Microbiology Chapter 4

capsule

(tan coating) layer of molecules external to the cell wall, serves to protect, adhesive, and receptor functions. may fit tightly, or be very loose an diffuse-slime layer or glycocalyx

capsules

- bound tightly to cell; thicker; gummy; sticky.

Glycocalyx

- coating that protects the cell and adheres to surfaces; these may vary among bacteria.

pilus (sex pilus)

- elongated, rigid tubular structure involved in mating process (conjugation).

slime layer

- loose, soluble shield; protects from dehydration and nutrient loss.

Lophotrichous

- small flagella bunches (tufts) emerging from same site

Fimbriae

- small, bristle-like fibers; stick to each there and to surfaces; cause colonization (rocks, infections).

What's considered slow speed

1 mm/minute

The cell membrane consists of a(n) bilayer with embedded .

1.phospholipid 2. proteins

Prokaryotic cells evolved on Earth about how many years ago?

3.5 billion years

Identify the term for multiple shapes and sizes among cells of the same species. A. Pleomorphism B. Polysomy C. Polycythemia

A

Which of the following is the movement towards or away from a chemical stimulus? A Chemotaxis B Dethantaxis C Phototaxis

A

spirochete

A coiled, spiral-shaped bacterium that has endoflagella and flexes as it moves.

biofilm

A complex aggregate of interacting microbial cells that adhere to each other and to surfaces by means of a polysaccharide matrix. Biofilms permit communication among participants, which facilitates their survival and adaptation.

fluid mosaic model

A conceptualization of the molecular architecture of cellular membranes as a bilipid layer containing proteins. Membrane proteins are embedded to some degree in this bilayer, where they float freely about

spheroplast

A gram-negative cell whose peptidoglycan, when digested by lysozyme, remains intact but is osmotically vulnerable.

Flagellum

A long, whiplike structure that helps a cell to move

lipopolysaccharide

A molecular complex of lipid and carbohydrate found in the bacterial cell wall. The lipopolysaccharide (LPS) of gram-negative bacteria is an endotoxin with generalized pathologic effects such as fever.

quorum sensing

A phenomenon occurring among microbes in a biofilm in which the members signal each other and coordinate their functions.

axial filament

A type of flagellum (called an endoflagellum) that lies in the periplasmic space of spirochetes and is responsible for locomotion; also called periplasmic flagellum

Which of the following are characteristics inherent to life? A Growth and development B Heredity C Metabolism D Sexual reproduction

A, B, C

All cells that are capable of replication and metabolism contain which of the following characteristics? A Chromosomes B Flagella C Cell membrane D Organelles E Ribosomes F Cell walls

A, C, E

Which of the following may be included in the sticky matrix formed by the colonists in a biofilm? A. Slime layers B. Plasma membranes C. Pili D. Ribosomes E. Fimbriae F. Capsules

A, C, E, F

Which of the following antibiotics affect the integrity of the cell wall of bacteria, thereby making them susceptible to lysis? A Penicillin B Tetracycline C Erythromycin D Cephalosporin

A, D

appendage

Accessory structure that sprouts from the surface of bacteria. They can be divided into two major groups: those that provide motility and those that enable adhesion.

periplasmic space

An open area between the cell wall and cell membrane in the cell envelopes of bacteria. Gram-negative bacteria have a a more extensive space than do gram-positive bacteria.

first cells to appear on earth

Archaea bacteria

How does a bacterial colony appear? As an individual isolate on solid agar Throughout liquid culture In a solid lawn of organisms on a solid agar plate

As an individual isolate on solid agar

Which of the following is considered to be the basic unit of life? A. Protein B. Cell C. Tissue D. Organism E.DNA

B

diphtheriae and pyogenes are gram-positive bacteria that have toxic properties due to proteins on their cell walls.

Blank 1. Corynebacterium, C., or C Blank 2: Streptococcus, S., or S

Identify the major structure component of the cell membrane. A. Nucleic acids B. Cholesterol C. Phospholipids D. Proteoglycans

C

Which structure is most closely associated with biofilm formation? A Endospores B Cell membrane C Slime layer

C

Endotoxins (LPS) can stimulate fever and shock during which gram-negative infections? A. Strep throat B. Toxic shock syndrome C. Typhoid fever D. Meningitis

C, D

Elongated, rigid tubes on gram-negative bacteria that are involved in the transfer of DNA from one cell to another are called ?

Conjugation pili

What structural difference is found in gram-positive cells but not in gram-negative cells? A. Peptidoglycan B. Outer membrane C. Plasma membrane D. Single cell membrane

D

Which bacteria have no cell wall, but have a cytoplasmic membrane that is stabilized by sterols? A. Streptococci B. Gram-positive C. Gram-negative D. Mycoplasma E. Mycobacterium

D

Monotrichous

Describing a microorganism that bears a single flagellum.

lophotrichous

Describing bacteria having a tuft of flagella at one or both poles.

Chemotaxis

Detects/moves in response to chemical signals.

outer membrane

Extra membrane similar to cell membrane but also containing lipopolysaccharide. Controls flow of materials, and portions of it are toxic to mammals when released

conjugation

In bacteria, the contact between donor and recipient cells associated with the transfer of genetic material such as plasmids. Can involve special (sex) pili. Also a form of sexual recombination in ciliated protozoans.

peritrichous

In bacterial morphology, having flagella distributed over the entire cell.

L form

L-phase variants; wall-less forms of some bacteria that are induced by drugs or chemicals. These forms can be involved in infections.

pleomorphism

Normal variability of cell shapes in a single species; bacteria having diverse shapes are called pleomorphic.

is a behavior of biofilms which occurs when individual species alter the expression of their genes to cooperate with other cells in the biofilm.

Quorum Sensing

.fimbria, fimbriae

Short, numerous surface appendages on some bacteria that provide adhesion but not locomotion.

pili

Small, stiff filamentous appendages in gram-negative bacteria that function in DNA exchange during bacterial conjugation.

mycoplasma

Species of mycoplasma are among the smallest self-replicating microorganisms. Mycoplasma naturally lack a cell wall. Most species are parasites of animals and plants.

What is the name for corkscrew-shaped bacteria?

Spirochetes

cell envelope

The Outer Wrapping of Bacteria includes plasma membrane, cell wall, and glycocalyx

chemotaxis

The tendency of cells to move in response to a chemical gradient (toward an attractant or to avoid adverse stimuli). In inflammation, it refers to the movement of blood cells in reaction to chemical signals.

porin.

Transmembrane proteins of the outer membrane of gram-negative cells that permit transport of small molecules into the periplasmic space but bar the penetration of larger molecules

.Gram-negative cell wall

a complete sandwich with three layers: an outer membrane, a thin peptidoglycan layer, and the cell membrane. Stains red.

cell wall

a semi rigid casing that provides structural support and shape of a cell

basal body

a stack of rings firmly anchored thru the cell wall to the cell membrane; anchors the hook that holds the filament

What's considered fast speed

about 5.2 mm/minute.

where can the basal body be found at?

all spirilla, 1/2 of bacilli, some cocci.

Pilus

an appendage used for drawing another bacterium close in order to transfer DNA to it

polar

attached at one or both cell ends; Term to describe a molecule with an asymmetrical distribution of charges. Such a molecule has a negative pole and a positive pole.

The two major types of prokaryotic cells are and .

bacteria & archaea

flagella

bacteria propellers

Viruses are not considered living things because they only show signs of life when they are inside a host

cell

lysis

cell destruction; bursting

All bacteria will have

cell membrane bacterial chromosomes ribosomes cytoplasm

The two main components of the cell envelope in most bacteria.

cell wall and cell membrane

7 characteristics of life

cellular organization, responsiveness, heredity &DNA, metabolism & Enzymes, growth & development, reproduction, transport

bacterial chromosome/ nucleoid

composed of condensed DNA molecules. DNA directs all genetics and heredity of the cell and codes for all proteins

The transfer of DNA between bacterial cells is called .

conjugation

The cell envelope encloses the

cytoplasm

The cell membrane surrounds a complex solution of organic materials and salts that is referred to as .

cytoplasm, cytoplasmic matrix, or cytosol

Endospore

dormant body formed within some bacteria that allows for their survival in adverse conditions

Fimbiae

fine, hair-like bristles extending from cell surface that help in adhesion to other cell and surfaces

Peritrichous

flagella are dispersed randomly

Amphitrichous

flagella at both poles

Cell (cytoplasmic/plasma) membrane

flexible; phospholipid bilayer with proteins. allows passage of nutrients into the cell and the discharge of wastes.

.peptidoglycan

glycan chains cross-linked by short peptide fragments.

peptidoglycan

glycan chains cross-linked by short peptide fragments.

filament

helical protein structure; inserted into a tubular hook

.cell wall

lies below glycocalyx; determines bacteria's shape; provides structural support.

actin cytoskeleton

long fibers of proteins that encircle the cell just inside the cell membrane and contribute to the shape of the cell

Biofilms

microbes cling together in complex masses

S-layer

monolayer of protein used for protection and/or attachment

Phototaxis

movement in response to light; exhibited by some photosynthetic bacteria

The bacteria naturally have no cell wall, but have a cytoplasmic membrane that is stabilized by sterols.

mycoplasma

The cell envelope of gram- bacteria is composed of an outer membrane, cell wall, and a cell membrane.

negative

the movement of an organism away from a chemical repellent is called chemotaxis.

negative

glycan

polysaccharide

bacterial microcompartments

protein coated packets used to localize enzymes and other proteins in the cytoplasm

A bacterial cell whose cell wall is completely lacking and that is vulnerable to osmotic lysis

protoplast

.Gram-positive cell wall

resembles an open-faced sandwich with two layers: the thick cell wall of peptidoglycan and the cell membrane. Stains purple; contains an evident periplasmic space.

motility

self-propulsion; swims freely

intracellular membranes

serve to compartmentalize functions within eukaryotic cells and are involved in synthesis, storage, transportation and detoxification

What structural difference is found in gram-positive cells but not in gram-negative cells?

single cell membrane

monotrichous

single flagellum

Plasmid

small, double stranded DNA molecule containing extra genes

are spiral-shaped bacteria characterized by periplasmic flagella and display a worm-like mode of locomotion.

spirochete

inclusion/granule

stored nutrients such as fat, phosphate, or glycogen deposited in dense crystals or particles that can be tapped into when needed

ribosomes

tiny particles composed of protein and RNA that are the sites of protein synthesis

The metabolically active and growing phase of endospore forming bacteria is called the .

vegetative cell

Cytoplasm

water based solution filling entire cell