Microbiology 6.1-6.2

true or false: the change in free energy for a given reaction is the same regardless of the number of steps involved.

true

match the term: 1. metabolism 2. catabolism 3. anabolism a. the set of chemical reactions that synthesize and assemble the units of macromolecules b. the sum total of chemical reactions in a cell c. the set of chemical reactions that degrade compounds, releasing their energy

1. b 2. c 3. a

consider the ATP-generating processes of prokaryotic chemoorganoheterotrophs. Match the process with its correct terminal electron acceptor. 1. aerobic respiration 2. anaerobic respiration 3. fermentation a. molecule other than O2 such as nitrate, nitrite, or sulfate b. organic molecule (private or a derivative) c. O2

1. c 2. a 3. b

match each type of enzyme inhibition with its characteristic 1. competitive inhibition 2. non-competitive inhibition by regulatory molecules 3. non-competitive inhibition by enzyme poisons a. inhibitor reversibly changes the shape of the enzyme so that the substrate can no longer bind to the active site b. inhibitor permanently changes the shape of the enzyme, making the enzyme nonfunctional c. inhibitor binds to the active site of the enzymes, blocking access of the substrate

1. c 2. a c. b

comparing the two drawings showing an interaction between a substrate and an enzyme, identify the substrate, the enzyme-substrate complex, the enzyme, and the active site of the enzyme. 1. pointing to larger multiunit molecule 2. pointing to smaller molecule near by the larger multiunit molecule 3. open gap in multiunit molecule 4. multiunit molecule and smaller molecule combined a. active site b. enzyme-substrate complex c. enzyme d. substrate

1. c 2. d 3. a 4. b

the series of sequential chemical reactions in a cell that converts a striating compound to an end product is called a ___ pathway.

metabolic

the sum total of all chemical reactions in a cell is called ____

metabolism

energy is the potential to do work and can exist as ___ energy (stored energy) and ____ energy (energy of motion)

potential; kinetic

when cells use glucose to make amino acids and other subunits for biosynthesis, certain intermediates of catabolism called ____ metabolites exit the "deconstruction line" of the breakdown process

precursor

in addition to yielding energy, catabolic pathways generate carbon intermediates that can be used in anabolic pathways for the biosynthesis of macromolecules. These carbon skeletons are called ______ ___.

precursor metabolites

when a molecule other than O2 serves as the terminal electron acceptor for the electron transport chain, the organism is utilizing ____ respiration

anaerobic

Compound X donates electrons to Compound Y. Which of the following correctly describes this process? a. X is oxidized by the reaction, and Y is reduced by the reaction b. X is the oxidizing agent, and Y is the reducing agent c. X is reduced by the reaction, and Y is oxidized by the reaction

X is oxidized by the reaction, and Y is reduced by the reaction

Free energy is best defined as ____. a. the energy available to do work b. the leftover energy that is not used by the cell c. energy of motion d. stored energy present in chemical bonds

a

when photosynthetic organisms convert the energy of sunlight to the energy of chemical bonds, and when chemoorganotrophs convert the energy of one type of chemical bond to that of another, they are ____. a. transforming energy b. making energy

a

which of the following correctly describe the transition step and the tricarboxylic acid (TCA) cycle a. the transition step concerts the pyruvate from glycolysis into acetyl-CoA b. together they generate the most reducing power of all the central metabolic pathways c. the TCA cycle reduces a 2-carbon acetyl group to release two molecules of CO2 d. the TCA cycle oxidizes a 2-carbon acetyl group to release two molecules of CO2 e. the TCA cycle generates most of the ATP for the cell

a, b, d

which of the following accurately describe fermentation? a. NAD+ is regenerated from NADH by the transfer of electrons to pyruvate or a derivative b. it generates more ATP than either glycolysis or respiration c. fermentation does not involve the tricarboxylic acid (TCA) cycle d. all cells are able to ferment certain substances e. glucose is broken down via glycolysis

a, c, d

consider the three key central metabolic pathways (glycolysis, the pentose phosphate pathway, and the TCA cycle). If you had to summarize what these pathways produce that is beneficial to the cell as they oxidize glucose, what three important items could you say they produce? a. reducing power b. water c. ATP d. oxidized electron carriers e. CO2 f. large carbon payments g. precursor metabolites

a, c, g

which of the following are true about glycolysis? a. the pathway provides the cell with a small amount of ATP, some reducing power, and six precursor metabolites b. the pathway provides the cell with a large amount of ATP, reducing power, and a number of precursor metabolites c. the pathway splits glucose and reduces it to form two molecules of pyruvate d. the pathway splits glucose and oxidizes it to form two molecules of pyruvate

a, d

the main energy currency of cells is ATP, which stands for ____ ___.

adenosine triphosphate

consider two different processes for converting glucose to CO2 and water. In the first, the glucose is burned (literally, as in fire); in the second, the glucose is covered in a series of multiple steps in a cell. Which of the following statements correctly describes the free energy of these two approaches? a. the change in free energy is grater in the first reaction, since the glucose is converted directly to CO2 and water b. the change in free energy is the same regardless of the number of steps involved c. the change in free energy is greater in the second reaction, since the glucose is carefully converted to CO2 and water d. there is not enough information to determine how the change in free energy will compare between the two approaches

b

which of the following is a true statement regarding forms of energy? a. energy can be created when it Isi changed from one form to another, for example, a hydroelectric dam generating electricity b. energy can be changed from one form to another c. when the form of energy is changed, some is lost forever d. the total amount of energy in the universe changes continuously as some is created and some is destroyed

b

Which of the following correctly describe respiration? a. all organisms that grow in the presence of O2 must use respiration for their energy needs b. electrons extracted from glucose are transferred to the ETC c. the ETC uses the electrons to generate a proton motive force that can be used to generate ATP d. it is only present in aerobic organisms

b and c

glucose catabolism encompasses two key processes: 1. oxidizing glucose molecules to generate ATP, reducing power, and precursor metabolites; and 2. transferring the electrons carried by NADH and FADH2 to the terminal electron acceptor. The second process, transfer of elections, is accomplished by which of the following? a. glycolysis b. cellular respiration c. fermentation d. the TCA cycle e. the pentose phosphate pathway

b and c

which of the following are important electron carriers for a cell? a. ADP/ATP b. NADP+/NADPH c. FAD/FADH2 d. NAD+/NADH

b, c, d

recall that E. coli can grow in glucose-salts medium ,which contains only glucose and a few inorganic salts. This means the glucose is serving what two purposes in the cell? a. source of phosphate b. starting point form which all cell components are made c. source of nitrogen d. energy source e. a monosaccharide that the cell can assemble into polysaccharides such as cellulose for its cell wall

b, d

proton motive force is ___. a. the positive charge that repels protons from the electrons orbiting around them in atoms b. the attractive force that makes up hydrogen bonds, for example, those holding together water molecules c. the form of energy that results for the electrochemical gradient established by the electron transport chain

c

consider a cell converting glucose into CO2 and water with the release of energy. This is an example of what type of metabolism, and the reactions themselves are considered to be what? a. anabolism; endergonic b. anabolism; exergonic c. catabolism; endergonic d. catabolism; exergonic

d

in order for cells to obtain energy, they remove electrons from an energy source and ultimately donate them to the terminal electron acceptor. What does this tell us about the electron affinity of the energy source and the terminal electron acceptor? a. this information doesn't tell us anything about the electron affinities of those molecules b. the energy source and the terminal electron acceptor have equal but opposite electron affinities c. the energy source has a high affinity for electrons, and the terminal electron acceptor has a lower affinity for electrons d. the energy source has a lower affinity for electrons, and the terminal electron acceptor has a higher affinity for electrons

d

consider the effect of temperature on enzyme activity. If the temperature is too high, proteins will ___ and no longer function

denature

proteins that function as biological catalysts are called ____.

enzymes

true or false: the sole function of glucose for cells growing in a glucose-salts medium is an energy source

false

the three central metabolic pathways that gradually oxidize glucose to CO2 are ____, the ___ ___ pathway, and the ____ cycle

glycolysis, pentose phosphate, TCA