Assignment 3 – Flashcards
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Which of the following is NOT a membranous organelle within a eukaryotic cell?
ribosome
nucleus
chloroplast
endoplasmic reticulum
answer
Ribosome
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The process of bringing a solid substance into the cell is known as __________.
phagocytosis
pinocytosis
pseudopodia
photosynthesis
answer
Phagocytosis
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Which of the following is NOT a characteristic of a eukaryotic cell?
presence of a nuclear envelope
presence of membrane-bound organelles
can undergo transcription and translation simultaneously
contain chromosomes composed of DNA and histones
answer
Can undergo transcription and translation simultaneously
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The archaea are similar to bacteria in all of the following aspects EXCEPT __________.
their cytoskeleton
their ribosomal proteins
their lack of membranous organelles
their mechanism of cell division
answer
Their ribosomal proteins.
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The hami of some archaea are used for which of the following processes?
reproduction
defense
locomotion
attachment
answer
Attachment
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PHB is NOT associated with which of the following words?
ribosome
inclusion
biodegradable
plastic
answer
ribosome
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A bacterial cell is placed in distilled water. Which of the following will happen?
There will be no net gain or loss of water in the cell.
The cell will gain water.
The cell will lose water.
The cell will shrink.
answer
the cell will gain water
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A bacterial cell stains positive with the acid-fast stain. Which of the following is FALSE?
It has a cell wall that contains endotoxin.
It will be difficult to stain this cell with the Gram stain.
It may be a member of the genus Mycobacterium.
It has a cell wall that contains waxy lipids.
answer
It has a cell wall that contains endotoxin.
Endotoxins are found in gram-negative cells, none of which are acid fast.
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A bacterial cell possesses a glycocalyx. Which of the following is FALSE?
It will be more pathogenic.
It will be engulfed more quickly by defensive cells of the host.
It will be less likely to dry out.
It will be able to attach to surfaces.
answer
It will be engulfed more quickly by defensive cells of the host
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If a eukaryotic cell suffers damage to its mitochondria, which of the following processes of life would be most immediately affected?
reproduction
responsiveness
energy production
growth
answer
Energy production
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Which of the following is NOT a basic process of life?
sexual reproduction
metabolism
responsiveness
growth
answer
Sexual reproduction
Not all living organisms reproduce sexually.
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The filament and basal body are associated with which of the following external structures found in some bacterial cells?
glycocalyx
fimbriae
pili
flagella
answer
Flagella
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A periplasmic space is found in which of the following?
Gram-negative cells only
Gram-positive cells only
both Gram-positive and Gram-negative cells
neither Gram-positive nor Gram-negative cells
answer
Gram-negative cells ONLY
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Which of the following processes can be either specific or nonspecific depending upon the particular molecules that are transported?
osmosis
diffusion
facilitated diffusion
active transport
answer
Facilitated diffusion
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Which of the following would NOT be found in the cytoplasm of a bacterial cell?
nucleoid
endospores
ribosomes
porins
answer
Porins
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Archaeal flagella __________.
rotate as bacterial flagella do
grow by the addition of subunits at the tip
do not contain a filament
are powered by the flow of hydrogen ions across the membrane
answer
Rotate as bacterial flagella do
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Which of the following would NOT be expected to be present in a biochemical analysis of an archaeal cell?
phospholipids
peptidoglycan
ribosomes
membrane proteins
answer
Peptidoglycan
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Which of the following would contain teichoic acids?
a pseudomurin cell wall
a Gram-negative cell wall
the glycocalyx
a Gram-positive cell wall
answer
A gram-positive cell wall
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Which of the following is NOT a component of eukaryotic cell walls?
chitin
silicates
sterols
cellulose
answer
Sterols
Sterols may be found in cytoplasmic membranes, but not in cell walls.
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In a hypotonic environment, the vacuole of a plant cell enlarges and pushes the cytoplasm against the cell wall. Which organelles are most likely able to store that extra water?
mitochondria
vesicles
peroxisomes
vacuoles
answer
Vacuoles
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Peptidoglycans are composed of sugars and _____.
amino acids
nucleic acids
lipids
teichoic acids
answer
Amino acids.
Amino acids combine to form the peptide portion of the peptidoglycan
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One chain of alternating NAGs and NAMs is connected to another chain via _____.
enzymes
tetrapeptides
lipids
teichoic acids
answer
Tetrapeptides
Tetrapeptides are composed of four amino acids and make up the "peptido" portion of peptidoglycan.
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One of the main differences between a Gram-positive and a Gram-negative bacterial cell wall is that the peptidoglycan portion of a Gram-positive cell wall is _____ as compared to a Gram-negative cell wall.
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Thicker
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Within the peptidoglycan layer, the crossbridges that connect the chains of alternating sugar molecules extend between _____.
answer
two N-acetylmuramic acid molecules
The crossbridges link NAM molecules to one another and provide the structural integrity of the peptidoglycan layer
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The peptidoglycan cell wall of bacteria is most analogous to _____.
an impenetrable brick wall
a rain coat
a chain-link fence
a sugary candy shell
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A chain-link fence
The peptidoglycan cell wall is meshlike, allowing for easy passage of ions, amino acids, and nutrients and maintaining structural integrity.
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What role do the teichoic acids play within the cell wall of Gram-positive bacteria?
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They serve to stabilize the cell wall and hold it in place.
*Some of the teichoic acids are anchored to lipids within the cytoplasmic membrane and are thus called lipoteichoic acids*
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The region between the outer and inner membranes of a Gram-negative bacterial cell is known as the __________, and it is the location of enzymes that assemble peptidoglycan
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Periplasmic space
The periplasmic space is an area surrounding the bacterial cytoplasmic membrane
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A patient is infected with Gram-negative bacteria and is experiencing only mild symptoms. When the patient is given an antibiotic causing lysis of the bacterial cells, he suddenly experiences an increase in inflammation and fever, as well as the formation of blood clots. What explanation best describes what happened?
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The lysis of the cells releases lipid A from the lipopolysaccharide layer.
Lipid A is known to cause inflammation, fever, and blood clots.
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What is the composition of the peptidoglycan layers found in the cell wall of bacteria?
Pick the answer that lists the composition of the bacterial cell wall
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short amino acid chains, NAG, NAM, and some lipid protein
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Place each attribute into the bin of the bacterial group it belongs to, based on whether the bacterium is a Gram-positive or a Gram-negative cell.
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Gram positive:
-teichoic acids
-thick layer of peptidoglycan
-single lipid bilayer membrane
Gram negative:
-thin layer of peptidoglycan
-periplasmic space
-lipopolysaccharides
-dual lipid bilayer membranes
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The composition of the cell wall allows for the expansion and contraction of the cell wall in response to the gain or loss of water from the cell.
Choose True or False.
True
False
answer
False
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A cell wall is a requirement for all living bacteria.
Choose True or False.
True
False
answer
False
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Bin 1 - Image of a single round bacterium.
Bin 2 - Image of a single rodishaped bacterium.
Bin 3 - Image of a cluster of round bacteria.
Bin 4 - Image of a string of rodishaped bacteria.
Bin 5 - Image of a vibrio (commaishaped) bacterium.
Bin 6 - Image of a corkscrewishaped spirochete bacterium.
Drag the descriptive terms to the pictured bacterial shapes.
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Bin 1: cocci
Bin 2: bacilli
Bin 3: staphylococci
Bin 4: streptobaccili
Bin 5: vibrio
Bin 6: spirochete
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Bacterial flagella have a biological motor that spins within the cell wall and is powered by ATP. This allows the flagella to spin in a whiplike motion to propel the bacterium.
Is this statement True or False? Choose the answer that you think is correct.
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The biological motor that spins the flagella for bacterial propulsion is powered by the electron imbalance across the membrane that generates a gradient that the cell can harness for energy via proton motive force.
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what structural part of bacterial flagellum is composed of flagellin?
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Filament
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how are gram-positive and gram-negative flagella different?
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a gram-positive flagellum has only two rings in its basal body; gram-negatives each have four
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the rings...
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anchor the flagellum to the cell membrane
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the basal body is comprised of which structural components of flagella?
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rod and rings
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pathogenic bacteria
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can be identified and classified by differences in their flagellar proteins
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tumbles occur when
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the flagella rotate clockwise
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which of the following types of bacterial cells would have only a single flagellum?
answer
monotrichous
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amphitrichous flagella
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have a single flagellum on each end
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peritrichous flagella make a run when
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the flagella turn counter clockwise and become bundled
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which of the following types of bacterial cells would have flagella located at only one end of the cell?
answer
monotrichous and lophotrichous
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Which of the following statements about bacterial flagella is true?
Flagella can rotate 360 degrees.
Flagella work by undulating.
Bacteria can only rotate flagella clockwise.
Bacteria can only rotate flagella counterclockwise.
answer
flagella can rotate 360 degrees
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taxis
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movement towards or away from a stimulus
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positive phototaxis
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bacterium moving towards a light source
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as a bacterium approaches a food source, one would expect...
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runs to become more frequent
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why are receptors on the cell surface necessary for bacterial movement?
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the receptors sense the stimulus and send signals to the flagella
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Which of the following molecules would be blocked by a cell membrane?
Simple alcohols
Water
Ions
Dissolved oxygen
answer
Ions
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Hydrophobic molecules would enter a cell...
answer
through integral transport proteins
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What is a hallmark of passive transport across cell membranes?
It requires the use of ATP.
It may involve the use of transport proteins.
It occurs along an electrochemical gradient.
It cannot occur without assistance from an integral membrane protein.
It occurs along an electrochemical gradient, and may involve the use of transport proteins.
answer
It occurs along an electrochemical gradient, and may involve the use of transport proteins
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A positively charged sodium ion...
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would require the use of integral protein channels to pass through a cell membrane
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Which of the following statements regarding active transport is false?
It requires the use of a transport protein.
It requires ATP.
It powers the diffusion of water across the cell membrane.
answer
It powers the diffusion of water across the cell membrane
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What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass?
They are completely hydrophobic.
They have both hydrophilic and hydrophobic regions.
They are completely hydrophilic.
They are positively charged.
answer
They have both hydrophilic and hydrophobic regions
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Integral proteins are mostly involved in
enzymatic function.
receptors.
recognition sites.
transport function.
answer
Transport function
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How does water enter and exit a cell?
By simple diffusion or by use of an integral transport protein
By use of a peripheral transport protein
By simple diffusion across the membrane
By use of an integral transport protein
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By simple diffusion or by use of an integral transport protein
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A glycoprotein
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is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.
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Which of the following molecules is shared by both Gram-positive and Gram-negative organisms?
lipid A
lipopolysaccharide
N-acetylmuramic acid
lipoteichoic acid
answer
N-acetylmuramic acid
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Amoxicillin is an antibiotic that inhibits the formation of peptide cross-links. Amoxicillin, therefore, would most likely inhibit the growth of __________.
answer
Both gram-positive and gram-negative organisms
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Porins are present in ______________bacteria because, in these organisms, molecules entering the cell must pass through an extra layer of ___________.
answer
Gram negative; membrane
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Lipopolysaccharide (LPS)
answer
-Makes up the outer leaflet of the outer membrane of gram-negative bacterial cell walls
-union of lipid and sugar
-lipid portion is called Lipid A; endotoxin
a dead cell releases lipid A when the outer membrane disintegrates, and lipid A may trigger fever, inflammation, vasodilation, shock, and blood clotting in humans.
---so killing large numbers of gram-negative bacteria with antimicrobial drugs release large amounts of lipid A, which might threaten the patient more than the live bacteria itself.
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Periplasmic space
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Space between the cytoplasmic membrane and the outer membrane of gram-negative bacteria
-contains peptidoglycan and periplasm
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Why is ATP necessary for active transport?
answer
ATP provides energy to transfer material against its concentration gradient
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which type of active transport protein moves two molecules into the cell at one time?
answer
symport
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Which transport protein employs transporters that move molecules only in one direction?
answer
uniport and symport
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Which type of active transport protein uses one protein to pump two different molecules?
answer
antiport and symport
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Which of the active transport types employs diffusion?
answer
symport
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What type of transport uses two transport proteins?
answer
symport
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Sodium and potassium ions need to be pumped simultaneously against their concentration gradients. Which one of the transport proteins would be most effective at this?
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Antiport; transports two different molecules and in opposite directions
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Why are ATPases associated with active transport proteins?
answer
They provide transport proteins with the energy needed to pump molecules against their concentration gradients.
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Efflux pumps can be used to pump antibiotics out of a cell once they enter to protect the cell. This will be done against the concentration gradient of the antibiotic. Which of the active transports would most likely be used?
answer
Uniport
A uniport would pump the antibiotic out without needing to bring additonal molecules into the cell, and would not allow the antibiotic to diffuse back in
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Why is no energy required in passive transport?
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concentration gradient drives the movement
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once equilibrium is reached...
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molecules move, but there is no net movement in a particular direction.
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Which of the following would not move freely across the cytoplasmic membrane?
Small alcohols
Dissolved oxygen
Dissolved carbon dioxide
Positively charged hydrogen ions
answer
positively charged hydrogen ions
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How is osmosis different from simple diffusion?
answer
Water movement is driven by the concentration of solutes rather than its own concentration.
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non-specific permeases...
answer
allow a variety of molecules to cross the cytoplasmic membrane.
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What will happen to a cell that is placed in a solution containing a high concentration of sugar, a molecule that cannot pass across the cell membrane?
answer
the cell will lose its interior water, causing it to shrivel up and possibly die
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how is simple diffusion different from other types of passive transport?
answer
simple diffusion does not require a permease
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When the nurse practitioner looked into Nadia's throat, she saw white spots on the tonsils. These were white blood cells attempting to fight off the infection. Which of the following statements explains a key difference between Nadia's white blood cells and the Streptococcus pyogenes infecting her throat?
answer
Nadia's white blood cells have a nucleus, while the Streptococcus pyogenes do not.
*Nadia's white blood cells are eukaryotic, while the Streptococcus pyogenes are prokaryotic. The distinctive feature of prokaryotic cells is that they do not have a nucleus.*
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Which of the following is NOT a function of the Streptococcus pyogenes cytoplasmic membrane?
diffusion
active transport
endocytosis
selective permeability
answer
endocytosis
This is a function of eukaryotic cytoplasmic membranes and is not found in bacterial membranes.
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Nadia has an infection caused by Streptococcus pyogenes, which has a Gram-positive cell wall. What distinguishes Gram-positive bacterial cell walls from Gram-negative bacteria cell walls?
answer
the presence of teichoic acids
Teichoic acid is unique to Gram-positive organisms and anchors the peptidoglycan layer to the cell membrane.
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Penicillin is used to treat Streptococcus pyogenes infections. Treatment is successful when the pathogen is killed, but the medication does not harm the host cells. Penicillin disrupts the peptide bridges between NAM units. This results in __________.
answer
Damage to the bacterial cell wall.
Gram-positive bacteria have thick layers of peptidoglycan as part of their cell wall. These layers are stabilized by peptide bridges between NAM units. Without these cross bridges, the cell wall "crumbles".
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Which of the following bacterial cell structures plays an important role in the creation of biofilms?
fimbriae
pili
flagella
glycocalyces
both fimbriae and glycocalyces
answer
both frimbriae and glycocalyces
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Which of the following statements concerning prokaryotic flagella is TRUE?
Prokaryotic flagella are composed of tubulin.
Treponema is an example of a bacterium that has a tuft of polar flagella.
Prokaryotic flagella move in a whip-like manner.
Prokaryotic flagella are anchored to the cell wall by means of the basal body.
A "run" results from clockwise movement of the flagellum.
answer
Prokaryotic flagella are anchored to the cell wall by the basal body
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Which of the following statements concerning pili is FALSE?
A bacterial cell will usually have only one or two pili.
Pili facilitate the transfer of DNA among bacterial cells.
Pili are longer than fimbriae and flagella.
Pili are long, hollow tubules.
Not all bacteria have pili.
answer
Pili are longer than fimbriae and flagella
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Bacterial cell walls that are resistant to drying contain
answer
waxes
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lipid A is a component of
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lipopolysaccharides
*this is only in gram-NEGATIVE bacterial cell walls*
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Bacteria of the genus Mycoplasma lack cell walls. What sort of environment do they require for survival?
answer
isotonic
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Lipid-soluble molecules would be expected to cross the cytoplasmic membrane by which of the following processes?
group translocation
diffusion
facilitated diffusion
active transport
osmosis
answer
Diffusion
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Which of the following statements concerning osmosis is FALSE?
Osmosis stops when the system reaches equilibrium.
Cells placed in hypotonic solutions will gain water.
Osmosis requires a selectively permeable membrane.
During osmosis, water crosses to the side of the membrane with a lower solute concentration.
Crenation results when cells are placed in a hypertonic solution.
answer
During osmosis, water crosses to the side of the membrane with a lower solute concentration
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The accumulation of glucose 6-phosphate inside a bacterial cell via phosphorylation of glucose is an example of
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Group translocation
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Endocytosis and exocytosis are means of transport used by
bacteria.
eukaryotes.
archaea.
all prokaryotes.
nothing; no cells use both processes.
answer
eukaryotes
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Eukaryotic ribosomes are composed of 50S and 30S subunits.
True
False
answer
False
Eukaryotic ribosomes are composed of 60S and 40S subunits. Prokaryotic ribosomes are composed of 50S and 30S subunits.
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The short structures on the surface of the cell in the figure are cilia.
True
False
answer
False.
Pili
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Which of the following is classified as a nonmembranous organelle of eukaryotic cells?
centriole
peroxisome
mitochondrion
Golgi body
endoplasmic reticulum
answer
Centriole
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Which of the following statements accurately describes a difference between gram-positive and gram-negative cells?
Gram-positive cells contain less peptidoglycan than gram-negative cells.
Gram-negative cell walls contain teichoic acids.
Only gram-negative cells have a lipopolysaccharide (LPS) layer.
Only gram-positive cells have peptidoglycan that is made of a carbohydrate backbone.
answer
Only gram-negative cell walls have a lipopolysaccharide (LPS) layer
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The structural framework in a cell is the
extracellular matrix.
endoplasmic reticulum (ER).
cytoskeleton.
endomembrane system.
plasma membrane.
answer
Cytoskeleton
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Where in a cell is ATP made?
chloroplasts
nucleus
ribosomes
mitochondria
lysosomes
answer
mitochondria
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What carries instructions for making proteins from the nucleus into the cytoplasm?
answer
mRNA
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Which of the following is part of the endomembrane system?
cytoskeleton
mitochondria
Golgi apparatus
flagellum
ribosomes
answer
golgi apparatus
the endomembrane system includes the ER, golgi apparatus, lysosomes, and vesicles. It manufactures, processes, and transports lipids and proteins. The golgi apparatus processes and packages porteins.
question
Which of the following organelles breaks down worn-out organelles?
Golgi apparatus
mitochondria
lysosomes
smooth endoplasmic reticulum (ER)
rough endoplasmic reticulum (ER)
answer
lysosomes
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Where are lipids made in the cell?
ribosomes
Golgi apparatus
rough endoplasmic reticulum (ER)
smooth endoplasmic reticulum (ER)
mitochondria
answer
smooth ER
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What structure acts as a selective barrier, regulating the traffic of materials into and out of the cell?
plasma membrane
nuclear envelope
cytoskeleton
endomembrane system
extracellular matrix
answer
plasma membrane
