CHAPTER 4 GUIDE Flashcards
What are the parts of a bacterial cell from the outside inward?
Capsule,Fimbriae,Pili,Flagella,Cell Wall,Cell Membrane, Cytoplasmic Matrix, Cytoplasm, Glycocalyx, Ribosomes, inclusion Bodies,Nucleiod
What is the Capsule?
It is a polysaccharide layer that lies outside the cell envelope.
Is capsule part of the outer envelope of a bacterial cell?
Yes
What is the Nucleoid?
DNA/genetic information.
Is Nucleiod surrounded by a membrane?
No
What is the Cytoplasm?
It is where the functions for cell growth, metabolism, and replication are carried out.
What are Pili?
they are part of bacterial cell that transfer genetic information(conjugation).
What is the singular version of the Pili?
Pillus
Describe the Pili.
elongated tubes that has long tethers.
What are Fimbriae?
Velcro-like, short and numerous bristles
What do Fimbriae do?
stick to cells and surfaces
What is the Glycocalyx?
a glycoprotein and glycolipid covering that surrounds the cell membranes of some bacteria
What is the other term for Glycocalyx?
Pericelullar Matrix
What substance is the bacterial cell wall made of?
it is a rigid layer of polysaccharides
What is the Cell Membrane?
It is the actual barrier.
What are Ribosomes?
these are where protein synthesis occurs.
What are Inclusion Bodies?
storage sites
What is the other term for Inclusion Bodies?
Granules
What are Plasmids?
Extrachromosomal genetic units characterized by several features, is a double-stranded DNA that is smaller than and replicates indepently of the cell chromosome, it bears genes that are not essential for cell growth; it can bear genes that code for adaptive traits; and it is transmissible to other bacteria.
What is the typical size and shape of Plasmids?
They are usually small and circular.
What do Plasmids contains?
It contains non essential DNA and antibiotic resistance.
What is the Cytoplasmic Matrix?
the liquid found inside the cells.
Does typical bacterium have a cellular wall based on the cellular envelope?
Yes
Does non-typical bacterium have a cellular wall based on the cellular envelope?
No
Name two differences in cellular components between a typical bacterium and an archaeon.
- The cell walls of a typical bacterium have peptidoglycans while the cell walls of archeon do not have peptidoglycans.
- The cell membrane of an archaeon has ether linkages more stable and unique while a typical bacterium has ester linkages.
What are the 2 types of bacterium that help dictate the different cellular abilities of the organism, it’s environmental niche, and treatment with antibiotics?
- Gram-negative 2. Gram-positive
What are the 3 chemical compositions of Gram-positive cell wall?
- peptidoglycan 2. teichoic acid 3.lipoteichoic acid
What are the 3 chemical compositions of Gram-negative?
- Phospholipids 2. Lipoproteins 3. lipopolysaccharide.
What dictates the cellular activities and environmental niche of bacteria?
the presence of the chemicals in the cell envelopes of the respective bacterium.
What are the four functions of the presence of lipopolysaccharide in Gram-negative bacterium?
- aids in the stabilization of the membrane structure 2. acts as endotoxin 3. acts as a protective barrier, and imparts strong negative charge due to the charged sugars and phosphates.
What do the presence of the chemicals in Gram-negative and Gram-positive do?
The presence of the chemicals makes the Gram-negative bacterium more formidable than the Gram-positive bacterium.
Which has thicker peptidoglycan in its membrane: gram-positive or gram-negative?
Gram-positive
Which has thinner peptidoglycan in its membrane: gram-positive or gram-negative?
Gram-negative
What is the characteristic of the thick outer covering or membrane of the Gram-positive?
it is capable of absorbing a lot of foreign material just as fences and walls can absorb mold and moisture.
Because of their thin but difficult-to-penetrate cell membrane, gram-negative bacteria are often resistant to what?
antibiotics and other antibacterial interventions.
What are the six parts of the Gram-positive cell wall?
- peptidoglycan
- teichoic acid
- cell membrane
- lipoteichoic acid
- periplasmic space
- membrane protein
Describe Peptidoglycan.
it is thick (multilayered), a substance forming the cell walls of many bacteria
What are Teichnoic acids?
they are compound present in the walls of Gram-positive bacteria, a polymer of ribitol or glycerol phosphate.
What is the cell membrane?
the semipermeable membrane surrounding the cytoplasm of a cell.
What are lipoteichnoic acids?
a major constituent of the cell wall of gram-positive bacteria
What is the periplasmic space?
the space between the inner cytoplasmic membrane and the bacterial outer membrane.
What do the membrane proteins do?
perform a variety of functions vital to the survival of organisms.
What are the parts of the Gram-negative cell wall?
Lipopolysaccharides
Porins
Phospolids
Membrane proteins
Lipoproteins
Periplasmic space
Peptidoglycan
Outer membrane layer
Cell membrane
What are Lipopolysaccharides?
complex molecules containing both lipids and polysaccharide parts.
What are Porins?
a class of proteins whose molecules can form channels (large enough to allow the passage of small ions and molecules) through cellular membranes.
What are phospholipids?
lipids containing a phosphate group in its molecule
What are lipoproteins?
any of a group of soluble proteins that combine with and transport fat or other lipids in the blood plasma
Is the periplasmic space much smaller in gram-positive or in gram-negative bacteria?
Gram-positive bacteria
What is Peptidoglycan?
a substance forming the cell walls of many bacteria
Where can the outer membrane layer be found?
it is found in gram-negative bacteria among other things.
What do you call the lipid portion of the complex lipopolysaccharide?
Endotoxin
What is the cell membrane?
the semi-permeable membrane surrounding the cytoplasm of a cell
What is bacteria?
a microscopic single-celled organism
What are the 3 parts of the flagella?
- filament
- basal body
- hook
What is the filament of the flagella?
longest portion, helical propeller
Where is the basal body of the flagella?
embedded in the cell
Describe the hook of the flagella
short, curved segment
What is the meaning of monotrichous?
with 1 flagelllum
What is the meaning of lophotrichous?
cluster of flagella at one or both ends
What is the meaning of amphitrichous?
1 flagellum at each pole
What is the meaning of peritrichous?
flagella spread over the whole bacteria
What is Chemotaxis?
It is the movement of cells of organisms in response to chemicals
What are the two types of Chemotaxis?
- Positive Chemotaxis
- Negative Chemotaxis
What is Positive Chemotaxis?
cells are attracted
What is Negative Chemotaxis?
repelled by substances exhibiting chemical properties
What are Spirochetes?
extremely thin bacteria that move like a corkscrew (w/ the aid of a flagella) some of which are serious pathogens for humans causing diseases.
What are the common diseases that are brought by Spirochetes?
Syphilis and Lyme disease.
What is conjugation in cells?
transfer of genetic information via cell-to-cell contact
What is the slime layer?
it is an easily removed, unorganized layer of extracellular material that surrounds bacteria cells.
What are the 3 compositions of slime layer?
- exopolysaccharides 2. glycoproteins 3. glycolipids
What are the 2 functions of the slime layer?
- protects the bacteria cells from environmental dangers such as antibiotics and desiccation (extreme dryness)
- it allows bacteria to adhere to smooth surfaces.
What is a biofilm?
a thick layer of prokaryotic organisms that have aggregated to form a colony.
What is Gram stain?
a technique used to differentiate two large groups of bacteria based on their different cell wall constituents by coloring the cells red or violet.
What are the characteristics of a Gram-Positive cell wall?
thick, composed primarily of peptidoglycan (20-80 nm thick) wall cell, negatively charged, stain violet due to the presence of a thick layer of peptidoglycan in their cell walls which retains the color of crystal violet.
What are the characteristics of a Gram Negative cell wall?
more complex than Gram positive cell walls, with thin peptidoglycan layer (1-3 nm), may be in a form of a gel rather than a compact layer, stains red, does not retain the color of crystal violet due to its thinner peptidoglycan wall during the decoloring process.
What is the cell envelope?
represents the outermost layer of the bacterial cell that protects the cell.
What are the two categories of the cell envelope?
- Gram-positive type 2. Gram-negative type
What is the outer membrane?
protects Gram-negative bacteria against a harsh environment
What are the 3 parts of the outer membrane?
- phospholipids 2. lipoproteins 3. lipopolysaccharides
What is the other term for Peptidoglycan(PG)?
Murein
What is lysis?
the disintegration of a cell by rupture of the cell wall or membrane.
What is mycoplasma?
smallest and simplest self-replicating bacteria; lacks a cell wall around their cell membrane; typically parasitic
What are endospores?
dormant, non-reproductive, and enzymatically inert forms of bacterial vegetative cells.
What is sporulation?
refers to the formation of nearly dormant forms of bacteria.
What are bacilli?
a rod-shaped bacterium
What are cocci?
a spherical-shaped bacterium
What are vibrio?
a comma-shaped bacterium (curved rod)
What is the meaning of arrangement in bacterial cells?
refers to the placement of bacterial cells
What is the diplo arrangement?
bacterial cells are arranged in pairs
What is the strepto arrangement?
bacterial cells are arranged in chains
What is the staphylo arrangement?
bacterial cells are arranged in grape-like clusters
List the cellular components that all cells have.
plasma membrane cytoplasm ribosomes DNA
List the 7 characteristics of all life.
- responsiveness to the environment 2. growth and change 3. ability to reproduce 4. have a metabolism and breathe 5. maintain homeostasis 6. made up of cells 7. passing of traits onto offspring
What is the difference between flagella and periplasmic flagella?
Flagella can be found on the surface of the cell while periplasmic flagella can be found inside the cell within the periplasmic space.
What is meant by run-and-tumble motion?
It is a method used by bacteria that have several flagella to undergo random walks to find food. The “runs” are the steps in a random walk and the “tumbles” are the random changes in direction.
What are the 3 advantages of bacteria in biofilms?
- nutrient scavenging
- increased metabolic diversity
- efficiency resistance to antimicrobial action
What external cell structures might be involved in the formation of a biofilm?
Pili and fimbriae
What are the 2 types of glycocalyx?
- Capsules 2. Slime layers
When is the glycocalyx considered a capsule?
A glycocalyx is considered a capsule when the polysaccharides are more firmly attached to the cell wall.
What is the impact of bacteria being encapsulated?
Bacteria that have capsules generally have greater pathogenicity because the capsule protects the bacteria even from phagocytic white blood cells of the immune system.
What are the two main functions of the peptidoglycan in the bacteria?
- maintain the shape of the cell 2. to counteract the high osmotic pressure of the bacterial protoplast.
What happens if the peptidoglycan is disrupted or removed?
the bacteria undergo immediate osmotic lysis.
Describe the medical impact of the cell envelope of Gram-positive.
gram-positive bacteria lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the Gram-negative bacteria.
Describe the medical impact of the cell envelope of Gram-negative.
Gram-negative bacteria pose public health concern since it is responsible for the endotoxic shock associated with septicemia.
Which group of bacteria are more resistant to drugs - Gram-positive or Gram-negative?
Gram-negative bacteria
Why are Gram-negative bacteria resistant to drugs?
because of their largely impermeable cell wall.
What is commonly used as a microbial control agent?
Antibiotics are commonly used as microbial control agent.
Why are antibiotics effective?
because antibiotics are produced by microorganisms to kill or inhibit the growth of other microbes.
Where is the periplasmic space located in Gram-negative bacteria?
It is located between the inner and outer membrane.
Where can a smaller periplasmic space be found in Gram-positive bacteria?
a smaller periplasmic space is found between the inner membrane and the peptidoglycan layer.
What is the function of the periplasmic space?
it serves as a buffer between the external environment and the internal of the bacterium.
What component of acid-fast bacteria such as Mycobacterium species makes their cell walls unique?
Mycolic acid
What is the function of myotic acid in mycobacterium species?
Mycolic acid in the cell walls makes mycobacterium species impermeable to many staining procedures.
What are the 2 compositions of ribosomes?
special proteins and nucleic acids.
What is the function of ribosomes?
It function as a micro-machine for making proteins.
How many ribosomes sizes do the bacteria, achea and eukaryotes have?
Bacteria and archea both have 70S ribosomes while eukaryotes have 80S.
What condition stimulates endospore formation?
Endospores are formed via the conversion of a vegetative cell by a complicated pathway of gene expression triggered by nutrient exhaustion.
Is sporulation survival for the individual organism or just continuation of the species lineage?
Sporulation serves as a survival mechanism for the individual organism when conditions are inhospitable.
What is the medical significance of the bacterial endospores?
It is resistant to heat, chemicals, and radiation.
How do unique cellular components help dictate where a prokaryote can live?
Unique cellular components enables the organism to live in an environment where others can’t.
Which is more stable: ester linkages or ether linkages?
ether linkages
