Final Flashcards
If the broth in Pasteur’s swan-necked flask experiment had contained endospores, which of the following results might he have obtained?
The broth would seem sterile after boiling but would soon develop bacterial growth
In nature, bacteria: (all answers are correct)
- Often grow in close association with many other kinds of organisms
- frquently synthesize structures such as slime layers
- Often produce antibiotics to inhibit the growth of competitors
- may adhere to surfaces by means of pili and slime layers
Electron microscopes differ from light microscopes in that
- electrons replace light
- resolution is higher
- magnification is higher
- electromagnets replace glass lenses
Place steps of Gram stain in correct order
- crystal violet
- iodine
- alcohol-acetone
- safranin
Chemoheterotrophs
- use preformed organic molecules as an energy source
- use preformed organic molecules as a carbon source
Which of the following best describes how penicillin effects peptidoglycan?
Prevent cross-linking of adjacent glycan chains
Agar replaced gelatin as the gelling (solidifying) agent for media because
- agar is solid at body temp
- much fewer bacteria can break down agar than gelatin
Sugar or salt can be used for food preservation because
- they create a hypertonic environment, unfavorable for bacterial growth
- they may cause plasmolysis
- they dehydrate cells
Arrange the general size of microbes from the largest to smallest:
- Helminth
- Protozoa
- Bacteria
- Viruses
- Viroids
The outbreak of measles within the last few years was due to
a decline in vaccination of children in the previous years
Negative staining is commonly used to determine if bacterial cells have
capsules
All of the following are factors that account for the emergence of new diseases in developed countries EXCEPT:
parents do not have their children vaccinated
Check all statements that apply to the bacterial cytoplasmic membrane
- Proton motive force
- Barrier to large compounds
- aquaporins
A species of bacteria that is fastidious is least likely to be able to grow on which of the following media?
glue-salts agar
Facilitated diffusion and active transport
both transport molecules into or out of a cell
In the growth curve of a bacteria population, the bacteria are rapidly increasing in number in the
exponential (log) phase
In figure 6.3, which tube shows the expected growth pattern for a facultative anaerobe
b. a build up at the top but spread between the liquid
Ultraviolet radiation at the bactericidal wavelength destroy bacteria by
damaging nucleic acid
Pasteurization
is the use of heat to reduce numbers of pathogenic/spoilage bacteria in a food item to a safe level
Which of the following most likely contains human pathogens?
Mesophiles
A high-solute, or ___ environment causes plasmolysis which damages microbial cells
hypertonic
Which of the following stains is/are considered differential?
- Acid-fast stain
- gram stain
Antibiotic Killcillin targets 50S ribosome subunit and will kill
bacteria
If you wanted to increase your chances of isolating a member of the Archaea (rather than a member of another domain)
A 95 degree celsius hot spring in yellowstone national park
The idea of spontaneous generation postulated that
living organisms could spontaneously arise from non-living material
The opposite results obtained by scientists apparently doing the same experiments in investigating spontaneous generation
all of the choices are correct
Order the following situations from highest to lowest requirements of microbe-free environments:
- Open heart surgery
- pharmaceutical manufacturing facility
- food production facility
- kitchen counter
- bathroom counter
A microbiologist obtained two pure isolated biological samples: one of a virus and one of a viroid. The labels came off during a move from one lab to the next however the scientist felt she could distinguish between the two samples by analyzing for the presence of a single type of molecule would she be looking for to differentiate between the two?
protein
Which of the following are found in gram positive cells but not gram negative cells?
teichoic acids
A species of bacteria lacks superoxide disputasse and catalase. Which of the following groups does this species of bacteria likely belong to?
obligate anaerobes
Bacteria on fish caught in the arctic ocean would
- continue to grow while the fish is in the refrigerator
- be psychrophiles
a. sterilization
b. disinfection
c. antispesis
d. bacteriostasis
e. sanitation
1. removing pathogens to meet public health standards
2. inhibiting growth of bacteria
3. removing all microbial life forms
4. removing pathogens from living tissues
5. removing pathogens from inanimate objects
- sanitation (1): removing pathogens to meet public health standards
- bacteriostasis (2): inhibiting growth of bacteria
- sterilization (3): removing all microbial life forms
- antispesis (4): removing pathogens from living tissues
- Disinfection (5): removing pathogens from inanimate objects
Which is NOT true about smallpox?
-It still occasionally occurs in third world countries
The resolving power of a microscope is describe as the ability of the microscope to
separate clearly two objects that are very close together
A microbe is discovered growing near a deep sea thermal vent. When researchers bring a sample up to the surface and try to grow t in a lab at room temperature in a normal incubator, they are unsuccessful. Why?
All of the answers
To obtain an effective concentration of chlorine when using household bleach, a 1:100 dilution is made. This means that ___ mL of bleach is added to ___ mL of water
1,99
Boiling is not reliable for sterilization because
Heat-resistant endospores are unaffected
Which of the following is found exclusively in prokaryotic cells?
Endospore
Which is (are) true concerning the cell wall of all prokaryotes?
- it prevents the bacteria from bursting
- it determines the shape of the bacteria
A sterile item is free of:
- endospores
- archeae
- bacteria
- prions
- viruses
Which DOES NOT describe protozoa correctly?
ingest inorganic materials as main food source
The decimal reduction time is the time it takes to kill 90% of a given bacterial population under certain conditions. If 90% of a population of 10,000 bacteria is killed in 5 minutes, how long would it take to reduce the population to 10 cells?
15
Describe:
a. viruses
b. bacteria
c. archaea
d. protozoa
e. viroids
- viruses (1): made of nucleic acids and proteins
- bacteria: Single-celled organisms with peptidoglycan cell walls but without a nucleus
- archaea: single-celled organisms living in extreme environments and without a nucleus
- protozoa: single-celled organisms with a true nucleus
- viroids: naked nucleic acids
Which of the following is not a sterilization method?
Pasteurization
Which of the following pairs is most closely related and correctly written?
Staphylococcus aureus and Staphylococcus epidermis
MacConkey agar contains bile salts and dyes that inhibit Gram-positive organisms and Gram0negative cocci, making it ___; it also contains a pH indicator that turns pink-red when lactose in the medium is fermented, making it ____.
Selective, differential
Organisms may derive energy from
- metabolizing chemical compounds
- sunlight
In the presentation of Current Microbiology News, “Hygiene Hypothesis” was mentioned in relation to normal micro biome. Which statement best describe the Hygiene Hypothesis?
Early exposure to microbes in the environment allow immune system to be trained and developed well in children
If you remove the glycoocalyx of a bacterium, the organism would no longer be able to
survive in hypotonic solutions
Haemophilus influenza is a gram-negative coccobacilius. If you looked as a gram stained culture using a light microscope, you would expect to see
pink, very short rod
Consider how an aerobically respiring bacterial cell uses glycolysis, the TCA cycle, and oxidative phosphorylation to break apart and oxidize glucose. What are three main benefits these central metabolic pathways yield to the cell?
ATP
reduced electron carriers
precursor metabolites
Functions of the following tRNA mRNA rRNA miRNA
tRNA: Carries amino acids to the growing peptide chain during translation
mRNA: contains the genetic information decoded during translation
rRNA: components of ribosomes
miRNA: regulates gene expression
Functions of the following: DNA gyrase primase helicase okazzaki fragments DNA ligase
- DNA gyrase: enzyme that temporarily breaks the strands of DNA relieving the tension caused by unwinding the two strands of DNA helix
- Primase: Enzyme that synthesizes small fragments of RNA
- Helicase: Enzyme that unwinds DNA helix at the replication fork
- Okazzaki fragments: Nucleic acids produced during discontinuous synthesis of lagging strand of DNA
- DNA ligase: Enzyme that joins two DNA fragments together forming a covalent bond btw the sugar and phosphate residues`
Which of the following statements about the figure below are TRUE?
-The organism shown on the agar plate is likely a Pseudomonas species
Which of the following are correct regarding Restriction Enzymes?
- DNA fragments produced by restriction enzymes can be ligated together
- They evolved as a defense mechanism against bacteria
Place the steps of F plasmid transfer in order
- F plus makes contact with recipient cell
- one strand of the f plasmid is cut at the origin of transfer
- Single-stranded is transferred to the recipient
Which of the statements about DNA and RNA in prokaryotes and eukaryotes are FALSE?
- Eukaryotic mRNA is typically polycistronic
- RNA polymerase requires a primer
Which of the following would be the correct scientific name?
Homo sapiens (all italicized)