Micro ch5, ch6
What type of organism caused the outbreak at Seneca Lake Sprayground? ch5Quiz
Bacterium
Consider the biochemical pathway: A → B → C Enzyme 1 catalyzes A → B Enzyme 2 catalyzes B → C Enzyme 1 can use
Both A and B substrates
Consider the three key central metabolic pathways (glycolysis, pentose phosphate pathway, and the TCA cycle). What three beneficial products of these pathways? (ch6)
ATP precursor metabolites reducing power
Considering the general equation that describes photosynthesis, the rate of the process would be most influenced by the availability of _______ in the atmosphere. (ch6)
CO2
What happens to carbon dioxide after it is released during reactions of the TCA cycle?
It diffuses out of the cell.
Until the optimal temperature is reached, raising the temperature has what effect on the speed of enzymatic reactions? (ch6)
It increases their rate.
What happens to an organism if it lacks one or more enzymes in a given biosynthetic pathway? (ch6)
It must have the end product provided from an external source.
What part of the body is affected with hepatitis? ch5Quiz
Liver
The two 3-carbon molecules glucose is split into are converted through a series of steps into pyruvate. During these steps
NAD+ is converted to NADH.
The electron transport chain is a cluster of membrane-embedded electron carriers that accept electrons from the coenzymes ___ and ___ and then pass these electrons along the chain. (ch6)
NADH FADH2
Hydrogen is transported from other reactions to the electron transport chain by ______.
NADH & FADH2
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?
Only B
The terminal electron acceptor in aerobic respiration is ______.
Oxygen
Some members of which of the following groups can use inorganic chemicals such as hydrogen sulfide and ammonia for energy? (ch6)
Prokaryotes only
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?
Pyruvate
Identify what investigations would need to be done to eliminate the possibility that patient A contracted hepatitis C by occupational exposure at the facility where she worked. ch5Quiz
Reviewing records for all patients at the facility. Onsite inspection of the facility for evidence of HCV. Observation of the safety practices used by staff at the facility.
Consider the figure showing the relationship between catabolism and anabolism. Which side shows catabolism, and which side shows anabolism? (ch6)
The left side shows catabolism, and the right side shows anabolism.
What is oxidation?
The loss of electrons from a molecule.
Which of the following chemical classes destroy microorganisms by forming chemical bonds that cross-link and inactivate proteins and nucleic acids? ch5
aldehydes
The figure illustrates a type of regulation used by cells to rapidly control certain key enzymes. The arrow labeled "1" points to the _______________ site, and the arrow labeled "2" points to the _____________ site. (ch6)
allosteric active
Cells can quickly alter the activity of certain key enzymes, using other molecules that bind reversibly and distort them. This control of enzymes is called ___ regulation. (ch6)
allosteric (AKA: noncompetitive)
How do aqueous solutions of alcohol usually affect microbes? ch5
by denaturing proteins by damaging lipid membranes
The energy released by ______ is captured by cells to make ATP; this ATP can then be used for biosynthesis, or ______. (ch6)
catabolism, anabolism
High pressure (130,000 psi) is thought to kill microbes by altering their ______. ch5
cell membranes proteins
UV light causes ______ bonds to form between adjacent thymines on the same strand of DNA. ch5Quiz
covalent
Glycolysis takes place in the ______.
cytoplasm
The TCA (Krebs) cycle takes place in the mitochondria of eukaryote cells. Where does it take place in prokaryote cells?
cytoplasm
Where does the TCA cycle take place in bacteria?
cytoplasm
Consider the effect of temperature on enzyme activity. If the temperature is too high, proteins will ___ and no longer function. (ch6)
denature
Radio waves, X-rays, microwaves, UV light and gamma rays are all examples of ______. ch5
electromagnetic radiation
Glycolysis makes products that feed into
electron transport chain, TCA cycle/Krebs cycle AND fermentation.
The most highly resistant microbial structure is the bacterial ___. ch5
endospore
Hydrogen sulfide is produced as a result of certain types of anaerobic respiration. Some chemolithotrophs can then use this as a/an ______. (ch6)
energy source
In the case of plants, algae, and cyanobacteria, the two major products of photosynthesis are ______. (ch6)
glucose and oxygen
Lipid synthesis generally requires the ___ components and ___ acids. (ch6)
glycerol fatty
The primary pathway used by many organisms to convert glucose to pyruvate is ___ . (ch6)
glycolysis (AKA: Embden-Meyerhoff)
Chlorine and iodine are common disinfectants that belong to a class of chemicals called ___ . ch5
halogens
Chlorine and iodine are common disinfectants that belong to a class of chemicals called ___. ch5
halogens
Salting and drying decrease the availability of water in food, resulting in an environment that is ______ relative to microbes, thereby preventing their growth. ch5
hypertonic
Hydrogen peroxide is a more effective germicide on ______. ch5
inanimate objects
What is one disadvantage of using heat treatment to sterilize plastic items? ch5
items might melt
After glycolysis, pyruvate can be converted into ______ under anaerobic conditions.
lactic acid
Microorganisms that are free living are ______ to chemical disinfectants than microorganisms in a biofilm. ch5
less resistant
The reactions that capture radiant energy and convert it into chemical energy in the form of ATP are called the __ - __ reactions. (ch6)
light - dependent
A solution of sodium hypochlorite is more effective against bacteria at _______ pH. ch5
low
The sum total of all chemical reactions in a cell is called ___ . (ch6)
metabolism
The effectiveness of hydrogen peroxide as a germicide on living tissue like wounds is reduced because ______. ch5
our catalase enzymes quickly break it down
The TCA cycle completes the ______ of glucose. (ch6)
oxidation
The mechanism by which cellular respiration uses reducing power generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP is ___ phosphorylation. (ch6)
oxidative
Cells obtain energy by ______ food molecules such as glucose.
oxidizing
Halogens are highly reactive _______ agents that _______. ch5
oxidizing; cause damage to proteins
Used as an alternative to chlorine for disinfecting water, ___ is a strong but unstable oxidizing agent that must be generated on-site, usually be passing air or O2 between two electrodes. ch5
ozone or O3
When selecting an appropriate chemical disinfectant, it is important to realize that the death rate is significantly influenced by ______. ch5
pH, temperature
The central metabolic pathway that generates reducing power in the form of NADPH is the ___ ___ pathway. (ch6)
pentose phosphate
What is the active ingredient in Lysol? ch5
phenolics
A high-solute environment damages microbial cells by causing ______. ch5
plasmolysis
What are the two main forms of energy? (ch6)
potential & kinetic
Energy is the ability to do work and can exist as ___ energy (stored energy) and ___ energy (energy of motion). (ch6)
potential, kinetic
When a cell processes glucose or other organic molecules through its central metabolic pathways, it does so to generate what three critical things? (ch6)
ATP, reducing power, precursor metabolites
Chemicals called ___ are used to prevent the growth of undesirable organisms in foods and beverages. ch5
preservatives or additives
When boiling or pasteurizing a sample, microorganisms are destroyed because their ______. ch5
proteins are irreversibly denatured
Which metal compound is used as a disinfectant in burn creams and bandage pads? ch5
silver
The main effect of low temperature storage is to ______. ch5
slow the activity of microbes
Which of the following binds to the active site of an enzyme?
substrate
As part of cellular respiration, a membrane-bound enzyme called ATP ___ uses energy from a proton-motive force to add a phosphate group to ADP. (ch6)
synthase
In the electron transport chain, protons are pumped across the cell membrane. This results in
the formation of a proton motive force.
Metabolism is best defined as ______. (ch6)
the sum total of all chemical reactions in a cell
In aerobic respiration, oxygen acts as
the terminal electron acceptor
Cells prefer to use carbohydrates as energy sources because
they are such good donors of hydrogen and electrons.
Certain intermediates of catabolic pathways, called precursor metabolites, are important because ______. (ch6)
they serve as carbon skeletons from which subunits of macromolecules can be made
This picture of a set of stairs best exemplifies the electron ___ ___ . (ch6)
transport chain (AKA: transport system)
What happens to the protons received from NADH in bacteria?
transported across the cytoplasmic membrane, setting up a proton motive force
What was the most likely mode of transmission of Cryptosporidium at the Seneca Lake State Park Sprayground? ch5Quiz
water-borne
Consider the use of low temperature storage for the preservation of food. Which of the following are accurate statements? ch5
-Refrigeration inhibits the growth of many pathogens and spoilage microorganisms by slowing or stopping critical enzyme reactions. -Psychrotrophic and some psychrophilic microorganisms can grow at refrigeration temperatures.
Some enzymes act with the assistance of a non-protein component. This component is called a ___ ; if that component is an organic molecule it can be called a ___. (ch6)
cofactor coenzyme
Identify each of the following by the most precise descriptive term as either a cofactor or coenzyme: magnesium: ___ ; NADP+: ___ ; zinc: ___ . (ch6)
cofactor coenzyme cofactor
True or false: Cells can replicate and transcribe DNA that contains thymine dimers. ch5Quiz
false
True or false: In prokaryotes and eukaryotes, the TCA cycle takes place in the mitochondria.
false
_______ does not actually destroy microbes or inhibit their growth but instead removes them physically from samples. ch5
filtration
_______ is a physical means used for destroying or removing microorganisms. ch5
filtration
Microorganisms that can grow on polysaccharides and disaccharides first break these down to glucose or precursor metabolites that can then enter into the pathway of ___ to be oxidized. (ch6)
glycolysis
From reading this case, you know that... ch5Quiz
hepatitis C is caused by a virus
Purines and pyrimidines are synthesized ______. (ch6)
in distinctly different manners
______ is the destruction of microbes by subjecting them to extremes of dry heat, reducing them to ashes. ch5
incineration
The Calvin cycle ______. (ch6)
incorporates carbon dioxide into organic compounds
Ozone ______. ch5
is a strong oxidizing agent
The series of sequential chemical reactions in a cell that converts a starting compound to an end product is called a ___ pathway. (ch6)
metabolic
The enzymes of the tricarboxylic acid cycle are found in the ___ matrix in eukaryotes and in the ___ in prokaryotes. (ch6)
mitochondrial cytoplasm
Phenolic compounds are effective against ______. ch5
most vegetative bacterial cells
After a deamination reaction removes the amino group from amino acids, the remaining carbon skeletons are converted into the appropriate ___ metabolites for entry into central metabolic pathways. (ch6)
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 ___ ___ . (ch6)
precursor metabolites
The act of delaying spoilage is ______. ch5
preservation
Medical instruments are classified into three categories according to their risk for transmitting pathogens. These are: critical instruments, ___ instruments, and ___ instruments. ch5
semicritical, noncritical
______ destroy all microbes, including viruses and endospores. ch5
sterilants
True of false: Cryptosporidium was not susceptible to disinfection through filtration and chlorination of the spray park's water supply. ch5Quiz
true
UV irradiation inactivates Cryptosporidium because it... ch5Quiz
blocks the action of DNA polymerase
Early in glycolysis, two phosphates are added to the glucose molecule. These phosphates come from
breaking down ATP.
Silver is used as an antimicrobial in which of the following products? ch5
burn creams bandage pads
The process by which chemolithoautotrophs and photoautotrophs incorporate CO2 into organic compounds is called ___ ___ . (ch6)
carbon fixation
Enzymes are biological ______ that are typically _______. (ch6)
catalysts, protein
Adding sorbic, propionic, and benzoic acid to foods affects ______ of microbes. ch5
cell membrane function
True or false: The Calvin cycle is a two-step linear pathway that photosynthetic organisms use to fix carbon dioxide. (ch6)
false
True or false: There is a standard antimicrobial procedure available from the Centers for Disease Control and Prevention (CDC) that can be used for all different microorganisms under any condition. ch5
false
True or false: Choosing which germicide to use is not that complicated since we only consider how effective it is against the target microbes. ch5
false, it's a complicated decision
In terms of their metabolism, prokaryotes are _______ with respect to compounds they use for energy and _______ in their biosynthetic processes. (ch6)
highly diverse; remarkably similar
Cryptosporidium infection results in diarrhea that is self-limiting in healthy people, but in ______ patients, it can produce dehydration through severe diarrhea and can be life-threatening. ch5Quiz
infants & elderly
______ provides an alternative to heat for sterilization and disinfection, but the process damages some types of plastics. ch5
irradiation
High- ____ processing (HPP) is used to decrease the number of microbes in food while maintaining the color and flavor. ch5
pressure
The main purpose of cellular respiration is to
produce energy
Enzymes are usually ______.
protein
A common dry heat sterilization method used in the microbiology laboratory is ______. ch5
flaming the inoculating loop
The straining of a fluid or air through a membrane to trap microorganisms is known as ___ . ch5
filtration
Although generally less reliable than heat, germicidal chemicals are especially useful for treating ______. ch5
heat-sensitive items large surfaces
Disinfectants that destroy all viruses and vegetative organisms but not endospores are referred to as ____-level disinfectants. ch5
high
Metabolic pathways can be linear, ____ or ___ . (ch6)
branch, cycle
Which of the following are reasons an organism might use fermentation? (ch6)
- A suitable inorganic terminal electron acceptor is not available. - They lack an electron transport chain.
Match the term to its description to test your understanding of the use of moist heat to control microbial growth. ch5Quiz
- Commercial canning: Uses an autoclave called a retort to destroy the endospores of Clostridium botulinum. It will not destroy the endospores of some thermophiles. -Pasteurization: Heat applied to beverages to prevent spoilage and kill pathogens. High-temperature-short-time protocols include holding liquids at 72°C for 15 sec. Does not sterilize. -Steam under pressure: Requires use of an autoclave. To sterilize, temperature must reach 121°C for a minimum of 15 minutes.
Which of the following are true statements about what happens to glucose inside a cell? (ch6)
- Glucose can be used in catabolism to yield energy, or the precursor metabolites generated from its breakdown can be used in anabolism. - Some glucose might enter glycolysis, only to be siphoned off as a precursor metabolite for biosynthesis. - Some glucose might be oxidized to CO2, generating the maximum amount of ATP.
Oxidative phosphorylation, the mechanism by which cellular respiration uses the NADH and FADH2 generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP, involves what two steps? (ch6)
- The electron transport chain generates a proton motive force. - ATP synthase uses the energy of the proton motive force to drive the synthesis of ATP.
Phenolics kill microorganisms by ______. ch5
-destroying cytoplasmic membranes -denaturing proteins
Germicidal chemicals ______. ch5
- usually react irreversibly with proteins, DNA, cytoplasmic membranes, or viral envelopes - are often poorly understood with regards to mechanisms of action
In a one D process, how many D values would it take to reduce a population of 10^10 cells to one survivor? ch5Quiz
10
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
Hydrogen consists of
2 protons & 2 electrons
Proteins are composed of various combinations of usually how many different amino acids? (ch6)
20
How many molecules of NADH are generated for each turn of the TCA cycle?
3
If the theoretical maximum ATP yield in prokaryotes from oxidative phosphorylation is 34 ATP for a single glucose molecule, what is the total ATP gain when substrate-level phosphorylation is included? (ch6)
38 ATP
Excision repair, which is also used to correct thymine dimers, requires... ch5Quiz
CORRECT: None of the choices are correct. heat acid light RNA
Match up each type of enzyme inhibition with its characteristic. (ch6)
Competitive inhibition = Inhibitor binds to the active site of the enzyme, blocking access of the substrate Non-competitive inhibition by regulatory molecules drop zone empty = Inhibitor reversibly changes the shape of the enzyme so that the substrate can no longer bind to the active site Non-competitive inhibition by enzyme poisons = Inhibitor permanently changes the shape of the enzyme, making the enzyme non-functional
Categorize the given medical instruments as critical, semi-critical or non-critical. ch5Quiz
Critical: - Scalpel - Venous catheter - Needle Semicritical: - Thermometer - Endotracheal tube - Gastrointestinal endoscope Noncritical: - Blood pressure cuff - Stethoscope
What organism was the cause of the outbreak at the Seneca Lake Sprayground? ch5Quiz
Cryptosporidium
Which of the following contain a metal ion that can accept and donate electrons?
Cytochromes
What enzyme(s) is/ are involved in replacing the removed nucleotides following excision repair? ch5Quiz
DNA polymerase, followed by DNA ligase
In addition to glucose, which of the following organic compounds can serve as energy sources for microbes? (ch6)
Disaccharides, polysaccharides, lipids, fatty acids, monosaccharides, proteins
All of the following accurately describe enzymes EXCEPT ______. (ch6)
EXCEPT: enzymes provide energy to help reactions proceed more rapidly. - enzymes are very specific, usually acting on only one or a few substrates - the name of an enzyme typically reflects its function and ends in -ase - enzymes are biological catalysts - enzymes are not used up in the process of catalyzing reactions
All of the following are characteristics of bleach, a solution of sodium hypochlorite, EXCEPT ______? ch5
EXCEPT: it is only effective against a limited range of microorganisms -it reacts with some organic compounds to form carcinogens -it is irritating to skin and mucous membranes -its germicidal activity is disrupted by organic compounds -it is corrosive and toxic -it reacts with some organic compounds to form trihalomethanes
All of the following are examples of electromagnetic radiation EXCEPT ______. ch5
EXCEPT: sound waves - visible light - mass of an electron - gamma rays - x-rays
Chlorine-releasing compounds such as sodium hypochlorite (bleach is a 5.25% solution) are used for all of the following EXCEPT ______. ch5
EXCEPT: wound treatment and skin cleansing (because sodium hypochlorite is too irritating to skin and mucous membranes) -food equipment sanitation -sewage and waste water disinfection -household cleaning -swimming pool treatments
Where do NADH and FADH2 go after being produced in the TCA cycle?
Electron transport chain
___ oxide is an extremely useful gaseous sterilizing agent that destroys all microbes and is often used to sterilize fabric, equipment, and implantable devices. ch5
Ethylene
Match the descriptions and antimicrobial agents to the appropriate type of germicide to test your knowledge of alcohols, halogens, phenolic compounds, and quaternary ammonium compounds as germicidal chemicals. ch5Quiz
Halogens: - Chlorine, chlorine dioxide, iodine - Common disinfectant which oxidizes proteins and other cell components Quaternary ammonium compounds: - Cationic detergent which can be safely used on food preparation surfaces - Compounds reacts with membranes to destroy many vegetative bacteria and enveloped viruses - These compounds are ineffective against mycobacteria, naked viruses, and Pseudomonas species Alcohols: - Ethanol or isopropanol - Aqueous solutions which can kill vegetative bacteria and fungi, but not endospores or naked viruses - Solutions can be used as antiseptics or to disinfect instruments without leaving a residue Phenolic compounds: - Carbolic acid - Germicidal agent which can leave an antimicrobial residue after use
Autotrophs use carbon dioxide (CO2) to synthesize organic compounds. Which of the following descriptions of this process are true? (ch6)
In photosynthetic organisms, the process is called the light-independent reactions. It often involves the Calvin cycle. It is called carbon fixation.
Which of the following are physical ways to remove or destroy microbes? ch5
Incineration Ultraviolet radiation Filtration Autoclaving
What is the active site of an enzyme? (ch6)
The critical site to which a substrate binds by weak forces.
The light-independent reactions of photosynthesis occur _______ the light-dependent reactions, and function to _______. (ch6)
after; synthesize organic compounds from CO2
Fats are hydrolyzed by lipases. The glycerol component is then converted to a precursor metabolite, and the fatty acids are degraded using a series of reactions called β-oxidation that remove successive 2-carbon units. Where do these components enter the central metabolic pathways for further oxidation? (ch6)
The precursor metabolites from glycerol enter glycolysis; the 2-carbon units from fatty acids are added to coenzyme A and enter the TCA cycle.
Microorganisms can grow on a variety of organic compounds other than glucose, including polysaccharides, proteins, and lipids. How do they accomplish this? (ch6)
They break these macromolecules down into appropriate precursor metabolites that are then introduced into central metabolism or used in biosynthesis.
True or false: Chlorine treatment is effective in removing Cryptosporidium from water. ch5Quiz
True
For each six-carbon molecule of glucose that enters glycolysis, how many molecules of pyruvate are made, and how many carbon atoms does each pyruvate have? (ch6)
Two molecules of pyruvate, each with three carbon atoms.
What type of radiation in sunlight causes damage to DNA? ch5Quiz
UV radiation Alpha radiation Gamma radiation IR radiation Beta radiation
The critical site of an enzyme to which a substrate binds by weak forces is called the ___ ___ . (ch6)
active site
The critical site of an enzyme to which a substrate binds by weak forces is called the ____ ___ . (ch6)
active site
The energy released during the reactions of glycolysis is used to form ______.
adenosine triphosphate (aka: ATP)
Aldehydes typically kill microbes by ______. ch5
altering nucleic acids altering proteins
Proteins are hydrolyzed by proteases, enzymes that break the peptide bonds between ___ ___ subunits. (ch6)
amino acid
As bacteria grow in broth, oxygen becomes depleted. At that point, most bacteria switch to fermentation to continue growing. In tetrathionate broth however, S. enterica can switch to anaerobic respiration. This gives the organism a growth advantage because
anaerobic respiration yields more ATP per glucose molecule than fermentation.
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?
4
For each glucose molecule broken down by glycolysis, how many net ATP molecules are produced?
4
Aqueous solutions of alcohol at a concentration of ______ are more effective than 100% alcohol. ch5
60-80%
Consider the theoretical maximum ATP yield from the complete oxidation of glucose via aerobic respiration in prokaryotes. Match the relative contribution in terms of ATP (substrate-level phosphorylation plus oxidative phosphorylation) with the correct metabolic component. (ch6)
8 ATP = Glycolysis 6 ATP = Transition step 24 ATP = TCA Cycle 38 ATP = Total yield of aerobic respiration
During the electron transport chain, ATP will be made from
ADP + Pi
With respect to their synthesis, how are amino acids typically grouped? (ch6)
By structurally related families that share common biosynthesis pathways
Match the type of enzyme inhibition on the left with the example of an inhibitor on the right. (ch6)
Competitive inhibition = sulfa drugs Non-competitive inhibition by regulatory molecules = allosteric regulators Non-competitive inhibition by enzyme poisons = mercury
In order to form lipids, how are fatty acids and glycerol synthesized? (ch6)
Fatty acid chains are assembled from 2-carbon acetyl groups from the transition step; the precursor to glycerol comes from glycolysis.
Match each type of radiation with its description. ch5Quiz
Ionizing radiation: High energy radiation that directly destroys DNA and damages cytoplasmic membranes. It can also cause indirect damage by producing reactive oxygen species (ROS). Ultraviolet radiation: Not very penetrating radiation. Easily stopped by interfering materials. Works by producing thymine dimers in DNA strands. Most effective at close range and with long duration of exposure. Microwaves: Doesn't affect microorganisms directly, but can generate heat in fluids which can indirectly kill microbes.
In respiring bacteria, how does ATP synthase generate ATP? (ch6)
It uses the energy released from allowing protons to flow back into the cell to add a phosphate group to ADP.
Which of the following combinations of molecules is produced during the light-dependent reactions of photosynthesis and used in the light-independent reactions? (ch6)
NADPH and ATP
Which of the following would be an example of occupational exposure for a healthcare worker? ch5Quiz
Needle stick. Cut with sharp object such as scalpel. Contact of mucous membranes with blood.
Classify the given microbes and infectious agents into "sensitive" or "resistant" with regards to effect of antimicrobial procedures. ch5Quiz
Sensitive: -Escherichia species -bacillus vegetative cells -HIV (enveloped) Resistant: -Pseudomonas species -Giardia cysts -prion -bacillus endosperes -poliovirus -mycobacteria species
Which of the following statements accurately describe biochemical pathways? Choose all that apply.
They convert an initial substrate through a series of steps into an end product. They are well-organized and structured. They can be linear, branched, or cyclical. They are carefully regulated.
Although the actual procedure is much more involved, the basic metabolism of wine-making involves inoculating grape juice with a special strain of the yeast Saccharomyces cerevisiae. S. cerevisiae will preferentially perform aerobic respiration on sugars in the juice but can also ferment those sugars to yield CO2 and alcohol, an important component of wine. Assume you inoculate a completely full container of juice and then close the lid. What will the yeast do? (ch6)
They will grow aerobically, consume the O2 dissolved in the juice, and then switch to fermenting sugars to yield alcohol.
It is often difficult to choose which germicide to use because often the most effective options ______. ch5
are not the safest
Nucleotide subunits of DNA and RNA are composed of three units: a 5-carbon sugar, a phosphate group, and a nucleobase. They are initially synthesized ______. (ch6)
as ribonucleotides that can be converted to deoxyribonucleotides by replacing the 2' hydroxyl group with a hydrogen atom
UV water treatment systems are effective in treating... ch5Quiz
bacteria, viruses and protozoans.
Although the pentose phosphate pathway is used by cells to break down glucose, it is particularly important because of its contribution to ______. (ch6)
biosynthesis
In photosynthesis, what do the light reactions, or light-dependent reactions, accomplish? (ch6)
They capture radiant energy and convert it to chemical energy in the form of ATP.
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 electrons, is accomplished as part of which of the following? (ch6)
fermentation cellular respiration
Phenolics are ______. ch5
germicidal
Starch and cellulose are both polymers of ______ , which means that, following hydrolysis, the component monosaccharides can enter directly into the central metabolic pathway of ______ to be oxidized. (ch6)
glucose glycolysis
Glycolysis is the central metabolic pathway that involves the breakdown of ______.
glucose (AKA: sugar)
Fats, the most common simple lipids, are broken down by lipases into their component ______. (ch6)
glycerol and fatty acids
Which of the following use moist heat to destroy microbes? ch5
Pasteurization Pressurized steam Boiling
Ethylene oxide is gaseous agent that ______. ch5
is very useful for sterilizing heat- or moisture-sensitive items
Adding preservatives such as benzoic acid to food is important because ______. ch5
it inhibits growth of many bacteria and mold
