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Which of the following organisms have eukaryotic cells that do NOT contain a cell wall
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Which of the following statements about ribosomes is FALSE?
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Microbiology dcccd
Exam 2
| Question | Answer |
|---|---|
| Which of the following organisms have eukaryotic cells that do NOT contain a cell wall | Animals |
| Which of the following statements about ribosomes is FALSE? | Antibiotics that interfere with protein synthesis harm both prokaryotic and eukaryotic ribosomes. |
| Which of the following pairs is MISMATCHED? | Ribosomes; storage |
| A eukaryotic cell can ingest a prokaryotic cell by __________. | phagocytosis |
| Which of the following statements does NOT provide evidence for the endosymbiotic theory? | Prokaryotes contain peptidoglycan in their cell walls. |
| A population of bacterial cells has been placed in a very nutrient-poor environment with extremely low concentrations of sugars and amino acids. Which kind of membrane transport becomes crucial in this environment? | Active transport |
| The nucleoid of the bacterial cell __________. | contains the bacterial chromosome |
| Bacillus anthraciscauses the deadly disease anthrax. Organisms of the genus Bacillus may form endospores. This bacterium would be suitable for biological warfare because endospores __________. | are resistant to high temperatures, UV light, and desiccation |
| The endoplasmic reticulum that has ribosomes attached to its outer surface is referred to as __________. | rough ER |
| Which of the following is NOT a functionally analogous pair? | Pili; centrioles |
| A __________ solution is a medium in which the overall concentration of solutes equals that found inside the cell. Water enters and leaves the cell at the same rate. | isotonic |
| Which of the following processes occurs in bacterial plasma membranes but NOT in eukaryotic plasma membranes? | ATP synthesis |
| The __________ is a fluid structure that allows membrane proteins to move freely. 0 | cell membrane |
| The plasma membrane is considered a barrier to the environment because __________. | it controls the passage of molecules into the cell |
| The nucleus of a eukaryotic cell differs from the nucleoid of a prokaryotic cell in all of the following ways EXCEPT which one? | The prokaryotic nucleoid contains DNA combined with histones. Histones are lacking in the eukaryotic nucleus. |
| Polyphosphate (volutin), carboxysomes, and magnetosomes are examples of __________. | inclusion bodies |
| Which of the following processes uses membrane proteins that act as channels or carriers allowing ions or large molecules to move across the plasma membrane without using energy? | Facilitated diffusion |
| Which of the following statements is true? | Endospores are extremely durable structures that can survive high temperatures. |
| Which of the following membrane transport mechanisms takes place in eukaryotic cells but NOT in prokaryotic cells? | Endocytosis |
| Which of the following processes requires cellular energy in the form of ATP? | Active transport |
| Within the cytoplasm of bacterial cells are reserve deposits where certain nutrients accumulate. These are called __________. | inclusions |
| You have isolated a cell with a peptidoglycan cell wall. What other structure can you safely assume the cell has? | A plasma membrane |
| The antibiotic polymyxin B combines with phospholipids. This will cause __________. | leakage of intracellular contents |
| Assume you are growing a bacterial culture in a glucose medium. Your lab partner adds more glucose in hopes of speeding up the experiment. The bacteria suddenly die. The best explanation for this result is that __________. | the cells plasmolyzed |
| The term describing bacteria with flagella distributed over the entire surface of the cell is __________. | peritrichous |
| Cocci may be arranged as __________. | tetrads streptococci diplococcic staphylococci |
| The term describing bacteria with flagella that are arranged as a tuft coming from one pole is __________. | lophotrichous |
| Many pathogenic (disease-producing) bacteria produce a(n) __________ that protects them from phagocytosis by host cells. | capsule |
| With a light microscope, which of the following would allow discrimination between eukaryotes and prokaryotes? | Observation of nuclei |
| A Gram stain of a wound reveals purple, spherical bacteria that divide and remain attached in grapelike clusters. These are referred to as __________. | gram-positive staphylococci |
| Penicillin specifically interferes with peptidoglycan synthesis. Which of the following cells is most likely to be damaged by penicillin? | Gram-positive bacterial cells |
| Which of the following is NOT a structure of prokaryotic cells? | Chloroplast |
| Spirochetes and spirilla are both spiral-shaped bacteria. However, they differ in that spirochetes have __________ and spirilla do not. | endoflagella |
| In a prokaryotic cell, all of the following are functions of either fimbriae or pili EXCEPT __________. | protection from phagocytosis |
| Why is penicillin selectively toxic to bacterial cells but harmless to human cells? | Penicillin specifically weakens peptidoglycan, which is found only in bacterial cells. |
| Which of the following is NOT true of the gram-negative outer membrane? | It contains enzymes for energy synthesis. |
| Spherical bacteria that divide and remain attached in chainlike patterns are called __________. | streptococci |
| What will occur if a bacterial cell with a weakened or damaged cell wall is placed in pure water? | The cell will swell and burst. |
| Gram-negative cells contain a periplasmic space that is __________. | rich in degradative enzymes |
| You are observing a Gram stain of rod-shaped microorganisms that are linked in a chain and stain purple. How would you describe these bacteria using the correct terminology for the cell shape and arrangement? | Gram-positive streptobacilli |
| Chemotaxis refers to the ability of microorganisms to __________. | move toward or away from chemical stimuli |
| The motility of bacteria with flagella occurs through a series of "runs" and __________. | tumbles |
| All of the following are found in the cell walls of gram-positive bacteria EXCEPT __________. | lipid A |
| Which of the following is a likely outcome, based on the unique cell structure of members of the genus Mycoplasma? | Mycoplasma species have very flexible cells that can pass through bacteriologic filters. |
| Phototaxis refers to the ability of microorganisms to __________. | move toward a source of light. |
| Consider a gram-positive cell in a hypertonic medium. If the peptidoglycan were damaged, the cell would __________. | shrink |
| Which of the following pairs is matched correctly? | spheroplast—gram-negative bacteria that are exposed to lysozyme but retain some of the outer membrane |
| Which of the following bacterial structures is necessary for chemotaxis? | Flagella |
| Which of the following statements about a gram-negative cell wall is FALSE? | It contains teichoic acid. |
| Which of the following is NOT characteristic of the glycocalyx found in bacteria? | Creates a slimy, slippery coating that prevents bacteria form attaching to surfaces |
| Where is the genetic information of the cell stored? | nucleus |
| The structural framework in a cell is the | cytoskeleton. |
| Where in a cell is ATP made? | mitochondria |
| What carries instructions for making proteins from the nucleus into the cytoplasm? | mRNA |
| One of the ways smooth endoplasmic reticulum (ER) differs from rough endoplasmic reticulum is that rough ER is covered by | ribosomes. |
| Which of the following is part of the endomembrane system? | Golgi apparatus |
| Which of the following organelles breaks down worn-out organelles? | lysosomes |
| Where are lipids made in the cell? | smooth endoplasmic reticulum (ER) |
| What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell? | plasma membrane |
| Why is no energy required in passive transport? | The concentration gradient drives the movement. |
| Once equilibrium is reached, | molecules move, but there is no net movement in a particular direction. |
| Which of the following would not move freely across the cytoplasmic membrane? | Positively charged hydrogen ions |
| Prokaryotic cells | Circular chromosome, not enclosed within a nuclear envelope Peptidoglycan-containing cell wall Flagella that rotate, composed of flagellin 70s ribosomes |
| Eukaryotic cells | Linear chromosomes enclosed within a nuclear envelope Cellulose or chitin-containing cell wall Flagella that wave, composed of microtubules Golgi apparatus Lysosomes Mitochondria 80s ribosomes Endoplasmic reticulum |
| Select the structures below that are found in all bacterial cells. | nucleoid cytoplasm ribosomes plasma membrane |
| Indicate the bacterial structures that are likely to be antigens, to which host antibodies bind, marking the invader for phagocytosis | cell wall flagella capsule fimbriae |
| Identify antibacterial strategies that would likely be selectively toxic for bacteria. | interfering with translation at 70s ribosomes inhibition of peptidoglycan synthesis inhibition of fimbriae synthesis |
| A strain of Streptococcus pneumoniae is no longer able to synthesize its capsular polysaccharide. What is a likely outcome? | It will be readily phagocytized upon entering the host |
| A strain of Neisseria gonorrhoeae has been genetically altered and can no longer produce fimbriae. What is a likely outcome? | It will be unable to adhere to host tissue and establish infection |
| Which of the following structural features of E. coli is most responsible for the signs and symptoms of a urinary tract infection? | Fimbriae |
| Which statement best describes how streptomycin attacks bacterial cells? | Streptomycin targets the 70S ribosome and inhibits protein synthesis |
| Why are most Gram-negative bacteria resistant to the actions of penicillin? | Penicillin is unable to pass through the outer membrane of the cell wall. |
| Which of the following is NOT a classic sign and/or symptom of a urinary tract infection? | Blood in the urine |
| Pick the answer that lists the composition of the bacterial cell wall. | short amino acid chains, NAG, NAM, and some lipid proteins |
| Gram-positive bacterial cell wall | thick layer of peptidoglycan teichoic acids single lipid bilayer membrane |
| Gram-negative bacterial cell wall | thin layer of peptidoglycan periplasmic space lipopolysaccharides dual lipid bilayer membranes |
| A cell wall is a requirement for all living bacteria. | False |
| Prokaryote only | Capsule |
| Eukaryote only | Golgi complex Rough endoplasmic reticulum Mitochondria Nucleus |
| Eukaryote and Prokaryote | Flagella Plasma membrane Ribosomes Cytoplasm |
| Members of the Adenoviridae cause __________. | the common cold |
| How will the prescribed penicillin kill S. pyogenes that is causing Shelly’s infection? | Penicillin will interfere with peptidoglycan synthesis, ultimately weakening the cell wall and leading to cellular lysis. |
| What effect will the penicillin have on Shelly’s cells? | The penicillin will not have any impact on Shelly’s cells because it targets peptidoglycan, which is found only in bacteria. |
| Viruses that use RNA as a template for transcribing DNA include __________. | Retroviridae |
| A virus may contain any of any of the following EXCEPT (a) __________. | ribosomes |
| Some viruses have a membranelike structure on their surface, composed of lipids, proteins, and carbohydrates. This is called a(n) __________. | envelope |
| The potential use of viruses that infect bacteria to treat bacterial infections in humans is known as __________. | phage therapy |
| Which of these factors is NOT used in classifying viruses? | Disease symptoms |
| Which type of microscope is needed to view a virus in the laboratory? | Electron |
| Which of the following terms are NOT correctly matched? | Poxviridae; chickenpox |
| Influenza viruses are classified according to their hemagglutin and __________ proteins. | neuraminidase |
| Which of the following is NOT characteristic of viruses? | Viral nucleic acid is surrounded by a plasma membrane. |
| A double-stranded, enveloped DNA virus that contains reverse transcriptase belongs to which family? | Hepadnaviridae |
| The protein coat of a virus is called the __________. | capsid |
| Viruses possess genetic material comprised of DNA or __________. | RNA |
| Which statement about viruses is FALSE? | Viruses will usually infect any available cell, regardless of the cell type. |
| To what does the term viral species refer? | A group of viruses sharing the same genetic information and structure |
| What is the usual size range of viruses? | 30 to 300 nanometers |
| How does specialized transduction differ from regular lysogeny? | The prophage in specialized transduction carries with it pieces of the host chromosomal DNA. |
| What happens to the packaged DNA of a specialized transduced phage when it infects a new recipient cell? | The host DNA integrates, with the prophage, into the new recipient chromosome. |
| How can specialized transduction contribute to the transfer of antibiotic resistance genes in a bacterial population? | The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA. |
| How are viruses different from eukaryotic cells? | They require a host in order to reproduce. |
| What is the function of the structural elements of a virus? | To package and protect the viral genome |
| Lysogenic viral DNA which has integrated into the host genome is referred to as | a prophage |
| Which of the following events might trigger induction of a temperate bacteriophage? | Exposure to UV light |
| How is the lytic cycle different from the lysogenic cycle with respect to the infected host cell? | The host cell dies during the lytic stage. |
| What is the fate of the prophage during the lysogenic stage? | It is copied every time the host DNA replicates. |
| In which stage is the viral DNA introduced into the cell? | Penetration |
| In which stage does formation of mature viruses occur? | Assembly |
| The host DNA is usually degraded during which stage? | Biosynthesis |
| What would be the fate of a lytic bacteriophage if the host cell died prior to the assembly stage? | The virus would not be able to infect new hosts. |
| From which phrase is the term “prions” derived? | Proteinaceous infectious particles |
| In what year did Stanley Prusiner discover prions? | 1982 |
| Which disease did Stanley Prusiner first identify as being caused by prions? | Scrapie |
| How are prions different from other infectious agents? | They lack nucleic acid. |
| The normal function of the PrP protein in mammals is believed to be: | assisting in normal synaptic development and function. |
| How do normal prion proteins (PrP) differ from the infectious prion proteins? | Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets. |
| How does the number of infectious prions increase? | Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion. |
| Why are the beta-pleated multimers of PrP potentially pathogenic? | The multimers are more stable and resistant to protease. |
| Which of the following prion diseases is found in deer and elk? | Chronic wasting disease |
| Which of the following prion diseases was also known as laughing disease? | Kuru |
| Which of the following conditions in humans is linked to bovine spongiform encephalopathy? | Variant Creutzfeldt-Jakob disease |
| What part of the nervous system is most affected by fatal familial insomnia? | Thalamus |
| Where does the name “scrapie” come from? | The prion disorder causes infected sheep to scrape against objects until their skin is raw. |
| Which of the following is NOT a sign or symptom of the common cold? | Diarrhea |
| Which of the following are the main causative agents of the common cold? | Rhinoviruses and coronaviruses |
| Which of the following types of macromolecules are found in all viruses? Select all that apply. | Proteins Nucleic acids |
| Arrange the following steps in the order in which they occur during the reproductive cycle of the type of virus that causes the common cold. | Binding to protein receptors on cell surface Release of nucleic acid from capsid Transcription and translation Capsid assembly Release of virus from cell |
| Which of the following statements best describes why antibiotics are ineffective treatments for the common cold? | Viruses do not possess targets for antibiotics. |
| Which of the following statements concerning viruses is true? | The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach. |
| Which statement concerning viral structure is true? | Spikes are found on some viruses. They are very consistent in structure within a viral species and can be used for identification. |
| Each of the following can be used for the detection and/or identification of viruses except _______________. | fermentation tests |
| Which of the following is true regarding cultivation and isolation of animal viruses? | Diploid cell culture lines, developed from human embryos, are widely used for culturing viruses that require a human host. |
| Which statement is INCORRECT concerning animal viruses? | The genome of animal viruses is always single-stranded. |
| Which of the following is true concerning a lysogenic viral replication cycle? | During lysogeny, the viral genome integrates into the host DNA, becoming a physical part of the chromosome. |
| Which virus is NOT associated with cancer? | coronavirus |
| Which of the following statements regarding latent viral infections is true? | Latent infections can persist for years in an individual without causing any symptoms. |
| Which of the following statements concerning prion diseases is true? | Normal host cellular prion proteins (PrPC) are converted into scrapie proteins (PrPSc). |
| Which of the following would be the first step in biosynthesis of a virus with a - (minus) strand of RNA? | synthesis of double-stranded RNA from an RNA template |
| An envelope is acquired during which of the following steps? | release |
| All of the following are prion diseases EXCEPT __________. | Wiles-Davidoff syndrome |
| Which of the following is NOT an oncogenic virus? | Varicellovirus |
| Which of the following viruses may cause a persistent viral infection? | Measles virus |
| Which of the following are possible strategies for treating viral infections? | Blocking viral attachment to host cell receptors Blocking uncoating of the virus after entry Blocking insertion of viral DNA into the host cell chromosomes Blocking biosynthesis of viral nucleic acids |
| Which of the following pairs is NOT correctly matched? | Viroid: infectious DNA |
| Shingles is a medical condition that usually occurs years after chickenpox, even though no illness is present in the intervening period of time. This occurs because human herpes virus-3 (HHV-3) is capable of __________. | latent infection |
| Which of these viruses is known to cause a persistent viral infection? | Measles virus |
| Infectious agents known as __________ cause Creutzfeldt-Jakob disease (CJD). | prions |
| Which of the following is NOT an oncolytic virus? | Retrovirus |
| Prions cause disease by __________. | altering normal proteins |
| An example of a latent virus infection is __________. | shingles |
| What type of infectious agent causes potato spindle tuber disease? | Viroid |
| What is the name given to the viral DNA incorporated into a lysogenic cell? | Prophage |
| Which method CANNOT be used to culture viruses in a laboratory? | Nutrient agar culture medium |
| After the attachment and entry of a virus into a host cell, what is the next step in the multiplication of animal viruses? | Uncoating |
| During __________, the phage remains latent. | lysogeny |
| Which of these statements is NOT true? | Attachment of animal viruses to host cells is random and nonspecific. |
| Cell lines derived from transformed (cancerous) cells are called __________. | continuous cell lines |
| The toxin production by Corynebacterium diphtheriae carrying a temperate phage is an example of __________. | phage conversion |
| Which two virus families make DNA from an RNA template? | Hepadnaviridae and Retroviridae |
| How might a virus pick up a human oncogene? | Specialized transduction |
| How would you know that viruses were multiplying in a confluent lawn of E. coli on a solid culture medium? | There would be small zones of clearing in the bacterial culture. |
| Consider a virus whose genome is composed of minus (–) sense RNA (for example, the rabies virus). What would be the first step in the biosynthesis of this virus? | Synthesize mRNA from the – sense RNA genome |
| Retroviridae use an RNA-dependent DNA polymerase called __________ to transcribe DNA from an RNA strand. | reverse transcriptase |
| Some viruses leave a cell by pushing through the cell membrane (rather than lysing the cell). When this happens, a portion of the membrane wraps around the viral capsid, becoming the envelope. What is the name for this process? | Budding |
| In polio virus replication, the function of the antisense (– strand) RNA is to __________. | serve as a template for the production of sense (+ strand) RNA |
| Which of the following is the preferred method for cultivating many animal viruses? | Growing them in animal cell cultures |
| Why may you be asked whether you are allergic to eggs before receiving a vaccination? | Some viruses are grown and isolated in embryonated eggs; especially those used for vaccines. The egg proteins may still be present in the viral vaccine preparations. |
| During the bacteriophage lysogenic cycle, __________. | phage DNA is inserted into the host chromosome |
| Which of these processes of viral multiplication is most likely to damage the host cell? | Release of nonenveloped viruses |
| How would you know that viruses were multiplying in a confluent lawn of E. coli on a solid culture medium? | There would be small zones of clearing in the bacterial culture. |
| Which of these viruses can incorporate the molecule serving as mRNA into its capsid? | Picornavirus |
| Which of these enzymes is necessary for the replication of a + strand RNA virus? | RNA-dependent RNA polymerase |
| The following steps occur during bacteriophage replication. What is the second step? | Penetration |
| Which membrane transport mechanism requires ATP? | active transport |
| Which type of solution would cause a bacterium with a weak or damaged cell wall to burst as water moves into the cell? | a hypotonic solution |
| Which of the following statements accurately describes bacterial cell walls? | In gram-negative bacteria, the thin layer of peptidoglycan is surrounded by an outer membrane made of phospholipids, lipopolysaccharides, and proteins. |
| You are observing a Gram stain of spherical-shaped microorganisms that are linked in a chain and stain purple. How would you describe these bacteria using the correct terminology for the cell shape and arrangement? | gram-positive streptococci |
| What type of reaction is represented by the equation below? Molecule AB →Molecule A + Molecule B | decomposition reaction |
| Catabolic | pathways break down macromolecules into simple component parts pathways release energy reactions couple with ATP synthesis Some energy released by catabolic reactions is stored in the form of chemical bonds in ATP. |
| Anabolic | pathways build up macromolecules by combining simpler molecules pathways require energy reactions couple with ATP synthesis. |
| In the generation of ATP, energy is released when electrons are passed to a series of electron acceptors and finally to oxygen or another inorganic compound. What is this process called? | oxidative phosphorylation |
| What is the purpose of fermentation? | to regenerate NAD+ from NADH |
| Which type of metabolic diversity contains most pathogens? | chemoheterotroph |
| Why do all enzymatic reactions need activation energy? | Energy is required to disrupt a substrate’s stable electron configuration. |
| What is meant by the statement “Enzymes are biological catalysts”? | Enzymes speed up the chemical reactions in living cells. |
| Why are enzymes important to biological systems? | Enzymes decrease the amount of activation energy required for chemical reactions to occur. |
| How does a competitive inhibitor slow enzyme catalysis? | They compete with the substrate for the enzyme's active site. |
| What enables competitive inhibitors to bind to a specific enzyme? | Competitive inhibitors have structures that resemble the enzyme’s substrate. |
| If high amounts of sulfanilamide are in the presence of an enzyme whose substrate is PABA, what outcome is expected? | PABA will not be catalyzed. |
| Which of the following statements regarding competitive inhibitors is true? | Competitive inhibitors decrease the rate of enzyme activity. |
| How does a noncompetitive inhibitor reduce an enzyme’s activity? | The inhibitor binds to the enzyme in a location other than the active site, changing the shape of the active site. |
| What would be the likely outcome if you increased the concentration of substrate for an enzyme in the presence of a noncompetitive inhibitor? | No change in enzyme activity would be observed. |
| How is nevirapine used to treat HIV infections? | It alters the active site of reverse transcriptase, decreasing that enzyme’s activity. |
| A reaction that involves the transfer of electrons from one molecule to another is referred to as | a redox reaction. |
| During an oxidation reaction, | the donor molecule loses an electron and becomes oxidized. |
| Why is reduction the term used to describe the gain of an electron? | The electron acceptor’s net charge decreases. |
| Which of the following statements regarding redox reactions is true? | Redox reactions involve an oxidation reaction coupled with a reduction reaction. |
| Select all statements that correctly describe glycolysis. | The 6-carbon skeleton of glucose is enzymatically split into two 3-carbon compounds. Glucose is the original electron donor. Glyceraldehyde 3-phosphate is oxidized, and NAD+ is reduced to NADH. More ATP is formed than is consumed in this process |
| Why is ATP required for glycolysis? | ATP makes it easier to break apart glucose into two three-carbon molecules. |
| Glycolysis literally means | sugar splitting. |
| How many net ATPs can be made from one molecule of glucose in glycolysis? | Two |
| What carbon molecules remain at the end of glycolysis? | Pyruvic acid |
| Which of the following statements about glycolysis is true? | Glycolysis is also called the Embden-Meyerhof pathway. |
| Glycolysis produces energy in which form? | NADH and ATP |
| What is the fate of metabolites during respiration? | They are oxidized completely to carbon dioxide and water. |
| What is meant by substrate-level phosphorylation? | Production of ATP by transferring phosphates directly from metabolic products to ADP |
| Which of the following is needed as a reactant for the first step of the citric acid cycle? | Oxaloacetic acid |
| What is the net production of ATP in glycolysis? | Two ATP |
| Which of the following statements about fermentation is true? | It is an alternative way to return electron carriers to their oxidized state. |
| What is the role of pyruvic acid in fermentation? | It takes the electrons from NADH, oxidizing it back into NAD+. |
| What is the fate of the NAD+ newly regenerated by fermentation? | It returns to glycolysis to pick up more electrons. |
| Which of the following is an acid produced by fermentation? | Lactic acid and propionic acid |
| What is the intermediate product formed by pyruvic acid during alcoholic fermentation? | Acetaldehyde |
| Where would you expect to find electron transport chains in a prokaryote? | Along the plasma membrane |
| Where does the energy come from to power the formation of GTP? | Succinyl CoA |
| The process of generating ATP using a proton gradient is referred to as | chemiosmosis |
| Why does FADH2 yield less ATP than NADH? | FADH2 electrons enter the electron transport chain at a lower energy level. |
| Which of the following can be used as a final electron acceptor for aerobic respiration? | Molecular oxygen |
| What is one difference between ubiquinones and cytochromes? | Ubiquinones are not made of protein; cytochromes are. |
| How does the proton gradient help ATP synthase to make ATP? | Protons move from outside the membrane to inside the membrane. |
| Iron is considered an essential element for many bacteria. Based on the animation, how would lack of iron affect energy production of a bacterium? | Lack of iron would mean lack of heme, and thus lower amounts of functioning cytochrome proteins. This would mean lower energy yields. |
| What is the role of light energy in photosynthesis? | To produce a proton gradient to make ATP |
| Which of the following is used in photosynthesis by both plants and cyanobacteria? | Water, sunlight, and carbon dioxide |
| What molecule is used to capture light energy? | Chlorophyll |
| Where do the electrons from photosystem I ultimately go after they are passed through the electron transport proteins? | They return to photosystem I. |
| What drives the production of ATP in cyclic photophosphorylation? | NADPH |
| Where does the energy to excite the electrons in photosystem I come from? | Sunlight |
| Which of the following types of organisms uses hydrogen sulfide for reducing power? | Purple sulfur bacteria |
| In which organism would you likely find a chlorosome? | Green sulfur bacteria |
| Which of the following is a bacterium that performs oxygenic photosynthesis? | Cyanobacteria |
| What is the key difference between photoheterotrophs and photoautotrophs? | Photoheterotrophs use organic compounds as their carbon source; photoautotrophs use carbon dioxide as their carbon source. |
| Which of the following is a trait unique to photosynthetic eukaryotes? | The presence of chloroplasts |
| Noncyclic photophosphorylation employs which photosystem(s)? | Both photosystem I and photosystem II |
| What is the fate of electrons in noncyclic photophosphorylation? | Reduce NADP+ to NADPH |
| What is the fate of the NADPH molecules created during noncyclic photophosphorylation? | They are used in the Calvin-Benson cycle. |
| Why is the Calvin-Benson cycle also termed the "light independent reactions" of photosynthesis? | Sunlight is not directly needed to carry out this process. |
| What is the source of the electrons that reduce 1,3-bisphosphoglyceric acid? | NADPH |
| What is the key product formed by the Calvin-Benson cycle? | G3P |
| How many of the six G3P’s produced in one cycle are used to make one molecule of glucose? | One |
| Select the correct sequence of steps as energy is extracted from glucose during cellular respiration. | glycolysis → acetyl CoA → citric acid cycle → electron transport chain |
| What is the correct general equation for cellular respiration? | C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP energy |
| Which of the following processes takes place in the cytosol of a eukaryotic cell? | glycolysis |
| In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain? | mitochondrion |
| Which statement describes glycolysis? | This process splits glucose in half and produces 2 ATPs for each glucose. |
| Which statement describes the citric acid cycle? | This process produces some ATP and carbon dioxide in the mitochondrion. |
| Which statement describes the electron transport chain? | This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration. |
| Which of the following equations represents photosynthesis? | 6CO2 + 6H2O → C6H12O6 + 6O2 |
| In which of the following organelles does photosynthesis take place? | Chloroplast |
| What connects the two photosystems in the light reactions? | An electron transport chain |
| What two molecules are produced by the light reactions and used to power the Calvin cycle? | ATP and NADPH |
| What provides electrons for the light reactions? | H2O |
| What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle? | Carbon dioxide (CO2) |
| What transports electrons from the light reactions to the Calvin cycle? | NADPH |
| The light reactions take place in the _________ and the Calvin cycle takes place in the _________. | thylakoids; stroma |
| Which of the following actions would increase enzymatic activity in a bacterial cell that normally thrives in the human body? | slightly increasing the temperature within the optimum range |
| Which of the following is true concerning ribozymes? | Ribozymes have an active site and are not used up in chemical reactions. |
| Which of the following is true of aerobic respiration compared to anaerobic respiration? | Aerobic respiration uses oxygen as a final electron acceptor, whereas anaerobic respiration uses an inorganic molecule other than oxygen as the final electron acceptor. |
| Which of the following statements is FALSE regarding the oxidation of proteins? | Microbes produce extracellular enzymes to reduce proteins to their fatty acid and glycerol components so that each component can enter the Krebs cycle. |
| Which of the following best describes the role of the gut microbiome in human digestion? | The gut microbiome breaks down dietary compounds that human metabolic enzymes cannot break down. |
| What is the main function of fermentation? | To regenerate NAD+ for glycolysis. |
| Which of the following gases is or are produced during the breakdown of cysteine and methionine and is responsible for foul-smelling flatulence? | H2S |
| Which of the following is NOT a sign or symptom of irritable bowel syndrome (IBS)? | Fever |
| Agars can be used to select for growth of certain types of bacteria and then allow for you to identify the different bacteria that can grow on the plate. These agars may be considered both selective and differential. | True |
| Catabolic Reaction | Starches are digested into individual glucose molecules. Glucose is broken down into two pyruvates |
| Anabolic Reaction | Ammonia is added to glutamate to form glutamine .Four amino acids are linked together to form a tetrapeptide. Ribose and inorganic phosphate are bonded to form a nucleotide base. A uracil base is added to an mRNA strand by RNA polymerase |
| mesophile | 1. A bacterium that is a common cause of human infections but is also part of our microflora would have to be in the mesophile class of bacteria. |
| psychrophile | 2. A bacterium with increased cholesterol in its cytoplasmic membrane to maintain membrane fluidity at extremely low temperatures would probably fall in the psychrophile class of bacteria. |
| thermophile | 3. A bacterium that can be found growing in a hot spring would be considered a thermophile. 4. The thermophile bacteria have evolved to grow and excel in temperatures that denature most protein and kill most organisms. |
| Glycolysis generates energy by producing? | 2 ATP and 2 NADH |
| In aerobic cellular respiration, if four molecules of pyruvic acid enter steps two, the formation of acetyl CoA and three, the Krebs cycle, how many molecules of ATP, NADH, and FADH2 will be formed? | 4 ATP, 16 NADH, 4 FADH2 |
| Cyanide is a poison that induces cell death by preventing the electron transport chain from functioning. Which of the below statements best describes how cyanide kills cells. | Without the movement of electrons through the electron transport chain, the hydrogen ion gradient is not produced, chemiosmosis will not occur. Without chemiosmosis, the cell is unable to produce enough cellular ATP to survive. |
| The step that precedes the Krebs cycle in aerobic cellular respiration is? | The intermediate step |
| Which of the following statements accurately describes the difference between aerobic and anaerobic respiration? | Aerobic respiration uses oxygen as the final electron acceptor, and anaerobic respiration uses either an inorganic molecule, such as nitrate ions or sulfate ions, or an organic molecule, such as an acid or alcohol. |
| Which of the following is true of catabolism? | Catabolic reactions are exergonic; they break down complex organic molecules into simpler ones. |
| Which of the following statements is correct about enzymes? | Each enzyme has a characteristic three-dimensional shape. |
| All of the following pairs are correctly matched EXCEPT __________. | oxidation—reaction in which electrons are gained |
| The chemical reactions involved in synthesizing proteins and cell wall peptidoglycan are examples of __________ reactions. | anabolic |
| Unlike chemiosmosis in eukaryotes, prokaryotes chemiosmosis __________. | occurs at the plasma membrane and not the mitochondria |
| Competitive inhibition of enzyme action involves __________. | competition with the substrate for binding at the active site |
| In an enzymatic reaction involving oxidation of a substrate, which of the following would be required? | NAD+ |
| Which of the following pairs is NOT correctly matched? | Oxidation; reaction in which electrons are gained |
| Enzymes work most effectively at their optimal __________. | temperature amount of substrate pH |
| In __________ an end-product of an anabolic pathway inhibits the activity of one or more enzymes in a pathway. | feedback inhibition |
| A coenzyme assists an enzyme by accepting or donating matter. What does NAD+ transfer? | Electrons |
| All of the following are required for the generation of ATP by chemiosmosis EXCEPT __________. | conversion of pyruvic acid to lactic acid |
| Which of the following mechanisms does NOT generate ATP using an electron transport chain? | Substrate-level phosphorylation |
| Enzymes are important in living organisms because they __________. | bring together reactants or properly orient a molecule for a reaction |
| Some amino acids are synthesized by adding an amine group to pyruvic acid or to one of the Krebs cycle intermediates. This process is known as __________. | amination |
| When fermentation tests are used to help identify bacteria, which of the following end-products is typically detected by a color change? | acid |
| During the light-independent reactions of photosynthesis, organisms __________. | synthesize sugars |
| A Thiobacillus bacterium uses the Calvin-Benson cycle to reduce CO2 and the oxidation of sulfide ions for energy. This organism is a __________. | chemoautotroph |
| Which of the following terms refers to pathways that can function in both anabolism and catabolism? | Amphibolic pathways |
| Which of the following are products of noncyclic photophosphorylation reactions in oxygenic organisms? | O2, ATP, and NADPH |
| Carbon fixation occurs during __________. | photosynthesis |
| Like glucose, amino acids are catabolized for energy, but these must be converted to a form in which they can enter the Krebs cycle for oxidation. All of the following reactions occur in the catabolism of amino acids EXCEPT __________. | carbon fixation |
| Which group of organisms has members representing each of the following nutritional classifications: chemoheterotrophs, chemoautotrophs, photoheterotrophs, and photoautotrophs? | Bacteria |
| Which organism is NOT correctly matched to its energy source? | Photoautotroph; CO2 |
| Which one molecule could provide the carbon source, the energy source, and the electron source for a chemoheterotroph? | Glucose |
| The __________ is commonly used to identify aerobic microorganisms. | oxidase test |
| Heterotrophs use organic molecules as energy and carbon sources. To produce five-carbon intermediates needed for synthesis of nucleic acids, the cell utilizes the __________. | pentose phosphate pathway |
| An organism uses glucose as energy source and respires O2. This organism is known as a(n) __________. | chemoheterotroph |
| Nitrobacter bacteria use carbon dioxide for their carbon source and nitrate ions as an energy source. This organism is a __________. | chemoautotroph |
| Which of the following molecules traps energy released during oxidation-reduction reactions? | ATP |
| You inoculate a bacterial culture into a tube containing glucose and peptides. The pH indicator shows that the pH decreased after 24 hours and then increased at 48 hours. What has caused the increase in pH? | deamination |
| Organisms that use carbon dioxide as a carbon source and ammonia or hydrogen sulfide as energy sources are called __________. | chemoautotrophs |
| Streptococci lack an electron transport chain. How many molecules of ATP can a Streptococcus cell net from one molecule of glucose? | 2 |
| Which of the following four stages of glucose oxidation during aerobic respiration requires molecular oxygen? | Oxidative phosphorylation |
| All of the following steps are involved in the aerobic electron transport chain. Which step happens last? | Electrons are transferred to O2. |
| Fermentation differs from anaerobic respiration in that fermentation does NOT __________. | use an electron transport chain |
| The complete oxidation of glucose in aerobic and anaerobic respiration involves which three stages? | Glycolysis, Krebs cycle, and the electron transport chain |
| The proton motive force is __________. | an electrochemical gradient formed across a membrane |
| One of the sites of allosteric regulation of the Krebs cycle is the conversion of pyruvic acid to acetyl CoA. Which of the following conditions would you expect to inhibit the conversion of pyruvic acid to acetyl CoA? | High ATP and high NADH |
| The complete oxidation (catabolism) of glucose typically involves three stages. The greatest number of ATPs is produced in which stage? | The electron transport chain |
| At the completion of the Krebs cycle, the carbons from glucose are found in __________. | CO2 |
| Which of the following statements is accurate concerning glucose metabolism? | Pyruvic acid, the product of glycolysis, is the starting block for both the Krebs cycle and fermentation. |
| Which of the following molecules carry electrons during various stages of glucose catabolism? | NADH and FADH2 |
| During glycolysis, electrons from the oxidation of glucose are transferred to __________. | NAD+ |
| Which of the following would you predict to be a feedback inhibitor of the glycolytic enzyme phosphofructokinase? | ATP |
| Glycolysis produces ATP through __________. | substrate level phosphorylation |
| NADH molecules formed during glycolysis and in the Krebs cycle are __________. | oxidized when electrons are passed to the electron transport chain |
| __________ may serve as substrate(s) of glycolysis. | Lipids Proteins Sugars |
| All of the following are potential end-products of fermentation EXCEPT __________. | All of the following are potential end-products of fermentation EXCEPT __________. |
| In which phase of the growth curve is the population-doubling time fastest? | Log phase |
| Before bacteria can be identified, mixed cultures must be separated. What technique is used to separate bacteria and get individual colonies? | Streak plate |
| If 52 bacterial colonies grow on a nutrient agar plate inoculated with 1 ml of a 1:1000 dilution of hamburger, how many bacteria are in the original hamburger sample? | 52,000 bacteria per gram |
| Assume that you inoculated potato salad with 10 bacterial cells and stored it at room temperature. After 3 hours, there are 640 cells. How many generations did the cells go through? | 6 generations |
| During log phase, bacteria are __________. | dividing at the fastest possible rate |
| When a bacterial cell reproduces by splitting into two daughter cells, the process is called __________. | binary fission |
| The following steps occur during binary fission. What is the third step? | Inward growth of membrane |
| You are testing the number of coliforms in a drinking water source. Which of the following test methods would be best to use? | Filtration |
| All of the following are true of the plate count method EXCEPT that it __________. | takes less than 12 hours to complete |
| Bacterial growth refers to an increase in the __________ of bacterial cells. | number |
| In a(n) __________, cells are added to melted agar and poured into a Petri dish. | pour plate |
| All of the following can be used to preserve bacterial cultures EXCEPT __________. | storing cultures at room temperature (25°C) |
| During which phase of the cell cycle are bacteria dividing equal to bacteria dying? | Stationary phase |
| During the lag phase, __________. | cells are engaged in intense enzymatic activity |
| Which of the following is NOT a step in binary fission? | Lysis of the existing cell wall |
| Which of the following is NOT a method used for the direct measurement of microbial growth? | Turbidity |
| If a single bacterium replicated every 30 minutes, how many bacteria would be present in 2 hours? | 16 |
| Bacteria that CANNOT grow in the presence of oxygen (O2) are called __________. | obligate anaerobes |
| An organism that grows both in the presence and the absence of oxygen and uses oxygen when it is available is called a(n) __________. | facultative anaerobe |
| __________ organisms are often responsible for food spoilage in refrigerated foods. | Psychotroph |
| What do all of these bacteria have in common? Bacteria in the rumen of cattle and sheep Bacteria in a sewage treatment plant Bacteria growing in the middle ear in chronic otitis media Bacteria growing on the teeth in dental plaque | The bacteria are most likely growing in biofilms. |
| Bacteria growing in and on the human body, including normal microbiota as well as pathogens, are classified as __________. | mesophilic and heterotrophic |
| Which of the following statements regarding biofilms is true? | The microbes in biofilms can work cooperatively to carry out complex tasks. |
| Campylobacter bacteria are grown with a CampyPak that produces 5% carbon dioxide and 15% oxygen. This bacterium is __________. | a microaerophile |
| What is quorum sensing? | The ability of bacteria in a biofilm to communicate with each other and coordinate their activities |
| The ability of microbes to utilize N2 as a nitrogen source is called __________. | nitrogen fixation |
| An unknown organism grows at the top of a tube of thioglycolate broth. This organism is best described as a(n) __________ for its oxygen requirements. | obligate aerobe |
| Which of the following is NOT a chemical requirement of all bacteria? | Molecular oxygen |
| An organism displays some growth at 4°C and at 25°C. However, it grows best at 20°C. This organism would be classified as a __________. | psychrotroph |
| Bacteria that spoil food in the refrigerator are most likely __________. | psychrotrophs |
| Instead of oxygen, __________ may utilize nitrate or sulfate as their final electron acceptors. | obligate anaerobes |
| Which of the following terms are mismatched? | Hyperthermophiles; 0°C |
| To look for bacteria that degrade petroleum, a culture medium containing crude oil, sodium nitrate, phosphate buffer, and magnesium sulfate is inoculated with soil. This medium is __________. | complex |
| A bacterial medium contains chemicals that inhibit gram-positive bacteria and indicators so that bacteria that ferment lactose produce red colonies, and bacteria that do not ferment lactose produce colorless colonies. Such a medium is called __________. | both selective and differential |
| Clostridium can be cultured in an anaerobic incubator or in the presence of atmospheric oxygen if thioglycolate is added to the nutrient broth. The addition of thioglycolate makes the medium __________. | reduced |
| Which biosafety level features open laboratory bench tops, gloves, lab coat, and face and eye protection? | BSL-2 |
| A medium containing chemicals to inhibit the growth of gram-positive bacteria would be called __________. | selective |
| Which of the following statements about culture media is FALSE? | Nutrient agar contains ingredients that combine with oxygen and remove it. |
| A culture medium consisting of agar, peptone, and beef-heart extract is a(n) __________. | complex medium |
| Niacin, when added to a medium, would be considered a(n) __________. | organic growth factor |
| A medium containing lauryl sulfate inhibits the growth of gram-positive bacteria. This medium is __________. | selective |
| Blood agar used to observe hemolysis or clearing around Streptococcus pyogenes colonies is an example of a(n) __________. | differential medium |
| Which level of biosafety (BSL) is appropriate for handling organisms that present the highest risk level for infection and the lowest success rate for prevention and treatment? | BSL-4 |
| Bacteria require nitrogen for the synthesis of __________. | proteins |
| Members of the genus Clostridium display the following properties: Gram-positive bacilli Endospore formation Anaerobic growth Which of the following would be appropriate for the culture of members of this genus? | Both a blood agar plate in an anaerobe jar and sodium thioglycolate broth |
| Salt agar tends to inhibit the growth of most organisms, except Staphylococci. This is an example of a(n) __________ medium. | selective |
| Through metabolism, pathogens often produce acids that interfere with their own growth. __________ are/is added to media to control pH changes. | buffers |
| Martian soil is inoculated into a glucose-containing medium. The radioactive form of carbon, 14C, is used in the glucose. After incubation for five days, which of the following would provide evidence suggesting that there is life on Mars? | Radioactive carbon dioxide |
| Which of the following terms refers to pathways that can function both in anabolism and catabolism? | amphibolic pathways |
| In cellular respiration of glucose, what are the three principal stages? | glycolysis, Krebs cycle, and the electron transport chain |
| What type of reaction is represented by the equation below? Molecule AB →Molecule A + Molecule B | decomposition reaction |
| When bacteria are inoculated into a new sterile nutrient broth, their numbers don’t begin to increase immediately. Instead, there is a lag phase that may last for an hour or even several days. Why don’t bacterial numbers increase immediately? | The bacteria must adjust to the nutrient content in the new medium, synthesizing necessary amino acids, growth factors, and enzymes. |
| A chemostat is continuous culture system that is designed to promote and prolong exponential growth and prevent bacteria from entering stationary phase. How might this work? | Chemostats provide a continued source of fresh nutrients and remove wastes and dead bacterial cells. |
| What results when a single bacterium reproduces? | Two genetically identical daughter cells |
| If you begin with six cells, how many cells would you have after three rounds of division? | Forty-eight cells |
| Which of the following is NOT a step in bacterial cell division? | Disappearance of nuclear envelope |
| Which step of binary fission is the reason for genetically identical daughter cells? | Replication of the bacterial chromosome |
| Microbes have very narrow optimum temperature ranges. Which of the following classifications of microbes are most likely to cause human disease, based on their temperature requirements? | mesophiles |
| Bacteria that can grow in the presence or absence of oxygen (O2) are called __________. | facultative anaerobes |
| Which of the following statements accurately describes the culture medium necessary for growing an obligate anaerobe, such as Clostridium tetani? | Reducing media are complex media containing chemicals, such as thioglycolate, that combine with oxygen, creating an anaerobic environment. |
| Which of the following phases of the bacterial growth curve is matched with the correct definition? | log phase--the phase in which organisms are actively dividing and the generation time is constant |
| Which process is best for the short-term storage of bacterial cultures? | refrigeration |
| What enables the copied chromosomes to separate during binary fission? | The chromosomes are attached to different parts of cell membrane, which elongates and thus separates the chromosomes. |
| How long does it take for the daughter cells to initiate or start the next round of replication? | No time is required -- they are ready to divide immediately after DNA replication and separation of the daughter cells is complete if conditions are right. |
| Put the following steps of bacterial replication in the correct order, starting from a parent cell. Cell elongation Septum formation Chromosome replication Separation of daughter cells | 3, 1, 2, 4 |
| What would happen if the septum did not form during binary fission? | The parent cell would now have two copies of the chromosome. |
| Starting with three cells, how many cells would result from three rounds of replication? | Twenty-four |
| Patients with indwelling catheters (long-term tubes inserted into body orifices for drainage, such as through the urethra and into the urinary bladder) are susceptible to infections because | biofilms develop on catheters. |
| For which of the following types of microbes would a microbiologist employ living host cells to support their growth? | obligate intracellular organisms, such as chlamydias, rickettsias, and viruses |
| Which of the following methods used to count microbes is correctly identified as direct or indirect? | filtration--direct method |
| Which enzyme catalyzes the reaction: O2- + O2- + 2H+ → H2O2 + O2? | superoxide dismutase |
| Which enzyme catalyzes the following reaction? 2H2O2 → 2H2O + O2 | catalase |
| Which of the following pairs of microbe classification terms and optimal growth temperatures is mismatched? | thermophile – growth at 37°C |
| Most fungi grow best at pH | 5 |
| Most bacteria grow best at pH | 7. |
| The term aerotolerant anaerobe refers to an organism that | does not use oxygen but tolerates it. |
| The addition of which of the following to a culture medium will neutralize acids? | buffers |
| Which of the following elements is NOT correctly matched with its cellular function? | phosphorus – used for production of carbohydrates. |
| Pure cultures can easily be obtained on streak plates, even if the desired bacteria are present in very low concentrations in the initial culture broth. | False |
| Pathogenic bacteria isolated from the respiratory or intestinal tracts of humans are | capnophiles that grow best in carbon dioxide incubators. |
| What would you expect to observe when a halophile that cannot ferment mannitol is cultured on mannitol salts agar? | Good growth accompanied by no change in color of the medium. |
| How is pathogenic Staphylococcus aureus distinguished from other species of Staphylococcus? | Staphylococcus aureus is able to ferment mannitol, while other members of the genus are not. |
| What factors that are important when formulating culture media? | pH Oxygen (O2) levels Water availability |
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