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Flashcards in Cell Structure [1] Deck (43):

Which statement best illustrates the importance of a high surface-to-volume ratio that is found in microorganisms?
A If a cell has a high surface-to-volume ratio, the volume of the cell will be much larger than the surface area. There would NOT be enough surface area to get the needed nutrients in and the accumulated waste out.
B If a cell has a high surface-to-volume ratio, the volume of the cell will be much larger than the surface area. There would be enough surface area to get the needed nutrients in and the accumulated waste out.
C If a cell has a high surface-to-volume ratio, there will NOT be enough surface area to get the needed nutrients in to support cellular metabolism and the accumulated waste out.
D If a cell has a high surface-to-volume ratio, there will be enough surface area to get the needed nutrients in to support cellular metabolism and the accumulated waste out.



If an E. coli cell has a surface area-to-volume (S/V) ratio of 4.5, and a Pelagibacter ubique has an S/V ratio of 22, which cell will be able to exchange nutrients and wastes with the environment more efficiently?
A Pelagibacter ubique, because its cells are larger
B E. coli, because its cells are larger
C Pelagibacter ubique, because its cells are smaller
D E. coli, because its cells are smaller



What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass?

A They are completely hydrophilic.
B They are completely hydrophobic.
C They have both hydrophilic and hydrophobic regions.
D They are positively charged.



Integral proteins are mostly involved in

A recognition sites.
B receptors.
C transport function.
D enzymatic function.



How does water enter and exit a cell?

A By use of a peripheral transport protein
B By simple diffusion across the membrane
C By simple diffusion or by use of an integral transport protein
D By use of an integral transport protein



A glycoprotein

A can be used in enzymatic functions.
B is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.
C is a type of peripheral protein.
D can be used as a receptor.



Which type of active transport protein moves two molecules into the cell at the same time?

A Uniport
B Antiport
C Symport
D Antiport and Symport
E Uniport, Symport, and Antiport



Which transport protein employs transporters that move molecules only in one direction?

A Uniport
B Uniport and Symport
C Uniport and Antiport
D Symport
E Antiport
F Uniport, Antiport, and Symport



Which type of active transport protein uses one protein to pump two different molecules?

A Symport
B Uniport
C Uniport, Antiport, and Symport
D Antiport
E Antiport and Symport



Once equilibrium is reached,

A molecules move, but there is no net movement in a particular direction.
B passive transport starts over to create a concentration gradient.
C molecules no longer move.
D the membrane permits all molecules to freely move across the membrane.



Which of the following would not move freely across the cytoplasmic membrane?

A Dissolved oxygen
B Small alcohols
C Dissolved carbon dioxide
D Positively charged hydrogen ions



Which is valid cell morphology?

A square
B icosahedral
C triangular
D spirochete



An organism of the genus Staphylococcus is ________, while an organism of the genus Spirochaeta is ________.
A coiled / spherical
B spherical / coiled
C rod shaped / coiled
D spherical / rod shaped



The morphology of a cell influences its
A motility.
B motility and surface-to-volume ratio.
C surface-to-volume ratio.
D metabolism.



Compared to Eukaryotes, Bacteria and Archaea have ________ surface-to-volume ratios, causing ________ nutrient exchange and growth rates.
A lower / higher
B lower / lower
C higher / higher
D higher / lower



Carrier-mediated transport is necessary when
A movement into the cell is against a concentration gradient.
B nutrient concentration is very low in the environment, is higher inside of the cell, or diffusion is not possible.
C diffusion will not allow adequate amounts of a substance to enter the cell.
D the level of nutrients in nature is very low.



Smaller prokaryotic cells generally grow faster than larger ones due to a higher surface-area-to-volume ratio.
A True
B False



Given that the cytoplasmic membrane has a fluid dynamic nature, with phospholipids and proteins able to move about within the bilayer structure, what force or structure keeps the membrane from falling apart?
A hydrophilic/hydrophobic forces
B osmosis
C the proton motive force
D rigid sterol lipids



The use of the Gram stain in microbiology is important because it differentiates
A archaeal cells with different types of metabolism.
B prokaryotic from eukaryotic cells.
C Bacteria from Archaea.
D bacterial cells with different types of cell walls.



Some archaea have unique phospholipids in their cytoplasmic membrane that
A form a monolayer due to the presence of diglycerol tetraethers.
B form a bilayer due to the presence of sterols.
C form a bilayer due to the presence of phosphatidylethanolamine.
D form a stable ring structure due to the presence of crenarchaeol



The lipids in the cytoplasmic membrane of Bacteria and ________ contain ester linkages, while the cytoplasmic membrane of ________ contain ether linkages.
A Eukarya / prokaryotes
B Eukarya / Archaea
C Archaea / fungi
D Archaea / Eukarya



Eukaryotes have ________ in their cytoplasmic membranes, which serve to strengthen and stabilize the membrane and make it less flexible. Many bacteria have similar molecules, known as ________, in their cytoplasmic membranes that have a similar role.
A sterols / hopanoids
B ether bonds / ester bonds
C lipids / phospholipids
D phospholipids / lipopolysaccharides



In general, lipids in archaeal cytoplasmic membranes lack true fatty acids.

A True
B False



The cytoplasmic membrane is termed "semi-permeable" because some substances, like water and alcohols, can pass freely through while others, like sugars, amino acids, and ions, cannot. What molecular characteristics largely determine whether or not a substance can pass through the membrane?

A usefulness to the cell
B organic versus inorganic molecules
C osmolarity
D size and hydrophobicity



Transport proteins can become saturated with solute, have high specificity for certain substances, undergo conformational (shape) changes, and are highly regulated by the cell. What other type of cellular proteins have these four general characteristics?

A porins
B enzymes
C flagella
D ribosomes



Identify which of the following is a major function of the cytoplasmic membrane.

A impermeable barrier
B rigid shape defining layer
C energy conservation
D anchor for carbohydrates



Aquaporins are
A water transport proteins.
B cations bound to water molecules.
C enzymes involved in the generation of water within cells.
D molecules that prevent water from crossing a membrane.



Which is/are a function(s) of the cytoplasmic membrane in prokaryotes?
A It functions as a permeability barrier.
B It serves as a permeability barrier, a docking station for proteins involved in bioenergetics reactions and transport, and a site for energy conservation.
C It is an anchor for many proteins involved in bioenergetic reactions and transport.
D It is a major site of energy conservation.



Which of the active transport types employs diffusion?
A Antiport
B Uniport
C Uniport and Antiport
D All types of active transport make use of some form of diffusion.
E Symport



What type of transport uses two transport proteins?
A Uniport
B Antiport
C Symport
D None of the proteins do
E All of the proteins do



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?
A Uniport
B Antiport
C Symport
D Any would work, as they can all pump ions out.



Why are ATPases associated with active transport proteins?
A They allow for the production of ATP that is needed during active transport.
B They help pump phosphate ions across the membrane to maintain the electrochemical gradient.
C They provide transport proteins with the energy needed to pump molecules against their concentration gradients.
D They are important only in symport proteins, because two are required.
E All of the above



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?
A Uniport
B Symport
C Antiport



Nonspecific permeases
A are not used for passive transport.
B allow a variety of molecules to cross the cytoplasmic membrane.
C allow only water to cross the cytoplasmic membrane.
D allow only one type of solute to pass through the membrane.



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?
A The cell will swell up with water and burst.
B The cell will pump the salt in the cytoplasm out of the cell via simple diffusion.
C The cell will lose its interior water, causing it to shrivel up and possibly die.



How is simple diffusion different from other types of passive transport?
A Simple diffusion only brings material into the cell, not out of it.
B Simple diffusion requires ATP.
C Simple diffusion is only the diffusion of water.
D Simple diffusion does not require a permease.



Transport proteins (transporters) require energy expenditure for each molecule of substrate transported. The reason for this energy requirement is __________.
A the solute must be chemically altered
B the conformational shape of the solute must be changed during transport
C the solute must be transported against a concentration gradient
D the solute must be forced through the hydrophobic membrane



The cytoplasmic membrane could best be described as
A an impermeable barrier.
B a passive conduit for intracellular transport.
C a rigid structure that protects the cell.
D a highly selective permeability barrier.



Nutrient transport requires energy because the nutrients must be transported into the cell against a concentration gradient. The energy required for nutrient transport is supplied by
A the proton motive force.
C phosphoenol pyruvate.
D ATP, the proton motive force, or phosphoenol pyruvate.



Hydrolytic enzymes function in the
A regeneration of the periplasm.
B transport of substrates within the cell.
C chemotactic response, particularly in gram-negative Bacteria.
D initial degradation of nutrients.



The prokaryotic transport system that involves a substrate-binding protein, a membrane-integrated transporter, and an ATP-hydrolyzing protein is
A simple transport.
B the ABC transport system.
C group translocation.
D symport.



Some membrane proteins are involved in bioenergetic reactions, while others are involved in membrane transport.
A True
B False



ATP-binding cassette transport systems have high substrate affinity and thus help microorganisms survive in low nutrient environments.
A True
B False