Deck 3: Cell Structure and Function

Question 1

The most highly expressed proteins in a cell are the __________ proteins and the __________ factors.

A) transport; transcription
B) ribosomal; translation
C) structural; replication
D) enzymatic; catalytic
E) replication; transcription

Answer 1

B

Question 2

Cell membranes are composed of approximately equal parts of __________ and __________.

A) polysaccharides; peptides
B) sugars; amino acids
C) phospholipids; proteins
D) lipopolysaccharides; sugars
E) nucleotides; phospholipids

Answer 2

C

Question 3

Polyamines are __________ charged when the pH is near neutral.

A) not
B) negatively
C) positively
D) super
E) electrically

Answer 3

C

Question 4

All of the following statements regarding phospholipids are true EXCEPT:

A) They consist of glycerol with ester links to two fatty acids and a phosphoryl group.
B) They impart rigidity to the membrane.
C) All face each other tail-to-tail.
D) The two layers in the bilayer are called leaflets.
E) They give the membrane a consistent thickness.

Question 5

__________ is impractical for proteins of a flexible nature.

A) Electrophoresis
B) Sonication
C) X-ray crystallography
D) Fractionation
E) Ultracentrifugation

Question 6

For SDS electrophoresis, proteins are coated with a reagent to give them a uniform __________ charge so that their distance of migration depends on __________.

A) positive; molecular weight
B) negative; shape
C) positive; shape
D) negative; molecular weight
E) neutral; molecular weight

Question 7

Functions of the cytoplasmic membrane include all of the following EXCEPT:

A) permeability barrier
B) assemble proteins
C) store energy
D) transport
E) structural support

Question 8

__________ and __________ are the product of ancestral engulfment of prokaryotic cells, followed by evolution of endosymbiosis.

A) Nucleus; mitochondria
B) Chloroplasts; Golgi apparatus
C) Nucleolus; nucleus
D) Mitochondria; chloroplasts
E) Thylakoids; carboxysomes

Question 9

In a two-dimensional gel of E. coli proteins, about __________ different proteins can be distinguished.

A) 5
B) 10
C) 50
D) 500
E) 1,000

Question 10

Two-dimensional polyacrylamide gel electrophoresis involves all of these EXCEPT:

A) isoelectric focusing
B) electrophoresis
C) sodium dodecyl sulfate (SDS)
D) staining for detection
E) DNA sequencing

Question 11

__________ stabilize ribosomes during translation.

A) Polysaccharides
B) Nucleic acids
C) Polyamines
D) Lipids
E) Phospholipids

Question 12

__________ reinforce and stiffen membranes in bacteria.

A) Hopanoids
B) Plyamines
C) Sterols
D) Peptidoglycans
E) Lipids

Question 13

The 70S prokaryotic ribosome is composed of a 30S and a __________ subunit.

A) 30S
B) 40S
C) 50S
D) 60S
E) 70S

Question 14

The capsule polysaccharides form a slippery mucous layer that inhibits __________.

A) diffusion
B) phagocytosis
C) attachment
D) lysis
E) osmosis

Question 15

Studying ribosome structure helps us to design new __________.

A) enzymes
B) models
C) analysis techniques
D) antibiotics
E) sequences

Question 16

Transport __________ mediate both active and passive transport.

A) polysaccharides
B) proteins
C) lipids
D) hopanoids
E) sterols

Question 17

We cannot literally see the molecules within a cell, but __________ and __________ analysis generate a remarkably detailed view.

A) structural; genetic
B) microscopy; genetic
C) structural; subcellular
D) microscopy; subcellular
E) chemical; genetic

Question 18

All of the proteins encoded by the genome, which are capable of expression in the cell, are known as the __________.

A) proteomes
B) chromosomes
C) proteases
D) genes
E) ribosomes

Question 19

Fred Neidhardt carried out experiments to define the proteome of a cell by using:

A) genetic analysis
B) X-ray crystallography
C) two-dimensional polyacrylamide gel electrophoresis
D) protein synthesis
E) subcellular fractionation

Question 20

The contribution of particle mass and shape to sedimentation rate is defined as its __________ coefficient.

A) radius
B) rotation
C) sedimentation
D) Svedberg
E) ultracentrifugation

Question 21

Lipopolysaccharides are found in:

A) all bacteria
B) Gram-positive bacteria
C) Gram-negative bacteria
D) Archaea
E) eukaryotes

Question 22

Profiles of which component of the membrane may be used to identify certain kinds of pathogens?

A) phospholipids
B) proteins
C) fatty acids
D) polysaccharides
E) leaflets

Question 23

All of the following are components of peptidoglycan EXCEPT:

A) N-acetylglucosamine
B) N-acetylmuramic acid
C) lipopolysaccharide
D) amino acids
E) peptide cross-links

Question 24

The increased stability of __________ supercoils in archaea allows them to grow in more extreme environments.

A) extra
B) negative
C) no
D) flexible
E) positive

Question 25

All of the following statements are true EXCEPT:

A) Chaperones were first discovered in E. coli.
B) Chaperones fold the new peptide into its functional tertiary structure.
C) Chaperone defects are associated with genetic diseases in mammals.
D) Chaperones have been found in all organisms except humans.
E) Chaperones protect proteins from denaturation by heat.

Question 26

A __________ is a term used to designate a single messenger RNA molecule being translated by multiple ribosomes.

A) coupled
B) periplasm
C) carboxysome
D) thylakoid
E) polysome

Question 27

All of the following are true of supercoiling in chromosomal DNA EXCEPT:

A) DNA doubles back and twists upon itself.
B) In bacteria and eukaryotic cells, there is positive supercoiling.
C) This results in compaction.
D) It is generated by gyrase.
E) It is maintained by DNA-binding proteins.

Question 28

All archaeal phospholipids have a/an __________ link between glycerol and the lipid component.

A) ester
B) ether
C) ethanolamine
D) unsaturated
E) phosphatidyl

Question 29

Specific membrane components, particularly __________, determine which substances are transported across the membrane.

A) phospholipids
B) proteins
C) ions
D) polysaccharides
E) leaflets

Question 30

What part of a cell is referred to as the sacculus?

A) nucleoid
B) cytoplasm
C) cell membrane
D) cell wall
E) outer membrane

Question 31

All of the following are true statements about bacterial S-layers EXCEPT:

A) They are commonly found in Gram-positive cells as well as in archaea.
B) They are a crystalline layer consisting of protein or glycoprotein.
C) They present a formidable physical barrier to predators or parasites.
D) They are found in bacteria freshly isolated from natural sources.
E) They are found in bacteria isolated from laboratory cultures.

Question 32

Which is NOT a component of any bacterial cells wall?

A) peptidoglycan
B) techoic acids
C) N-acetylmuramic acid
D) cellulose
E) L-lysine

Question 33

Eukaryotic microbes that lack a cell wall possess __________ to circumvent osmotic shock.

A) Golgi bodies
B) contractile vacuoles
C) endoplasmic reticulum
D) lysosomes
E) gas vesicles

Question 34

The thin layer of peptidoglycan in Gram-negative cells is believed, based on calculations of __________, to be a single sheet.

A) shape
B) genetic analysis
C) width
D) X-ray crystallography
E) molecular density

Question 35

A medically important example of active transport is that of drug __________ proteins powered by the hydrogen ion gradient.

A) efflux
B) porin
C) membrane permeant
D) diffusion
E) lysis

Question 36

All of the following represent components of eukaryotic organisms that help avoid osmotic shock EXCEPT:

A) cellulose fibers
B) chitin
C) silicate exoskeleton
D) contractile vacuole
E) peptidoglycan

Question 37

The lipopolysaccharide of the outer membrane is of medical importance because it acts as a/an __________.

A) endotoxin
B) exotoxin
C) toxoid
D) enterotoxin
E) antibiotic

Question 38

The __________ is the region between the cytoplasmic membrane and the outer membrane in Gram-negative cells.

A) periplasm
B) cytoplasm
C) lysozyme
D) lipoploysaccharide
E) S-layer

Question 39

All of the following are true about prokaryotic outer membranes EXCEPT:

A) They are composed of a phospholipid bilayer.
B) They are found only in Gram-negative bacteria.
C) They contain endotoxin.
D) They contain proteins involved in transport.
E) They contain lipopolysaccharide.

Question 40

Each dividing nucleoid requires __________ DNA polymerase complexes overall.

A) 1
B) 2
C) 4
D) 6
E) 8

Question 41

From your knowledge of Gram-positive and Gram-negative cell envelopes, why would penicillin be more effective in killing Gram-positive organisms than Gram-negative organisms?

Question 42

Light is harvested by protein complexes called __________.

A) phycobilisomes
B) carboxysomes
C) gas vesicles
D) storage granules
E) magnetosomes

Question 43

Which of the following materials found in storage granules is used as an energy source?

A) gas vesicle
B) sulfur
C) polyphosphate
D) glycogen
E) magnetosome

Question 44

Which name refers to having flagella attached at one or both ends of the cell?

A) peritrichous
B) lophotrichous
C) monotrichous
D) bitrichous
E) flagellated

Question 45

Which of the following is described as an attachment organelle that is a membrane-bound extension of the cytoplasm?

A) pili
B) fimbriae
C) sex pili
D) stalks
E) flagella

Question 46

Describe four ways cells can be broken open in order to isolate the cellular components.

Question 47

The bacterial flagellum is a helical protein filament whose __________ motor moves the cell in search of a more favorable environment.

A) shaking
B) vibrating
C) wavelike
D) whiplike
E) propeller-like

Question 48

Why can't most kinds of bacteria be eaten as a major part of our diet?

Question 49

List and briefly describe four components of a typical bacterial cell.

Question 50

The partition that is a result of the inward growth of the cell envelope from opposite directions is known as the:

A) divisome
B) septum
C) wall
D) colony
E) Z ring

Question 51

How could you use green fluorescent protein as a reporter gene to compare production of a specific protein in a cell culture when the culture is growing under different environmental conditions?

Question 52

What are some of the limitations of X-ray crystallography?

Question 53

Prokaryotic genomes are more compact than eukaryotes and the content of nucleic acids in prokaryotes is much higher than in most eukaryotes. Explain this and why this is necessary for prokaryotes survival?

Question 54

If a prokaryotic intact ribosome is 70S, why are its subunits 30S and 50S, and not 30S and 40S?

Question 55

All of the following are used by prokaryotic cells for attaching to solid surfaces EXCEPT:

A) endospore
B) capsule
C) stalks
D) fimbriae
E) pili

Question 56

Directed movements toward or away from a chemical or physical signal are known as:

A) gliding
B) flagellation
C) taxes
D) locomotion
E) slime layer

Question 57

The bacterial membrane ATP synthase has two subunits, referred to as F₀ and F₁. What are the location and the function of each?

Question 58

Explain what happens when a cell comes into contact with water or with ethanol. Why is 70% ethanol commonly used to treat wounds and surfaces?

Question 59

Which of the following statements about the prokaryotic flagellar motor is incorrect?

A) It is driven by the cell's transmembrane proton current.
B) It is embedded in the layers of the cell envelope.
C) It is observed by EM.
D) It moves with a whiplike motion.
E) It is used for chemotaxis.

Question 60

Fts proteins do which of the following?

A) form a ring in the area where cell division will occur
B) aid in DNA replication
C) are involved in peptidoglycan synthesis
D) are involved in making proteins
E) are important in transcription

Question 61

When designing an antibiotic, one should target what aspect of a prokaryote? Give at least two specific examples of drugs and their target.

Question 62

Caulobacter crescentus exists in two forms. What are they? Describe replication and what determines which form a cell takes. Why is the ability to exist in two forms advantageous?

Question 63

Describe how and why magnetotactic bacteria might be used in wastewater management.

Question 64

Describe the Gram-negative cell envelope. Why are porins necessary in the outer membrane of Gram-negative cells?

Question 65

How can some prokaryotes double in as little as ten minutes?

Question 66

How is supercoiling different in bacteria and archaea. Why is this important for archaea?

Question 67

What unusual lipids are found in mycobacteria and of what benefit are they to these bacteria?

Question 68

Explain the movement of a bacterium possessing flagella away from a toxic chemical.

Question 69

Compare and contrast FtsZ and tubulin. Why do the similarities support evolution of prokaryotes and eukaryotes from a common ancestor?

Question 70

Describe two specialized structures that photosynthetic organisms may possess and why the structures are needed by these organisms.