Living Systems Require a Flow of Energy
In a phrase, how do physicists define “energy”?
How would a cell biologist define “energy”?
The physicist’s definition of energy is not _______________ for use in defining energy changes within a living cell.
List five major sorts or categories of energy change within the cell.
On a cold day, which of the following processes do your cells depend on to maintain an operating temperature of 37 degrees Celsius?
b. muscle contraction
c. respiration energy production
d. metabolic heat generation
e. all of the above
Sometimes the cell pumps substances against diffusion forces that would carry those substances the other way. What term would we give to this process?
Laws of Energy Flow in the Living World
______ is freely convertible from one form to another but _______ can never be created or destroyed.
Systems that convert energy from one form to another are not 100% efficient, thus the amount of useful energy ___________.
In nature, as energy freely changes from one form to another, the total amount of energy _________ _________.
In living things, energy conversion is inefficient, with much energy being lost in the form of _______.
What form of energy do producers use when they set about to generate chemical energy—the energy of C―H and C―O―H bonds.
Thus, a producer organism is called a “producer” because it produces usable ______ _______.
When your car engine burns the octane in gasoline, in what form does at least 50% of the energy of the octane end up?
A lit match cannot continue to burn when the wood of the match stick is consumed. This statement illustrates what general law of energy flow?
In a crowded, unventilated room, what causes the temperature to rise?
Energy Flows in Chemical Reactions
Existing chemical bonds between atoms are broken and new ones are formed between different atoms. In the broadest sense, this is the definition for a _______ _________.
Give an example of a chemical reaction.
Whenever chemical bonds are broken, energy is __________. Whenever chemical bonds form, energy is __________.
Does an endergonic reaction require the input of energy, or does it give off energy?
What term is given to the amount of energy required to break the bonds in reactant molecules?
What is true of the bonds in reactant molecules that keeps most chemical reactions in nature from occurring?
When ________ energy is not available for a given chemical reaction, the reaction will not go.
Enzymes Direct Energy Flow
How is the activation energy of desired reactions lowered in living things, so that the desired reactions are able to go forward?
What words best describe the way in which enzymes bind to reactant molecules?
What exactly does an enzyme do the chemical bonds within the reactant molecule?
By binding to reactant molecules, what effect does an enzyme have on the activation energy for a given reaction?
Energy Flow in Reaction Pathways: Metabolism
What name do we give to sequences of chemical reactions within cells?
In a (n) ________ the product of one reaction becomes the reactant of the next reaction and so on.
If the final end product of a metabolic pathway is continually removed and used elsewhere, then the reactions of the entire pathway will be pulled in the direction of making more _____ ____________.
Suppose an excess amount of product accumulates at the end of a metabolic pathway. The product then binds to the allosteric site of the first enzyme along the pathway, shutting down the pathway. What do we call this regulatory process?
An allosteric enzyme has a second binding site other than its own active site for converting substrate to product. What does this second site bind to?
If the final product of a metabolic pathway begins to build up in excess, the pathway can often be slowed down by a process called ______________ ____________.
A single regulatory molecule can shut down multiple metabolic pathways if it is able to add _________ groups that alter the active site of the first enzyme in each pathway.
Energy Pools in the Cell: ATP
Three phosphate groups linked to a ribose sugar which, in turn, is linked to a pyrimidine base known as adenine: this phrase describes the structure of _______.
Where in the ATP molecule is the “high energy” bond that carries potential energy and is easily broken?
To derive energy from an ATP molecule, what bond must be broken?
Energy-releasing reactions drive biosynthetic ones forward by contributing to a pool of _____ molecules.
The substance _______ would most likely enable a flagellum to drive a bacterium forward through the medium in which it is swimming.
Energy Flow from Carbohydrates to ATP: Respiration
In respiration, chemical energy is transferred from glucose to ATP. The energy transfer, however, is not 100% efficient. In the transfer, some of the energy is lost as _______. (Review Section 6.2 above)
In what major cellular process are three interrelated, exergonic pathways and oxygen used to generate large amounts of ATP from glucose molecules?
The term ___________________ could be defined as about 30 individual, sequential chemical reactions that form three metabolic pathways: one in the cytoplasm and two within the mitochondrion.
List the reactants and products of the summary reaction for aerobic respiration.
Write out the summary reaction for aerobic respiration.
Name the three stages of aerobic respiration.
The three metabolic pathways that make up aerobic respiration are really all parts of one larger pathway because the products of early pathways (like NADH) become _______ in the last one.
Aerobic Respiration: Stage 1 – Glycolysis
What is the first stage of aerobic respiration?
In the process of glycolysis, one molecule of _______ is converted to two molecules of __________.
Is carbon dioxide either a reactant in or product of glycolysis?
Glycolysis is valuable to a cell because it produces _______ for driving biosynthetic processes.
Glycolysis is valuable to a cell because supplies minimal energy without requiring the presences of __________ as a reactant.
Glycolysis is valuable to a cell because it generates _____ that can be “cashed in” for ATPs later.
Glycolysis is valuable to a cell because it produces ___________, which the Krebs cycle can further degrade for more energy.
Aerobic Respiration: Stage 2 – The Krebs Cycle
All of the six carbon atoms in each glucose molecule leave respiration in the form of carbon dioxide. Most of them leave during which part of aerobic respiration?
Which of the following is not a product of the Krebs cycle?
b. carbon dioxide
The Krebs cycle’s NADH products are of value. In what way?
The most energetic and useful product of the Krebs cycle is ________.
Aerobic Respiration: Stage 3 – Electron Transfer Phosphorylation
What is the immediate source of electrons for electron transfer phosphorylation?
The final stage of aerobic respiration involves the phosphorylation of ____ to ____ by transfer of electrons.
During the electron transfer reactions, protons (H+ ions) are pumped (moved) to one side of the inner membrane of the mitochondrion. The value of this pumping is that the resulting proton gradient is then used to ____________.
What is the most valuable product, energetically, of electron transfer phosphorylation?
The value of the three stages of aerobic respiration is their ability to break down glucose, a single molecule, with the resultant production of about ____ ATP molecules.
Energy Flow from Photons to Carbohydrates: Photosynthesis
________organisms build their own energy-rich molecules using solar energy.
Plants are considered autotrophic because their cells contain what critical molecule?
Name a process that uses chlorophyll molecules to produce high-energy carbohydrates.
List the reactants and products for the overall process of photosynthesis.
In photosynthesis, the H atoms used to make high-energy carbohydrates like glucose come from which reactant molecule?
Photosynthesis: Stage 1 – Light-Dependent Reactions
The wavelengths of light used in photosynthesis are found in the _________ portion of the electromagnetic spectrum.
Each wavelength of light has its own _______ level.
When light of the correct wavelength hits a photosynthetic pigment molecule, an electron within one of its atoms becomes ________.
What is the value of accessory pigments within the chloroplast’s structure?
they transfer the energy of absorption to nearby chlorophyll molecules
Accessory pigments and chlorophylls work together within the thylakoid membrane in clusters called __________.
Photosystems harvest light energy and use it to transfer electrons to _________ molecules.
The light-dependent reaction is like the last stage of aerobic respiration in that both reaction sequences carry out ________ _________ phosphorylations.
The light-dependent reaction is like the last stage of aerobic respiration in that both processes generate the energy-rich _____ molecule.
The light-dependent reaction is like the last stage of aerobic respiration in that both processes involve the flow of __________.
The light-dependent reaction is like the last stage of aerobic respiration in that both systems are lodged within a ___________ surface.
What is the role of NADPH in the process of photosynthesis? What does it carry? From where to where?
NADPH is formed when it accepts high-energy __________ from an excited photosystem.
List three products of the light-dependent reaction.
Photosynthesis: Stage 2 – Light-Independent Reactions
In the chloroplast, light dependent reactions take place in the __________________ membrane, while light independent reactions take place in the fluid of the ___________.
Where, within the chloroplast, are new molecules of glucose generated?
The immediate product of photosynthesis, three-carbon PGALs can be assembled together to generate _______ molecules.
The immediate product of photosynthesis, three-carbon PGALs can also find their way into _______ sugar molecules.
The immediate product of photosynthesis, three-carbon PGALs may eventually become part of the subunits of ________ polymers.
The immediate product of photosynthesis, three-carbon PGALs are used to generate, transport, and __________ forms of carbohydrates
Energy Flow: An Integrated Picture
The overall process that uptakes energy-poor molecules (CO2 and H2O) from their reservoirs in nature and converts them into energy-rich molecules is ___________.
What two processes complement each other within the global carbon cycle?
___________ organisms specialize in capturing energy.
___________ organisms are highly efficient at handling energy.
___________ organisms generate far more C―H bond energy than they themselves utilize.
Information and Its Expression in the Cell
The Need for Biological Information
Biological information must exist because cell structure is ________ enough to require information for its construction.
The Nature of Biological Information
Who discovered DNA, and from what source did he isolate it?
What was the principle tool Rosalind Franklin used to unravel the structure of DNA?
DNA contains two chains of nucleotides in which ______ and ______ alternate in supporting each chain structurally.
Where in the DNA molecule’s structure is the genetic information located?
Where in the cell is DNA stored?
DNA is stored within in a partiallycondensed fiber called __________.
Griffith exposed weak living bacteria to just the fluids from heat-killed virulent bacteria. Some of these weak bacteria became virulent and could now kill mice. What control experiment did he do to argue that his weak bacteria changed to virulence in these studies? (select a choice from below)
a.He grew his non-virulent bacteria for several years before infecting mice with them.
b.He injected viruses into his mice to test their resistance to viral infection.
c.He injected virulent bacteria into rabbits to see if they would die.
d.He injected heat-killed virulent bacterial fluids into a mouse to make sure the mouse would survive.
e.He isolated two strains of bacteria and maintained them in colonies.