module 4a (ch 13-14) (week 5+6), ch13, NEEGA
Transposons can cause mutations by
"jumping" into a gene and disrupting its function.
Enzymes and their catalytic activity is affected by changes in temp. The velocity of the reaction roughly doubles for every __C rise in temp
- 10
Standard conditions for sterilization in an autoclave are
- 121C and 15 pounds of pressure
Generation number
- 2^n
Replisome
- A large protein complex that copies the DNA double helix to form two daughter chromosomes
Compatible solute
- A low molecular weight molecule used to protect cells against changes in solute conc (osmolarity) in their habitat; it can exist at high concentrations within the cell without hindering metabolism or growth
psychrotolerant (aka psychrotrophs) microorganisms
- A microorganism that has a growth optimum between 20 and 30C and a max of about 35C
Psychrophiles (aka cryophiles)
- A microorganism that has an optimum growth temp of 15 C or lower and a temp max around 20C - Oceans constitute an enormous habitat for psychrophiles because 90% of ocean water is 5C or colder
Halophiles
- A microorganism that requires high levels of sodium chloride (salt) for growth
Microaerophiles
- A microorganism that requires low levels of O2 for growth, around 2 to 10%, but it is damaged by normal atm O2 (20%) levels
- The origin of replication
- A site on a chromosome or plasmid where DNA replication is initiated
HEPA filters
- A type of depth filter made from fiberglass - remove 99.97% of particles 0.3 micrometer or larger by both physical retention and electrostatic interactions - Sterilize air by removing viruses 0.1 micrometer or smaller
Autoclave
- An apparatus for sterilizing objects by the use of steam under pressure - Hot saturated steam continuously enters the chamber until the chamber reaches the desired temp and pressure, usually 121 C and 15 psi.
Oligotrophic environment
- An environment containing low levels of nutrients that support microbial growth
Binary fission
- Asexual reproduction in which cells separates into two identical daughter cells
Explain how is the exponential phase saturable and why
- At sufficiently high conc of nutrient levels, the transport systems are saturated, and the growth rate does not rise further with increasing nutrient conc.
Why does sunlight appears white?
- Because it is evenly distributed across the ROYGBV wavelengths
Microbial growth has a characteristic temp dependence with distinct
- Cardinal temperatures
Why is max growth temp for an organism variable? a strict characteristic of each organism, determined by the properties of its molecular components
- Cardinal temps are not rigidly fixed, depending on other environmental factors including pH and nutrients
The ____ ________ is the complete sequence of events extending from formation of a new cell through the next division
- Cell cycle
When organisms are above or below their optimum temp, both cell ______ and _____ are affected
- Cell function and structure
Biocide
- Chemical or physical agent, usually with a broad spectrum of biological activity, that inactivates microorganisms
Which three properties are important for a good, general purpose, chemical disinfectant?
- Contains viricidal properties - Effective against a range of microorganisms - Non-toxic to humans or animals
Vibriod shape is determined by ________ in caulobacter crescentus
- Crescentin
Describe step 4 (final) of binary fission
- Daughter cells are divided - Some species separate completely, while others remain attached, forming chains, doublets, or other cellular arrangements
When pairing a depth filter and a membrane filter, which order is best?
- Depth filter, then membrane filter
What are the types of filters?
- Depth filters - Membrane filters
What could cause irreparable damage to cells in a batch culture?
- Detrimental environmental changes such as nutrient deprivation - The build up of toxic wastes
What is special about the long-term stationary phase?
- During this phase, the bacterial population continually evolves - This dynamic process is marked by successive waves of genetically distinct variants
What are the two molecular machines that synthesize the peptidoglycan of rod-shaped cells?
- Elongasome and divisome
Mechanism of action of sterilizing gases
- EtO is a strong alkylating agent that kills by reacting with DNA and proteins to block replication and enzymatic activity
Depth filters
- Filters composed of fibrous or granular materials that are used to decrease microbial load and sometimes to sterilize solutions - Consist of fibrous or granular materials that have been bonded into a thick layer filled with narrow, twisting channels
The placement of protein _______ determines the site of cell wall growth by recruiting enzymes needed for peptidoglycan synthesis to the divisome
- FtsZ
Batch culture
- Growth of microorganisms in a closed culture vessel without adding fresh or removing old (spent) medium
What are the most frequently employed physical agents used to control microbial growth and sterilize objects?
- Heat and radiation
UV radiation
- High energy radiation of short wavelength, about 10 to 400 nm - around 260 nm is quite lethal. It causes thymine-thymine dimerization of DNA, preventing replication and transcription
Calc of generation (doubling) time
- If a pop doubles, then -- Nt = 2No Generation time g = 1 k
How are microorganisms controlled?
- If you can starve or poison microbes, or inhibit or prevent growth or replication, you can control them
What is the predominant component of sunlight?
- Infrared rays make up almost 60% of the Sun's radiation - Infrared radiation is the major source of Earth's heat
Halogens
- Iodine and chlorine are important antimicrobial agents - idoine is used as a skin antiseptic and kills by oxidizing cell constituents and iodinating proteins
One of the most harmful form of electromagnetic radiation to microorganisms is
- Ionizing radiation
In ocean depths (1000 m or more), the hydrostatic pressure can reach 600 to 1,100 atm and the temp is about 2 to 3C. How does it affect microbes?
- It can affect the fluidity and membrane-associated functions
What is the importance of MreB proteins in determining cell shape?
- It is demonstrated by two observations: - Rod-shaped cells in which MreB has been depleted assume a spherical shape - While almost all rod-shaped bateria and archaea synthesize at least one MreB homologue, coccoid-shaped cells lack proteins in the MreB family
Phenomenon of osmosis
- It is observed when two solutions are separated by a semipermeable membrane that allows movement of water but not solutes - Water moves from solutions with lower solute conc to those with higher solute conc
Elongasome (molecular machine)
- It is responsible for elongation of the cell that occurs prior to septum formation - The actin homologue MreB family play an important role during elogantion
Where does the protein crescentin localize in the cell?
- It localizes to one side of the cell, where it slows the insertion of new peptidoglycan units into the peptidoglycan sacculus, which results in an asymmetric cell wall growth given the cell its inner curvature that characterizes the comma shape
Which is the term for the period of adaptation that typically occurs when fresh growth medium is inoculated with a microbial culture?
- Lag phase
what is the phase in the microbial growth curve where microbes are only synthesizing new components?
- Lag phase
Sterilization
- Latin sterilis, unable to produce offspring - The process by which all living cells, spores, and acellular entities(e.g., viruses, viroids, and prions) are either destroyed or removed from an object or habitat
Aerobetolerant anaerobes
- Microbes that grow equally well whether or not O2 is present
Facultative anaerobes
- Microorganisms that do not require O2 for growth, but grow better in its presence - In the presence of O2, they use it as the terminal electron acceptor during aerobic respiration.
Extremophiles
- Microorganisms that grow in extreme environments
Piezophilic (barophilic)
- Microorganisms that prefer or require high pressures for growth and reproduction
How does heat disinfect?
- Moist heat destroys cells and viruses by degrading nucleic acids, denaturing proteins, and disrupting cell membranes. - Boiling can be used for disinfecting drinking water and objects not harmed by water, but it does not sterilize
Which proteins are important in maintaining the cell shape of vibrios?
- MreB - actin homologue - FtsZ- tubulin-like protein - Crescentin - homologue of eukaryotic intermediate filaments (shape-determining protein of vibrioid cells)
MreB protein
- MreB functions as a scaffold upon which the cell-wall synthesizing machinery assembles - MreB proteins and other elongasome proteins redeploy from the sidewalls to the midcell, where they contribute to cell wall synthesis during cytokinesis; thus, cell wall growth switches from the side wall to the septum at this time
What two filters used to filter air?
- N95 disposable masks used in hospitals and labs - High-efficiency particulate air (HEPA) filters
Almost all multicellular organisms are ______ aerobes because
- Obligate aerobes because they completely depend on atmospheric O2 for growth
Where is crescentin localized and what is its function?
- On one side of the wall, where it slows the insertion of new peptidoglycan units into the peptidoglycan sacculus - The resulting asymmetric cell wall growth gives rise to the inner curvature that characterizes the comma shape
How many origins of replication are found on most bacterial chromosomes?
- One
Obligate aerobes
- Organisms that grow only in the presence of oxygen
________ serves as the terminal electron acceptor for the _____ in the metabolic process called _______ respiration
- Oxygen - ETC - aerobic
The partitioning system for bacterial chromosomes has three components:
- ParA and ParB proteins - and a parS region on the chromosome
What is the function of ParA?
- ParA is mostly concentrated at the opposite pole of the cells from the partitioning complex. - ParA is also distributed in a gradient in the cell. - ParA molecules in complex with ATP are bound loosely and nonspecifically to the chromosome - They move the partitioning complex from pole to another
Peptidoglycan synthesis involves an enzyme called ________
- Penicillin-binding proteins (PBPs) so named because they were first noted for their capacity to bind penicillin
__________ is a rigid but elastic structure that protects the cell from lysis.
- Peptidoglycan - The strength of the existing peptidoglycan in the cell wall must be maintained as new peptidoglycan subunits are added
What are the type of antimicrobial agents?
- Physical agents - Chemical agents - Mechanical agents - Biological agents
Cytokinesis
- Processes that apportion the cytoplasm and organelles, synthesize a septum, and divide a cell into two daughter cells during cell division
Sunlight is the major source of ______ on Earth, and it includes ______
- Radiation -- Includes: visible light, ultraviolet radiation, infrared rays, and radio waves
Ionizing radiation is the most damaging because
- Radiation of very short wavelength and high energy causes atoms to lose electrons (ionize)
Sanitization
- Reduction of the microbial population on an inanimate object to levels judged safe by public health standards
The part of the microbial growth curve when cells reach their max density is called the
- Stationary phase
Describe step 1 of binary fission
- Step 1: A cell prepares for division by enlarging its cell wall, plasma membrane, and overall volume. DNA replication then starts
Exponential microbial growth
- The growth curve is exponential, as demonstrated by the linearity of the log plot
Microbial nutrition can be exploited to control
- The growth of microorganisms
Disinfection
- The killing, inhibition, or removal of microorganisms that may cause disease - It usually refers to the treatment of inanimate objects with chemicals
Generation time
- The length of time that it takes a culture to double in cell number
What is the most lethal UV radiation?
- The most lethal UV radiation has a wavelength of 260 nm, which is the wavelength most effectively absorbed by and damaging to DNA
Death phase
- The number of viable cells declines exponentially, with cells dying at a constant rate
What is the name of the protein-DNA assembly between two parS and multiple ParB bound to parS sites on each chromosome, in C. crescentus?
- The partitioning complex
Stationary phase
- The phase of microbial growth in a batch culture when population growth ceases and the growth curve levels off (becomes horizontal) - Some bacteria reach a population level of around 10^9 cell/ mL - Protist cultures often have max conc of about 10^6 cells/ mL
Exponential phase
- The phase where microorganisms grow and divide at the maximal rate possible given their genetic potential, the nature of the medium, and the environmental conditions
Pasteurization
- The process of heating liquids to destroy microorganisms that can cause spoilage or disease
Tyndallization
- The process of repeated heating and incubation to destroy bacterial spores
The Growth rate constant (k)
- The rate of microbial population growth expressed in terms of the number of generations per unit time (hr - 1) - it can be used to calc the generation time - k = n*t = log Nt - log No * 0.301t
Phrases that describe "disinfection"
- The reduction of the microbial population - The destruction of potential pathogens
Describe step 2 of binary fission
- The septum begins to grow inward as the chromosomes move toward opposite ends of the cell. - Other cytoplasmic components are distributed to the two developing cells
Describe step 3 of binary fission
- The septum is synthesized completely through the cell center, creating two separate cell chambers
Generation (doubling) time
- The time required for a microbial population to double in number
Chemotherapy
- The use of chemical agents to kill or inhibit the growth of microorganisms within host tissue and to treat disease
What is the function of PBPs enzymes in peptidoglycan synthesis?
- Their function is to link strands of peptidoglycan together or hydrolyze bonds in existing strands so that new units can be inserted during cell growth
Obligate anaerobes
- They cannot tolerate O2 and die if exposed to it.
What do the dotted lines shown during the long-term stationary phase, in a microbial growth curve, represent?
- They represent successive waves of genetic variants that evolve during the stationary phase of the growth curve
How can heat be used for sterilization?
- To destroy endospores, moist heat must be carried out at temp above 100C, requiring the use of saturated steam under pressure.
True or false: As most viruses are smaller than 0.2 μm, they will not be removed from solutions by membrane filtration.
- True --Membrane filters only remove objects larger than the pore size. - Although a wide variety of pore sizes are available, membranes with pores about 0.2 micrometer in diameter are used to remove most vegetative cells, but not viruses, from liquids.
How can wall-less microbes protect themselves against changes in osmotic concentrations?
- Wall-less microbes reduce the osmotic concentration of their cytoplasm by lowering the solute concentration using mechanosensitive (MS) channels. - Protists use contractile vacuoles to expel excess water
What happens if microbes are placed in a hypotonic solution?
- Water moves from solutions with lower conc of solute to those with higher conc of solute - Thus, water will enter the cell and cause it to burst unless something prevents the influx of water or inhibits plasma membrane expansion
What happens to a cell in a hypertonic solution?
- Water will flow out of the cell - Cell shrinks - In microbes that have cell walls, the membrane shrinks away from the cell wall - Dehydration might cause the cell to become metabolically inactive
Alcohol
- Widely used as disinfectants, antiseptics, and sanitizers. - Bacterial and fungicidal but not sporicidal; some enveloped viruses are also destroyed
Two major forms of ionizing radiation are __ _____, which are artificially produced, and _____ ______, which are emitted during natural radioisotope decay
- X-rays - Gamma rays
Lag phase
- a period following the introduction of microorganisms into fresh culture medium when there is no increase in cell numbers or mass during batch culture; rather cells are synthesizing new components
Quorum
- a quorum usually refers to the mim number of members in an organization, such as a legistalive body, needed to conduct business.
Why the total number of viable microorganisms remains constant during the stationary phase?
- a results from a balance between cell division and cell death - or the population ceased to divided but remained metabolically active
pH is a measure of the relative _______ solution and is defined as the ________ ....
- acidity of a solution and is defined as the negative logarithm of the hydrogen ion concn (expressed in terms of molarity) - pH = - log [H+] = log[1/H+]
Long-Term Stationary Phase
- aka extended stationary phase - The phase following the death phase, in which the population size remains at a more or less constant level that can last months to years
What is filtration?
- an excellent way to reduce the microbial population in solutions of heat-sensitive material and can be used to sterilize liquids and gases (including air) - It does not destroy microbes, but rather acts as a barrier to retain them
Which group of enzymes is required for limited peptidoglycan degradation, so that new units can be inserted during cell growth?
- autolysins
What is the name of the PBPs enzymes that hydrolyze bonds of peptidoglycan?
- autolysins; other autolysins besides PBPs also help sculpt the peptidoglycan sacculus during cell growth and cell division
Microbes that can grow at high physical pressures are considered to be
- barotolerant - barophilic - barophiles - piezophilic
In bacterial binary fission, DNA replication proceeds in _____ direction(s) from the _______
- both - origin
When microorganisms are cultivated in ______, they usually are grown in a _____ _____. Which is?
- broth; batch culture - That is, they are incubated in a closed culture vessel like a test tube or a flask with single batch of medium
In a hypotonic solution, cells will often
- burst
How do membrane filters remove microorganisms?
- by screening them out much as a sieve separates large sand particles from small ones
What type of microbial control agent are disinfectants usually?
- chemical agents
The rate of growth of microorganisms is ______ during the exponential phase
- constant, which mean that they are completing the cell cycle and doubling in number at regular intervals
Heat-sensitive solutions are best sterilized by _______ or ________ filtration
- depth or membrane filtration
Which of the following influence(s) the efficiency of an antimicrobial agent?
- duration of exposure - conc of the agent - temp
The two most popular alcohol germicides are
- ethanol and isopropanol in about 60 to 80% concentration - They denature proteins and possibly dissolve their membrane lipids
Habitats that are rich in nutrients are called _________ environments
- eutrophic
N95 disposable masks
- exclude 95% of particles that are larger than 0.3 micrometer
Certain cyanobacteria reproduce by undergoing multiple ______
- fission; the progeny cells, called baeocytes, are held within the cell wall of the parent cell until they mature
Thermophiles
- grow at temps between 45 and 85C and have optima between 55 and 65C
Hyperthermophiles
- have a growth optima between 85 and 113 C, and they usually do not grow below 55 C
Only some ______ metals have _________ properties
- heavy metals - antimicrobial properties
Cells are likely to shrivel when placed in a _________ solution
- hypertonic
If the environment has a lower solute concn than the interior of the cell, the environment is
- hypotonic
Radiation with very short wavelengths and high energies called ________ radiation is particularly damaging to cells
- ionizing radiation
Divisome (molecular machine)
- it synthesizes peptidoglycan during cytokinesis
An organism's optimal growth temp is closest to its
- maximum growth temp
Almost all human pathogens are
- mesophiles
Heavy metals
- metal ions such as mercury, silver, arsenic, zinc, and copper were used as germicides
Barotolerant microbes
- microbes that can grow and reproduce at high pressures but do not require them - High pressures adversely affect them but not as much as nontolerant microbes
Mesophiles
- microorganisms living in moderate temp - Growth optima around 20 to 45C and often have a temp minimum of 15 to 20C and max of about 45C
Dry heat
- moderate to high temperatures; dehydration, alters protein structure; incineration - kills by oxidation; microbial death results from the oxidation of cell constituents and protein denaturation - use of a bench-top incinerator or an oven at 160 to 170C for 2 to 3 hours
When the population has been greatly reduced, the rate of killing may slow due to survival of a
- more resistant strain of the microorganisms
As the two chromosomes are replicated, the two origins
- move toward opposite cell poles
Other bacteria, such as members of the genus Streptomyces, form __________ filaments that eventually divide to form ___________ spores
- multinucleoid - uninucleoid
The growth rate during exponential phase depends on different factors, like
- nutrient availability
Photosynthetic protists are usually _______ aerobes
- obligate
Environments that are low in nutrients are
- oligotrophic
The synthesis of peptidoglycan requires a group of enzymes called
- penicillin-binding proteins (PBPs)
Characteristics of membrane filters
- porous membranes a little over 0.1 mm thick - Made of cellulose acetate, cellulose nitrate, polycarbonate, polyvinylidene fluoride, or other synthetic material
Using molecular signals to communicate microbial density is referred to as
- quorum sensing
Membrane filters
- replaced depth filters -porous material that retains microorganisms as the suspending liquid passes through the pores
What is the name of the bacterial DNA synthesizing machinery?
- replisome
The growth rate of microbial organisms during the exponential phase is ________ like is seen with many enzymes
- saturable
Microbes that naturally live attached to surfaces in aquatic environments are
- sessile
For bacteria growing in batch culture conditions, the long-term stationary phase may last up to
- several years - months to years
Most bacteria have a _____ ______ chromosome
- single circular
Most bacteria have a _____ _______ chromosome
- single circular
Substances (chemical) that do not kill but rather prevent growth of microorganisms often have the suffix
- static (Greek statikos, causing to stand or stopping)
Membrane filters are used to
- sterilize pharmaceuticals, contact lens cleaner, ophthalmic solutions, culture media, oils, antibiotics, and other heat-sensitive solutions
Replication is completed at the ______, located directly opposite the ________
- terminus - origin
Each circular bacterial chromosome has a single site at which replication starts called the ______ ___ ______
- the origin of replication
Antisepsis
- the prevention of infection or sepsis
Quorum sensing
- the process in which bacteria monitor their own population density or the presence of other species of bacteria by sensing the levels of signal molecules (e.g., N-acylhomoserine lactone) released by the microorganisms. When these signals reach a threshold concentration, quorum-dependent genes are expressed.
How is stem sterilization carried out?
- with an autoclave, a device somewhat like a fancy pressure cooker
Standard autoclave conditions (121°C, 15 pounds of pressure, 15 minutes) will sterilize which two of the following?
-3 ml bacterial broth culture in a test tube -250 ml empty Pyrex flasks
Two important sites recognized by the sigma subunit and used to direct RNA polymerase core enzyme to the gene to be transcribed are the ______ and ______ sites.
-35; -10
Which two of the following statements regarding proteins secreted by the Tat system are false? -Any protein with two arginine residues will be secreted by the Tat system. -The Tat system for protein secretion is found in both Gram-positives and Gram-negatives. -The Tat system for protein secretion derives its energy from the proton motive force. -Proteins secreted by the Tat system must remain unfolded until transport to the membrane.
-Any protein with two arginine residues will be secreted by the Tat system. -Proteins secreted by the Tat system must remain unfolded until transport to the membrane.
Which three of the following statements are true of Z form DNA? -It has a vertical rise of 2.6 Angstroms. -It has a vertical rise of 3.4 Angstroms. -It is a left-handed helical structure. -It is a right-handed helical structure. -It has 11 base pairs per helical turn. -It has 10.5 base pairs per helical turn. -It has 12 base pairs per helical turn. -It has a vertical rise of 3.7 Angstroms.
-It is a left-handed helical structure. -It has 12 base pairs per helical turn. -It has a vertical rise of 3.7 Angstroms.
Which three of the following statements are true regarding the antiparallel nature of double-stranded DNA? -One strand is oriented in the 5' to 3' direction while the other strand is oriented in the 3' to 5' direction. -Both strands possess a free hydroxyl group on their 3' ends. -Both strands possess a free hydroxyl group on their 5' ends. -Both strands possess a free phosphate group on their 3' ends. -Both strands possess a free phosphate group on their 5' ends. -Both strands are oriented in the 5' to 3' direction in relation to each other.
-One strand is oriented in the 5' to 3' direction while the other strand is oriented in the 3' to 5' direction. -Both strands possess a free hydroxyl group on their 3' ends. -Both strands possess a free phosphate group on their 5' ends.
Mechanism of action of halogens
-Oxidize proteins (cell constituents) resulting in denaturation of proteins
Which two of the following statements are true of the Tat system for protein secretion? -Proteins moved by the system must possess two arginine residues in their signal sequence. -Proteins moved by the system must possess two alanine residues in their signal sequence. -The system moves only folded proteins. -The system moves both folded and unfolded proteins.
-Proteins moved by the system must possess two arginine residues in their signal sequence. -The system moves only folded proteins.
The visible spectrum consists of the ________ wavelengths
-ROYGBV -
Which two of the following statements regarding the signal recognition particle (SRP) are false? -SRP and trigger factor survey actively translating ribosomes at the same time. -SRP binds SecA to escort membrane proteins to the plasma membrane. -SRP is a protein-lipid complex that directs proteins to the plasma membrane. -SRP recognizes a transmembrane α-helix on membrane proteins.
-SRP binds SecA to escort membrane proteins to the plasma membrane. -SRP is a protein-lipid complex that directs proteins to the plasma membrane.
Which two of the following statements regarding the signal recognition particle (SRP) are false? -SRP and trigger factor survey actively translating ribosomes at the same time. -SRP recognizes a transmembrane α-helix on membrane proteins. -SRP binds SecA to escort membrane proteins to the plasma membrane. -SRP is a protein-lipid complex that directs proteins to the plasma membrane.
-SRP binds SecA to escort membrane proteins to the plasma membrane. -SRP is a protein-lipid complex that directs proteins to the plasma membrane.
Which three of the following statements regarding proteins secreted by the Tat system are false? -Proteins secreted by the Tat system must completely fold in the cytoplasm. -The Tat system for protein secretion derives its energy from ATP hydrolysis. -The Tat system can transport proteins across the inner and outer membranes of a Gram-negative. -The Tat system for protein secretion is found in both bacteria and archaea. -The signal peptide of Tat-secreted proteins contains two arginine residues.
-The Tat system for protein secretion derives its energy from ATP hydrolysis. -The Tat system can transport proteins across the inner and outer membranes of a Gram-negative. -The Tat system for protein secretion is found in both bacteria and archaea.
Which three pieces of evidence did Fred Griffith use to infer that there was something from the dead virulent bacteria that was capable of transforming the living avirulent bacteria into a virulent form? -When virulent bacteria were boiled prior to injection into mice, they lost the ability to kill the mice. -When boiled avirulent bacteria were mixed with living virulent bacteria before injection, living virulent bacteria were isolated from the animals. -Mice were killed by living virulent bacteria. -Mice were killed by living avirulent bacteria. -When the mixture of both was injected into mice, the mice died and virulent living bacteria were isolated from them. -When avirulent bacteria were boiled prior to injection into mice, they killed the animals.
-When the mixture of both was injected into mice, the mice died and virulent living bacteria were isolated from them. -Mice were killed by living virulent bacteria. -When virulent bacteria were boiled prior to injection into mice, they lost the ability to kill the mice.
Aldehydes
-cause cross-linking that inactivates proteins and nucleic acids - The two most commonly used are formaldehyde and glutaraldehyde
Substances that kill microorganisms often have the suffix
-cide (Latin cida, to kill)
Which two of the following protein maturation reactions occur after the polypeptide has been translocated out of the cell? -cis/trans proline isomerization -cysteine oxidation to a disulfide -removal of the signal peptide -insertion of metal cofactors -removal of the N-terminal methionine
-cysteine oxidation to a disulfide -removal of the signal peptide
The mechanism of action of quaternary ammonium compounds is
-denaturation of proteins -disruption of microbial membranes
Coupled transcription/translation is found in domains where there is no membrane-enclosed nucleus (Bacteria and Archaea) because _____. [Choose two.] -in Eukarya, RNA polymerase transcribes mRNA within the nucleus, while ribosomes are located in the cytoplasm -the conditions within the nucleus prevent formation of peptide bonds by the ribosomes present -the machinery for both systems are in the same location (cytoplasm) in such domains -in Eukarya, ribosomes transcribe mRNA within the nucleus, while RNA polymerases are located in the cytoplasm -RNA molecules are destroyed by ribonucleases within the nucleus -eukaryotic ribosomes are more complex than those found in other domains and can't work near RNA polymerases
-in Eukarya, RNA polymerase transcribes mRNA within the nucleus, while ribosomes are located in the cytoplasm -the machinery for both systems are in the same location (cytoplasm) in such domains
Osmophiles
-live in habitats with high solute concentration - organisms that require high conc of sugars - include halophiles
In which two of the following ways do A form DNA and B form DNA differ? -positive vs negative supercoiling -number of bases per helical turn -presence of uracil in place of thymine -number of hydrogen bonds between strands -length of a base pair
-number of bases per helical turn -length of a base pair
Early in the cell cycle, the ______ and ______ move to ______, and proteins needed for chromosome replication assemble at the ______.
-origin and terminus - midcell - origin
Bacteria typically contain _____ type(s) of RNA polymerase.
1
In bacteria and archaea, septation is divided into several steps:
1) Selection of site where septum will be formed 2) Assembly of the Z ring (composed of the cytoskeletal protein FtsZ) 3) Assembly of the cell wall-synthesizing machinery - Constriction of the cell and septum formation
By using mutagens, the mutation rate can be increased to one mutant cell out of approximately how many cells?
1,000 to 1,000,000
Okazaki fragments are approximately _________ nucleotides long in bacteria and approximately ___________ nucleotides long in eukaryotic cells.
1,000-3,000; 100
The following steps are carried out by DNA polymerase III for lagging strand synthesis (specifically synthesis of a single fragment on the lagging strand). Place them in the correct order with the first event at the top.
1. synthesize RNA primer 2. discard old beta clamp proteins 3. load new beta clamp to the next spot on the DNA to be replicated 4. tether the template to the core enzyme
The DNA polymerase III holoenzyme is currently thought to be composed of _____.
10 different proteins, including 3 core enzymes
The primer that is formed to initiate DNA synthesis is composed of ____.
10 ribonucleotides + 20 deoxyribonucleotides
Under normal conditions, the rate of naturally occurring mutant cells is one mutant cell out of approximately how many cells?
107 to 1011
In an autoclave, bacterial endospores will be killed only if they are kept at ____C for ___ to ___ minutes
121C for 10 to 12 minutes
Eukaryotic nucleosomes are composed of histone octamers that wrap _____ base pairs of DNA around themselves.
146
After fMet-tRNA has bound to the 30S ribosomal subunit, the ______ rRNA portion of the 30S subunit aligns with the Shine-Dalgarno sequence in the leader region of the mRNA.
16S
In addition to the 20 amino acids normally found in protein, _______ additional and unusual amino acids have been discovered.
2
A total of _______ amino acids are normally observed in proteins.
20
RNA is synthesized from a DNA template by adding ribonucleotides to the Blank _______-prime end of the transcript.
3
RNA is synthesized from a DNA template by adding ribonucleotides to the _____-prime end of the transcript.
3
The eukaryotic chromosome diagrammed here has _____ replicon(s).
3
The genetic code is translated in groups of __________ bases.
3
The lac operon is composed of _____ (number) structural genes
3
As RNA polymerase synthesizes the transcript, new nucleotides are added to the _____ end of the growing chain.
3'
As RNA polymerase synthesizes the transcript, new nucleotides are added to the _______ end of the growing chain.
3'
RNA is synthesized from a DNA template by adding ribonucleotides to the _____ end of the transcript.
3'
If 20% of nucleotides in the DNA of a particular organism contain thymine, estimate the percentage of cytosine that is present in the DNA.
30%
Hershey and Chase utilized _________ to radioactively label bacteriophage DNA and __________ to radioactively label bacteriophage proteins. By doing so, they could follow which molecule type found its way into host cells.
32P; 35S
The eukaryotic small ribosomal subunit has a size of ____.
40s
Riboswitches contain effector-binding elements at the ____ of the mRNA.
5' end
During RNA synthesis, the newly synthesized strand is created in the _______ direction.
5' to 3'
In bacteria, once the _____ S ribosomal subunit is brought in and bound to the small ribosomal subunit on the mRNA molecule, the initiator fMet-tRNA molecule will be located within the ____ site. At this point, a complete translation initiation complex has formed.
50 P or peptidyl
Which three of the following factors are required for bacterial translation initiation?
50S and 30S ribosomal subunits Initiation factors (IFs) fMet-tRNA
How many different ORC (origin recognition complex) proteins have been identified?
6
How many DNA triplets encode 60 amino acids?
60
What size are the small nuclear RNA molecules in a snRNP?
60-300 nucleotides
The 5' cap of a eukaryotic transcript is ____.
7-methylguanosine
The standard or housekeeping sigma factor used most often by E. coli RNA polymerase under normal growth conditions is called sigma ___.
70
A typical tRNA molecule is
70-95
In bacteria, an insertion sequence (or IS element) is typically about what size?
750-1600 base pairs
Translation is terminated when a stop codon is presented at the ________ site.
A
In this image of a eukaryotic chromosome, where would the telomere (or telomeres if there are more than one) be located?
A and D
Which four of the following are components of an amino acid?
A carboxyl group A side chain (R group) An amino group An α carbon atom
vesicular transport
A form of transport that uses vesicles to deliver proteins to their destinations; This form does not involve the direct translocation of proteins across membranes.
riboprotein
A molecule with an RNA component and a protein component
nonsense mutation
A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.
Which three types of mutations are classified as reversion mutations?
A second mutation that restores the original wild-type sequence. A second mutation creates a codon that replaces the wild type amino acid with a similar amino acid. A second mutation that creates a new codon that codes for the wild type amino acid.
Hypotonic solution
A solution in which the concentration of solutes is less than that of the cell that resides in the solution
During translation elongation, which event happens last?
A tRNA molecule translocates from the P site to the E site.
transposable elements
AKA jumping gene; A segment of DNA that can repeatedly insert into one or more sites of one or more genomes.
DnaJ/DnaK/GrpE chaperones help fold proteins into their functional shapes via hydrolysis of the energy molecule_____
ATP
The adenyl cyclase enzyme converts _____ to cAMP and PPi.
ATP
Which of the following is the initiator codon?
AUG
Which of the following is not a termination codon?
AUG (Termination codons: UGA, UAA, UAG)
To initiate DNA replication, DnaA binds to the region known as _________and recruits _________ enzyme to denature DNA
Acceptable Answers Blank 1: oriC, ori, origin, or origin of replication Acceptable Answers Blank 2: helicase or DnaB helicase
Which two of the following describe the catabolite activator protein?
Activates specific operons when glucose is not available and Represses specific operons when glucose is available
enhancers
Activator protein that is located far away from the gene they activate (either up or downstream)
Describe the steps of pre-mRNA modification.
Addition of 5' 7-methylguanosine capAddition of 3' poly-A tailExcision of introns, or intervening sequences, from the transcript
Which of the following is not a pyrimidine?
Adenine Is a pyrimidine: Thymine Cytosine Uracil
Which nitrogenous bases typically pair in DNA?
Adenine and thymine; guanine and cytosine
Which nitrogenous bases typically pair in DNA? Adenine pairs with __________ Guanine pairs with _________
Adenine pairs with thymine Guanine pairs with cytosine
Which of the following is not a complementary base pair found in DNA molecules?
Adenine-uracil
Sterilant
Agent that kills all microorganisms
Genomics is the study of
All of the choices are correct. (the information content of genomes, he molecular organization of genomes, the gene products that genomes encode)
A molecular biologist is interested in purify a recombinant protein by His-tagging, but the protein and vector both lack histidine residues. In this case, the molecular biologist could use which of the following technique(s) to acheive purification?
All of the choices are correct. (Add a series of histidine residues to the N-terminus of the protein, Add a 6xHis-tag to the C-terminus of the protein, and Amplify the histidine-encoding sequence by PCR and add it to the gene of interest.)
Insertion sequences are
All of the choices are correct. (capable of transposition, normally relatively short (700 to 1,650 bp), and are discrete genetic elements bounded at both ends with inverted repeats)
Cell-to-cell communication by quorum sensing has been shown to be important in the regulation of genes needed for
All of the choices are correct. (virulence, plasmid transfer, and biofilm production)
Which of the following can be used as vectors for cloning DNA fragments?
All of the choices are correct. (plasmids, cosmids, bacteriophages)
Which of the following is correct regarding the relatedness of the protein subunits in eukaryotic and bacterial core RNA polymerases?
All of the five bacterial RNA polymerase subunit have homologues in the eukaryotic RNA polymerases.
DNA modifying agents
Alter a single base pair causing mispairings
DNA polymerases have been sorted into seven families on the basis of their (choose two)
Amino acid sequence and Three-dimensional structure
Which four of the following are components of an amino acid?
An α carbon atom A carboxyl group An amino group A side chain (R group)
Which of the following is NOT used by Bacillus subtilis to regulate sporulation?
Antisense RNAs
Which of the following statements is correct regarding the structure of archaeal chromosomes?
Archaeal chromosomes are similar in size to bacterial chromosomes.
Which of the following statements regarding archaeal-histone DNA complexes is false? Multiple choice question.
Archaeal histones bind to DNA as octamers.
Which two of the following statements about archaeal translation initiation are correct?
As in bacteria, archaeal transcription and translation are coupled. As in bacteria, some archaeal mRNAs have a Shine-Dalgarno sequence.
Which of the following statements about archaeal translation initiation is correct?
As in eukaryotes, the archaeal initiation tRNA is Met-tRNA.
In this image of a single base pair, the deoxyribose in the backbone is indicated by the letter _____.
B
Which scientist discovered mobile genetic elements?
Barbara McClintock
Which two of the following are characteristics of transcriptional regulatory proteins?
Bind to palindromes and Bind to DNA
______ is a general term describing all antimicrobial agents that can be used to control microorganisms. Some _______ growth or ______ replication, rather than _____ microbes
Biocide; inhibit; prevent; killing
transformation
Bits are incorporated into chromosomes through homologous
Transcription is the synthesis of __________from a DNA template. The product will possess a sequence _________ to the DNA template directing its synthesis.
Blank 1: RNA Blank 2: complementary or complementarity
Not all genes code for proteins - some code for ___________RNA or __________RNA
Blank 1: transfer or t Blank 2: ribosomal or r
Which of the following is correct regarding the transcription of genes that contain exons and introns?
Both introns and exons are transcribed and introns are removed by splicing.
Replication of which strand begins with a primer?
Both strands
By which mechanism may small RNA molecules affect gene expression in eukaryotes?
By defining mRNA splice sites
Which three of these statements are correct about nonsense mutations?
By definition, they always produce stop codons. Effects range from mild to complete loss of normal gene function. They cause the early termination of translation.
The catabolite activator protein binds to a specific DNA sequence called the _____ recognition site.
CAP
Catabolite operons cannot be transcribed unless the catabolite activator protein is bound to the ____. Multiple choice question.
CAP recognition site
The scientist who first discovered that bacteria and archaea were distinct phylogenetic groups based on differences in their rRNA sequences is _____ _____
Carl Woese
induced mutation
Caused by a mutagen - chemical or physical factors that directly damage DNA.
frameshift mutation
Caused by insertion or deletion of bases in a way that throws off the reading frame
Which components of the pre-replication complex (pre-RC) are not a part of the complete replication machinery?
Cdc6 and Cdt1
The disinfectant of choice for municipal water supplies is
Chlorine
During translation, a triplet _____ corresponds to a 'word' being 'read' from the mRNA to be translated into a particular amino acid in the polypeptide.
Codon
To recreate the basic chromosome structure of a eukaryote following DNA replication, the newly synthesized chromosome must ____.
Complex with histones
Which two of the following are characteristics of the lac repressor protein?
Composed of four identical subunits and Each monomer has a helix-turn-helix domain
Which of the following is NOT a characteristic of regulatory proteins?
Controls which molecules can be transported across a biological membrane
Place the molecules related to the direction of the flow of genetic information into the correct order, beginning with the genetic information. Protein DNA RNA
DNA RNA Protein
What best describes transcription?
DNA -> RNA
The single-stranded ends of DNA molecules can be joined together by ______.
DNA ligase
The enzyme that catalyzes DNA synthesis is
DNA polymerase
The enzyme that catalyzes DNA synthesis is _____.
DNA polymerase
The enzyme that catalyzes DNA synthesis is________________________
DNA polymerase
The enzyme that catalyzes the formation of phosphodiester bonds between nucleotides aligned on a template DNA is
DNA polymerase
100 million
DNA polymerase's proofreading function reduces the error rate from about 1 in 1 million base pairs to about ___ base pairs.
Which two of the following statements correctly describe properties of DNA polymerase?
DNA polymerases add deoxynucleoside triphosophates (dNTPs) to the growing strand of DNA. All known DNA polymerases catalyze synthesis of DNA in the 5' to 3' direction.
The replisome is a protein complex that performs which of the following processes?
DNA replication
The type IV secretion system is most commonly used for _____.
DNA transfer
Select three examples of chemical mutagens.
DNA-modifying agents base analogs intercalating agents
Sessile
Describes an organism that remains attached to a surface for its entire life and does not move
Planktonic
Describes bacteria that are freely floating in water.
The easiest and most straightforward example of screening for a mutant phenotype would be which of these?
Detecting an albino mutant when the wild type is blue
Which protein binds to oriC and recruits helicase to initiate DNA replication?
DnaA
Which three of the following statements are correct regarding conjugation in Gram-positive bacteria such as Enterococcus faecalis.
Donor and recipient cells adhere directly to each other. Peptides are released to activate transfer genes. A sex pilus may not be required.
Which two statements correctly describe missense mutations?
Effects range from no change to complete loss of normal gene function. They involve a single base substitution that changes a codon for one amino acid into another.
Which of the following statements about upstream activating sequences and enhancers is correct?
Either type of sequence may be found upstream of a gene.
Much like transcription and DNA replication, there are multiple stages of protein translation. The first stage is initiation. What are the second and third stages, in the correct order?
Elongation; termination
Which is the most frequently chosen prokaryotic host for use in cloning techniques?
Escherichia coli
Which of the following bacterial hosts would should be used to avoid degradation of DNA that is introduced via a cloning vector?
Escherichia coli that lack endonucleases
In which domain does DNA replication initiate with a bifunctional enzyme called DNA polymerase α-primase?
Eukarya
This linear chromosome with three replicons comes from a(n) _____.
Eukaryote
Which of the following statements regarding the composition of bacterial and eukaryotic chromosomes is correct?
Eukaryotes have multiple chromosomes while bacteria generally have a single chromosome.
Which of the following statements regarding the relative sizes of bacterial and eukaryotic chromosomes is correct?
Eukaryotic chromosomes are larger than bacterial chromosomes.
In this diagram of a eukaryotic mRNA prior to translation initiation, the purple sphere represents the 5' cap. What components are indicated by the 3 red arrows?
Eukaryotic initiation factors (eIFs)
In this image of a spliceosome acting on mRNA, the red arrow indicates the _____.
Exon
Which of these is the defining characteristic of an Hfr strain?
F plasmid integrated into the host chromosome
An F plasmid that has been excised from a bacterial chromosome, and which therefore also includes some chromosomal genes, is called a(n) _____.
F' plasmid
Organisms that do not require oxygen for growth but grow better in its presence are called
Facultative anaerobes
Postranscriptional modification to remove introns is needed for the bacterial RNA that has codon, rather than anticodon, sequences
False
Postranscriptional modification to remove introns is needed for the bacterial RNA that has codon, rather than anticodon, sequences.
False
Restriction enzymes cut only at specific sites and therefore are not useful for genetic engineering.
False
T/F: As the mRNA in synthesized, new nucleotides are added to the 5' end so that the transcript grows in the 3' to 5' direction.
False
T/F: The codon of tRNA is complementary to the anticodon of mRNA.
False
T/F: The first amino acid enters through the A site.
False
T/F: The terminator of a gene is located upstream of the coding region.
False
True or false: All genes code for proteins.
False
True or false: Eukaryotes have a single type of RNA polymerase that transcribes all genes.
False
True or false: The DNA polymerase enzyme is composed of a single protein with multiple catalytic sites.
False
True or false: The TATA sequence is conserved in every eukaryotic promoter.
False
True or false: The composition of the origin recognition complex (ORC) is identical in all eukaryotes.
False
True or false: The lac operon is an example of a positive control system, implying that it is turned "on" until turned "off".
False
True or false: Uracil is a base found in DNA.
False
Unwinding of the DNA during transcription is the result of the activity of a helicase enzyme downstream of the RNA polymerase.
False
Unwinding of the DNA during transcription is the result of the activity of a helicase enzyme downstream of the RNA polymerase.
False (RNA polymerase causes the DNA to unwind in order for transcription to proceed.)
True or false: Uracil is a base found in DNA.
False, Uracil is a base found in RNA, not DNA.
Which kind of sterilization procedure takes advantage of the size of microorganisms?
Filtration
Equations for the growth rate constant
For populations reproducing by binary fission: - Nt = No * 2n -- Nt = pop # at time t --No = initial pop # -- n = # generations in time t
It recognizes the promoter region.
Formation of a holoenzyme
Which of the following occurs first in transcription?
Formation of a holoenzyme
Which researcher's work in the late 1920s provided early evidence that DNA was the genetic material of cells by using Streptococcus pneumoniae?
Fred Griffith
What DNA base sequence could NOT be the recognition site of a restriction endonculease?
GCTTGC CGAACG
What DNA base sequence could NOT be the recognition site of a restriction endonuclease?
GCTTGC CGAACG
In this diagram of the telomerase reaction, the tandem repeat within the telomere is _____.
GGGTTG
The term "regulation of _____ expression" refers to the process of controlling transcription and/or translation.
Gene
Which of the following statements is correct regarding the structure of archaeal chromosomes? Multiple choice question.
Generally, archaeal chromosomes are circular.
Match each bacterial group with their most common use of riboswitches. Gram-positive bacteria Gram-negative bacteria
Gram-positvie bacteria= control of transcription Gram-negative bacteria= control of translation
Griffith's experiment demonstrated transformation because a mouse injected with live R and heat-killed S strains of Streptococcus pneumoniae resulted in death of the mouse and the isolation of live R as well as live S cells. Hypothesize as to the type of cells that Griffith would have observed if transformation had not occurred.
Griffith would have isolated only live R cells from the mouse host.
Griffith's experiment demonstrated transformation because a mouse injected with live R and heat-killed S strains of Streptococcus pneumoniae resulted in the death of the mouse and the isolation of live R as well as live S cells. Hypothesize as to the type of cells that Griffith would have observed if transformation had not occurred.
Griffith would have isolated only live R cells from the mouse host.
Which of the following bases are found in DNA molecules?
Guanine, adenine, cytosine, thymine
silent mutation
Have no impact on final polypeptide product; code the same amino acid
During pasteurization, milk is treated for a defined time at what temperature?
Heated but not to boiling
An enzyme that unwinds DNA is a(n) ______
Helicase
____ enzymes unwind the DNA, while ____ enzymes relieve the torsional stress on the molecules as they're being unwound. Both are required for DNA replication.
Helicase; topoisomerase
During replication, which enzyme unwinds the two strands of the DNA molecule from one another?
Helicases
When an F plasmid integrates into the host chromosome, the strain is referred to as
Hfr
Eukaryotic DNA is packaged by wrapping around structural proteins called _____
Histones
How are RNA polymerase core enzyme and RNA polymerase holoenzyme different?
Holoenzyme includes the sigma factor.
Enzymes that catalyze reactions that are in constant demand in a cell are encoded by genes referred to as ______ genes
Housekeeping
What is the name given to genes whose protein products must be present all the time?
Housekeeping genes
In this image of double-stranded DNA, the arrow points to a(n) _____ bond.
Hydrogen
Why is it a good thing that DNA replication is high-fidelity (low-error)?
If it weren't, we'd have a large number of potentially damaging mutations introduced each time DNA was replicated.
In a eukaryotic cell, where does transcription occur?
In the nucleus
__________ alter repressor proteins thereby increasing the rate of transcription initiation.
Inducers
The first processes that regulate gene expression to be understood in detail were...
Induction and repression
Transcription involves three separate processes: _____, elongation, and termination.
Initiation
In which of the core promoter elements does transcription initiate? Multiple choice question.
Inr
homologous recombination
Involves exchange of homologous sequences of DNA between two DNA molecules
transduction
Involves the transfer of genetic material that is mediated by a virus.
horizontal gene transfer
Involves the transmission of genetic information from one independent, mature organism o another independent, mature organism
vertical gene transfer
Involves transmission of genetic information from parent to offspring during normal cell division.
transformation
Involves uptake of naked DNA from environment
Select each item that is true of A form DNA. It has a vertical length of 3.4 Angstroms per base pair. It has 11 base pairs per helical turn. It has 10.5 base pairs per helical turn. It has a vertical length of 2.6 Angstroms per base pair.
It has 11 base pairs per helical turn. It has a vertical length of 2.6 Angstroms per base pair.
Which three of the following descriptions apply to an F' plasmid?
It includes some chromosomal genes. it is an erroneously excised plasmid. It has been excised from a bacterial chromosome.
Which three of the following statements regarding homologous recombination are correct?
It is the most common mechanism of DNA recombination. RecA protein is involved. Similar or identical DNA strands are broken and reunited.
What statement is correct regarding sigma factor?
It recognizes the promoter region
What statement is correct regarding sigma factor?
It recognizes the promoter region.
Which three of the following are true of a helicase?
It uses energy obtained from ATP hydrolysis. It works ahead of the DNA replication fork. It is responsible for unwinding the 2 template strands of parent DNA.
Which three of the following are true of a helicase?
It works ahead of the DNA replication fork. It is responsible for denaturing the 2 template strands of parent DNA. It moves using energy obtained from ATP hydrolysis.
Which two of the following conditions must exist to fully induce the lac operon?
Lactose present in the medium and Lack of preferred carbon and energy source
During DNA replication, the ______ strand is replicated by the replisome in the direction opposite to the movement of the replication fork.
Lagging
During which portion of the eukaryotic cell cycle do Cdc6 and Cdt1 proteins bind the ORC (origin recognition complex)?
Late M, early G1 phase
During DNA replication, one strand of DNA is replicated as the replisome moves in the same direction as the replication fork. This strand is called the _____ strand.
Leading
A key component of the SOS response is the destruction of a transcriptional repressor protein called _____.
LexA
intercalating agents
Ligands that fit in between nucleotides
The DNA in eukaryotic chromosomes is in which format?
Linear
When is adenyl cyclase active?
Little or no glucose is available
Which two of the following conditions are required for full activation of the lac operon?
Low levels or absence of glucose and Presence of lactose
Which of the following statements is correct about the organization of genes in eukaryotes?
Most genes are present in single units, not in operons.
Initiation of replication for large eukaryotic chromosomes occurs at ____.
Multiple origins of replication
point mutation
Mutation that affects single base pair
spontaneous mutations
Naturally occurring mutation in the absence of an external agent, or mutagen.
Which of the following terms indicates that the binding of a protein to DNA inhibits transcription initiation?
Negative transcriptional control
Which statement best describes the lac operon in E. coli?
Negative transcriptional control of inducible genes (i.e., turned "off" until turned "on")
Bacterial DNA is generally found in a _____ supercoiled state.
Negatively
Which of the following is in the coding region of a gene?
None of the choices are correct.
site-specific recombination
Occurs at specific target sites and is carried out by enzymes called recombinases
In bacteria, repressor proteins bind to a specific DNA sequence called the ____.
Operator
Biofilms
Organized microbial communities encased in extracellular polymeric substances and associated with surfaces, often with complex structural and functional characteristics
The ____ of replication is the specific site on a circular bacterial chromosome where DNA replication begins.
Origin
Short, inverted sequences of bases in DNA are called ____.
Palidromes
The abundance of ____-____ at the opposite pole directs chromosome movement from one pole to other
ParA-ATP
Phenolics
Phenol and its derivatives (phenolics) are used as disinfectants in labs and hospitals. Lysos is a mixture of phenolics
The backbone of DNA molecules is formed by _____ bonds between individual deoxynucleotides.
Phosphodiester
Which three of the following mechanisms are used by Bacillus subtilis to control sporulation?
Phosphorelay, Post translational modification, and Alternate sigma factors
r plasmids
Plasmids with genes that decrease the bacterial susceptibility to antibiotics.
The type of mutation that affects only a single base pair at a given DNA location is called a(n) _____ mutation.
Point
In this image of a eukaryotic mRNA prior to translation initiation, the purple sphere represents the 5' cap. What components are indicated by the 2 red arrows?
Poly-A binding proteins (PABPs)
_____ transcriptional control occurs when transcription initiation is promoted by a protein binding to DNA.
Positive
Which of the following terms indicates that the binding of a protein to DNA promotes transcription initiation?
Positive transcriptional control
Transcription of the trp operon is controlled by which two of the following mechanisms?
Premature termination through attenuation and Repressor protein inhibits initiation
In which situation might methylation of membrane proteins in Escherichia coli initiate a phosphorelay system that evokes clockwise rotation of flagella?
Presence of a chemorepellent in the extracellular environment.
The enzyme _____ works to synthesize a short stretch of RNA complementary to the parent strand to begin synthesis of DNA by DNA polymerase III enzymes.
Primase
The enzyme that synthesizes RNA primers as complements to the template strand of DNA as needed to begin DNA replication is _____.
Primase
transposition recombination
Process by which a mobile genetic element such as transposable element moves.
Which statement defends the concept that the term "gene" is better defined as a nucleotide sequence that encodes for one or more functional products rather than encoding for one or more functional proteins?
Products of genes include ribonucleotides as well as proteins.
The transcription enzyme first attaches to the ________ of the gene.
Promoter
heat-shock proteins
Protect cells from thermal damage due to dramatic increases in heat.
molecular chaperones
Proteins that bind to the nascent polypeptide and ensure that they fold correctly, with the help of energy input from ATP.
insulators
Proteins that prevent enhancers or silencers from affecting the transcription of the wrong gene by "insulating" those genes.
Which two of the following might be used to supply energy required by secretion systems? -Proton motive force -Hydrolysis of ATP -High energy bonds between amino acids -Covalent bonds in sugar molecules
Proton motive force Hydrolysis of ATP
If an RNA virus had been used in Hershey and Chase's experiments rather than a DNA virus, they might have concluded that _____ was the carrier of genetic information.
RNA
What type of nucleic acid is indicated by the thick red arrow in this diagram of the telomerase reaction?
RNA
_____ uses the sugar ribose instead of deoxyribose and the base uracil instead of thymine.
RNA
_________uses the sugar ribose instead of deoxyribose and the base uracil instead of thymine.
RNA
Which of the following apply to the product of the primase enzyme?
RNA complementary to the DNA about 10 bases long
Which two of the following types of molecules are found in a spliceosome?
RNA protein
What best describes translation?
RNA -> Protein
The enzyme that accomplishes transcription is termed ______.
RNA Polymerase
In eukaryotes, the primer that is formed to initiate DNA synthesis is composed of ____. Multiple choice question.
RNA and DNA
Recombinant DNA technology does not rely on which of the following enzymes?
RNA methylase
Match the eukaryotic RNA polymerase that catalyzes each type of RNA. RNA pol I RNA pol II RNA pol III
RNA pol I; rRNA RNA pol II; mRNA RNA pol III; tRNA and 5S rRNA
The enzyme that catalyzes transcription is ...
RNA polymerase
Which of the following statements is false regarding the RNA polymerase core enzyme?
RNA polymerase core enzyme has five types of polypeptide chains: α, β, β', ω, and σ.
The promoter of a gene is the location where _____.
RNA polymerase will bind
Transcription is the synthesis of _____ from a DNA template. The product will possess a sequence _____to the DNA template directing its synthesis.
RNA; complementary
Riboswitches in eukaryotes perform which of the following?
Regulate mRNA splicing
Proteins that are responsible for the induction or repression of enzyme encoding genes are referred to as ______ genes.
Regulatory
The transcription of all catabolite operons are regulated by which two of the following?
Regulatory protein specific to the operon and Catabolite activator protein
What term describes a set of genes that is controlled by a common regulatory protein?
Regulon
Which example of a missense mutation in a protein-encoding gene would most likely be a neutral mutation?
Replacement of a polar amino acid with another polar amino acid at the protein's surface
DNA replication is performed by a protein complex called the _____
Replisome
The complex of ten or more proteins that replicates the DNA is called the ...
Replisome
Transcription is turned off by _________.
Repression
Which were the first mechanisms of gene regulation to be understood?
Repression and induction
When _____ proteins bind to the operator they block the binding of RNA polymerase or inhibit its movement.
Repressor
silencers
Repressor protein that is able to regulate transcription even when far away from gene's promoter sequence.
Carl Woese first noted that bacteria and archaea formed distinct phylogenetic groups by studying _____ RNA
Ribosomal
When DNA damage is so great that DNA synthesis stops, a control system called the _____ response occurs.
SOS
Proteins responsible for preventing unpaired DNA from re-annealing until the DNA replication machinery replicates the template are called _______.
SSB
Proteins responsible for preventing DNA from re-annealing until the DNA replication machinery passes are called
SSBP
DNA polymerase alpha
Same function as primase (RNA primer)
The reduction of the microbial population to levels that are considered safe by public health standards is called
Sanitization
Binds to other Sec proteins and acts as a motor, hydrolyzing ATP for energy
SecA
Proteins that use proton motive force to help fuel translocation.
SecDF
Forms a channel in the membrane through which the preprotein passes
SecYEG
The SecA protein passes through which set of proteins that form a channel in the plasma membrane?
SecYEG
During the investigation of a convenience store robbery, witnesses report that the perpetrator exited through a main entry door without wearing gloves. The police are holding a prime suspect in custody while samples from the door are collected and analyzed for a DNA match. Since the door was handled by many people before the robbery, how will the forensics department distinguish the suspect's DNA from the DNA of others using PCR?
Sequence-specific primers to the suspect's DNA will be used for PCR amplification.
conjugation
Sex pilus is found on the donor cell, but not on recipient. Therefore, DNA is transferred in one direction.
The _____ factor subunit of bacterial RNA polymerase recognizes a sequence of six bases about 35 base pairs before the transcription start point and a TATAAT sequence (the Pribnow box) about 10 base pairs before the transcription start point.
Sigma
Which of the following subunits of bacterial RNA polymerase does not catalyze RNA synthesis?
Sigma
Which of the following best describes the role of the sigma subunit of bacterial RNA polymerase?
Sigma positions the core enzyme at the promoter.
Which two of the following are components of a snRNP?
Small nuclear RNA Protein
Which two of the following statements are correct regarding the phylogenetic distribution of the core RNA polymerase subunits?
Some eukaryotic core RNA polymerase subunits are found only in eukaryotes. All bacterial core RNA polymerase subunits are found in both bacteria and in eukaryotes.
Which protein controls initiation of sporulation in Bacillus subtilis?
SpoOA
The work of Fred Griffith in the late 1920s on the bacterium _____ pneumoniae provided early evidence on the identify of the genetic material of cells.
Streptococcus
Guanine tetraphosphate (ppGpp) is particularly associated with which process?
Stringent response in Escherichia
DNA polymerase delta
Synthesize new DNA along lagging strand
DNA polymerase epsilon
Synthesizes new DNA along leading strand
When an amino acid is covalently bound to a tRNA molecule by aminoacyl-tRNA _____ enzyme, the tRNA is said to be _____ .
Synthetase; activated
One of the elements in a eukaryotic core promoter is named for the nucleotides in the element, the _____ box
TATA
Match each extrinsic transcription factor with its role in transcription initiation. TBP TFIID SAGA Mediator
TBP-binds to the TATA box TFIID-binds to the region around the core promoter SAGA-binds to upstream activating sequences Mediator-stabilizes the entire pre-initiation complex
Telomeric DNA contains which feature?
Tandem repeats
Which of the following statements is the best definition of a telomerase?
Telomerase is an enzyme that helps solve the "end replication problem."
The end of a linear DNA chromosome complexed with proteins is called a(n) _____
Telomere
The enzyme whose function is to maintain the length of eukaryotic linear chromosomes is called _____
Telomere
Which of the following is a region of DNA at the end of a linear chromosome?
Telomere
Transcription _____ occurs when the core RNA polymerase dissociates from the template DNA and the transcription bubble closes, renaturing the two DNA strands.
Termination
Which is the correct sequence of events in eukaryotic translation initiation?
The 43S complex binds the mRNA, then it scans the mRNA for the start codon, and then the 60S subunit binds to form the complete 80S ribosome.
GAL4 regulation
The GAL gene in yeast produce the proteins needed for the uptake and catabolism of galactose. GAL4 is an activator that binds to the upstream activating sequence near the promoter sequence of each GAL gene. When galactose is absent, GAL80 inhibits GAL4. GAL80 cannot inhibit GAL4 when galactose is present, so transcription of GAL gene occurs.
Which of the following statements is correct regarding the function of the eukaryotic ORC (origin recognition complex)?
The ORC is a platform on which the other proteins of the pre-replicative complex assemble.
After radioactively labeling DNA and proteins in 2 separate batches of bacteriophage, E. coli cells were infected with each batch. When the infection was interrupted and bacteria were pelleted using a centrifuge, which pairing showed radioactivity in the cell pellet and why?
The cells infected with the radioactive DNA bacteriophage, were in the pellet because DNA is the carrier of genetic information in some viruses.
alternative splicing
The idea that the same pre-mRNA can be spliced differently, to include or exclude certain sequences.
Which of the following statements regarding methionine tRNAs is false? -The N-terminus of every polypeptide synthesized has a formyl group that must be removed. -The initiator tRNA has a formyl group bound to the sulfur in the methionine side chain. -AUG codons in any position other than first in a polypeptide chain are matched with a normal Met-tRNA. -The presence of the formyl group in fMet-tRNA makes it available only for initiating protein synthesis.
The initiator tRNA has a formyl group bound to the sulfur in the methionine side chain.
Which statement regarding methionine tRNAs is false?
The initiator tRNA has a formyl group bound to the sulfur in the methionine side chain.
Why must noncoding sequences (leaders, spacers, etc.) be removed from transcribed tRNAs before they can become fully functional? Multiple choice question.
The noncoding sequences may link multiple tRNAs, preventing them from functioning properly.
Why must noncoding sequences (leaders, spacers, etc.) must be removed from transcribed tRNAs before they can become fully functional?
The noncoding sequences may tie multiple transcribed tRNAs together, preventing them from functioning properly.
Which of the following statements regarding the type VI secretion system (T6SS) is false? -The target cell of a T6SS may be either bacterial or eukaryotic. -The T6SS has two concentric cylinders, and the inner cylinder is injected into a target cell. -The inner cylinder is injected following contact with a target cell. -The outcome of target cell penetration is lysis from the T6SS puncture.
The outcome of target cell penetration is lysis from the T6SS puncture.
Which of the following statements regarding methionine tRNAs is true?
The presence of the formyl group in fMet-tRNA makes it available only for initiating protein synthesis.
Which of the following statements regarding methionine tRNAs is true? -The initiator tRNA has a formyl group bound to the carboxyl group of methionine. -The first position in a polypeptide must be fMet; internal AUG codons can be matched with either fMet or Met. -The presence of the formyl group in fMet-tRNA makes it available only for initiating protein synthesis. -Every bacterial polypeptide requires a formyl group for full enzymatic activity.
The presence of the formyl group in fMet-tRNA makes it available only for initiating protein synthesis.
Which statement best summarizes the major distinction between horizontal gene transfer and vertical gene transfer?
The recipient of genes in horizontal transfer is a mature cell, whereas the recipient of genes in vertical transfer is a progeny cell.
What is the critical event of binary fission?
The replication and elongation of the nucleoid since it is present as a single entity in the cell
Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis?
The smallest fragments will migrate fastest.
The decimal reduction time (D or D value)
The time required to kill 90% of the microorganisms or endospores in a sample at a specified temp -The temp change (Z) can also be determined or predicted from a semilogarithmic plot of D versus temp
Which of these descriptions applies to prototrophs?
They are chemoorganotrophs able to grow on a minimal medium containing only salts and a carbon source.
Which of the following is not true of cloning vectors?They contain at least two replication origins.
They contain at least two replication origins.
Which two of these descriptions apply to auxotrophs?
They have a conditional phenotype. They are unable to grow on medium lacking a particular molecule, where the wild-type strain could grow.
If Hershey and Chase had selected an RNA virus for their experiments rather than a DNA virus, how might they have misinterpreted their results?
They might have mistakenly thought RNA was the carrier of genetic information since it could also be labeled with the radioactive phosphorus.
During DNA replication, DNA polymerases require a primer (of either DNA or RNA) to begin synthesis of DNA. Why?
They need a 'starting point' free 3' hydroxyl group to attach nucleotides to.
Which two of these statements are correct about frameshift mutations?
They usually yield mutant phenotypes. They usually result in the synthesis of nonfunctional proteins.
In eukaryotes, how many DNA polymerases are replicative polymerases?
Three
At which times is the origin recognition complex present at eukaryotic origins of replication?
Throughout the cell cycle
Which three of the following are functions of the 5'-cap at the 5' end of eukaryotic protein-encoding gene transcripts?
To signal that the transcript may be exported from the nucleus To initiate translation on the ribosome To protect the 5' end from RNases
Which two of the following are functions of the poly-A tail at the 3' end of eukaryotic protein-encoding gene transcripts?
To signal that the transcript may be exported from the nucleus and To protect the 3' end from RNases
Predict the outcome of protein synthesis if a gene undergoes a mutation in its anticodon region where a charged tRNA recognizes a nonsense mutation.
Transcription and translation both would continue.
Which of the following best describes the localization of transcription and translation within a bacteria cell?
Transcription occurs in the nucleoid and RNA polymerase moves toward the cytoplasm to hand off the transcript to a 30S ribosomal subunit.
Which statement is correct about the spatial arrangement of transcription and translation in a eukaryotic cell? Multiple choice question.
Transcription occurs in the nucleus and the transcript is exported to the cytoplasm for translation.
________ is the process of producing a messenger RNA molecule using DNA as a template, while ________ is the process of producing protein from the messenger RNA.
Transcription; translation
_______ molecules deliver amino acids to ribosomes during translation.
Transfer RNA (tRNA)
________ molecules deliver amino acids to ribosomes during translation
Transfer RNA (tRNA)
________ molecules deliver amino acids to ribosomes during translation.
Transfer RNA (tRNA)
Initiation of which bacterial process requires (among other factors) initiation factors (IFs) and an initiator tRNA?
Translation
Which is true regarding translation in bacteria?
Translation begins with formation of the 30S initiation complex.
_____ involves decoding mRNA and covalently linking amino acids together to form a(n) _____ ; this occurs at the ribosome.
Translation; polypeptide
A structural gene encodes the information for a specific protein.
True
Bacterial chromosomes, unlike eukaryotic chromosomes, often consist of a single replicon.
True
By using enzymes that destroyed DNA, RNA, or protein, scientists (Avery and colleagues) were able to determine which of the three molecules was required to transform bacterial cells
True
By using enzymes that destroyed DNA, RNA, or protein, scientists (Avery and colleagues) were able to determine which of the three molecules was required to transform bacterial cells.
True
Catenanes are interlocked chromosomes that form during the termination stage of DNA replication.
True
DNA polymerase and aminoacyl-tRNA synthase are similar in that both have proofreading ability, but differ in the substrates that they act upon.
True
Horizontal gene transfer occurs frequently between the nuclear, mitochondrial, and chloroplast genomes of some eukaryotes.
True
If the DNA of a new discovered organism exhibits genes that are arranged as operons and lacks intron sequences, the hypothesis that this organism is bacterial rather than mammalian would be supported by the evidence.
True
In the Sanger method, examining the electrophoresis gel and reading from bottom to top, one base at a time, gives the sequence of DNA.
True
Regulation of translation initiation by micro RNAs and small interfering RNAs is possible since transcription and translation are spatially separated in eukaryotes. This is not the case in bacteria and archaea, where translation begins before transcription has ended.
True
T/F: Some degradative pathways are regulated by an activator protein. An activator is a regulatory protein that facilitates transcription by binding to DNA.
True
The RNA transcript being produced by the RNA polymerase is complementary to the template strand of the DNA.
True
The amino acid sequence of a protein determines its shape and specific function.
True
The basic differences between RNA and DNA reside in their sugar and pyrimidine bases; RNA has ribose and uracil whereas DNA has deoxyribose and thymine.
True
The joining of sticky ends involves the formation of phosphodiester bonds.
True
To sequence DNA by the Sanger method, the DNA must first be made in single stranded form.
True
To sequence DNA by the Sanger method, the DNA must first be made in single stranded form. DNA sequencing is a technique for determining the complete sequence of bases (i.e., As, Ts, Gs, and Cs) for a particular piece of DNA. Sanger sequencing is the most popular method for DNA sequencing.
True
To sequence DNA by the Sanger method, the DNA must first be made in single stranded form. DNA sequencing is a technique for determining the complete sequence of bases (i.e., As, Ts, Gs, and Cs) for a particular piece of DNA. Sanger sequencing is the most popular method for DNA sequencing. View the animation below, then complete the quiz to test your knowledge of the concept.
True
To sequence DNA by the Sanger method, the DNA must first be made in single stranded form. DNA sequencing is a technique for determining the complete sequence of bases (i.e., As, Ts, Gs, and Cs) for a particular piece of DNA. Sanger sequencing is the most popular method for DNA sequencing. View the animation below, then complete the quiz to test your knowledge of the concept.
True
True or false: All catabolite operons are regulated by CAP and a regulatory protein that is specific to each operon.
True
True or false: Bacterial DNA is generally negatively supercoiled.
True
True or false: The CRISPR/Cas system "remembers" previous bacteriophage attacks, similarly to the animal immune system. True false question.
True
True or false: The ara operon is an example of both a positive and negative control system.
True
True or false: The notation 'prime' is used after the number of a particular carbon in a ribose or deoxyribose sugar to differentiate them from the carbons/nitrogens in the nitrogenous bases.
True
True or false: There is no sequence or structural similarities between eukaryotic and bacterial DNA polymerases.
True
When RNA polymerase is bound to the lac promoter sequence, transcription of the lac operon is on.
True
The inducer of the lac operon is an isomer of lactose.
True (allolactose)
true
True or False: Bacteria chromosomes consist of a single replicon, while eukaryotes have multiple replicons.
False; eukaryotes have the largest with 80S ribosomes
True or False: Bacterial ribosomes are the largest and require more initiation factors.
True
True or False: Eukaryotes control transcription through chromatin modeling and histone acetylation.
True
True or False: Gamete fusion and crossing over are types of vertical gene transfer for eukaryotes.
True
True or False: In Hfr strains, the F factor is integrated into the chromosome rather than in the cytoplasm.
Which two statements about bacterial flagellar movement are true?
Tumble results from clockwise motion and Run results from counterclockwise motion
How are the four subunits of DNA polymerase α-primase organized?
Two catalyze DNA synthesis and two catalyze RNA synthesis
Which of the following nitrogenous bases is usually found in RNA but not in DNA?
Uracil
Sterilizing gases
Used to sterilize heat-sensitive materials Microbicidal and sporicidal Ethylene oxide sterilization is carried out in equipment resembling an autoclave Betapropiolactone and vaporized hydrogen peroxide Combine with and inactivate DNA and proteins - used in items such as Petri dishes, heart-lung machine components, sutures, and catheters
Which of the following methods of genetic recombination is common to both eukaryotic and bacterial cells?
Vertical gene transfer
Which of the following statements regarding viruses is false?
Viruses can replicate either within a host cell or autonomously.
Which of the following statements about viruses and transduction is false?
Viruses escaping a bacterium can move genes to an archaeon when they find a new host cell.
RNA polymerase 1- catalyzes synthesis of rRNA RNA polymerase 2- catalyzes synthesis of mRNA RNA polymerase 3- catalyzes synthesis of tRNA
What are the 3 major types of RNA polymerase in eukaryotes?
conjugation, transformation, transduction
What are the 3 mechanisms of horizontal gene transfer?
transposase
What enzyme catalyzes simple transposition?
Occurs when small bits of RNA (miRNA or siRNA) inhibit gene expression by binding to the messenger RNA and either degrading it or preventing translation.
What is RNA interference
N-formylmethionine- tRNA
What is the initiator tRNA for bacteria
Met-tRNAiMet
What is the initiator tRNA for eukaryotes and archaea
lethal mutation
What type of mutation results in death of an organism?
Which arrow points to the α carbon of the amino acid?
X
Which of the following indicates a peptide bond? (Image)
Y
Which cloning vector should be used to express a 500-kb DNA fragment in Saccharomyces cerevisiae?
YAC
Each pH unit represents
a 10-fold change in the concentration of H+ in a solution
missense mutation
a change in one DNA base pair that results in the substitution of one amino acid for another in the protein made by a gene.
A suppressor mutation, which returns a mutant back to its wild-type phenotype, occurs at ____________ the first mutation.
a different site from
Select two examples of mutations that affect regulatory sequences of microbial genes.
a mutation in the lac operator so the lac repressor cannot bind a mutation in a promoter so that RNA polymerase cannot bind
A change in genotype, but not in phenotype, is most likely due to
a point mutation in the third position of a DNA triplet.
The internal RNA template of the enzyme telomerase is complementary to ____.
a portion of the G-tail
A cistron is
a segment of DNA that encodes a single polypeptide
A cistron is _____.
a segment of DNA that encodes a single polypeptide
The poly-A tail of a eukaryotic transcript is ____.
a series of adenosines
A signal peptide is _____.
a short amino acid sequence tag at the N terminus of a protein
Each of the four Sanger sequencing reactions include
a single dideoxynucleotide triphosphate
DNA replication in a circular bacterial chromosome begins at _____.
a single specific origin of replication site
In eukaryotes, the primer that is formed to initiate DNA synthesis is ____.
a single stranded molecule with both ribonucleotides and deoxyribonucleotides
RNA can become double-stranded as _____.
a single-stranded RNA molecule folds onto itself, forming noncovalent hydrogen bonds between bases
mutation
a stable, heritable change in a DNA sequence
Because the oriC locus in E. coli cells is rich in AT base pairs, it has ______ , hydrogen bonds overall, making it easier for it to become single-stranded to initiate DNA replication.
acceptable answers: fewer, less, two, or 2
The amino acid is added to the ______ of a tRNA
acceptor stem
he large amount of energy required to synthesize proteins is to ensure the ______ of the protein synthesis process.
accuracy or fidelity
A(n) _____ protein is a DNA-binding protein that promotes transcription initiation.
activator
Proteins that promote transcription initiation by binding to DNA are called ____.
activator proteins
In the absence of lactose, the lac repressor is
active and can bind to the operator.
In eukaryotes a series of __________ residues are added to the 3' end of an RNA molecule as part of the posttranscriptional processing used to produce functional mRNA.
adenine
The 200 nucleotides added to the 3' end of a eukaryotic protein-encoding transcript is called a poly- _____ ______
adenine tail
ATP is converted to cAMP by the enzyme _____ _____
adenyl cyclase
The vast majority of proteins must ________ to become functionally active.
adopt a three-dimensional shape
Most fungi are _______, but a number of species -- particularly among yeasts-- are facultative anaerobes.
aerobic
Which of these types of DNA damage are usually mended by direct DNA repair?
alkylated bases thymine dimers
The proteome refers to
all of the proteins that an organism produces.
Alternative forms of a gene are called _____
alleles
The process in which amino acids are covalently bound to a tRNA molecule by an aminoacyl-tRNA synthetase is known as ______.
amino acid activation
The stringent response is induced when bacterial cells are starved for ______.
amino acids
Proteins are also known as polypeptides because they are polymers of _____.
amino acids linked by peptide bonds
There are three phases of the translation elongation cycle. In order, they are ________, the transpeptidation reaction, and ________.
aminoacyl-tRNA binding; translocation
In regulation by repression...
an amino acid activates the repressor so that the repressor binds to the operator and prevents transcription
DNA polymerase catalyzes the formation of a phosphodiester bond between an existing DNA strand and _____.
an incoming nucleoside triphosphate
Plasmid vectors often contain __________ genes that can be used to screen for recombinants.
antibiotic resistance
Each codon on the mRNA molecule is recognized and bound by the ___________________present on the tRNA molecule.
anticodon
The term _______is used to describe the situation where one strand of DNA is oriented in the 5' to 3' direction while its complementary strand is oriented in the reverse 3' to 5' direction.
antiparallel
Polycistronic operons are found in ____.
archaea and bacteria
Transcription occurs in the cytoplasm in ____.
archaea and bacteria
Antiseptics
are chemical agents applied to tissue to prevent infection by killing or inhibiting pathogen growth
Most eukaryotic genes are divided into introns and exons. Introns are the portion of the gene that ____.
are excised from the transcript
Eukaryotic ribosomes differ from bacterial ribosomes in that the eukaryotic ribosomes
are larger in size and require more initiation factors in order to be positioned properly on the mRNA.
The presence of two_____ , residues in the signal sequence of proteins indicates they will be bound and moved via the Tat translocation system.
arginine or Arg
What wavelengths of light constitute ultraviolet radiation?
around 260 nm
Vibrioid-shaped cells derive their cell shape from
asymmetric cell wall growth - the protein crescentin is involved
A regulatory process that results in transcription termination within a leader sequence that precedes the structural genes is termed _____
attenuation
Termination of transcription elongation before RNA polymerase enters the first structural gene of an operon is called ____.
attenuation
Transcription of the trp operon is regulated at the level of initiation by the trp repressor, and at the level of elongation by a process called _____
attenuation
A signaling molecule of an quorum sensing system is called a(n) ______.
autoinducer
The AHL signaling molecule is termed a(n) _____(AI) to reflect the autoregulatory nature of the system.
autoinducer
An organism with a mutation that affects its ability to synthesize a biochemical essential for its growth is known as a(n) _____
auxotroph
To copy (aka, clone) a human DNA sequence to be placed into a bacterial plasmid DNA, human DNA must be cut with restriction "enzyme A" then it can be joined to ________.
bacterial DNA cut with restriction "enzyme A"
Which of the following types of cloning vector can carry the largest amount of foreign DNA?
bacterial artificial chromosome
Type VI secretion systems in Gram-negative bacteria are of interest because they are very similar to systems used by _________ to inject their genomes into the cytoplasm of their bacterial hosts.
bacteriophages or viruses
There are two types of excision repair systems that correct damage that causes distortions in the DNA double helix: _____ excision repair and ______ excision repair.
base nucleotide
When microorganisms are cultivated in broth, they usually grow in a ____ ____
batch culture
A cell that has been targeted by a T6SS will ______.
be poisoned by toxins
Why are microorganisms particularly sensible to external temps?
because they cannot regulate their internal temp
Information about a protein's maturation is interpreted by the cell _____.
before translation is complete
The promoter for a gene is located at the _____.
beginning of the gene on the template strand
Horizontal gene transfer is the transfer of DNA
between different genomes
Horizontal gene transfer is the transfer of DNA
between different genomes.
Most bacterial and archaeal cells reproduce by
binary fission
An active repressor protein...
binds to the DNA molecule and prevents transcription
DNA-bound repressor proteins inhibit the initiation of transcription by either ____.
blocking the binding of RNA polymerase and preventing the movement of RNA polymerase
Nucleotides are the building blocks of ______
both DNA and RNA
Nucleotides are the building blocks of ______.
both DNA and RNA
This image shows the molecules involved in transcriptional regulation of the lac operon. Considering the lac repressor and CAP proteins illustrated here, which carbon sources are available?
both lactose and glucose
Which statement best describes the ara operon?
both negative and positive transcriptional control
Some bacteria reproduce by forming a
bud
The binding of _____ to the catabolite activator protein causes it to change to the active form.
cAMP
Which cyclic nucleotide activates CAP?
cAMP
Which two of the following are examples of second messengers?
cAMP and ppGpp
When in a complex with ________, the CAP protein binds to the CAP site and ________ the expression of the lac operon
cAMP; switches on
When in a complex with ________, the CAP protein binds to the CAP site and ________ the expression of the lac operon.
cAMP; switches on
It is easier to transform bacteria with plasmid DNA since plasmids
can independently replicate within the host and are not as easily degraded as are linear fragments.
The 7-methylguanosine nucleotide added to the 5' end of a eukaryotic protein-encoding transcript is called a 5' - ______
cap
When a microorganism such as E. coli is grown on glucose it is
capable of amino acid production
In translation elongation, each new amino acid is added to the ____ terminus of the polypeptide.
carboxyl
A chemical agent that causes cancer is specifically called a(n) ____
carcinogen
The mim, max, and optimum temp for growth are the __________ temps
cardinal
R plasmids are best described as plasmids that _____.
carry genes that confer antibiotic resistance
In E. coli, the proteins necessary to utilize lactose as an energy and carbon source will not be expressed, even when lactose is present, unless the _____ _____ protein is activated by the absence of glucose in the cell.
catabolite activator
The global control of operons encoding enzymes for the catabolism of carbohydrates that must be modified prior to entering glycolysis is referred to as ____.
catabolite repression
The positive regulatory system called _____ _____ prevents the expression of genes encoding proteins necessary for the utilization of sugars other than glucose when adequate supplies of glucose are present.
catabolite repression
After DNA replication, the two daughter chromosomes may be topologically linked, like two links in a chain. These linked chromosomes are called
catenated
In bacteria, conjugation refers to the transfer of DNA by _____.
cell-to-cell contact
DnaJ/DnaK/GrpE are a type of _____ protein that help fold other proteins back their functional configurations.
chaperone
Base analogues, DNA-modifying agents, and intercalating agents are three types of _____ mutagens.
chemical
A resistance mutant may have acquired resistance to which three of the following?
chemical pathogen antibiotic
A protein used to sense the presence of specific chemicals in the environment is a(n) _____
chemoreceptor
E. coli detects the presence of specific molecular attractants with ____.
chemoreceptors
Hfr strains contain the F factor integrated into their ________, rather than in the __________.
chromosome; cytoplasm
plasmids
circular, double-stranded, extrachromosomal bits of DNA
A segment of DNA that encodes a single polypeptide is a(n)...
cistron
The transcribed and translated region of a gene is the __________ region.
coding
During translation, a triplet____________ corresponds to a 'word' being 'read' from the mRNA to be translated into a particular amino acid in the polypeptide.
codon
A bacterial cell that is able to take up DNA and be transformed is said to be _____
competent
The term ____ base pairing refers to the manner in which the bases found on one strand of DNA match up with those of the opposite strand according to specific base-pairing rules.
complementary
The term _____ binding refers to the manner in which the bases found on one strand of DNA match up with those of the opposing strand according to specific base-pairing rules.
complementary
The term________binding refers to the manner in which the bases found on one strand of DNA match up with those of the opposing strand according to specific base-pairing rules.
complementary
Osmotic concentration
concentration of all solutes in a solution
A mutant strain of E. coli that grows normally at 30°C, but dies at 40°C, is a(n)_________ mutant.
conditional
Mutations that are expressed only under certain environmental conditions are called _____mutations.
conditional
Horizontal gene transfer can occur via _________.
conjugation
Transfer of genetic information via direct cell-cell contact is called
conjugation
Enzymes that are expressed at a constant level all the time are said to be .
constitutive
Multisubunit protein complexes like SAGA and Mediator are required as co-activators of transcription initiation. These complexes function to _____.
coordinate input from transcription factors and chromatin structure
In E. coli, rotation of the flagella in a ________ direction result in a cellular motion called a run.
counterclockwise
In this image of double-stranded DNA, the arrow points to a(n) _____ bond.
covalent
Topoisomerase resolves catenated daughter chromosomes by
creating a double-stranded break in one chromosome, then rejoining the strands after the chromosomes are separated
Cells depleted of _________ are rod-shaped
crescentin
The cell shape comma-shaped cells is determined by the protein
crescentin (creS)
The cytoskeletal protein ___________ is needed for vibrioid cells to develop and maintain the curvature that characterizes their shape
crescentin (creS)
The chemical environment of the cytoplasm does not support _____, so the reaction can only be carried out following secretion.
cysteine oxidation
The genetic code is said to be __________ because more than one codon will specify a particular amino acid.
degenerate
Moist heat destroy cells and viruses by
degrading nucleic acids, denaturing proteins, and disrupting cell membranes
Each new base to be incorporated during DNA replication is a(n)
deoxyribonucleoside triphosphate (dNTP)
DNA is a polymer composed of ________.
deoxyribonucleotides
The sugar molecule found in DNA is _______, while the sugar molecule used in RNA is ________.
deoxyribose; ribose
Antibiotic resistance genes like those found on R plasmids often code for enzymes that _____.
destroy or modify antibiotics
An organic antimicrobial agent with an amphipathic structure (having both polar and nonpolar components) is termed a(n)
detergent
In some circumstances, when two different carbon sources are available, growth will occur first using one carbon source, then after a short lag period, growth will resume using the second carbon source. This process is called __________ growth.
diauxic
When E. coli is grown on medium containing glucose and lactose, a two phase pattern called _____ growth is seen as the glucose is preferentially metabolized.
diauxic
A pattern of bacterial growth in two phases caused by the presence of two sugars in the media is called ____.
diauxic growth
Thymine dimers can be corrected by photoreactivation, which is a type of _____ DNA repair.
direct
Riboswitches are regulatory mRNAs that can fold into different patterns based upon ____.
direct binding of an effector molecule to mRNA
The chromosomes of most bacteria are comprised of
double stranded circular molecules
When does DNA proofreading occur?
during DNA replication, before the next nucleotide is added
Vertical gene transfer is the transfer of DNA
during normal cell division.
Modification of eukaryotic transcripts begins ____.
during transcription elongation
The term 'semiconservative' in DNA replication means that ______.
each double-stranded molecule produced will contain 1 parent strand and 1 new daughter strand
Most eukaryotic genes are monocistronic, meaning that ____.
each gene has its own promoter and each transcript has only one gene
The total number of viable microorganisms remains constant in stationary phase because
either there is a balance between cell division and cell death or there is a cessation of cell division even though the cells may remain metabolically active.
Movement of charged molecules in an electrical field, which is used to separate nucleic acid fragments for recombinant DNA work, is called
electrophoresis
The unusual amino acid selenocysteine is inserted into proteins via recognition with a specific ________ factor. This is followed by incorporation when a UGA stop codon is encountered in association with nucleotide sequences called cis-acting selenocysteine insertion sequence elements (SECIS).
elongation
There are three stages of translation: initiation, _____, and termination.
elongation
Most eukaryotic genes are divided into introns and exons. Exons are the portion of the gene that ____.
encodes the polypeptide product
All protein translocation and secretion systems require ________ at some step in the process.
energy
A binding site for a transcriptional activator that may be upstream or downstream and sometimes a great distance away from the promoter is termed a(n) _____
enhancer
Two-component signal transduction systems link changes in _________ to gene expression.
environmental conditions
Chemotaxis in E. coli utilizes a phosphorelay system to regulate ____.
enzyme activity
Avery and his colleagues used _______ to selectively destroy DNA, RNA, or protein in purified extracts of virulent pneumococci.
enzymes
In chemotaxis, E. coli uses a signal transduction system to regulate the activity of _____ involved in flagellar rotation
enzymes
DnaJ and DnaK
example of molecular chaperones in bacteria
telomerase
example of riboprotein
Which type of DNA repair corrects damage (e.g., thymine dimers) that causes distortions in the DNA double helix?
excision repair
Population death is generally _________; that is, the population is reduced by the same fraction at constant intervals
exponential
Upon treatment with a biocidal agent, a microbial population decreases by the same fraction at constant intervals. What kind of decrease is this?
exponential
Eukaryotic transcription factors are referred to as _____ factors because they are not part of RNA polymerase.
extrinsic
The N-formylmethionine-tRNA that is used in bacteria to deliver the initial amino acid to the ribosome is termed ______-tRNA
fMet
the term _____-tRNA is used to describe the N-formylmethionine-tRNA that is used in bacteria to deliver the initial amino acid used in protein synthesis to the ribosome
fMet
True or false: Conjugation occurs only in Gram-negative bacteria.
false
True or false: The Ames test can determine whether a particular substance is carcinogenic.
false
True or false: The trp operon is an example of a positive control system.
false
True or false: Type VI secretion systems appear to function similarly to DNA-injection systems of animal viruses.
false
William Hayes' 1952 experiments demonstrated that conjugation is unidirectional and identified strains he named F+ and F-. The "F" stands for _____
fertile
The large amount of energy required to synthesize proteins is to ensure the _____ of the protein synthesis process.
fidelity
Which two of the following are examples of bacterial proteins secreted out of the cell? -DNA polymerase I -flagellin -toxins -helicase -elongation factors
flagellin toxins
During DNA replication, the holoenzyme must discard old clamps, load new clamps, and tether the template to the core enzyme
for each Okazaki fragment
The Y-shaped part of the DNA molecule where the actual replication process occurs is called the replication __________.
fork
A mutation that leads to a change from wild type to a mutant form is called a(n) _____ mutation.
forward
The addition of one amino acid to a polypeptide is an energy-intensive process. For each amino acid added, _____ GTPs are hydrolyzed and _______ ATPs are required for amino acid activation.
four two
Mutations that arise from the insertion or deletion of base pairs within the coding region of a gene are specifically called _____ mutations.
frameshift
The N terminus of a protein is the _____.
free amino group of the first amino acid in the protein
The C terminus of a protein is the _____.
free carboxyl group of the last amino acid in the protein
Vertical gene transfer can be best defined as the transfer of genes _____.
from parents to progeny
A(n) __________can be defined as a polynucleotide sequence that codes for one or more functional products (e.g., mRNA/protein, tRNA or rRNA).
gene
Which two of these features are common to all transposable elements?
gene for a recombinase (e.g., transposase) inverted repeats
The major conclusion of Hayes' 1952 experiments, which demonstrated the existence of F+ and F- strains, was that _____.
gene transfer by conjugation is unidirectional
The transfer of random bacterial DNA during the lytic cycle of a bacteriophage is called ____ transduction.
generalized
The genetic information in DNA is divided into units called
genes
Regulatory systems that simultaneously control the expression of multiple operons or pathways are referred to as ________.
global regulatory systems
Adenyl cyclase activity is inversely proportional to the level of _____ in the cell
glucose
This image depicts the molecules involved in transcriptional regulation of the lac operon. With the lac repressor and CAP proteins illustrated here, which carbon sources are available?
glucose but not lactose
When purified virulent pneumococci DNA was introduced to avirulent pneumococci, Avery and his colleagues observed _____.
growth of virulent pneumococci, indicating DNA was the agent of transformation
The guanosine-rich single-stranded region at the very end of a linear chromosome is called the _____ _____
guanosine tail
Gamma radiation
has a longer wavelength than UV radiation.
Escherichia coli that lack endonucleases
has a nucleotide sequence complementary to the 3' end of the region to be copied.
The primer used in Sanger sequencing
has a nucleotide sequence complementary to the 3' end of the region to be copied.
A polycistronic mRNA _____.
has multiple gene coding regions for several polypeptides
denature
heat cases proteins to ____
Protein chaperones were first discovered in studies of thermally stressed cells, and are also referred to as HSPs, or _____ _____ proteins
heat shock
The enzyme responsible for denaturing DNA in front of the replication fork is
helicase
The enzyme responsible for unwinding DNA in front of the replication fork is ...
helicase
Hfr strains of bacteria are so named because they undergo a _____ (high/low) frequency of ______
high recombination
DNA replication could be categorized as a ____. (Choose all that apply)
high-fidelity process low-error process
The most common type of DNA recombination (e.g., during meiosis or bacterial horizontal gene transfer) is _____ recombination between similar or identical DNA strands.
homologous
Mechanisms that result in the transfer of genes from one independent, mature organism to another are collectively called _____ gene transfer.
horizontal
Transfer of genes from one mature independent organism to another is called
horizontal gene transfer.
Membrane proteins that must be translocated to the plasma membrane have a(n) _______ to direct them to the correct location.
hydrophobic signal peptide
Because coupled transcription/translation requires that the two processes occur in the same subcellular space, it is likely that this coupling is found _____.
in both the Bacteria and Archaea domains
The "end replication problem" occurs _____. [Choose two.]
in cells with linear chromosomes only in the lagging strand DNA
The information about a protein's maturation is found _____.
in its primary and secondary structure
In general, as genome size of organisms increase, the metabolic and morphological complexity of the cell ______.
increases
When a repressor binds to the operator site on the DNA it normally
inhibits the initiation of transcription.
In bacteria, protein translation begins when
initiation factors help fMet-tRNA assemble with the 16S rRNA within the 30S subunit
Transposases are enzymes that recognize the ends of a(n) _______.
insertion sequence
conjugation
involves the transfer of genetic material between bacteria through direct cell-to-cell contact
The coding region of a gene _____.
is between the start and stop codons
In vesicular transport, the protein to be transported ____.
is enclosed in a vesicle
A signal peptide _____.
is specific for the type of secretion system
The proteome
is the entire collection of proteins that an organism can produce.
The application called multiple strand displacement amplification is a powerful tool because
it allows single-cell genomic sequencing that can analyze uncultivated microorganisms.
The circled bond can be identified as the peptide bond in this polypeptide because _____. [Choose two.]
it does not involve either α carbon it is a carbon-nitrogen bond
How is disinfection different from sterilization?
it doesn't sterilize an object because viable spores and a few microorganisms may remain, whereas in sterilization everything is destroyed or removed
In E. coli, the oriC locus is a good point for the initiation of DNA replication because _____.
it is rich in AT base pairs
While there are several characteristics that are true and important for DNA polymerases, one of the most important to remember in terms of understanding how DNA replication works is that _____.
it synthesizes the new DNA in the 5' to 3' direction
Increasing the size of peptidoglycan during cell division is a challenge because
its strength must be maintained when new subunits are added
The protein factor NusG interacts with both the RNA polymerase and the 30S ribosomal subunit and is believed to act to
keep the mRNA single-stranded
A cidal agent _____ microbes but not necessarily ____
kills endospores
Which two of the following are encoded by the lac operon?
lacI and Three structural genes
The lac operon is expressed at high levels when the sugar _____ is available and a preferred source of carbon and energy is lacking.
lactose
This image shows the molecules involved in transcriptional regulation of the lac operon. With the lac repressor and CAP proteins illustrated here, which carbon sources are available?
lactose but no glucose
Full transcriptional activation of the lac operon requires high levels of the sugar _____ and low levels or the absence of the sugar ______
lactose; glucose
The transcribed, but not translated, sequence that is immediately upstream of the region that encodes the functional product is called the __________ region.
leader
The trpL operon encodes the _____ peptide and attenuator sequences.
leader
Dry air heat is _____ effective than moist heat
less
Mutations that result in the death of an organism when expressed are called __________ mutations.
lethal
DNA microarray technology is used to measure the
levels of specific RNAs expressed by cells.
Population growth is often studied by analyzing the growth of microbes in ________ (broth) culture
liquid
The purpose of the clamp loader protein associated with DNA polymerase III is to _____.
load the beta clamp protein onto the DNA
The "end replication problem" will result in a _____ of genetic information if it isn't resolved properly.
loss
The lac operon is expressed when glucose is
low and lactose is present.
DNA replication could be categorized as a ____ and _____
low-error process high-fidelity process
RNA polymerase II of eukaryotes is responsible for transcribing _______.
mRNA
The G-tail in a telomere functions to ____.
maintain chromosome length
Mobile genetic elements were discovered by Barbara McClintock in the 1940s, during her studies of what organism?
maize
In the modern proteomic analysis, the amino acid sequence of a protein can be determined by
mass spectrometry
In modern proteomic analysis the amino acid sequence of a protein can be determined by
mass spectrometry.
The purpose of the clamp loader protein associated with DNA polymerase III is to
mediate polymerase attachment to the primosome
Microbes that grow best at 37C are called
mesophiles
base analogs
mimic naturally occurring bases but do not have the same function
A mutation that changes the amino acid sequence of the resulting protein by substitution is called a __________ mutation.
missense
Point mutations that involve a single base substitution and result in a change to the amino acid encoded are called _____ mutations. These mutations may or may not have a significant impact on the protein structure.
missense
A point mutation that involves a single base substitution and results in a change to the amino acid encoded by that codon is specifically called a _____.
missense mutation
Select three synonyms for genetic elements that can move around genomes by transposition.
mobile genetic elements jumping genes transposable elements
Transition mutations, which result in substitution of the alternate purine for the original purine, or the alternate pyrimidine for the original pyrimidine, are __________ common than transversion mutations.
more
Protein translocation is _____.
movement of proteins from the cytoplasm to or across the plasma membrane
Protein secretion is _____.
movement of proteins from the cytoplasm to the external environment
Proteins secreted by Gram-negative cells face multiple obstacles, including _____.
moving across both the plasma membrane and the outer membrane
Generally speaking, Okazaki fragments in eukaryotic organisms are typically _________ those in bacterial organisms.
much shorter than
Code degeneracy and "wobble" in the genetic code means that _____.
multiple codons can bind with the same anticodon on a tRNA molecule
The T4 phage of E. coli is a virulent bacteriophage, meaning that it _____.
multiplies in and lyses its host after infection
The general term for heritable changes in DNA sequence is .....
mutation
______ transcriptional control occurs when transcription initiation is inhibited by a protein binding to DNA.
negative
A transcriptional repressor that decreases transcription levels is a ____.
negative regulator
The trp operon is best described as an example of the ______.
negative transcriptional control of repressible genes
This image shows the molecules involved in transcriptional regulation of the lac operon. Which carbon sources are available when considering the lac repressor and CAP proteins illustrated here?
neither glucose nor lactose
A missense mutation that has little to no effect on the activity of a gene product is called a(n) _____ mutation.
neutral
A tautomeric form is an isomer of a nucleotide in which the _____ is changed.
nitrogenous base
Single-stranded RNA that has folded onto itself can become partially double-stranded through _______, bond interactions.
noncovalent or hydrogen
The method used in horizontal gene transfer is
nonhomologous recombination
A __________ mutation is one that causes premature termination of the synthesis of the protein product.
nonsense
Point mutations that result in a new stop codon are called _____ mutations.
nonsense
Eutrophic environment
nutrient rich environment
Bacteria typically contain _____ type(s) of RNA polymerase.
one
Termination of translation occurs when _____.
one of three stop codons is reached by the ribosome
A gene can be defined as a polynucleotide sequence that codes for _____.
one or more functional products
Bacterial repressor proteins bind to a DNA sequence called the ...
operator
The site on the DNA to which a repressor protein binds is the __________.
operator
To initiate DNA replication, DnaA binds to the region known as ____and recruits ____ enzyme to denature the DNA.
oriC; helicase
Each chromosome has one or more __________ site(s) where replication begins.
origin
Eukaryotic origins of replication are marked by a cluster of proteins known as the _____ _____ complex.
origin recognition
In the microbiology laboratory, the inoculating loop is sterilized by holding it in the flame of a burner until it glows red hot. This is example of sterilization by
oxidation
Many transcriptional regulatory proteins bind to short, inverted sequences in DNA called ....
palidromes
When two or more genes from the same genome have nucleotide sequences so alike that they most probably arose from gene duplication those genes are called _______.
paralogs
The group of enzymes responsible for peptidoglycan synthesis are notable for their binding to
penicillin
Proteins are polymers of amino acids linked by ______.
peptide bonds
After proteins are secreted across the plasma membrane of Gram-positive cells, they must either pass through the relatively porous _____________ layer into the external environment or become embedded in or attached to it.
peptidoglycan
Chemical compounds like cresols, xylenols, and ortho-phenylphenol are collectively referred to as
phenolics
The backbone structure of DNA possesses a _________ chemical group between the deoxyribose portions of two adjacent deoxyribonucleotides.
phosphate
DNA polymerase catalyzes the formation of a(n) _____ bond between an existing DNA strand and an incoming nucleoside triphosphate
phosphodiester
DNA polymerase catalyzes the formation of a(n) _____ bond between an existing DNA strand and an incoming nucleoside triphosphate.
phosphodiester
The backbone of DNA molecules is formed by _____ bonds between individual deoxyribonucleotides.
phosphodiester
In this image of double-stranded DNA, the arrow points to a(n) Blank______ bond.
phosphodiester (between pentose and phosphate)
The mechanism to synthesize cAMP when glucose is absent involves the system for _____.
phosphorylating glucose as it enters the cell
The covalent bond between ribonucleotides in a strand of RNA is a __________ bond.
phospodiester
Silent, missense, nonsense, and frameshift are all common types of _____ mutations.
point
A single ___________ mRNA molecule contains multiple coding regions that can be translated into several polypeptides by ribosomes.
polycistronic
end replication problem
polymerase cannot replicate the 5' (beginning) end of the new strand because that's where the primer was. DNA strands lose 50-200 bases per replication solved by using Telomeres- nucleotide sequences that repeat several hundreds of times at the end of the chromosomes
A complex consisting of a single mRNA molecule with several ribosomes is called a
polysome
A transcriptional activator that increases transcription levels is a ____.
positive regulator
In terms of global gene regulation, which of the following molecules is most similar to c-di-GMP and cAMP?
ppGpp
The linear sequence of amino acids is the__________protein structure.
primary
The transcript of a gene that contains introns and exons and has not yet been processed is called a ____.
primary RNA and pre-mRNA
A short RNA strand of around 10 nucleotides complementary to the DNA template is the product of the ______ enzyme
primase
The enzyme DNA ___ synthesizes RNA primers as needed for the initiation of new-strand DNA synthesis.
primase
The enzyme _____ works to synthesize a short stretch of RNA complementary to the parent strand to begin synthesis of DNA by DNA polymerase III enzymes.
primase
The numbers used to designate the carbons in the sugar of a deoxyribonucleotide are given the notation ________, following their number to distinguish them from the carbons/nitrogens in the nitrogenous bases.
prime
In __________, ribosomes can attach to the mRNA and begin translation even though transcription has not been completed.
prokaryotes
The coding sequence in the DNA of __________ is normally continuous; that is, it is not interrupted by noncoding sequences.
prokaryotes
A bacterial __________ is the nontranscribed region of the DNA to which RNA polymerase binds in order to initiate transcription.
promoter
The region at which the RNA polymerase binds is the __________ region.
promoter
When bound to the DNA, the repressor protein usually prevents attachment of the RNA polymerase to the __________.
promoter
The ability of DNA polymerase to detect and correct errors before the next nucleotide is added is called _____
proofreading
A telomere is composed of ____.
protein and DNA
Translation is the synthesis of ______.
proteins from mRNA
A wild-type chemoorganotroph able to grow on a minimal medium containing only salts and a carbon source is known as a(n) _____ . These wild-type stains may give rise to mutants incapable of survival without additional nutrients, like a particular amino acid.
prototroph
Two amino acids that are found in some proteins due to exceptions in the universal genetic code are
pyrrolysine and selenocysteine.
The interaction of multiple polypeptide subunits into a final functional form is the___________level of protein structure.
quaternary
UV radiation is another very damaging form of
radiation
Which three of these factors contribute to the extreme radiation resistance of Deinococcus radiodurans?
radiation-resistant proteins two homologous chromosomes proteins that quickly repair damage to genome
In the ribosome's translational domain, the A site
receives tRNAs carrying the next amino acid to be added
In the ribosome's translational domain, the A site _____.
receives tRNAs carrying the next amino acid to be added
The sigma factor of bacterial RNA polymerase enables the enzyme to _____.
recognize the promoter
Damage to DNA in which both bases of a pair are missing or damaged, or where there is a gap opposite a lesion, is usually repaired by a process called _____ repair.
recombination
The process in which one or more nucleic acid molecules are rearranged or combined to produce a new nucleotide sequence is called
recombination
Proteins involved in the control of gene expression in processes such as induction and repression are referred to as ____.
regulatory proteins
What term describes a set of genes that are controlled by a common regulatory protein?
regulon
Which two of these missense mutations would be likely to have a significant effect on the function of the protein encoded by the mutated gene?
replacement of a nonpolar amino acid with a polar amino acid substitution of an amino acid located at the active site of an enzyme
The advantage of having multiple origins of replication for a eukaryotic chromosome is that ____.
replication is faster
The complex of ten or more proteins that replicates the DNA is called the _____.
replisome
A(n) _____ protein is a DNA-binding protein that inhibits transcription initiation.
repressor
Proteins that inhibit transcription initiation by binding to DNA are called _____.
repressor proteins
The bacterium Deinococcus radiodurans is best known for its ability to ________.
resist damage by radiation
A mutant that can survive exposure to some pathogen, chemical, or antibiotic, is a(n) _____ mutant.
resistance
Plasmids that have genes that decrease bacterial susceptibility to antibiotics are called __________ factors.
resistance
In the sporulation initiation pathway of Bacillus subtilis, SpoOA acts as a(n) _____ regulator
response
SpoOA is best described as a ____.
response regulator
Which two of the following are bacterial defense mechanisms against viruses?
restriction/modification and CRISPR/Cas
During posttranscriptional modification of RNA segments containing multiple tRNAs, the activity of _____(enzymes that cut RNA) is required.
ribonucleases
During posttranscriptional modification of transcripts containing multiple tRNAs, the activity of __________ (enzymes that cut RNA) is required.
ribonucleases, ribonuclease, ribozymes, or RNases
Ribose in RNA is different from deoxyribose in DNA because ______.
ribose has a hydroxyl group attached to the 2' carbon
In riboswitches that control translation, the binding of an effector molecule alters the shape of the mRNA leader sequence and inhibits ______ binding at the Shine-Dalgarno sequence.
ribosome
Production of polypeptides/proteins through decoding of mRNA is achieved by which "tool?"
ribosome
_____ can fold into different patterns based upon the binding of an effector molecule to the mRNA.
riboswitches
As drawn here, the replication fork moves to the _____, to continue DNA replication.
right
The two types of flagellar movement in E. coli are
run and tumble
Flagellar movement in E. coli involves a combination of smooth swimming motions called _____, and nonspecific rotations are called _____
runs; tumbles
RNA molecules that do not function as mRNA, tRNA, or rRNA are referred to as _____ or noncoding RNAs.
sRNAs
The use of a detection system to locate a microbe with a particular mutant phenotype is generally known as ____.
screening
_____ _____ are small molecules produced inside of cells in response to an external signaling event.
second messangers
cAMP, ppGpp, and cyclic dimeric GMP are all examples of _____.
second messengers
The interaction of side chain groups on amino acids, folding a protein into a three dimensional shape, is considered the _________ and ___________ levels of protein structure.
secondary and tertiary
Flagella and fimbriae proteins are examples of protein subunits that must be _____ after translation.
secreted
The Sec (or __________) pathway is the main pathway used to translocate proteins across the plasma membrane of cells.
secretion
An allele is most likely to persist in a population if it confers a survival advantage under _________ pressure.
selective
DNA replication uses each parent strand as a template to produce a new daughter strand. In the replicated molecules, each has one parent strand and one newly-synthesized daughter strand. The term used to describe this phenomenon is __________ DNA replication.
semiconservative
DNA helicase acts near the DNA unwinding element (DUE) to
separate the two strands of parental DNA
The process of forming a cross wall between two daughter cells is known as
septation
Which process forms cross walls between daughter cells during cytokinesis?
septation
The unusual amino acid selenocysteine is synthesized from ______ after it has been attached to certain tRNA molecules by the enzyme ______.
serine; selenocysteine synthase.
Producing alternate versions of ________ factors can immediately change the expression of many bacterial genes.
sigma
The bacterial RNA polymerase core enzyme needs the assistance of a(n) _____ factor to bind to the promoter and initiate transcription. By producing alternate versions of this factor, the expression of gene sets can be rapidly switched.
sigma
Changes in environmental conditions are linked to changes in gene expression by regulatory proteins of two-component _____ _____ systems
signal transduction
The binding site for a transcriptional repressor in eukaryotes is called a(n) ____.
silencer
A __________ mutation does not alter the amino acid sequence of the resulting protein.
silent
Point mutations that change the nucleotide sequence of a codon but do not change the amino acid encoded by that codon are called _____mutations.
silent
A mutation that caused the codon CGU to change to CGC, which does not affect the amino acid encoded, could be described by which two of these terms?
silent and point
Global regulatory systems are not likely to involve the regulation of _____.
single operons
The proteins that keep the two parental template strands apart during DNA replication are _____.
single-stranded DNA binding proteins
The proteins that keep the two parental template strands apart during DNA replication are
single-stranded DNA binding proteins (SSBP)
To carry out Sanger sequencing a mixture is needed containing
single-stranded DNA, DNA polymerase, complemetary DNA primer, and four deoxyribonucleotides A,T,C,G.
Heat shock proteins (HSPs) are categorized according to their ____
size
sRNAs are _____.
small RNAs
Second messengers are _____ in response to an external signal.
small molecules produced
histones
small proteins that DNA wraps around
The transfer of specific chromosomal DNA following induction of a lysogenic phage is called _____ transduction.
specialized
Select the best definition of transposable elements.
specific DNA segments that can repeatedly insert into one or more sites or into one or more genomes
The complex of proteins and RNA that removes introns from a pre-mRNA is called a _____
spliceosome
Mutations that result from the activity of mobile genetic elements called transposons are considered to be which type of mutations?
spontaneous
Possible causes of spontaneous mutation include
spontaneous lesions in DNA errors in DNA replication transposons
Initation of _____ in Bacillus subtilis is controlled by the protein SpoOA.
sporulation
The purpose of the clamp protein associated with the DNA polymerase III enzyme is to
stabilize the DNA polymerase III core enzyme on the template DNA
When an object is totally free of viable microorganisms, spores, viruses, prions, and other infection agents, it is said to be
sterilized
The process of translation continues until a(n) _____ codon is reached.
stop
When a dideoxyribonucleotide is added to the tube, replication of the strand ______.
stops
The work of Fred Griffith in the late 1920s on the bacterium_________ pneumoniae provided early evidence on the identify of the genetic material of cells.
streptococcus
The _____ response is observed in many bacteria that are starved for amino acids.
stringent
Genes that encode the non-regulatory proteins in an operon are referred to as _____ genes
structural
Which term is used to describe genes that encode the non-regulatory proteins (enzymes) in an operon?
structural genes
nucleosome
structure made by the combination of DNA and histones
The phosphodiester bond in RNA occurs between a phosphate group and adjacent _______ components of nucleotides.
sugar or ribose
A second mutation that occurs at a different site from the first mutation, and which returns the mutant back to the wild-type phenotype, is a(n) _____ mutation.
suppressor
Transcription is _____.
synthesis of RNA from a DNA template
The function of primase during DNA replication is to
synthesize a short strand of RNA to provide a starting point for DNA polymerase III
The function of primase during DNA replication is to _____.
synthesize a short strand of RNA to provide a starting point for DNA polymerase III
The function of eukaryotic DNA polymerase δ is to ____.
synthesize the lagging strand
The function of eukaryotic DNA polymerase ε is to ____.
synthesize the leading strand
Genome sequencing and annotation of metabolic pathways has led to predicted interactions that can be tested by transcriptomics, proteomics, and metabolomics. These interactions between the individual products can then be linked in a predictive network and used to construct testable hypotheses. The field best suited to investigate these statements would be ______
systems biology
Genome sequencing and annotation of metabolic pathways has led to predicted interactions that can be tested by transcriptomics, proteomics, and metabolomics. These interactions between the individual products can then be linked in a predictive network and used to construct testable hypotheses. The field best suited to investigate these statements would be ______.
systems biology
If the product of a functional gene is not a protein, what other product(s) might be encoded by the gene?
tRNA and rRNA
If a bacterial cell is competent, that means it can _____.
take up DNA and become transformed
Spontaneous mutations can occur when a nitrogenous base shifts to a different isomer, also called a(n) ____.
tautomeric form
Since DNA is a double-stranded molecule, there are 2 possible strands that could serve to code for the production of a messenger RNA molecule. The strand that is used to direct mRNA synthesis is known as the ____ strand.
template
The strand of DNA for a particular gene that is copied by the RNA polymerase to form mRNA is called the __________ strand.
template
Which two of the following does DNA polymerase require to catalyze the synthesis of DNA?
template DNA a primer (DNA or RNA) to provide a free 3' hydroxyl group
Which three of the following components does DNA polymerase require to catalyze the synthesis of DNA?
template DNA a primer (DNA or RNA) to provide a free 3' hydroxyl group deoxyribonucleotides
Since DNA is a double-stranded molecule, there are 2 possible strands that could serve to code for the production of a messenger RNA molecule. The strand that is used to direct mRNA synthesis is known as the__________strand.
template or coding
The Rho protein is involved in the _____ stage of transcription.
termination
Transcription _____ occurs when the core RNA polymerase dissociates from the template DNA and the transcription bubble closes, renaturing the two DNA strands.
termination
he Rho protein is involved in the _____ stage of transcription.
termination
The sequence that causes transcription to stop is known as the ______.
terminator
The sequence that signals RNA polymerase to stop is known as the
terminator
The purpose of the beta clamp protein associated with the DNA polymerase III enzyme is to _____.
tether the DNA polymerase III core enzyme to the template DNA
The lac repressor is composed of four identical subunits, called a(n) _____.
tetramer
Silencers act on genes ____.
that can be far away from their location
The eukaryotic 43S complex is formed by an association of ____.
the 40S ribosomal subunit and the initiator tRNA
The eukaryotic 43S complex is formed by an association of ____. Multiple choice question.
the 40S ribosomal subunit and the initiator tRNA
The three sites in the translational domain of the ribosome are _____.
the A, P, and E sites
Each codon on the mRNA molecule is recognized by _____ during translation.
the anticodon on tRNA
The fMet-tRNA differs from the Met-tRNA in that
the fMet-tRNA has a formyl group covalently bound to the amino group of the methionine
The AUG codon is almost always _____.
the first codon in the protein-coding portion of mRNA molecules
Quaternary protein structure is _____.
the interaction of multiple polypeptide subunits to form the complete functional unit
Primary protein structure is _____.
the linear sequence of amino acids of a protein
Cardinal temperatures
the minimum, optimum, and maximum growth temperatures - Optimum is always closer to the max than the mim. - These are not rigidly fixed; instead, they depend to some extend on other environmental factors such as pH and available nutrients
If one reproductive strategy of a eukaryotic organism is gamete fusion, what can be concluded about that organism?
the organism participates in vertical gene transfer
In this diagram of a eukaryotic core promoter, the numbers below each component refer to _____.
the position of that component relative to the start site of transcription
The limitation on microbial growth rate at high nutrient levels is/are
the saturation of the transport proteins for nutrient uptake.
The 43S•mRNA complex scans a message until it encounters ____.
the start codon
The coding region of a gene typically begins with _____.
the start codon
The template strand of a gene is
the strand copied for the mRNA transcript
The template strand of a gene is _____
the strand used to assemble the mRNA transcript
The template strand of a gene is _____.
the strand used to assemble the mRNA transcript
What event occurs as the ribosome shifts down the mRNA by a distance of three nucleotides?
the tRNA that was in the P site moves into the E site
In bacterial genetics, transformation is _____.
the uptake of DNA by a bacterial cell
Complementary base pairing in DNA refers to
the way that bases on opposing strands match up and hydrogen bond according to specific base-pairing rules
Complementary binding in DNA refers to _____.
the way that bases on opposing strands match up and hydrogen bound according to specific base-pairing rules
The reading frame of an mRNA molecule is
the way triplets of bases are read to code for individual amino acids
The reading frame of an mRNA molecule is ___________.
the way triplets of bases are read to code for individual amino acids
This base pair can be identified as a G-C base pair because _____.
there are three hydrogen bonds between the bases on each strand
This base pair can be identified as a G-C base pair because _____. (Picture)
there are three hydrogen bonds between the bases on each strand
The consequence of having a linear chromosome in eukaryotes is that ____.
there must be a mechanism to replicate the ends of the chromosome
Eukaryotic transcription factors are referred to as extrinsic factors because _____.
they are not part of RNA polymerase
Which of the following is not true of cloning vectors?
they contain at least two replication origins
Selenocysteine and pyrrolysine differ from the other twenty amino acids because _____.
they do not have a specific codon, but are inserted at a stop codon
Guanine pairs with cytosine using ______ noncovalent hydrogen bonds, while adenine pairs with thymidine using ______ noncovalent hydrogen bonds
three; two
Guanine pairs with cytosine using ______ noncovalent hydrogen bonds, while adenine pairs with thymidine using ______ noncovalent hydrogen bonds.
three; two
DNA helicase unwinds DNA with the aid of ____ and keeps the DNA strands separated using ____.
topoisomerases; single-strand binding proteins (SSBs)
The process by which the base sequence of all or a portion of a DNA molecule is used to direct the synthesis of an RNA molecule is called
transcription
The process by which the base sequence of all or a portion of a DNA molecule is used to direct the synthesis of an RNA molecule is called _______.
transcription
The three stages of the mRNA synthesis are initiation, elongation, and termination and they are often referred to collectively as the _____ cycle.
transcription
The three stages of the mRNA synthesis are initiation, elongation, and termination and they are often referred to collectively as the__________cycle
transcription
The three stages of the mRNA synthesis are initiation, elongation, and termination and they are often referred to collectively as the______cycle.
transcription
The term "regulation of gene expression" refers to the processes that controls ____.
transcription and translation
In eukaryotes, miRNAs can form a silencing complex, which base pairs to a target mRNA preventing translation. This is possible because
transcription and translation are spatially separated in eukaryotes.
When bacterial genes are transferred to another bacterium by a virus, it is called
transduction
Select the best definition of horizontal gene transfer.
transfer of genes from one independent, mature organism to another
The process of taking up DNA from the surroundings, and maintenance of the DNA in a heritable form, is called _____
transformation
a point mutation in the third position of a DNA triplet.
transformation
When a recipient cell acquires a piece of naked DNA from the environment, it is called
transformation.
Nucleotide substitutions that result in purine for purine or pyrimidine for pyrimidine mutations are known as _____ mutations.
transition
The initial transcript synthesized from an eukaryotic protein-encoding gene must be modified before ____.
translation
The process by which the base sequence of an RNA molecule is used to direct the synthesis of a protein is called
translation
The process by which the base sequence of an RNA mol
translation.
As a general rule, Gram-negative bacteria use riboswitches to regulate the _____ of mRNA, and Gram-positive bacteria use riboswitches to regulate _____ termination.
translation; transcriptional
Proper folding of proteins into their functional 3D shape, association with other protein subunits, and delivery to the correct subcellular or extracellular site are all considered to be post- _____________events.
translational
The major pathway for ________ proteins across the plasma membrane of bacterial cells is the Sec (secretion) pathway.
translocating
There are three phases of the translation elongation cycle. They include aminoacyl-tRNA binding, the ______ reaction, and translocation.
transpeptidation
DNA segments that can repeatedly insert into one or more sites or into one or more genomes are called _____ elements.
transposable
An insertion sequence or IS element consists only of a pair of inverted repeats surrounding a gene coding for the enzyme _____.
transposase
Which enzyme is encoded by insertion sequences, recognizes inverted repeats, and cuts DNA to remove a mobile genetic element?
transposase
The movement of a mobile genetic element is called _____
transposition
The nucleotide sequence that encodes the leader sequence of the trp operon is ____.
trpL
True or false: A mutation can prevent a gene from being expressed, even if the coding sequence is completely unchanged. True false question.
true
True or false: Lethal mutants can be recovered only if they are conditional mutants. True false question.
true
True or false: Most transposable elements contain a transposase gene and inverted repeats.
true
True or false: The intracellular level of cAMP depends on the state of a protein that functions in the phosphoenolpyruvate:sugar phosphotransferase system (PTS).
true
The frequency of which type of flagellar movement decrease when E. coli moves towards the source of a chemical attractant?
tumbles
When E. coli is in the presence of a chemical gradient, the frequency of movements called _____ decreases as long as the cell moves towards the chemical attractant.
tumbles
The cell wall constrains the _______ pressure exerted by the cytoplasm, preventing the cell from swelling and bursting
turgor
In addition to the 20 amino acids normally found in protein, _____ additional and unusual amino acids have been discovered.
two
Which of the following describes a catenane?
two interlocked chromosomes similar to two joined chain links
A dimerized chromosome is formed when _____.
two newly replicated chromosomes are joined together at their ends to create a single chromosome that is twice as long.
The addition of one amino acid to a polypeptide is a very energy-intensive process. For each amino acid added, _____GTPs are hydrolyzed, while _____ ATPs are required for amino acid activation.
two;two
If Escherichia coli is cultured in broth containing both glucose and lactose, it
uses glucose preferentially until the supply is exhausted, then uses lactose
Which two of the following properties describe RNA?
uses the base uracil instead of thymine contains the sugar ribose instead of deoxyribose
A DNA molecule used to carry a foreign gene into a host organism is called a
vector
Another term for the transfer of genes from parents to progeny is _____ gene transfer.
vertical
The mechanism for moving proteins to a target location by small vesicles that pinch off from the membrane of one organelle then fuse with another membrane is called _____ ______
vesicular transport
Bacteriophages that lyse their host cells soon after infection are called ______ bacteriophages.
virulent
In the Griffith transformation experiment, when living avirulent bacteria were mixed with killed __________ bacteria before being injected into mice, the mice died.
virulent
An organism's ability to eliminate or neutralize the effect of an antimicrobial drug
what does drug resistance refer to?
The most prevalent form of a gene, and its associated phenotype, is called the ______ type.
wild
The most prevalent form of a gene, and its associated phenotype, is called the _______.
wild type
Code degeneracy and _____________ in the genetic code allows several codons to pair with the same___________, on a tRNA molecule. This means that although there are 61 sense codons, there are NOT 61 different tRNA molecules.
wobble; anticodon
Which of the following are the three replicative polymerases in eukaryotes?
ε α-primase δ