Cell Structure [1]

Question 1

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.

Answer 1

D

Question 2

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

Answer 2

C

Question 3

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.

Answer 3

C

Question 4

Integral proteins are mostly involved in

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

Answer 4

C

Question 5

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

Answer 5

C

Question 6

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.

Answer 6

B

Question 7

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

Answer 7

C

Question 8

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

Answer 8

B

Question 9

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

Answer 9

E

Question 10

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.

Answer 10

A

Question 11

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

Answer 11

D

Question 12

Which is valid cell morphology?

A square
B icosahedral
C triangular
D spirochete

Answer 12

D

Question 13

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

Answer 13

B

Question 14

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

Answer 14

B

Question 15

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

Answer 15

C

Question 16

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.

Answer 16

B

Question 17

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

Answer 17

A

Question 18

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

Answer 18

A

Question 19

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.

Answer 19

D

Question 20

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

Answer 20

A

Question 21

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

Answer 21

B

Question 22

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

Answer 22

A

Question 23

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

A True
B False

Answer 23

A

Question 24

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

Answer 24

D

Question 25

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

Answer 25

B

Question 26

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

Answer 26

C

Question 27

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.

Answer 27

A

Question 28

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.

Answer 28

B

Question 29

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

Answer 29

E

Question 30

``` 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 ```

Answer 30

C

Question 31

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.

Answer 31

B

Question 32

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

Answer 32

C

Question 33

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

Answer 33

A

Question 34

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.

Answer 34

B

Question 35

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.

Answer 35

C

Question 36

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.

Answer 36

D

Question 37

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

Answer 37

C

Question 38

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.

Answer 38

D

Question 39

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. B ATP. C phosphoenol pyruvate. D ATP, the proton motive force, or phosphoenol pyruvate.

Answer 39

D

Question 40

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.

Answer 40

D

Question 41

``` 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. ```

Answer 41

B

Question 42

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

Answer 42

A

Question 43

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

Answer 43

A