Bacteria Flashcards
Are Archaea pathogenic
No known pathaogens.
Used to think they were extremfiles, but currently are finding them everywhere. Slow to grow
How are bacteria different from Archaea?
Archaea have distinct in there cellular processes and biochemistry. (Uniques membrane phospholipids)
Compare and contract Prokaryotes and Eukaryotes in terms of the following: DNA, Chromosome(s), organelles (membrane bound), Cell wall, Cell division.
DNA: Pro = No, Eu = Yes
Chromosome(s): Pro = Circular, usually one, Euk = linear, many can be diploid or haploid. In humans have 23 pairs
Plasmids: Pro = often, Euk = rare
Organelles: Pro = No, Euk = yes
Cell wall= Pro = Bacteria = peptidoglycan either Gram (+) or (-). Archaea = yes, Euk = no in animals, yes in plants (Cellulose), Fungi yes (Chitin), Protists (Varies)
Cell division: Pro = binary fission, Euk = mitosis, meiosis
What do prokaryotes lack?
Nucleus and other membrane bound organelles
Where is the DNA found in a Bacteria?
In the nucleotide region.
Typically are circular chromosomes.
What is a plasmid?
Small rings of DNA (found in some strains) that help Bacterium live in unique environments (ie antibiotic resistance)
What does it use to stick to surfaces?
A pious
What is unique about plasmids?
They can be exchanged by bacteria that are not the same species.
Why is it important that prokaryotes have unique ribosomes (smaller/different proteins) than Eukaryotes?
Can design drugs to specially attack the prokaryotic ribosomes.
How to prokaryotes divide?
By binary fission.
The chromosome will duplicate, attach to cell membrane, and the cell will split in half
What is peptidoglycan?
It’s a carbohydrate/peptide molecule used for cell walls in bacteria.
What is an endospore?
A resistant/dormant structure of a prokaryote.
What is a pili/fimbriae?
A proteinceous structure for attchment/sex pilus for conjugation
What is flagella
Protein used for motility/swimming
What is a glychocalyx capsule?
Carbohydrate layers of attachment end evasion of the immune cells
What is a biofilm?
Carbohydrates and glycoproteins secretions that allow microbes to live as a community on. Surface. Very hard to get ride of
How are bacteria classified?
Historically: based off of shape, response to stains (microscope obs), biochemical characterization, more recent using serological (recognize specific antibodies) and compare DNA sequence. (Use the genes to rRNA)
What shape is a coccus?
Circle
What shape is a bacillus?
Rod
What shape is a vibrio?
Banana
What shape is a sprillum?
Spiral
What is a diplo?
A pair of cells.
What does Straphlo mean?
A cluster of cells
What does strepto mean?
A chain of cells
What were prokaryotes initially grouped with due to the presence of a cell wall found outside the membrane?
Plants
What does peptidoglycan broken down into?
Peptide= protein Gly= carbohydrate.
Chemically describe a peptidoglycan
Peptidoglycan is made up of a polysacchride ( carbohydrate = glycan) with a backbone of covalently-bound polypeptides (proteins = peptides)
What stains Gram + and what does it mean?
Crystal violet stains gram positive. It means it has a thick layer of peptidoglycan outside the membrane.
What is an example of gram +
Streptococcus
Staphylococcus
Bacillus
What purpose does peptidoglycan serve?
It forms a strong mesh-like structure that protects the cell from osmotic pressure and provides the cell with shape and support.
How does the drug Penicillin work?
It interferes with peptidoglycan synthesis and weakens it. The cell easily burst due to osmotic pressures.
What do you stain with Safranin red?
Gram -
Why can’t you use Crystal violet to stain gram - bacteria?
Crystal violet doesn’t stick to gram (-) so need to you safranin red to stain. It’s double membrane system keeps Crystal violet out.
Describe a gram (-) wall/membrane.
Has a thin layer of peptidoglycan sandwiched between the cell membrane and a second ‘outer membrane’
Give an example of a gram (-)
Neisseria
Escherichia coli
What is unique about the outermost layer of a gram (-) membrane.
Has LPS (Lipopolysaccharide) and endotoxin (unique to bacteria)
What is the space called where peptidoglycan is on a gram (-)
The periplasm
What is the benefit to Gram (-) bacteria about the periplasm?
The periplasm acts as a storage compartment for things like enzymes that can degrade toxins and antibiotics to help in its survival.
What is LPS and how is it effective in resistance to the immune cell?
Lipopolysccharide is an endotoxin (can cause severe immune rxn). This outter membrane also helps prevent many types of antibiotics from entering the cell.
What is an acid-fast cell wall?
It’s a staining tech. (Fusia colour)for bacteria that contain mycolic acid (a waxy substance) and resists most stains
What are bacteria that have the mycolic acid referred to as?
Mycobacteria
Do Gram (-) or (+) produce endospores?
Gram positive
What is an endospore?
Endospore= bit of cytoplasm + DNA + thick coat of peptidoglycan
What is the purpose of an endospore?
To survival environmental conditons that are not conducive to life. Ie) change pH, starvation.
What are the Benifits of an endospore?
Allows for mass/widespread dispersal & survival in harsh conditions.
How long are endospores good for?
Have successfully grown from Egyptian mummies
Give some examples of endospore forming bacteria
Bacillus anthracis, cereus
Clostridium botulinum, difficile, perfringens, tetani
What allows for attachment?
Fimbriae & Pili
What is a pili made out of and wht is its purpose?
A pili is made out of protein
, its like a sticky finger, helps to stick to tissue (useful for pathogens)
What is the difference between a Fimbriae and a Flagella?
Fimbriae is like a a sticky finger used for attachment. Where as a Flagella is used for motility.
Give an example of somthing that uses a fimbriae/pili
Some strains of E.coli have this pili and can stick to your bladder.
What is bacterial conjugation?
Bacterial sex
Do bacteria have to conjugate with the same species?
NO-> only exchange of DNA no reproduction involved
Walk through the steps of Bacterial conjugation.
1) Donor cell attaches to the recipient cell with pilus
2) the cells contact
3) 1 strand of plasmid DNA is transferred to the recipient cell
4) recipient cell makes complimentary strand of DNA
What is the beneficent to the bacteria about conjugation?
Allows unlike species to transfer genetic traits such as antibiotic resistance
What is an endoflagella?
It’s a Flagella built into cell wall so the whole cell moves
What movement does a flagella have?
Corkscrew movement
What is flagella made out of ? What does it attach to?
It is made out of Flagellin protein. And attached to a protein hook
What is a Flagella anchored to?
To the wall and membrane by the basal body
What type of bacteria have endoflagella?
Spiral shaped
What does glycocalyx break down into?
Glyc= carboohydrate (sugar) Calyx = coat
What is the difference between a capsule and a slime layer?
Capsules are smaller, tighter, organized
Slime layers are loose. The carbohydrates absorb a lot of water, coat looks slimy.
Where is the glycocalyx found?
Outside the cell wall
How do you stain a bacteria that has a glycocalyx (capsule or slime layer)
They don’t stain well, so you stain the background and create. Ghost image as everything will be dark and they won’t stain
What is the purpose of glycocalyx (capsule/slime layer)
Gives additional protection
Helps attachment to other cells, evasion of host (slippery)
Give an example of a bacteria that has a capsule
Streptococcus pneumoniae
Give an example of a bacteria tht has a slime layer
Pseudomonas aeruginosa
What is a biofilm?
A community of organism
What % of infections are associated with the production of biofilm in the body.
75%
Give two examples of biofilm
Slim on rocks in rivers,
Diabetic ulcer-> chronic wounds-> leads to necrotic tissue
Name the different things that antibiotics can target
Plasma membrane: PL and protein
DNA (chromosomes & plasmid)
Ribosomes: RNA & protein
Cell wall: peptidoglycan
Where are ribosomes in the bacterial cell?
Free floating in the cytoplasm
Where is the DNA in a bacteria?
In the nucleoid region
What is a lysozyme? And where can it be found?
It’s an enzyme that degrades peptidoglycan. It can be found in tears (helps keep the eyes sterile)
What are enzymes?
Lg molecules (proteins) that catalyze metabolic rxn
What suffix do enzymes usually have?
-are
List what the following enzymes do?
Protease, DNA polymerase, Collagenase, Reverse Transcriptase
Protease: digest protein
DNA polymerase: makes the new daughter strand of DNA in DNA replication
Collagenase: used by some pathogenic bacteria to break peptide bonds in collagen (connective tissue)
Reverse Transcriptase: used by HIV to transcribe its RNA genome to a DNA
What affects enzymes?
Temp, pH and inhibitors
What are inhibitors?
chemicals that prevent enzymes from functioning
Give examples of inhibitors
Sarin= nerve G4S->binds to neurotransmitter, paralysis ASA= reversibility binds to pain receptors
What is metabolism?
Chemical rxn within an organism that allows it grow, reproduce and maintain structures and respond to its envrionment
What is an anabolic rxn?
Builds up more complex molecules with the help of ATP
What is a catabolic rxn?
Breaks down molecules and releases energy (ATP) and small molecules.
What is aerobic cellular respiration?
Uses O2, produces lg amounts of ATP: uses pathways of glycolysis, Citric acid cycle (Kreb’s) and electron transport chain.. releases CO2 and produces ATP
What is anaerobic cellular respiration?
Respiration without O2, produces less ATP, may uses things like S, NO3, Fe instead
What does fermintation do?
Uses glycolysis and partially breaks down glucose to produce small amounts of ATP. Produces the least amout of ATP and ethanol, CO2 are byproducts
What is an obligate aerobe?
Requires 02 for respiration/terminal elector acceptor
What is a facultative aerobe?
Can use O2 if present but can use alternative electron acceptors
What is an anaerobic respiration?
Can only use alternate to 02 as terminal electron acceptor
What is an obligate anaerobes?
Poisoned by O2
What is unique about Phylum Proteobacteri?
Gram (-)
Lg diverse group with wide range of nutritional requirements.
Divided into 5 classes based on rRNA sequences: Alpha, beta, gamma, delta, epsilon
Give an example of a bacteria that belongs to phylum Proteobacteria
Escherichia coli: gram (-)
Facultative aerobe
What is unique about phylum Firmicutes?
Gram (+)->thick peptidoglycan
Cocci & rods
May be endospores former
What is an example of a bacteria that belongs to phylum Firmicutes?
Clostridium, Bacillus, Staphylococcus, Streptococcus
What is another subdivison of Phylum Firmicutes
Mycoplasma
No cell wall & appear gram (-)
Ie)Mycoplasma pneumonia
What is unique about phylum Actinobacteria?
Phylum Actinobacteria appears Gram (-), but the cell wall is more gram (+) like.
In this phylum is mycobacterium
Give some examples of Bacteria that belong in phylum Actinobacteria
Mycobacterium tuberculosis
Mycobacterium leprae
What is unique about phylum Spriochetes?
Gram (-), helical shaped, large, flexible, axial filaments (endoflagella),
Give an example of an a bacteria that is part of the Phylum Spriochetes
Eg) Treponema pallidum, Borrelia bergdorgeri.(Lyme disease->ticks are vectors from deer->bull’s eye rash)
What is unique about phylum Chlamydiae?
Small & irregularly shaped
Obligatory intracelluar parasites (they lack the ability to make their own ATP). Closed to related to spirochaetes
What type of drugs are used to treat bacterial infections?
Penicillin, amoxicillin, erythromycin, tetracycline
How do Bacteria differ from eurkaryotes cells?
Their DNA typically is circular, found in the nuceliod region. The ribosomes are free floating in the cytoplasm, they may have things such as pili for attachment and conjugation. May have a separate circular DNA called plasmids. Also have a cell wall usually made out of peptidoglycan
How are bacteria classified?
By shape, structure, biochemistry, metabolism and rRNA sequences
Name the adaptations and cellar features that make aid in pathogens and make difficult to kill.
Gram (-) outer membrane is an exotoxins (LPS). It also have a periplasm that can store additional enzymes that can aid in pathogenicity.
Gram(+) can create endospore so that they can survive harsh conditions.
Bacteria can also have pili that allow them to exchange plasmids to completely unrelated species. Some can even have glycocalyx layers either a capsule (can prevent phagocytosis) or. Slime layer. They can also live in a biofilm Nd stick to each other
What is the difference between catabolism and anabolism?
Catabolism takes a big molecule and breaks it down to produce ATP where as anabolism consumes ATP to make a small molecule bigger
What is the difference between inhibited competitively or non-competitively?
Competitively binds with an enzyme on the spot where it would normally with either a substrate or receptors. Effectively reducing the number of enzyme around. Where as a non-competitive inhibitor will bind with an enzyme at a different location
