Flashcards in Chapter 3: Energy, Chemical Reactions, and Cellular Respiration Deck (237):
Defined as the capacity to do work.
Energy differs from matter in that it has no mass and ________.
does not take up space.
What are the two classes of energy?
potential energy and kinetic energy
The energy of position or stored energy
The energy of motion
Potential energy can be _______ or changed to kinetic energy and vice versa.
Water at the top of dam has _____ energy because of its position; when the water falls over the dam it now has _____ energy.
Potential energy is exhibited in cells of living organisms when a _______ exists across the plasma membrane, which is the boundary between the inside and outside of a cell.
The movement of NA+ from a high concentration outside the cell to a low concentration inside the cell is an example of ______ energy.
Movements of electrons from high-energy shells have ____ energy.
Energy that is stored in a molecule's chemical bonds, and is the most important form of energy in the human body.
The chemical bonds of all molecules have ____.
Three important molecules in the human body function primarily in chemical energy storage: ____, _____, and _____.
triglycerides, glucose, and adenosine triphosphate (ATP)
Triglycerides are involved in the ________ in adipose connective tissue.
long term energy storage
ATP is stored in _____ in limited amounts and is produced continuously and used immediately for cells' energy required process.
Chemical energy is used for the energy-requiring process of movement, _____ and ________.
synthesis of molecules, establishment of concentration gradients
Forms of kinetic energy.
electric, mechanical, sound, radiant
This energy is the movement of charged particles.
This energy is exhibited by an object in motion due to an applied force.
This energy occurs when the compression of molecules that move in a solid, liquid, or gas is caused by a vibrating object.
The energy of electromagnetic waves traveling in the universe.
The kinetic energy associated with random motion of atoms, ions, or molecules.
Gamma rays have the ____ amount of radiant energy, and radio waves have the ____.
Muscle contraction is an example of what type of energy?
The study of energy transformations.
States that energy can neither be created nor destroyed, it can only be transformed or converted from one form to another
First law of thermodynamics
One of the functions of muscle tissue is to produce ___ that keeps the body warm
States that every time energy is transformed from one form to another, some of that energy is converted to heat.
Second law of thermodynamics
The collective term for all biochemical reactions in living organisms.
When chemical bonds in an existing molecular structure are broken and new ones formed to produce a different structure.
When chemical structures are changed , summary of their changes is written as a __________.
The substrates, or substances, that are present prior to the start of the chemical reaction. Generally on the left side of the equation.
Substances that are formed by the subsequent chemical reaction and they are generally written on the right side of the equation.
A + B -----> C
What are A + B
What are C
In a __________ the number of elements on one side of the reaction is equal to the number on the other side.
balanced chemical equation
The three different criteria that chemical reactions are classified into.
changes in chemical structure
changes in chemical energy
whether the reaction is irreversible or reversible
The general categories of chemical reactions based on changes in chemical structure include ______, ______, and ______.
The initial large molecule is digested or broken down into smaller structures.
All the decomposition reactions in the body are collectively referred to as either _________ or _______.
catabolism or catabolic reactions
Occurs when two or more atoms, ion, or molecules are combined to form a larger chemical structure as existing bonds are broken and new bonds are formed.
The collective term for all synthesis reactions in the body.
anabolism or anabolic reactions
AB ------> A + B
is an example of what type of chemical reaction
When atoms, molecules, ions, or electrons are exchanged between two chemical structures.
A + B ------> AB is an example of what type of chemical reaction?
AB + C ------> is an example of what type of chemical reaction?
The most prevalent type of chemical reaction in the human body.
The production of ATP in the muscle tissue is an example of what type of reaction?
A specific type of exchange reaction that involves the movement of electrons from one chemical structure to another.
Occurs as a molecule, atoms, or ion loses an electron(s) and thus becomes oxidized.
LEO = chemical structure loses electrons is oxidized
Occurs as a molecule, atom, or ion gains an electron(s) and thus becomes reduced
GER= chemical structure gains electrons is reduced
The term "reduced" is used because the chemical structure gains an electron, ________, so it can be thought of as "reduced" in charge.
a negatively charged particle
_________ and _________ always occur together because one chemical structure loses the electron(s) and another gains the electrons.
Oxidation and Reduction
An electron transferred from one chemical structure may move alone or with _____.
Electron transfer occurs when NAD+ becomes NADH. is this oxidized or reduced?
The movement of electrons can be harnessed to ______.
The electrons in oxidation-reduction reactions represent _____________.
When glucose oxidized is losing its electrons it is also releasing its _______, when other molecules are reduced and gain both electrons and energy.
Chemical reaction are classified by the relative amounts of chemical energy associated with the ______ and ______.
reactants and products
Are reactions that involve reactants at the start of a reaction that have more potential energy within their chemical bonds than do the products that are formed.
i.e. the decomposition of glucose to carbon dioxide and water
Means that energy "goes out".
Are reactions that involve reactants that have less energy within their chemical bonds than do the products.
Means that energy must be "put in"
Reactions that yield products that have a net increase in potential energy as compared to what was present in the substrates.
i.e. synthesis reactions
The continuous formation and breakdown of ATP.
ATP is formed when energy is released in _________ using glucose or other fuel molecules from the foods we eat. These molecules undergo ______, and energy stored within their chemical bonds is transferred to ADP and P1 (free phosphate) to form ATP. ATP is then split into ADP and P1, and the energy released is used for endergonic reactions, as well as other energy-requiring cellular processes.
A cell cannot stockpile ATP, so only a _______ worth of ATP is present.
The formation of ATP must occur _______ through the processes of breakdown of glucose.
Another way of classifying chemical reactions is based upon whether they are _____ or ______.
irreversible or reversible
A reaction that involves reactants converted to product at a rate that yields a net loss of reactants and a net gain in product.
An irreversible reaction is written with the arrow to the _____.
A + B -----> AB
A reaction in which reactants become products at a rate equal to products becoming reactants (once equilibrium is reached).
The relationship of the reactants and products in a reversible reaction is shown with arrows in _______.
A + B
If left undisturbed a reversible reaction remains in ______, however a change in either the amount of reactant or the amount of product occurs.
The measure of how quickly a chemical reaction takes place; this rate determines the amount of product formed per time
A primary factor that influences the reaction rate is the energy required to break the __________ in a molecule so that new bonds can form the product.
The energy required to break existing chemical bonds for the chemical reaction to proceed is called ________.
the activation energy or Ea
When sufficient energy is supplied to overcome the Ea a ______ occurs.
An elevation in _______ increases the kinetic energy of the molecules, providing enough energy to break chemical bonds, but this is not feasible in a living cell.
In a cell an increase in temperature would denature all of its __________ and cause its death.
________ are the chemical structures that facilitate the millions of chemical changes that occur within the human body every second, and their importance cannot be overstated.
Biologically active catalysts that function to accelerate normal physiologic activities by decreasing the activation energy (Ea) of chemical reactions.
A chemical reaction without an enzyme.
A chemical reaction with an enzyme.
_______ is required to initiate the reaction to occur even though it is exergonic.
Most ______ are globular proteins that rand in size from relatively small proteins composed of about 60 amino acids to very large proteins of more than 2500 amino acids.
The amino acids in the protein chain form a unique three-dimensional molecular structure with a region called the _______.
The _______ in the shape of the active site permits only a single substrate, or type of substrate, to bind to the active site, and thus the enzyme is capable of catalyzing only one specific reaction.
The active site accommodates the substrate(s) of a reaction to temporarily form an _____________.
Enzymes are produced by normal protein synthesis processes with _____, but once formed, the location of the enzyme varies.
Enzymes may remain within ______.
i.e. DNA polymerase
Enzymes may become embedded within the ______.
i.e. lactase, which digests the milk sugar lactose and is found in plasma membranes of cells
Enzymes may be secreted from the ___.
i.e. pancreatic amylase released from the pancreas into the small intestine to participate in the digestion of starch
Step 1 of enzyme catalyzes a reaction
The substrate enters the _____ of the enzyme, and the enzyme temporarily binds with the substrate to form an enzyme-substrate complex.
Step 2 of enzyme catalyzes a reaction
Entry of the substrate into the active site induces the _________ of the enzyme to change slightly, resulting in an even closer fit between substrate and enzyme. This response is referred to as the induced-fit model of enzyme function.
Step 3 of enzyme catalyzes a reaction
Stress on ______ in the substrate molecule is caused by the change in enzyme shape. This stress lowers Ea, and the bonds in the substrates are more easily broken permitting new chemical bonds to be formed.
Step 4 of enzyme catalyzes a reaction
The newly formed molecule, now called the ______, is released from the enzyme. The enzyme is then free to repeat that process again and again with other substrates.
Enzymes often require _______ that are "helper ion or molecules to ensure that a reaction occurs.
A cofactor is a nonprotein structure that may be either and _______ or ______ substance.
inorganic or organic
A _______ is associated with a particular enzyme or enzymatic reaction.
Inorganic cofactors are attached to the enzyme and are required for their ________.
___________ are not attached to enzymes and have specific functions in assisting enzymes.
Organic cofactors are more specifically referred to as _________.
The six major classes of enzymes
Transfers a functional group.
Splits a chemical bond using water.
Transfers electrons from one substance to another.
Converts one isomer to another.
Bonds two molecules together.
Splits a chemical bond in the absence of water.
Enzymes in the oxidoreductase class participate in _____ reactions.
A subcatagory of enzymes within the oxidoreductase class.
Dehydrogenase participate in oxidation-reduction reactions by moving __________ between molecules.
These enzymes transfer atoms or molecules between chemical structures.
______ enzymes belong to this class because they specifically transfer a phosphate functional group, usually from ATP to another molecule.
An enzyme that transfers a hydrogen, specifically from a pyruvate molecule
*the name of a given enzyme is generally based upon the name of the substrate or product involved in the chemical reaction, and the suffix -ase added
Is central to the formation of the polymer DNA from deoxyribonucleotides.
Digests the disaccharide lactose "lactose intolerance"
The name of an enzyme generally contains an -ase suffix and the rest of the name reflects its ______, but there are exceptions.
Several conditions influence the reaction rates catalyzed by enzymes. The most significant factors are ________, ________, and _____.
enzyme and substrate concentration
An increase in _______, however, increases the rate of reaction only to the point of ________ of the enzyme.
This occurs when so much substrate is present that all enzyme molecules are actively engaged in the chemical reaction, resulting in no further (notable) increase in rate reaction.
Human enzymes function efficiently at their ___________, usually 98.6F or 37C, which is the normal body temperature.
Temperature increases in the body increases enzymatic activity; one advantage is that this enhance __________.
the body's ability to fight infectious agents
Severe increases in temperature, 104F or 40C, weaken the intramolecular bonds that hold an enzyme's protein structure in its three-dimensional shape. Permanently _______.
Enzymes function most efficiently at their ______.
For most human enzymes the optimal pH is between pH _____
6 and 8
An increase in H+ causes a _______ in pH and results in additional H+ binding to the enzyme.
A decrease in H+ causes an ______ in pH, which results in the release of H+ from an enzyme.
A change in the amount of H+ attached to the enzyme disrupts the _________ that hold the enzyme protein in its shape. A significant disruptions results in ______ of the enzyme.
Not all enzymes have an optimal pH between 6 and 8. Name an example.
the pH of the stomach is between 2 and 4; the stomach enzyme pepsin corresponds to this pH range.
the pH of the small intestine is between 6 and 9; thus when stomach contents move into the small intestine, pepsin is inactivated.
An enzyme continues to facilitate the conversion to facilitate the conversion of its substrate(s) to product as long as ______ substrate is present and environmental conditions are close to normal.
Uncontrolled enzymes would result in substrate levels and conenctration of products that _______ what is needed.
Enzymes must be ______ turned off to prevent overproduction.
Substances that bind to an enzyme and turn it off, thus preventing from catalyzing the reaction.
A ________ resembles the substrate and binds to the active site of the enzyme.
The substrate and the regulatory compound compete with each other for occupation of the enzyme's _____ in competitive inhibitors.
The determines of substrate relative to the amount of competitive inhibitor determines the _______.
degree of inhibition
If greater the concentration of the substrate, the ____ the competitive inhibitor will occupy the enzyme's active site and vice versa.
The type of inhibitor that resembles the substrate.
They inhibit an enzyme by binding to a site in the enzyme other than the active site, a site termed the _________.
Noncompetitive inhibitors bind to the ______.
Usually multiple enzymes are required to convert an initial substrate to a _____.
Depending on both the substrate and sequence of conversion, these multiple enzymes are arranged either in a ______ or as a _______.
This pathway is formed by numerous enzymes.
A drug that inhibits enzymes include ______.
When each enzyme catalyzes one progressive change to its specific substrate molecule and then release the product. Then the product of one enzyme becomes the substrate of the next enzyme.
A group of enzymes that are physically attached to each other through noncovalent bonds to form the complex. These enzymes work in a sequence of reactions.
A multienzyme complexes has two major advantages. The product from one chemical reaction is immediately bound to the next enzyme in the _________. This makes it more likely that the needed product is formed and less likely that the substance will _____ away and come into contact with an enzyme.
The second major advantage of a Multienzyme complex is the ________ can be regulated by controlling the single complex rather than multiple individual enzymes.
Metabolic pathways and multienzyme complexes must be regulated to prevent _________of an unneeded product and exhaustion of substrates that could be used elsewhere. The regulation occurs through the process of ________.
One specific mechanism for regulating enzymes is by either ________ or ______ of the enzyme.
phosphorylation or dephosphorylation
The addition of a phosphate group.
The removal of a phosphate group.
__________ may turn on some enzymes but turn off other enzymes.
_________ may cause opposite effects in activity by different types of enzymes.
Enzymes that add phosphate are generally called _______.
Enzymes that remove the phosphates are called ________.
A multistep metabolic pathway whereby organic molecules are disassembled (broken down) in a controlled manner by a series of enzymes.
Potential energy stored in the molecule's chemical bonds is released, during ________.
The energy released during disassembly makes new bonds between ____ and ____ to form ATP.
ADP and Pi
Cellular respiration is _________ or energy releasing.
The organic molecules that have given up their energy during cellular respiration by releasing _________, thus the molecule said to be __________.
The energy used to synthesize ATP comes from __________, and is an endergoic process.
_______ is required for maximum ATP production.
Occurs within cells and is a step-by-step enzymatic breakdown of glucose with the accompanying release of energy to synthesize ATP. If _____ is available, glucose is completely broken down and carbon dioxide and water are formed.
Chemical formula for glucose.
C6H12O6 + 6 O2 -------> 6 CO2 + 6 H2O
Glucose is an energy rich molecule because of its many _____, _____, and ______ chemical bonds.
Carbon - Carbon
Carbon - Hydrogen
Carbon - Oxygen
Glucose oxidation is an _____ reaction.
The energy transfer from bonds in the glucose molecule can be used either directly, _____, or indirectly, _______ to form ATP.
least common way
most common way
the direct method of synthesizing ATP
the indirect method in which the energy is first released to coenzymes that ten transfer the energy to form ATP
The complete oxidation of glucose requires at least ____ different enzymes that are located in both the cell's cytosol and its mitochondria.
The semifluid contents of the cell.
Small organelles within the cell.
Glucose oxidation (cellular respiration) is separated into four stages
citric acid cycle
electron transport system
Glycolysis occurs in the ______ and does not require oxygen.
Glycolysis can occur either in the presence of oxygen or ________.
the absence of oxygen
The other three stages of glucose oxidation occur in the _______.
__________ does not require oxygen.
Glucose is broken down in the metabolic pathway into _____ pyruvate molecules with an accompanying energy transfer to form a net production of ______ and ____.
Steps of Glycolysis 1 - 5
Steps 1 through 5 of glycolysis involve splitting glucose into two molecules of glyceraldehyde 3-phosphate (G3P) through the action of the first five enzymes. ATP is "invested" with kinase enzymes transfer Pi from ATP to glucose and the breakdown products of glucose (steps 1 and 3). Thus, and investment of 2 ATP molecules occurs at these two steps..
Steps of Glycolysis 6-7
Glycolysis occurs twice in oxidation of a glucose molecule. Step 6 involves transferring an unattached Pi to the substrate (so this molecule now has two phosphates), and two hydrogen atoms are released to NAD+ to form an NADH (add H+). This transfer of hydrogen is catalyzed by a hydrogenase enzyme. In step 7, the original Pi is transferred to ADP to form ATP through substrate-level phosphorylation by a kinase enzyme.
Steps of Glycolysis 8-10
Steps 8 through 10 of glycolysis also occur twice in oxidation of a glucose molecule. These steps involve converting the molecule produced in step 7 to an isomer (step 8) and then the loss of water molecule (step 9). The remaining Pi is transferred to ADP to form ATP through substrate-level phosphorylation by a kinase enzyme (step 10), forming the final product of pyruvate.
Gylcolysis is a metabolic process that occurs in the ________ without the requirement of oxygen.
Glucose is the _____ substrate and _______ is the final product.
The net transfer of energy is used in the formation of _______ and _____ molecules.
Two ______ molecules are invested early in the glycolysis (steps 1 -3).
______ molecules are formed during glycolysis (steps 7 - 10, which occur twice per the original glucose molecule).
There is a net ____ molecules formed during glycolysis.
of 2 ATP
Two ____ molecules are formed form glucose breakdown during glycolysis (step 6, which occurs twice per the original glucose molecule)
Glycolysis is regulated through ________ like many metabolic pathways.
ATP acts as an _______ inhibitor to "turn off" phosphofructokinase (PFK).
As ATP levels increase in the cell cytosol, ATP binding inhibits ______, and the glycolytic pathway is progressively shut down.
As ATP levels decreases, _______ increases.
Phosphofructokinase is also regulated in a similar way by other substances that indicate the _______ of the cell, including NADH, citrate, fatty acids, and other fuel molecules.
Increased levels in substances that indicate the energy status of the cell results in a decrease in _________.
the process of glycolysis
The final product of glycolysis.
What chemical changes are then made to pyruvate depend upon the ________.
availability of oxygen
If sufficient O2 is available, pyruvate enters a _______ to complete its aerobic breakdown yielding carbon dioxide and water.
In contrast, if sufficient oxygen is not available, pyruvate is converted to _______.
The remaining stages of cellular respiration, including the intermediate stage, citric acid cycle, and the electron transport system are aerobic processes that occur within _____.
A double-membrane organelle, composed of an outer membrane and an inner membrane that has inward folds.
The inner membrane of mitochondrion is made up of inward folds called _____.
The fluid filled space between the two membranes of the mitochnodrion is the _______.
The innermost space in a mitochndrion is called the _____matrix.
Both the multienzyme complex of the intermediate stage and the enzymes of the _______ cycle metabolic pathway reside in the matrix.
citric acid cycle
The "link" between the multi-step metabolic processes of glycolysis (first stage) with the multistep metabolic processes that occur in the citric acid cycle (3rd stage).
The intermediate stage is catalyzed by a multienzyme complex called ______.
During the ____ stage, pyruvate dehydrogenase brings together pyruvate and a molecule of ______ that is already present within the matrix to form acetyl CoA.
coenzyme A (CoA)
At the same time the pyruvate dehydrogenase is bringing together pyruvate and a molecule of Co, a carboxyl group, consisting of one carbon atom and two oxygen atoms is released from the _______ as _____, called ______.
pyruvate as CO2 called decarboxylation
______ is released during decarboxylation as two hydrogen atoms are transferred to the coenzyme NAD+ to form _____. during this process.
After decarboxylation, the acetyl CoA then enters the third stage of _______, termed the _________.
citric acid cycle
The citric acid cycle is also known as the _____ cycle.
A cyclic metabolic pathway that occurs through the activity of nine enzymes located within the matrix of mitochondria.
Citric Acid Cycle
During the citric acid cycle, the acetyl CoA produced in the intermediate stage is converted to two _____ molecules and a CoA molecule is _______.
Energy is transferred to form one ATP molecule, three _____ molecules, and ______ molecule during one turn of the citric acid cycle.
3 NADH molecules
1 FADH2 molecule
Glycolysis occurs in _______.
The Intermediate Stage take place in the ________.
The Citric Acid Cycle takes place in the _____.
Glycolysis requires oxygen. T or F
The Intermediate Stage requires oxygen. T or F
The Citric Acid Cycle requires oxygen.
T or F
The substrate of glycolysis is _____.
The substrate of the intermediate stage is ________.
Pyruvate (2 pyruvates from each glucose)
The substrate of the Citric Acid Cycle is ______.
Acetyl CoA (2 Acetyl CoA from each glucose)
The product of glycolysis _______.
2 pyruvate molecules
The product of the Intermediate stage is _________.
Acetyl CoA and 1 CO2 per pyruvate
The product of the citric acid cycle _______.
2 CO2 per acetyl CoA
pathway or complex
pathway or complex
Citric Acid Cycle
pathway or complex
net energy molecules produced
2 ATP (net) and 2 NADH
net energy molecules produced
1 NADH per pyruvate
Citric Acid Cycle
net energy molecules produced
1 ATP per acetyl CoA
3 NADH per acetyl CoA
1 FADH2 per acetyl CoA
Lack of O2 affects the stage
Lactate produced (to regenerate NAD+ so glycolysis can continue)
Lack of O2 affects the stage
Pathway inhibited by lack of oxygen