Microbiology - Chapter 3: Cell Structure

Bacterial components unique to bacteria are potential targets for antibacterial medications used to treat infectious diseases.

True or False

True

The surface layers of a prokaryotic cell are collectively referred to as the cell _______.

1. envelope

2. matrix

3. wall

4. exopolysaccharide

5. capsule

envelope

The ______ is the inner thick substance of a cell. It is filled with nutrients, ribosomes and enzymes.

1. cytokinin

2. cytoplasm

3. cytoskeleton

4. cytosol

cytoplasm

The cytoplasmic membrane of prokaryotes is composed of a(n)
________ bilayer embedded with proteins.

phospholipid

Which of the following molecules can freely pass through the phospholipid bilayer? Select all that apply.

1. CO₂

2. ions

3. small hydrophobic compounds

4. amino acids

5. O₂

6. water

7. sugars

1. CO₂

2. small hydrophobic compounds

3. O₂

4. water

Compounds unique to bacteria or certain other microbial groups can be detected by "alarm systems" in the body.

True or False

True

The cytoplasmic membrane of prokaryotic cells plays a crucial role in transforming energy. This means that the membrane is directly involved in ______.

1. converting the energy of sunlight or food into ATP

2. contributing phospholipids as the primary energy supply

3. propelling the cell to an energy source

converting the energy of sunlight or food into ATP

The prokaryotic cell envelope consists of which of the following? Select all that apply.

1. cytoplasmic membrane

2. nucleoid

3. capsule

4. cell wall

5. extracellular matrix

6. cytoplasm

1. cytoplasmic membrane

2. capsule

3. cell wall

Mechanisms cells use to bring in nutrients and other small molecules are called _______ systems.

transport

The part of the cell that is enclosed by the cell envelope is called the ________.

cytoplasm or cytosol

Which two macromolecules are the major components of cytoplasmic membranes? Select all that apply.

1. carbohydrates

2. waxes

3. proteins

4. nucleic acids

5. lipids

1. proteins

2. lipids

Certain transporters are used by the cell to move waste products and other toxic compounds out of the cytoplasm. These are called ______ pumps.

efflux

The cytoplasmic membrane is a(n) _______ permeable barrier of the cell.

semi or selective

Which mechanisms of energy transformation match which types of organism?

prokaryote → ________

eukaryotes → ________

1. Membrane-bound organelles transform energy

2. Cytoplasmic membrane plays a critical role in transforming energy

prokaryote → Cytoplasmic membrane plays a critical role in transforming energy

eukaryote → Membrane-bound organelles transform energy

Suppose that the concentration of an ion is higher in the cytoplasm than in the extracellular environment. If the bacterium wants to bring in more of that ion into the cell, which description best describes this type of transport?

1. requires energy from the cell, moves with the concentration gradient

2. requires no energy usage by the cell, moves against the concentration gradient

3. requires energy from the cell, moves against the concentration gradient

4. requires no energy usage by the cell, moves with the concentration gradient

requires energy from the cell, moves against the concentration gradient

Which of the following are functions of membrane transport systems? Select all that apply.

1. Break down nutrients for energy creation

2. Expel wastes from cell

3. Allow nutrients to enter cell

1. Expel wastes from cell

2. Allow nutrients to enter cell

Some secreted proteins will act as ___________ outside of the cell and catalyze the breakdown of large macromolecules.

enzymes

Which structure provides strength and rigidity to a cell?

1. cell membrane

2. glycocalyx

3. flagellum

4. cell wall

cell wall

Some bacteria can become resistant to an antibiotic by exporting it across the cell membrane. This is most likely due to ______.

1. efflux pumps

2. influx pumps

3. passive transport

4. facilitated diffusion

efflux pumps

Peptidoglycan provides strength to the cell walls of ______.

1. fungi

2. archaea

3. bacteria

4. protozoa

bacteria

The cell wall of Gram-positive bacteria is characterized by ______.

1. thin layer of peptidoglycan

2. thin layer of chitin

3. thick layer of peptidoglycan

4. thick layer of chitin

thick layer of peptidoglycan

Active transport moves compounds against their concentration gradient. The form of energy used for this purpose is either
_______ or the _________ force.

ATP; proton motive

This figure shows a micrograph of a Gram-_______ bacterium.

negative

Cells use a process called ______ to move certain enzymes and other proteins they synthesize out of the cell.

secretion

The Gram-negative cell wall is characterized by a(n) _______ that contains a molecule called _______.

1. inner membrane; lipopolysaccharide

2. outer membrane; lipopolysaccharide

3. outer membrane; mycolic acid

4. inner membrane; mycolic acid

outer membrane; lipopolysaccharide

The function of the cell wall is to ______.

1. prevent wastes from entering the cell

2. prevent the cell from bursting

3. contain components for cellular respiration

4. store nutrients

prevent the cell from bursting

The strength of the bacterial cell wall is due to the layer of
__________.

peptidoglycan

Which of the following bacterial components is referred to as endotoxin?

1. lipopolysaccharide

2. lipoarabinamannan

3. capsule

4. teichoic acid

lipopolysaccharide

Gram-_______ cell walls have less peptidoglycan than Gram-_______ cell walls.

negative; positive

Which of the following is a component of Gram-negative cells but not Gram-positive cells?

1. peptidoglycan

2. cytoplasmic membrane

3. outer membrane

4. teichoic acid

outer membrane

The outer membrane of a Gram-negative cell is a lipid bilayer that contains ______.

1. lipopeptide

2. teichoic acid

3. peptidoglycan

4. lipopolysaccharide

lipopolysaccharide

Because of its potential lethal effect, the lipopolysaccharide (LPS) of Gram-negative bacteria is sometimes called a(n) _______.

1. endotoxin

2. cytotoxin

3. ribotoxin

4. exotoxin

endotoxin

Penicillin interferes with the synthesis of peptidoglycan, and lysozyme degrades peptidoglycan. Based on this information, you can conclude that penicillin and lysozyme may result in bursting (lysing) of which type of cells?

1. fungal

2. bacterial

3. archaeal

4. protozoan

bacterial

Bacteria of the genus _______ do not have cell walls, and so they are naturally resistant to the antibiotic _______.

1. Mycoplasma; penicillin

2. Histoplasma; tetracycline

3. Mycoplasma; tetracycline

4. Histoplasma; penicillin

Mycoplasma; penicillin

None of the Archaea have peptidoglycan in their cell walls. However, some have a similar molecule called ________.

pseudopeptidoglycan

Some bacteria are covered with a substance that creates a diffuse irregular layer called a ___________.

slime layer

Compounds that interfere with the synthesis or structural integrity of peptidoglycan can ______.

1. interfere with nutrient uptake by a fungal cell

2. result in bursting of a fungal cell

3. interfere with nutrient uptake by a bacterial cell

4. result in bursting of a bacterial cell

result in bursting of a bacterial cell

Which of the following structures is external and can protect the bacterial cell from various host immune responses?

1. Flagella

2. Cell wall

3. Capsule

4. Cell membrane

Capsule

Penicillin is ineffective against Mycoplasma species because the organism lacks a rigid _________.

cell wall or peptidoglycan layer

What long protein structures are responsible for most types of prokaryotic motility?

1. Pili

2. Flagella

3. Fimbriae

4. Glycocalyx

Flagella

Many members of the Archaea have _________, which are sheets of flat proteins or glycoprotein subunits.

S-layers

A distinct and gelatinous layer surrounding a cell is called a ______.

1. capsule

2. slime layer

3. plaque

4. biofilm

capsule

Which three parts comprise a bacterial flagellum? Select all that apply.

1. periplasmic space

2. hook

3. centrioles

4. basal body

5. filament

1. hook

2. basal body

3. filament

A ________ is a distinct and gelatinous layer on the outside of the cell. Most are composed of polysaccharides but some are made of polypeptides.

capsule

The motility of bacteria is typically facilitated by long appendages called ________.

flagellum

In a bacterium, pili are typically _______ than flagella.

1. shorter and less numerous

2. shorter but more numerous

3. longer and more numerous

4. longer but less numerous

shorter but more numerous

None of the Archaea have peptidoglycan in their cell walls. However, some have a similar molecule called _________.

pseudopeptidoglycan

The bacterial ________ is typically a single, circular, double-stranded DNA molecule that contains all of the essential genetic information required by a cell.

chromosome or genome

Ribosomes are directly involved in ______.

1. the breakdown of sugars

2. the synthesis of proteins

3. the breakdown of lipids

4. the synthesis of DNA

the synthesis of proteins

The flagellum of a Gram-negative bacterium is shown here. A =
_______; B = _______; C = _______.

A = filament

B = hook

C = basal

Which of the following structures is external and can protect the bacterial cell from various host immune responses?

1. Cell membrane

2. Capsule

3. Flagella

4. Cell wall

Capsule

This micrograph shows the appendages of a bacterium. A = ______; and B = _______.

A = flagellum

B = pili

A typical bacterium possesses ______.

1. a single, circular chromosome

2. a single, linear chromosome

3. multiple, linear chromosomes

4. multiple, circular chromosomes

a single, circular chromosome

What internal structure helps control cell shape and is involved in cell division?

1. Cytoskeleton

2. Cell membrane

3. Inclusion body

4. Cell wall

Cytoskeleton

The joining of amino acids to synthesize proteins is facilitated by cytoplasmic structures called _________.

ribosomes

_______ are accumulations of high-molecular weight polymers synthesized from a nutrient that a cell has in relative excess.

1. Gas vesicles

2. Vacuole regions

3. Storage granules

4. Bacterial microcompartments

Storage granules

Bacteria use gas vesicles to float to the surface of water to better access _______ as a source of energy.

sunlight

From a bacterium's perspective, what are the advantages of endospore formation? Select all that apply.

1. The endospore is more resistant to disinfectants.

2. The endospore provides cell shape.

3. The endospore withstands dry conditions.

4. The endospore allows faster cell replication.

5. Endospores are highly resistant to radiation and heat.

1. The endospore is more resistant to disinfectants.

2. The endospore withstands dry conditions.

3. Endospores are highly resistant to radiation and heat.

Previously it was thought that bacteria lacked a(n) _______, a network of interior proteins that provides support and structure to the eukaryotic cell. Recently though, similar proteins have been characterized in bacteria.

cytoskeleton

If a cell has a nutrient in relative excess, it may accumulate that compound in a storage _______.

granule

Members of the genera Bacillus and Clostridium ______.

1. are drug-resistant Gram-negative pathogens

2. are the biggest producers of antibiotics

3. produce dormant cells called endospores

produce dormant cells called endospores

An endospore is ______.

1. a dormant cell type

2. a mode of bacterial reproduction

3. a type of bacterial microcompartment

4. an obligate intracellular parasite

a dormant cell type

Small, rigid, protein-bound compartments that provide buoyancy to some aquatic bacterial cells are called _______ vesicles.

gas

In contrast to an endospore, a typical multiplying cell is called a(n) ______ cell.

vegetative

Endospores ______. Select all that apply.

1. may germinate to produce vegetative cells, which can then multiply.

2. are very resistant to damaging conditions, including high heat, toxic chemicals, and UV light.

3. are produced by a wide range of Gram-positive and Gram-negative bacteria

4. are common in soil, and can therefore be found nearly anywhere.

1. may germinate to produce vegetative cells, which can then multiply.

2. are very resistant to damaging conditions, including high heat, toxic chemicals, and UV light.

3. are common in soil, and can therefore be found nearly anywhere.

Brief exposure to which of the following can induce endospore germination?

1. antibiotics

2. drying

3. heat

4. moisture

heat

The two most common examples of endospore-forming genera are
_______ and _______.

bacillus; clostridium

Compared to sporulation, the process of germination is ______.

1. longer

2. about the same

3. shorter

shorter

Some bacterial species such as members of the genera Bacillus and Clostridium, produce a unique type of dormant cell called a(n)
__________.

endospore

The most significant structural difference between eukaryotic and prokaryotic cells is the presence or absence of a membrane-bound
__________, which contains the genetic material.

nucleus

A vegetative cell is one that ______.

1. has entered a dormant stage

2. is a typical multiplying cell

3. is resistant to more than one antibiotic

4. has lost its cell wall

is a typical multiplying cell

All cells have a _______ membrane, also called the cell membrane or the plasma membrane.

cytoplasmic

An endospore can be triggered to ________ by a brief exposure to heat or certain chemicals. This results in the formation of a vegetative cell.

germinate

Pinocytosis and phagocytosis are two of the three examples of
__________.

endocytosis

Which process involving endospores takes longer?

1. germination

2. sporulation

sporulation

Which term is used to describe the process by which cells take up liquids from the surrounding environment?

1. Exocytosis

2. Aquacytosis

3. Phagocytosis

4. Pinocytosis

Pinocytosis

Eukaryotic cells have a nucleus, which contains the cell's genetic information.

True or False

True

Which process would take up the greatest variety of substances?

1. Receptor-mediated endocytosis

2. Pinocytosis

Pinocytosis

The cytoplasmic membrane is a _______ bilayer embedded with _________.

phospholipid; proteins

The engulfment of large particles such as bacteria by a eukaryotic cell is called ______.

1. exocytosis

2. pinocytosis

3. phagocytosis

phagocytosis

Endospores ______. Select all that apply.

1. are produced by a wide range of Gram-positive and Gram-negative bacteria.

2. are common in soil, and can therefore be found nearly anywhere.

3. may germinate to produce vegetative cells, which can then multiply.

4. are very resistant to damaging conditions, including high heat, toxic chemica

1. are common in soil, and can therefore be found nearly anywhere.

2. may germinate to produce vegetative cells, which can then multiply.

3. are very resistant to damaging conditions, including high heat, toxic chemica

Eukaryotic cells use the process of ______ to take in substances too large to move through a transport protein.

endocytosis

In eukaryotes, a cytoplasmic ribosome has a size of _______, and is made up of a small 40S subunit and a large _______ subunit.

80S; 60S

During the endocytic process of ________, the eukaryotic cell takes in liquids by making small invaginations in the membrane, eventually forming a membrane-bound intracellular compartment called an endosome.

pinocytosis

A flexible molecular framework throughout the cytoplasm that anchors organelles and permits shape changes in some cells is called the _________.

cytoskeleton

Unlike pinocytosis, receptor-mediated endocytocis takes up ______ that bind to receptors on the cell surface.

1. protozoa

2. ligands

3. endosomes

4. viruses

ligands

Although eukaryotic flagella and cilia appear to project out of the cell, they are covered by extensions of the cytoplasmic membrane.

True or False

True

During the endocytic process of _______, the eukaryotic cell engulfs large particles such as bacteria, forming a membrane-bound compartment called a phagosome.

phagocytosis

Where is DNA contained in eukaryotes?

1. nucleolus

2. cytoplasm

3. nucleus

4. nucleoid

nucleus

What is the principal function of mitochondria?

1. ATP production

2. DNA synthesis

3. secretion

4. motility

5. lipid synthesis

ATP production

The eukaryotic ribosome found outside the mitochondria is best described as ______.

1. 40S + 60S = 100S

2. 30S + 60S = 80S

3. 30S + 50S = 80S

4. 40S + 60S = 80S

5. 30S + 50S = 70S

40S + 60S = 80S

What collective name is given to the various proteins that criss-cross the cell's interior, hold various organelles in place, enable movement of intracellular structures, and give the cell internal structural integrity?

1. Cytoskeleton

2. Lysosomes

3. Cytoplasm

4. Golgi

Cytoskeleton

In plant and algae cells, _______ are organelles that contain pigments for photosynthesis.

chloroplasts

Eukaryotic flagella and cilia are ______. Select all that apply.

1. flexible structures

2. composed of long microtubules

3. anchored in the outside layer of the cytoplasmic membrane

1. flexible structures

2. composed of long microtubules

The _______ of eukaryotic cells is a complex system of flattened sheets, sacs, and tubes.

1. mitochondria

2. endoplasmic reticulum

3. lysosomal complex

4. Golgi apparatus

5. peroxisome

endoplasmic reticulum

In eukaryotic cells, the genetic material is found in the ________.

nucleus

Which eukaryotic organelle consists of a series of membrane-bound flattened compartments?

1. golgi apparatus

2. peroxisome

3. mitochondrion

4. chloroplast

5. rough endoplasmic reticulum

golgi apparatus

_______ function as ATP-generating powerhouses and are found in nearly all eukaryotic cells.

Mitochondria

What is the main function of lysosomes?

1. degradation

2. motility

3. synthesis

4. aggregation

5. secretion

degradation

Which organelle is the site of photosynthesis?

1. Chloroplast

2. Peroxisome

3. Endoplasmic reticulum

4. Mitochondrion

5. Nucleus

6. Golgi

7. Lysosome

Chloroplast