concentration.

Each of the following is a true statement, except one. Identify the exception.

A) Noncoding segments of mRNA are referred to as introns. B) Alternative splicing allows the cell to construct different proteins from one segment of DNA. C) Segments of mRNA that are retained and used for protein synthesis are called exons. D) Initiation factors for gene activation must bind to the promoter region, allowing the RNA polymerase to bind to DNA, thus allowing transcription to proceed. E) Each of the above statements is true. Answer: E

Lactate dehydrogenase

A)catalyzes the reaction pyruvate → lactate. B) catalyzes the reaction lactate → pyruvate. C) uses NADH to produce NAD+. D) uses NAD+ to produce NADH. All true

In an equilibrium reaction

A)the rate of formation of products equals the rate of formation of reactants. B) increasing the amount of one of the reactants will increase the amount of product formed. C) increasing the amount of one of the products will increase the amount of reactants available. D) removing one of the products will increase the amount of product formed. (all true)

Consider the two chemical reactions. Identify each statement following as true or false, and clarify as needed. A + B → C C → A + B A. The enzyme catalyzing the formation of C must be different from that catalyzing the breakdown of C. B. The enzyme catalyzing the formation of C must be the same as that catalyzing the breakdown of C. C. Only one of the reactions could occur in a given container or cell or system. D. Both reactions must be occurring in an equilibrium situation. E. Equilibrium is always achieved in a chemical reaction. F. Equilibrium can be prevented from occurring by constantly removing the product of either reaction. G. An equilibrium, once established, cannot be disturbed.

A. false. There may be more than one enzyme for the reactions listed, but a given enzyme is often capable of performing a reaction in both directions. B. false. The enzyme for both reactions could be the same, but often a particular enzyme is more likely to perform the forward reaction while a different enzyme is more likely to perform the reverse. C. false. If the reactions are at equilibrium, both are occurring in the same location. If they are not at equilibrium, it is possible that the reaction is occurring only in one direction. D. true. By definition, a reaction is at equilibrium when both directions are occurring such that there is no net change in amounts of reactants and products. E. false. Equilibrium is not necessarily established, especially in a cell where a product is immediately removed from the system for use elsewhere, such as the product ATP, or if a given enzyme does not perform the reverse reaction. F. true. Any change in amounts of enzyme, substrate, or reactant will disturb an equilibrium, and if these things constantly change, equilibrium will not be established. G. false. Equilibrium can be disturbed by changing the amount of enzyme, substrate, or product, or by altering the enzyme's efficacy by changing temperature or pH.

What are the advantages of using ATP as the energy-transferring molecule in a cell?

ATP easily acquires the energy stored in complex biomolecules such as carbohydrates; its bonds are readily broken and it releases just the right amount of energy for cell needs so that the cell is protected from excessive energy release.

The protein in the mitochondria that captures the kinetic energy of moving H+ ions and converts it to the stored energy of ATP is called

ATP synthase

Transcription of the DNA triplet sequence ATC summons a tRNA bearing

AUC

What is alternative splicing and why is it necessary?

Alternative splicing occurs when enzymes clip segments out of the middle or off the ends of an mRNA strand and then splice the remaining piece back together. It is necessary because mRNA contains segments with exons (encode proteins) and introns (noncoding region). The introns of the mRNA are removed before it leaves the nucleus.

Explain how these statements differ, and identify which one(s) is/are correct. Explain what is wrong with each incorrect statement. Explain when chemical reactions continue and when they stop. A. A chemical reaction proceeds until the enzyme molecules are all consumed. B. A chemical reaction proceeds until the substrate molecules are all consumed. C. A chemical reaction proceeds until equilibrium is established. D. A chemical reaction proceeds until all the product molecules are removed.

B and C are correct as written, but B requires some clarification. A is incorrect because enzyme molecules are not consumed in chemical reactions and will continue to perform until something external to the reaction causes it to stop. B is correct if the product is removed from the system, but if the product remains, some of it will break down into substrates; therefore they would not be consumed. In D, if product molecules are removed, the reaction would continue to proceed to form new product (assuming enzymes and substrates are still available). Chemical reactions continue if conditions are favorable, including presence of substrate and enzyme and fairly constant temperature and pH. In living systems, most chemical reactions do not have a steady supply of substrate; for example, the chemical reactions of digestion will stop when the small intestine is empty.

__________ is the process where fatty acids are slowly disassembled into two-carbon units.

Beta oxidation

Explain how it is possible for an enzyme to catalyze a chemical reaction in two different directions.

Both the substrates of a reaction and the products have a 3-D shape complementary to the active site of the enzyme. In a synthesis reaction between two organic monomers, the enzyme holds the substrates in a position that greatly increases the likelihood of bond formation between them, and as the bond forms to produce a dimer, the affinity of the enzyme for the substrates increases. The dimer is also complementary to the active site of the enzyme, and if a dimer molecule happens to bind to the enzyme, becoming the substrate, the bond between the monomers becomes strained as the intermediate is formed and can break. If this happens, the reaction is a degradation and the products are the monomers. The tightest binding is between the enzyme and the intermediate form, different in structure compared to either the substrates or the product. Thus it is equally likely that the reaction will be a synthesis or a degradation, if no other factors are considered.

Why might a cell that lacks the ability to regulate its internal environment be described as a "ghost town"?

Building, maintaining, and removing worn-out parts is not possible without energy.

CO2 can combine with water to form two different products, carbonic acid or glucose. Write the summary equation for each reaction; don't worry about balancing.

CO2 + H2O → C6H12O6 CO2 + H2O → H2CO3

Candy bars are well known to supply large amounts of energy for metabolism. With all this energy trapped inside, how can the candy bar sit still on the shelf in the grocery store?

Candy bars contain large amounts of energy, but it is trapped as potential energy in carbohydrates (both simple and complex). The carbohydrates must be broken down and enter the cell's metabolic pathways in order to convert the potential energy to another form.

What is chemiostatic theory? What is its role in metabolism?

Chemiostatic theory is a model, and its role is to explain the movement of electrons through the electron transport system, an important component of metabolism.

Vitamins are precursors for __________. Name two vitamins that are required for metabolic reactions.

Coenzymes. Vitamins required for metabolic reactions include the B vitamins such as folic acid, biotin, and pantothenic acid and vitamin C.

When energy is released during catabolism, it is temporarily trapped in high energy bonds or electrons of certain compounds. Which of the following is NOT associated with carrying energy?

DNA

Regulatory-protein transcription factors bind to __________ and activate __________, which tells the RNA polymerase __________.

DNA, promoter, where to bind to the DNA

Enzymes are often useful as diagnostic tools. How?

Damaged cells release enzymes into the blood so that plasma levels of the enzyme are noticeably elevated.

A certain reaction pathway consists of four steps. How would decreasing the amount of enzyme that catalyzes the second step affect the process?

Decreasing the amount of enzyme at the second step would slow down the whole series of reactions because less substrate would be available for the next two steps. The net result would be a decrease in the rate of production of the product and therefore, within a specified time, a decrease in the amount of the product.

Explain how the analogy of a ball and a hill is useful for describing the forms of energy to beginning physiology students. Use the synthesis of glucose by plants and the decomposition of glucose by humans as specific examples of the energy hill.

Every student can relate to the fact that it takes energy for a person to move a ball from a lower height to a higher one, and that the ball will automatically roll down the hill if allowed to, without further input of energy. The substrates CO2 and H2O require energy to be combined into C6H12O6; the energy of the sun provides this energy to "roll" the substrates up the energy hill as they combine. The glucose then contains the potential energy provided by the sun. If an appropriate enzyme is present, the molecule easily decomposes to its components and this energy is transferred into work.

Glucose-6-phosphate (G6P) binds to the enzyme glycogen synthase (GS), increasing the probability of enzyme-substrate binding. G6P is an example of __________. Based on its name, what do you think is the role of GS and where would you expect to find this enzyme?

G6P is an example of an allosteric modulator of GS. GS is the glycogen synthesis. Since glycogen concentrations are the highest in the liver and skeletal muscle, you would expect to find GS in both the liver and skeletal muscle.

You have spent the day on the beach, basking in the sun. Why were your cells unable to capture the energy of the sun to do work?

Human cells lack the appropriate enzymes for converting the light and heat energy of the sun into useful forms of energy.

Carbonic acid will form easily in a student physiology lab, simply by bubbling CO2 into a beaker of water. Suppose it took you and your lab partner 5 minutes to perform this reaction. How would your results differ if you added the enzyme carbonic anhydrase? Explain using the concept of the energy hill.

In the presence of the enzyme, the reaction will occur much more rapidly. This is because the enzyme lowers the activation energy for the reaction. This is analogous to the ball being rolled up a lower hill before it rolls down, when the enzyme is present.

Some diseases, such as phenylketonuria, classical hemophilia, cystic fibrosis, and muscular dystrophy are a result of enzyme malfunction. Each of these diseases is inherited. Explain how there might be a relationship among these observations.

Inheritance is determined by the message coded into DNA; a mutation relays a faulty message, which disrupts protein synthesis, resulting in a complete absence of a protein product or production of a faulty protein. Enzymes are proteins. When the instructions for the synthesis of their structure is changed, they may not be able to perform their function, producing a disease condition. If the disease is not fatal prior to puberty and does not render its victim unable to reproduce, the faulty DNA will be copied during gametogenesis and will appear in a predictable percentage of offspring.

What happens to the oxygen that we breathe?

It is exhaled and It is combined with hydrogen to form water

High protein (low carbohydrate) diets have become popular in recent years. Based on what you've learned about metabolism and the body's energy needs, explain what might be some of the disadvantages of this type of diet.

Low carbohydrate diets shift the body to a fasting mode because glucose is needed for the brain, central nervous systems, and red blood cells. After glycogen stores have been depleted, the body will convert protein and fats into glucose and ketone bodies to provide the energy needed. The disadvantages of this shift are excess ketone bodies can seriously disrupt the body's pH balance (lead to ketosis) and loss of protein from body tissue (this occurs even when abundant protein from food is provided).

Explain how enzymes can be useful in the diagnosis of disease, giving specific examples. Is the change in enzyme concentration a direct or indirect result of the disease?

Many enzymes are normally present in the blood in a known range of typical concentrations. Alterations in these concentrations can be associated with abnormal conditions. For example, elevation in the digestive enzyme amylase, produced by the pancreas, may indicate pancreatic disease. Elevation of enzymes that normally operate inside cells can indicate tissue damage, such as the elevation of creatine kinase following myocardial infarction. Low amounts of hexosamidase A can indicate Tay-Sachs disease. In the examples given, the amylase and hexosamidase enzyme changes are direct results of the disease, whereas enzymes elevated because of tissue damage may simply result from cell rupture.

McArdle disease is a genetic disorder caused by a deficiency of the enzyme in muscle cells to stimulate the breakdown of glycogen to glucose. Based on what you know about metabolism, what advice would you give a patient who has McArdle disease?

McArdle patients should ingest glucose prior to exercise and during exercise. Exercising at lower intensities will also use less glucose and more fat than exercising at higher intensities.

__________ and __________ transfer their high-energy electrons to the electron transport system.

NADH, NAD+ and FADH2, FAD+

The human brain uses the same amount of energy in 30 minutes to watch a cartoon on TV, attend a space shuttle launch at Cape Canaveral, or to study a physiology textbook. From a caloric standpoint, why doesn't studying consume more energy than passively observing images on TV?

Neurons use energy primarily to transport ions across membranes. This transport occurs constantly to maintain resting potential, regardless of what one's attention is focused on. Neural signals are transmitted from cell to cell in the brain in the same way, regardless of the quality of what you are watching or thinking about. An analogy is that one letter-rate postage stamp can be used to send you a check for $100.00, a credit card bill, or some junk mail.

Based on the facts about chemical equilibria in animal systems, indicate for each summary reaction below if it is reversible or irreversible (don't worry about balancing the reactions). Explain the lack of reversibility. In what kind of system would the reaction(s) you selected as irreversible be reversible? Explain. A. C6H12O6 → CO2 + H2O B. ADP + Pi → ATP C. H2O + CO2 → H2CO3

Only A is irreversible in animal systems. The products are rapidly removed from the system as soon as they are formed, so they are not recombined. This reaction is reversible in plants, which form and store glucose for food, but also need to use some of the glucose to make ATP.

Explain how these statements differ, and identify which one(s) is/are correct. Explain what is wrong with each incorrect statement. A. A chemical reaction is at equilibrium when there is no further change in substrates. B. A chemical reaction is at equilibrium when the amounts of substrate and product no longer change. C. A chemical reaction stops when it reaches equilibrium. D. A chemical reaction is at equilibrium when the amount of substrate equals the amount of product.

Only B is correct as written. A could be corrected by clarifying that it is concentration or amount of substrates that ceases to change; individual molecules can form or break at any given time, but the overall amount will not change because synthesis will be balanced by degradation. C is incorrect because the reactions continue as long as conditions such as presence of catalysts, favorable temperature, and presence of substrates are maintained. As a given enzyme can both synthesize and degrade, both processes will continue even at equilibrium. D is incorrect because at equilibrium there is no net change in amounts, but it is not necessary for concentrations of substrates and products to be the same as each other.

Briefly define oxidation-reduction reactions. What does it mean for a molecule to be reduced or oxidized? Identify and explain the mnemonic device provided in the text for oxidation and reduction reactions. See if you can make one up yourself.

Oxidation-reduction reactions occur when either electrons or protons are transferred from one molecule to another. These reactions are important in energy extraction and transfer. The molecule that loses electrons (or gains protons) is oxidized, whereas the molecule that gains electrons (or loses protons) is reduced. OIL RIG (oxidation is loss, reduction is gain) is the device provided in the textbook.

Explain the different types of enzymatic reactions.

Oxidation-reduction reactions transfer electrons or protons between substrates. Hydrolysis-dehydration reactions form or break a chemical bond between organic substrates by removing or adding a water molecule. Addition-subtraction-exchange reactions add, remove, or exchange a functional group among the reactants. Ligation reactions involve synthetases and ATP.

Compare and contrast potential energy with kinetic energy.

Potential energy is the energy an object has stored in its position while kinetic energy is energy associated with a moving object / movement.

The enzyme __________ and __________ ions are required for the synthesis of mRNA.

RNA polymerase, magnesium or manganese

__________ is the disappearance rate of reactants or the appearance rate of the products of a reaction.

Reaction rate

Explain these types of chemical reactions: combination, decomposition, single displacement, and double displacement.

See Table 4-2 in the chapter.

What are the four categories of reactions catalyzed by enzymes? Give the common enzyme names for each reaction.

See Table 4-4 in the chapter.

If the sense strand of DNA's triple is ATC, its complementary antisense strand is

TAG

Estimates of the maximum possible ATP yield for one molecule of glucose total either 30 or 32 ATP. Why are there two different results?

The NADH molecules produced during glycolysis are in the cytoplasm; occasionally, electrons are carried by the lower energy FADH2 instead of NADH.

What is the common ultimate source of energy for all life on earth? Which types of organisms capture this energy? How do humans acquire this energy?

The energy comes from the sun and is captured by plants. Humans eat plants and/or animals that have eaten plants; thus the energy is transferred to us.

How would the lack of a required cofactor for an enzyme affect that enzyme's function?

The enzyme would not be able to function

What is the benefit of having some of the cellular organelles enclosed by a membrane similar to the cell membrane?

The isolation of the internal contents of membrane-bound organelles allows them to manufacture or store secretions, enzymes, or toxins that could adversely affect the cytoplasm in general. Another benefit is the increased efficiency of having specialized enzyme systems concentrated in one place. One example is the concentration of enzymes necessary for energy production in the mitochondrion.

Your body contains enzymes that catalyze the synthesis of RNA and DNA as well as different enzymes that catalyze their destruction. How is it possible for both enzymes to function without interfering with each other?

These enzymes are present in different locations. For example, DNA and RNA are synthesized within the cell's nucleus, while the nucleic acids present in the plant and animal cells we consume are destroyed in our digestive tracts.

Transcription of the DNA triplet sequence ATC yields

UAG

Define the law of mass reaction.

When a reaction is at equilibrium, the ratio of the substrate to the products is always the same.

A codon is

a meaningful series of three nucleotides found in mRNA

An allosteric modulator binds to

a region of the enzyme other than the active site

An exon is

a segment of mRNA that remains after editing

Each of the following is an acceptable definition of a gene except one. Identify the exception.

a strand of DNA that contains all the information needed to produce all of the proteins necessary to exhibit a given trait

During feedback inhibition, in order to slow or stop a cell from using a particular biochemical pathway, the end product of that pathway

accumulates inside the cell

Phosphate groups may be transferred from one molecule to another during

addition reaction and dehydration reaction.

Metabolism is a term that describes

all chemical reactions that take place within an organism

Match each term to its definition. reactions that result in the synthesis of large molecules

anabolism

Questions 179-185 look at picture in test bank

answer those questions

During the synthesis of proteins, amino acids are assembled in the proper sequence because the tRNA molecules that bring them to the ribosome have a(n) __________ that is complementary to a specific codon in the mRNA.

anticodon

Isozymes

are enzymes that catalyze the same reaction, play an important role in diagnosis of certain medical conditions and have complex structures with multiple protein chains.

In completing the phases of glucose catabolism leading to ATP, the carbons that start the reaction as glucose actually end up

as CO2

The process of disassembling fatty acids into two-carbon units inside mitochondria is called

beta-oxidation

Match each term to its definition. a series of interconnected chemical reactions

biochemical pathway

Match each term to its definition. reactions that result in the breakdown of large biomolecules

catabolism

Metabolism is often divided into __________, energy-producing reactions, and __________, energy-utilizing reactions.

catabolism; anabolism

As the environmental pH or temperature of a particular enzymatic reaction is changed, the activity of the enzyme may decrease due to

change of the three-dimensional structure of the enzyme

Classify each scenario below as to primarily which type of work is being done. Carrying a pregnancy to term

chemical work

Classify each scenario below as to primarily which type of work is being done. Enlarging one's muscles through body-building exercises

chemical work

Classify each scenario below as to primarily which type of work is being done. wound healing, recovering from surgery

chemical work

In the metabolic reactions of cells, molecules such as vitamin C and biotin act as

cofactors and coenzymes

an exergonic chemical reaction

converts molecules into molecules that have less free energy, and releases energy as the reaction progresses

Gluconeogenesis refers to

creating glucose from glycerol, amino acids, or lactate

The reactions of glycolysis occur in the cell's __________; the reactions of the citric acid cycle occur in the __________.

cytoplasm; mitochondria

Before converting amino acids into intermediates for energy metabolism, they must first undergo

deamination

When an enzyme's activity is destroyed by heat or a change in pH, the enzyme is said to be

denatured

Coenzymes are

derived from vitamins, organic molecules and organic cofactors

Chemical reactions that require an input of energy are said to be __________.

endergonic

Protein sorting ensures that newly synthesized proteins arrive at the organelles where they are needed. To help this process, proteins are often assembled directly into the

endoplasmic reticulum.

In the reaction shown, identify the role of each of the participants. CO2 + H2O --(carbonic anhydrase)--> H2CO3 carbonic anhydrase

enzyme

The rates of chemical reactions that occur in the human body are controlled by special molecules called __________.

enzymes

Chemical reactions that release energy are said to be __________.

exergonic

If a cell lacked the enzyme RNA polymerase, it could not

form protein

All of the triplet codes needed to produce exactly one specific polypeptide chain are found in one

gene

The brain relies solely on __________ as its energy source. If it is deprived of this substrate, the cells soon die.

glucose

Which can serve as substrates for ATP production?

glucose, amino acids, fatty acids, glycogen

Glucose is phosphorylated to __________ with the aid of __________.

glucose-6-phosphate, ATP

Lipids are broken down into __________, which feeds into glycolysis, and __________, which are metabolized to acetyl CoA.

glycerol, fatty acids

The liver and skeletal muscles store glucose as __________ for a ready energy source.

glycogen

Questions 186 - 194

graphing and quantitative

Compartmentation refers to

grouping related enzymes into specific organelles

Which of these is an inherited disease related to altered protein functions?

hemophilia, sickle cell anemia, cystic fibrosis, phenylketonuria

A(n) __________ is a covalent bond that stores an unusually large amount of energy.

high-energy bond

An enzyme that adds or subtracts water molecules is

hydrolase

Match the specific enzyme to its class. Lipase

hydrolase

Match the specific enzyme to its class. dehydratase

hydrolase

Cells need energy to

import raw materials, make new molecules, and repair or recycle aging parts.

NADH is produced from each reaction described except one. Identify the exception.

in the electron transport system

Oxidative phosphorylation occurs __________; the beneficial end product is __________.

in the mitochondria due to the electron transport system, ATP

During starvation, steroid hormones trigger the transcription of genes for lipid metabolism in their target cells. This would be an example of control by

inducers

The electron transport system is located in the __________ and includes enzymes and iron-containing proteins known as __________.

inner mitochondrial membrane, cytochromes

Match each term to its definition. an end product that immediately become a substrate

intermediate

Inside the matrix of the mitochondria, pyruvate

is converted to acetyl coenzyme A, loses a CO2 to become a two-carbon molecule, and interacts with a derivative of the vitamin pantothenic acid.

A harmful substance that the liver produces when metabolizing fatty acids is

ketone bodies

A certain molecule that participates in more than one biochemical pathway and acts as a branch point for channeling substrate in one direction or another is called __________.

key intermediate

Match each term to its definition. a molecule that participates at a branch point

key intermediate

When amino acids are metabolized for energy, the nitrogen is converted to urea and then is excreted from the body by the

kidneys

An enzyme that transfers phosphates is

kinase

ATP synthase tranfers the __________ energy of the H+ ions to the high-energy phosphate bond of __________.

kinetic, ATP

One way a cell can safely control physiological processes is by

letting an enzyme accumulate in order to increase its cellular concentration and breaking an enzyme down faster in order to decrease its cellular concentration.

An enzyme that joins monomers together is

ligase

Match the specific enzyme to its class. Synthetase

ligase

An enzyme that digests fats is

lipase

The reactions where fats are broken down into glycerol and fatty acids are called

lipolysis

One kilocalorie (kcal) is the amount of energy needed to raise one __________ of water by 1 degree Celsius.

liter

Which of these results in a REDUCED molecule?

loss of H+ and gain of electrons

Enzymes act by

lowering the activation energy of a reaction, increasing the likelihood that a reaction will start and binding to the reactants and putting them in favorable positions to react.

An enzyme that transfers chemical groups among substrates is

lyase

Match the specific enzyme to its class. aminase

lyase

Match the specific enzyme to its class. deaminase

lyase

A molecule of __________ consists of all the codons needed to produce a specific polypeptide chain at the ribosome.

mRNA

Enzymes

may be synthesized as inactive molecules and may require the binding of cofactors such as calcium.

Classify each scenario below as to primarily which type of work is being done. A thoroughbred horse, or greyhound dog, running around the track

mechanical work

Classify each scenario below as to primarily which type of work is being done. Working on a dock, loading and unloading boxes into trucks all day

mechanical work

The name for the process by which cells obtain and store energy in the chemical bonds of biomolecules is

metabolism

The activity of an enzyme is changed by environmental factors such as temperature or pH; these factors are referred to as

modulators.

An example of transamination is

moving amino acids from an amino acid to another molecule to manufacture a different amino acid.

The induced-fit model of enzyme activity states that

neither the substrate nor the products can bend to bind with the enzyme; the enzyme must bend to allow interaction.

To change the ability of some proteins to function, it is necessary to alter the amino acid content by a minimum __________ amino acid(s).

one

Match the specific enzyme to its class. Dehydrogenase

oxidoreductase

In the aerobic metabolism of glucose, __________ acts as the final electron acceptor.

oxygen

The availability of __________ determines if pyruvate continues into the citric acid cycle.

oxygen

The enzymatic reactions of metabolism form a network of interconnected biochemical __________ or reactions.

pathways

In the process of __________ a phosphate group is attached to a molecule.

phosphorylation

The addition of a phosphate group to a substrate is called __________. The enzyme that catalyzes this reaction is referred to as a __________.

phosphorylation; kinase

A molecule positioned on the high-concentration side of a concentration gradient stores __________ energy.

potential

Energy released by electrons moving through the electron transport system is stored as __________ by H+ ions concentrated in the __________.

potential energy; intermembrane space

In the reaction shown, identify the role of each of the participants. CO2 + H2O --(carbonic anhydrase)--> H2CO3 H2CO3

product

What is the result of alternative splicing?

production of similar yet distinct proteins from a single gene

Information stored in the nucleus is translated into

proteins

Which of the following is a key intermediate of glucose catabolism?

pyruvate

Anabolism is a term that describes

reactions that require a net input of energy and reactions that result in the synthesis of large biomolecules

The active sites of enzymes are

regions of an enzyme that are involved in bringing reactants together

Aerobic metabolism of glucose

requires oxygen and produces more ATP per glucose than anaerobic pathways

Animals extract energy from biomolecules through the process of __________, which consumes oxygen and produces __________ and __________.

respiration; carbon dioxide, water

A chemical reaction that can proceed in both directions is called a __________.

reversible reaction

Over time, mRNA is eventually broken down as its usefulness ends. Which enzymes destroy it?

ribonucleases

Translation occurs in/on the __________ of the cell.

ribosome

When an enzyme is working as fast as it can because its active site is continually refilled with substrate, the condition is referred to as

saturation.

What terms are used to distinguish the two strands of the DNA molecule?

sense strand and nonsense strand

The sense strand of DNA

serves as a guide for mRNA synthesis

RNA is usually __________ -stranded.

single

Two types of RNA block translation of mRNA. They are __________ RNA and __________ RNA.

small interfering, micro

Most lipids are synthesized in the

smooth endoplasmic reticulum and cytosol

An enzyme reacts with only limited, selected substrates; this characteristic is referred to as the enzyme's

specificity.

In the reaction shown, identify the role of each of the participants. CO2 + H2O --(carbonic anhydrase)--> H2CO3 CO2 + H2O

substrates

The __________ of glycogen from many glucose molecules is an __________ reaction.

synthesis, endergonic

After interacting with the ribosome, each codon of mRNA interacts with a third molecule. This molecule is called

tRNA

Amino acids are carried to the ribosomes to be incorporated into polypeptide chains by __________.

tRNA

Ribosomes are composed of protein and __________.

tRNA

A competitive inhibitor binds to

the active site

According to the second law of thermodynamics

the amount of entropy increases during natural processes.

Energy is defined as

the capacity to do work

The explanation for how ATP bonds are actually formed during oxidative phosphorylation is called

the chemiosmotic theory

The first law of thermodynamics states that

the total amount of energy in the universe is constant. and energy can be neither created nor destroyed

When a chemical reaction is in equilibrium

there is no net change in the amount of reactants or products.

The process of forming mRNA is called

trancription

Match the specific enzyme to its class. kinase

tranferase

mRNA is created in a process called __________. It then leaves the __________ and enters the cytosol to direct __________, the assembly of amino acids into protein.

transcription; nucleus; translation

Classify each scenario below as to primarily which type of work is being done. Bringing glucose molecules inside brain cells so one can think

transport work

Classify each scenario below as to primarily which type of work is being done. Maintaining a concentration gradient across a membrane

transport work

The net energy yield for the anaerobic metabolism of one glucose molecule is

two molecules of ATP and 0 NADH.