Microbiology - Chapter 4
All Living Cells can be classified into 2 groups.Name them______________ and _____________.
True or False prokaryotes are simpler and smaller in structure than eukaryotes?
True or false plants and animals are completely comprised of eukaryotic cells?
Prokaryotes and eukaryotes are similar are chemically similar in that they both contain _______, _________,__________,and ________________.
They use the same kinds of chemical reactions to ___________, _______________, and _______________.
It is primarily the structure of the cell and the absence of organelles (specialized cell structures that have specific functions) that distinguish ____________ from ___________________.
prokaryotes from eukaryotes
Chief distinguishing characteristics of prokaryotes ( from the Greek meaning prenucleus) are:
1.Their DNA is not enclosed within a membrane and is usually a singular, circularly arranged chromosome.(Some bacteria such as Vibrio cholerae, have 2 chromosomes and some have linearly arranged chromosome)
2.Their DNA is not associated with histones (special chromosome proteins found in eukaryotes); other proteins associated with the DNA.
3.They lack membrane-enclosed organelles.
4.Their cell walls almost always contain the complex polysaccharide peptidoglycan.
5. They usually divide by binary fission. During this process the DNA is copied and the cells split into 2 cells. Binary fission involves fewer structures and processes than eukaryotic cell division.
Chief distinguishing characteristics of eukaryotes (from the Greek meaning true nucleus) are:
1. Their DNA is found in the cell's nucleus which is separated from the cytoplasm by the nuclear membrane and the DNA is found in multiple chromosomes.
2. Their DNA is consistently associated with chromosomal proteins called histones and non-histones.
3.They have a number of membrane-enclosed organelles, including mitochondria, endoplasmic reticulum, Golgi complex, lysomes and sometimes chloroplasts.
4.Their cell walls when present are chemically simple.
5.Cell division usually involves mitosis, in which chromosomes replicate and an identical set is distributed into each of two nuclei. The process is guided by the mitotic spindle a football shaped assembly of microtubules. Division of the cytoplasm and other organelles follows so that the two cells produced are identical to each other.
Prokaryotic cells include _________ and _________.
bacteria and archaea
True or false. It is estimated that 99% of the bacteria in nature exist in biofilm.
The 1000s of bacteria are differentiated by many factors such as_________, ________________,______________,and ____________.
chemical composition ( often detected by staining reactions)nutritional requirements, biochemical activities and sources of energy (sunlight or chemicals)
Most bacteria rage in size from _______ to _________ in length.
0.2 to 2.0 um in diameter and from 2 to 8 um in length.
They have a few basic shapes: ______________, ______________, and _______________.
coccus (plural cocci meaning berries); bacillus (rod shaped)-plural bacilli- little staffs; spiral.
Cocci are usually round but can be _________,________,or ________________.
oval or flattened on one side
When cocci divide to reproduce, the cells can remain
a) attached to one another
b) get pulled apart
a) attached to one another
Cocci that remain in pairs after dividing are called ____________________.
The cocci that divide and remain attached in chainlike patterns are called?
The cocci that divide in two planes and remain in groups of four are known as?
The cocci that divide in multiple planes and remain attached in cube-like groups of 8 are called
The cocci that divide in multiple planes and form grapelike clusters or broad sheets are called?
Bacilli divide only across?
their short axis
Most bacilli appear as single rods called?
Diplobacilli appear in _______ after division.
Streptobacilli appear in _____________.
Some bacilli look like straws. Others have _______
ends that look like cigars.
Some are oval and look so much like cocci that they are called______________.
True or false? bacillus can not form staphylo arrangement
True- because it divides along its shortest axis
Spirilla have _______________ and _______________ and _____________________.
thicker flagella and thinner endoflagella and axial flagella spin.
Which bacillus is the cause of syphilis?
Bacillus has 2 meanings in microbiology what are they?
One pertains to morphology of the bacteria and the other to a specific genus
Other cell shapes such as star, rectangular are usually what?
archae- environmental bacteria don't usually cause harm to human such as disease
Prokaryotic cell is dependent on what?
What does a prokaryotic cell get its energy and food from?
What are the typical structures of bacteria?
Nucleoid containing DNA
Spirochetes use what to move?
What is the chief job of the capsule?
Help cells attach to host cell and one another
What is the prokaryotic cells food source?
What is glycocalyx?
Bacterial glycocalyx is?
sticky and viscous gelatinous polymer that is external to cell wall and composed of polysaccharide, polypeptide or both.
What is capsule?
a substance that is organized and firmly attached to the cell wall the glycocalyx is described as capsule. Has rigid tight matrix and doesn't allow small particles to penetrate.
Harder for immune system (WBCs)to phagocyte
How can you detect capsule?
by using negative staining
What is the glycocalyx substance that is loosely attached to the cell wall and unorganized?
slime layer- doesn't let small particles to penetrate and easily deformed.
Who was the first person to show direct evidence that DNA is genetic material?
Frederick Griffith's Experiment (Sneak Peek)through a process called bacterial transformation
Used Streptococcus pneumoniae: used mice and injected them with the S strain-which were encapsulated which killed the mice. The R strain couldn't attach and the WBCs could kill it- it is virulent. Heat killed S strain but when the R strain was put in with the heat killed S strain there was just enough to activate the S- strain and kill the mice.
Motility occurs in when bacteria have?
flagella (singular- flagellum)which are long filamentous appendages that propel bacteria
Flagella may be:
peritrochous-distributed over entire organism
polar-at one or both poles at ends of cells
monotrichus-one polar flagellum
lophotrichus-a tuft of flagella at one end
amphitrichous-flagella at both ends
Flagella have 2 types of movement what are they?
Runs- move from one location to another
If bacteria is in an unfavorable environment there will be more tumbles and less runs and opposite if environment is favorable there will be more runs less tumbles.
What is taxis?
allowing bacteria to move either towards or away from a particular stimulus through the use its flagella. Bacteria respond environment via receptors. Receptors interact with cytoplasmic proteins which in turn affect the rotation of the flagella.
Chemotaxis is a response to a chemical
Phototaxis is a response to light
The 3 components of flagellar anatomy:
Filament: protrudes from cell, made of protein-flagellin- could be different types of flagellins
Hook (anchors filament) connects filament to motor protein
Basal Body rod and rings
Gram - 4 rings anchor basal body into cell
Gram + 2 rings anchor basal body into cell
Axial filaments are:
unique to spirochetes
also called endoflagella
always gram -
spirals around cell under sheath- skin
endoflagella rotates causing cell to move in corkscrew fashion- which may allow certain bacteria to move through bodily fluids easily.
Fimbriae can occur at ________ or _____________.
polar ends or all over the surface of the cell
there can be a few or 100s
Fimbriae are for? And are made of?
attachment to surfaces or hosts
What are pili and what is their job?
Are shorter than fimbriae and only number in 1 or 2
They are involved in motility and DNA transfer
Conjugation is when the pili allow the transfer of DNA from one cell to another (sex pili)
The prokaryotic cell wall has:
High concentration of solutes - solute concentration changes between cell walls- subjects the wall to turgor pressure
The main function of the prokaryotic cell wall is to____________?
Prevent bacterial cells from rupturing when the water pressure inside the cell is greater than the outside. Helps maintain the shape of the bacterium and serves as a point of anchorage for the flagella.
Do Mycoplasma and Archaea have cell walls?
Bacterial cell wall is made up of ______________.
peptidoglycan (or murein) = protein and sugar
Archaea is made up of?
pseudopeptidoglycan or pseudomurein
The disaccharide is made up monosaccharides called?
N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)
True or false.90% of cell wall consists of peptidoglycans?
How do antibiotics affect the cell wall?
penicillin interferes with the final linking of the peptidoglycan rows by peptide cross over bridges. As a result the cell wall is greatly weakened and the cell undergoes lysis, destruction caused by the rupture of the plasma membrane and the loss of cytoplasm.
Because of cell lysis with antibiotics you may feel worse before you feel better.
Gram positive cell walls consists of many layers of _________ and gram negative cell walls ________.
peptidoglycan forming a thick, rigid structure
thin layer of peptidoglycan
The cell walls of gram positive cell walls contain teichoic acid which primarily consist of an alcohol and phosphate. The 2 classes of teichoic acid are ________ and _______________.
lipoteichoic acid-which spans the peptidoglycan layer and is linked to the plasma membrane.
wall teichoic acid which is inked to the peptidoglycan layer.
Because of the negative charge from the phosphates the teichoic acids may bind and regulate the movements of the ____________ into and out of the cell.
Cations- positive ions
Gram negative cell walls are only ________% of ________.
10% of peptidoglycan
The cell wall of a gram negative cell is embedded into the_________________.
periplasm a gel like fluid between the outer membrane and the plasma membrane.
The outer membrane of the gram - cell is
lipopolysaccharides, lipoproteins and phospholipids
The gram negative bacterial wall has a lipid A component of the LPS which is _____________.
The lipid A is released when the______________.
bacterial cell dies
Lipid A is associated with the symptoms of infection by gram negative bacteria such as ______,
_________,_________, and ___________________.
dilation of blood vessels
plasma membrane has a lipid bi-layer which consists mainly of ________________.
Phospholipids are _______ or ______________ and have 2 components ____________ or ________________.
saturated or unsaturated
fatty acids- hydrophobic (water fearing)
glycerol- hydrophilic (water loving)
Tails of phospholipids are ______________ the polar heads are ___________________.
Simple diffusion is the movement of molecules or ions from an area of _________ to __________.
high concentration to an area of low concentration
Equilibrium is when______________________.
The ions or molecules are of even distribution.
Water is a ______________?
Moving high to low is going _________________.
with the concentration gradient
Moving low to high is going ___________.
against the concentration gradient- requires a lot of energy
Facilitated diffusion is?
going from higher to lower but needing the help of a protein to get across the membrane the protein is the channel.
Transport is solvent moving such as ______________.
osmosis - more water to dilute the solutes down
Osmosis is the?
The net movement of solvent molecules across a selectively permeable membrane from an area of high concentration of solvent molecules (low concentration of solute molecules) to a low concentration of solvent molecules (high solute concentration).
No net movement =
outside the cell concentration of solutes lower than inside the cell.
What are ribosomes?
They are the site for protein synthesis
What is an inclusion body?
are storage compartments for different substances
internal features of bacteria are:
Nucleoid- contains DNA-mass of genetic material
plasmids- circular double stranded DNA-this is not required for day to day survival and turns on only when needed (e.g. antibiotic resistance)
Endospores- reserve some genetic material-older the growth the more endospores
storage of compounds- polysaccharide granules, lipid inclusions, sulfur granules, carboxysomes, magnetosomes, gas vacuoles- which are photosynthetic and make them float
not usually a storage compartment
contains chains of magnetic particles
function as internal magnets