Micro HW # 2 (Ch 4, 5, 6)
Which of the following destroys acellular infectious agents?
Virucides
For each glucose molecule broken down by glycolysis, how many net ATP molecules are produced?
2
For each glucose molecule that enters glycolysis, how many times does the TCA cycle "turn"?
2
How many ATP molecules are produced in the TCA cycle for each glucose molecule that enters glycolysis?
2
How many molecules of NADH are generated for each turn of the TCA cycle?
3
After glycolysis, pyruvate can be converted into ______ under anaerobic conditions. A. lactic acid B. cytochrome c C. NADH D. ATP E. glucose
A
From which of the following would you be most likely to obtain a pure culture? A. A single colony on a streak plate. B. A streak growing on an agar slant. C. A biofilm growing on a surface. D. A culture growing in a flask. E. None of these will yield a pure culture.
A
Hydrogen consists of A. one proton and one electron. B. one proton and two electrons. C. two protons and one electron. D. two protons and two electrons. E. one proton and two neutrons.
A
If conditions are favorable, the generation time of bacteria A. can be as short as 30 minutes. B. cannot be measured. C. can be as short as 12 hours. D. is remarkably stable, showing little change. E. usually exceeds 48 hours.
A
In aerobic respiration, the last carrier protein in the electron transport chain transfers A. two electrons to oxygen. B. two protons to Coenzyme Q. C. two electrons to ATP synthase. D. two hydrogens to ATP. E. two electrons outside the cell.
A
In bacteria, the electron transport chain is located in A. the cytoplasmic membrane B. cristae C. the glycocalyx D. the cell wall E. mitochondria
A
In the electron transport chain, protons are pumped across the cell membrane. This results in A. the formation of a proton motive force. B. the release of CO2. C. the creation of water. D. the reduction of NADH. E. the loss of electrons.
A
Most bacteria reproduce by ______. A. binary fission B. budding C. endospores D. mitosis E. sexual reproduction
A
Some enzymes require a cofactor or a coeznyme in order to be active. What is the difference between cofactors and coenzymes? A. Cofactors are non-protein components that assist enzymes and are typically trace elements; coenzymes are organic cofactors that loosely carry molecules or electrons. B. Cofactors transfer molecules or electrons from one compound to another while coenzymes are trace elements that assist in enzyme function. C. Cofactors are non-protein molecules while coenzymes are composed of amino acids. D. Coenzymes are non-protein molecules while cofactors are composed of amino acids. E. There is no difference between cofactors and coenzymes. They are the same thing and are usually trace elements.
A
The coenzyme NADH is generated by A. by oxidation reactions in glycolysis and the Krebs cycle. B. reduction reactions in glycolysis only. C. reduction reactions in glycolysis and the TCA cycle. D. oxidation reactions in the TCA cycle only. E. reduction reactions in the TCA cycle only.
A
The electron transport chain is part of ______. A. respiration B. glycolysis C. pyruvate oxidation D. fermentation E. All of these
A
The most common organisms causing food spoilage are A. bacteria, yeasts, and molds. B. yeasts, insects, and bacteria. C. bacteria, molds, and insects. D. yeasts, molds, and insects. E. molds, insects, and parasites.
A
The structure that divides the bacterial cell in two is called the? A. cross septum. B. cell plate. C. cleavage septum. D. cleavage furrow. E. fission line.
A
The synthesis of ATP via ATP synthase, driven by a proton motive force, is called ______. A. chemiosmosis B. glycolysis C. cyclophosphorylation D. the TCA cycle E. substrate-level phosphorylation
A
The two 3-carbon molecules that glucose is split into during glycolysis are converted through a series of steps ending in what 3-carbon molecule? A. Pyruvate B. Citric acid C. Diphosphglyceric acid D. Acetyl-CoA E. Fructose-1,6-diphosphate
A
What happens to carbon dioxide after it is released during reactions of the TCA cycle? A. It diffuses out of the cell. B. It enters a fermentation pathway to form ATP. C. It catalyzes a glycolytic reaction. D. It donates electrons to the electron transport chain for ATP production. E. It combines with H to form water.
A
What is oxidation? A. The loss of electrons from a molecule. B. The loss of electrons and protons from a molecule. C. The loss of protons from a molecule. D. The gain of electrons by a molecule. E. The gain of protons by a molecule.
A
When polysaccharides are broken down, their breakdown products can be oxidized for energy by entering which of the following metabolic pathways? A. Glycolysis B. Transition step via acetyl-CoA C. TCA cycle D. Electron transport chain E. All of these
A
Which is the best definition of generation time? A. The time it takes for the number of cells in a population to double. B. The time it takes for a bacterial cell to complete one round of mitosis. C. The time it takes for a bacterial cell to duplicate its DNA. D. The time it takes it takes for a bacterial population to exponentially decrease. E. The 24 hours it takes for cells to achieve maximum growth rate.
A
Which of the following contain a metal ion that can accept and donate electrons? A. Cytochromes B. Chelators C. Quinolones D. Fluorochromes E. All of these
A
Which of the following environmental factors is the most important in influencing the growth rate of bacteria? A. Temperature B. Nutrients C. Oxygen D. pH E. Moisture F. Chemical inhibitors
A
Which of the following is a method of choice for achieving a sufficient level of microbial control in routine day to day situations? A. Washing and scrubbing with soaps and detergents. B. Treatment of any materials both before and after they come into contact with human tissues. C. Boiling all items that come into contact with intact skin. D. Sterilization of tools/instruments that come into contact with human tissues. E. Irradiation of all products to sterilize them prior to use.
A
According to the graph, what is the impact of cold temperatures on E. coli? A. As temperatures increase, the growth rate decreases. B. As temperatures decrease, the growth rate decreases. C. Below 6 degrees celsius, all the cells die. D. There is no impact of cold temperatures on cell growth. E. As temperatures drop below 30 degrees celsius, cells begin to die.
B
Cells prefer to use carbohydrates as energy sources because A. the waste products of their breakdown are non-toxic B. they are such good donors of hydrogen and electrons C. their internal bonds are so easy to cleave D. they contain the greatest amount of energy per unit
B
Choose which of the following best describe the difference between a disinfectant and an antiseptic. A. Disinfectants and antiseptics are both types of chemicals used to remove microbes from any kind of surface. They are used interchangeably. B. Disinfectants are antimicrobial chemicals used on inanimate surfaces or objects to remove most of the pathogenic microorganisms. Antiseptics are antimicrobial chemicals that can be used on skin or tissues to achieve the same result. C. Disinfectants are chemicals that completely destroys all microbes on a product. Antiseptics are chemicals that reduce the number of microbes on a product. D. Disinfectants are chemicals that reduce the number of pathogenic microbes on an inanimate surface or object. Antiseptics are chemicals used to delay the spoilage of food or other perishable materials by slowing the growth of microorganisms. E. Disinfectants are chemicals that reduce the number of microbes to meet accepted health standards. Antiseptics are chemicals that completely eliminate of all microbes/viruses from a surface.
B
Consider the biochemical pathway: A → B → C Enzyme 1 catalyzes A → B Enzyme 2 catalyzes B → C If enzyme 2 is inactive, which of the following compounds will accumulate? A. C only B. B only C. B and C D. A and B E. A only
B
Hydrogen is transported from other reactions to the electron transport chain by ______. A. Coenzyme Q and FADH2 B. NADH and FADH2 C. Cytochrome c and Coenzyme Q D. NADH and Coenzyme A E. NADH and Coenzyme Q
B
In prokaryotic cells, the electron transport chain (ETC) is located in the ______, whereas in eukaryotic cells, the ETC is located in the ______. A. periplasmic space; cytoplasmic membrane B. cytoplasmic membrane; inner membrane of mitochondria C. mitochondrial cristae; mitochondrial matrix D. cytoplasm; mitochondrial matrix E. cytoplasmic membrane; outer membrane of mitochondria
B
Most cultured bacteria tend to multiply by _____. A. sexual reproduction B. binary fission C. budding D. fragmentation E. binary fusion
B
The electron carrier proteins in the electron transport chain shuttle electrons to A. transmembrane channels. B. a terminal electron acceptor. C. ATP synthase. D. the cell wall. E. ribosomes.
B
The environmental factor that influences bacterial growth the most is A. moisture B temperature C. chemical inhibitors D. pH E. oxygen F. nutrients
B
What happens to the protons received from NADH in bacteria? A. They act as terminal electron acceptors. B. They are transported across the cytoplasmic membrane, setting up a proton motive force. C. They are passed along the electron transport chain along with the electrons, setting up a proton motive force. D. They act as coenzymes in chemical reactions. E. They are transported to the nucleoid region of the cell.
B
When studying microbes, why is it important to separate mixed communities into individual pure cultures of the different species? A. So we can clearly see what color the microbial colony is on the agar plate. B. So we can understand the biochemical characteristics of one species without confusing it with another species. C. Separation is important because in a mixed culture, one species always inhibits the growth of the other species. D. It actually isn't that important to separate out mixtures. E. Microbes grow more slowly in mixed cultures, so separating them out will help their growth rate.
B
Which of the following binds to the active site of an enzyme? A. product B. substrate C. water D. another enzyme E. ATP
B
You have a culture of bacteria in which cells are actively expressing genes and synthesizing enzymes, but cells are not dividing. This culture is most likely in ______ phase. A. death B. lag C. stationary D. log E. prolonged decline
B
he safe temperature ranges for the storage of foods are determined by A. the low temperature at which microbes die and the high temperature at which they die. B. the low temperature at which microbes stop multiplying and the high temperature at which they die. C. the low temperature at which they stop multiplying and the high temperature at which their growth accelerates. D. the low temperature at which microbes stop multiplying and the high temperature at which they stop multiplying. E. the low temperature at which they die and the high temperature at which they stop multiplying.
B
Select the reasons sugar or salt can be used for food preservation. A. They disrupt the cytoplasmic membrane B. They may cause plasmolysis C. They create a hypertonic environment, unfavorable for growth D. They dehydrate the bacterial cell E. They create a hypotonic environment, unfavorable for growth F. They cause lyophilization
B, C, D
Which of the following are considered the major elements that primarily make up components of cells in microorganisms and all living things? A. Nitrogen B. Zinc C. Phosphorus D. Sulfur E. Carbon F. Oxygen G. Hydrogen H. Potassium I. Magnesium J. Calcium K. Iron L. Cobalt M. Copper N. Molybdenum O. Manganese
B, L, M, N, O
Consider the biochemical pathway: A → B → C Enzyme 1 catalyzes A → B Enzyme 2 catalyzes B → C Enzyme 1 can use A. only B as a substrate. B. either A or B as substrate, but not both. C. both A and B as substrates. only A as a substrate. D. neither A nor B as substrate.
C
Microbes that grow readily on the bench top or in a temperature-controlled incubator that is not sealed from the atmosphere in the room are ______. A. microaerophiles B. obligate anaerobes C. aerobes D. all pathogens E. capnophiles
C
The energy released during the reactions of glycolysis is used to form ______. A. glycogen B. guanine triphosphate C. adenosine triphosphate D. glycerol E. adenosine monophosphate
C
The two 3-carbon molecules glucose is split into are converted through a series of steps into pyruvate. During these steps A. ATP is converted into ADP. B. acetyl CoA is converted into oxaloacetic acid. C. NAD+ is converted to NADH. D. NADH is converted to NAD+. E. ADP is converted to AMP.
C
What happens to bacterial cells when their maximum growth temperature is exceeded? A. The rate of cell division decreases, but cells survive when the maximum temperature is exceeded. B. Cells achieve their maximum growth rate when the maximum growth temperature is exceeded. C. Cells begin to die when their maximum growth temperature is exceeded. D. All bacteria produce endospores by which they can survive the increased temperature. E. Cells divide more rapidly as the optimum temperature is exceeded.
C
Where do NADH and FADH2 go after being produced in the TCA cycle? A. Fermentation pathways. B. ATP synthase. C. Electron transport chain. D. Substrate-level phosphorylation. E. The Calvin cycle.
C
Which of the following is not a catabolic process? A. Glycolysis B. TCA cycle C. Protein synthesis D. Fermentation E. These are all catabolic processes.
C
______ refers to energy-requiring metabolic processes that result in the biosynthesis of macromolecules and cellular structures. A. Metabolism B. Antagonism C. Anabolism D. Catabolism E. Anabolism and Metabolism
C
Cells must ______ their DNA prior to cell division. A. denature B. transcribe C. hydrolyze D. replicate E. translate
D
During the electron transport chain, ATP will be made from A. AMP + 2Pi B. AMP + Pi C. Adenosine + P3 D. ADP + Pi E. ADP + H2O
D
Glycolysis makes products that feed into A. electron transport chain B. fermentation C. TCA cycle D. electron transport chain, TCA cycle AND fermentation E. TCA cycle AND fermentation
D
In aerobic respiration, oxygen acts as A. an ATP synthase. B. a coenzyme. C. an electron carrier in the ETC. D. the terminal electron acceptor. E. a reducing agent.
D
In bacteria, proton pumps are protein complexes that A. move protons from the exterior of the cell to the interior. B. pump protons and electrons through the cell membrane. C. synthesize water from hydrogen and oxygen. D. move protons from the interior of the cell to the exterior. E. break down water into hydrogen and oxygen.
D
In eukaryotic cells undergoing respiration, protons are pumped A. from inside the cell to outside the cell. B. from inside the mitochondria to the cytoplasm. C. across the cytoplasmic membrane. D. from the mitochondrial matrix to the intermembrane space. E. down the electron transport chain.
D
Starting from a single bacterium, after six generations of binary fission, how many bacterial cells will be present? A. 32 B. 6 C. 12 D. 64 E. 127
D
The TCA (Krebs) cycle takes place in the mitochondria of eukaryote cells. Where does it take place in prokaryote cells? A. The nucleus B. The ribosomes C. The cell wall D. The cytoplasm E. The mitochondrion
D
The Tricarboxylic Acid Cycle (TCA cycle) occurs after ______. A. photosynthesis B. the electron transport chain C. the Calvin cycle D. glycolysis E. fermentation
D
Which of the following are examples of biofilms? A. Dental plaque. B. Scum accumulating in toilet bowls. C. Slipperiness on rocks in stream beds. D. Capsule formation around Streptococcus pneumoniae. E. Furry grayish-white growth on old bread or fruit.
D, E
Mechanical removal of most microbes from living or inanimate surfaces
Decontamination
Moist heat primarily destroys microbes by?
Denaturing their proteins
Reduction of most microbial life on inanimate surfaces
Disinfection
A culture of bacteria is breaking down sugars to yield energy. This is best described as ______. A. anabolism B. canabolism C. metabolism D. biosynthesis E. catabolism
E
By keeping food cold, the growth rate of food spoilage microorganisms is? A. increased. B. not changed. C. stopped, and the microbes are killed. D. first increased, then decreased. E. Decreased
E
During glycolysis, a single 6-carbon molecule of glucose is converted to two 3-carbon pyruvate molecules. During the later steps in this process, how many molecules of ATP are generated? A. 12 B. 1 C. 2 D. 6 E. 4
E
During the electron transport chain in bacteria, protons are A. attached to molecules in the glycocalyx. B. carried along the electron transport chain. C. shuttled to the inside of the membrane. D. shuttled to the inner space of the mitochondria. E. shuttled to the outside of the cell membrane.
E
During which stage of growth does cell division equal the rate of cell death? A. Phase of prolonged decline B. Log phase C. Lag phase D. Death phase E. Stationary phase
E
Early in glycolysis, two phosphates are added to the glucose molecule. These phosphates come from A. conversion of NADH. B. hydrolysis of pyruvate. C. protein denaturation. D. transfer of phospholipids. E. breaking down ATP. Correct
E
Glycolysis is the central metabolic pathway that involves the breakdown of ______. A. starch B. glycogen C. fatty acids D. protein E. glucose
E
Glycolysis takes place in the ______. A. cell wall B. cytoplasmic membrane C. endoplasmic reticulum D. mitochondria E. cytoplasm
E
The enzyme ATP synthase uses energy from ______ to make ATP. A. electrons passed from cytochromes. B. water exiting the cell. C. protons stripped from water. D. protons passed from cytochromes. E. protons re-entering the cell.
E
The main purpose of cellular respiration is to A. produce glucose. B. remove oxygen. C. produce carbon dioxide. D. produce water. E. produce energy.
E
The terminal electron acceptor in aerobic respiration is ______. A. pyruvic acid B. water C. sulfate D. nitrate E. oxygen
E
Where does the TCA cycle take place in bacteria? A. Mitochondria B. Cell wall C. Nucleus D. Cell membrane E. Cytoplasm
E
T/F: According to the figure, food stored for one to two hours at a temperature of 32 degrees Celsius would be safe to eat.
F
T/F: All biochemical pathways have the same number of enzymatic reactions.
F
T/F: An enzyme speeds up a chemical reaction in the cell, but can only be used once.
F
T/F: Both human cells and bacterial cells divide by mitosis.
F
T/F: Cell division is triggered exclusively when cells attain a threshold mass.
F
T/F: DNA helicase is responsible for adding nucleotides to the growing end of the DNA.
F
T/F: Handwashing with regular soap removes all normal microbiota from the skin.
F
T/F: In anaerobic respiration, the terminal electron acceptor would also be oxygen.
F
T/F: In prokaryotes and eukaryotes, the TCA cycle takes place in the mitochondria.
F
T/F: Regarding use of heat to control microbial growth, dry heat at lower temperatures is as effective as moist heat at the same temperature.
F
T/F: The cytoplasmic membrane is permeable to protons.
F
Boiling is not a reliable method for sterilization because
It does not destroys heat-resistant endospores
Cells obtain energy by ______ food molecules such as glucose.
Oxidizing
Slows microbial growth but does not reduce the number of existing microbes.
Preservation
Enzymes are usually ______.
Proteins
T/F: Environmental factors control microbial growth through their effect on enzyme activity.
T
T/F: In a biochemical pathway, the product of the first reaction becomes the substrate in the second reaction.
T
T/F: Microbes will only grow until the least represented (limiting) nutrient is used up.
T
T/F: Protons used to set up the proton motive force are generated as macromolecules like glucose are oxidized in the cell.
T
T/F: The energy captured in the phosphorylation of ADP to ATP comes from the proton motive force created in respiration.
T
T/F: The more bacteria present on or in something, the longer it takes to kill them all.
T
T/F: Whenever a molecule is oxidized, another molecule must be reduced.
T
A hydrogen atom consists of?
a proton and an electron.
Destruction of all microbial life
sterilization
