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40 Cards in this Set
- Front
- Back
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Anton von Leeuwenhoek
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Father of microbiology
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Louis Pasteur
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Germ theory of disease
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Robert Koch
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Growing and staining bacteria
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List the size of microbes from smallest to largest
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Viruses --> Bacteria --> Protozoa --> Fungi --> Multicellular
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Eukaryotes - Characteristics
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True nucleus with chromosomes and Nuclear membrane surrounding it
Diploid genome Different organelles (mitochondria, lysosomes, rough or smooth ER, golgi, ribosomes) Absent cell wall (or composed of chitin) Both sexual and asexual reproduction Respiration via mitochondria |
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Prokaryotes - Characteristics
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Complex Cell wall w/ peptidoglycan
Haploid or Single stranded, Super coiled, circular chromosome DNA is 1000 times the length of the cell No nuclear membrane surrounding "nucleus" called nucleoid Contains plasmids Contains ribosomes Many have extra appendages like flagellum or pili Cytoplasmic membrane does not contain sterols Asexual reproduction Respiration via cytoplasmic membrane |
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Nucleoid
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Bacterial nucleus but does not contain nuclear membrane
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Plasmid
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Extrachromosomal DNA
Haploid (single stranded), circular, coiled DNA Holds certain genes that are beneficial to the life of the bacteria but the bacteria do not need them to survive |
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Pilus
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Type of appendage found on some Prokaryotes
Used for adhesion to other cells and tissues |
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Flagellum
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Type of appendage found on some Prokaryotes
Used for motility |
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Cell Envelope of bacteria
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Contains the cell membrane and cell wall of bacteria
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Types of bacteria are based on what?
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Cell wall composition
2 types Gram+ Gram- |
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Which bacteria have unusual cell walls?
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Mycobacterium tuberculosis
& Mycoplasma sp 1. contains waxes and fatty acids called mycolic acid |
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Mycolic acid
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Waves and fatty acids found in the cell wall of only Mycobacterium tubercolosis making it unique.
2. Has no cell wall |
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Which bacterium has no cell wall?
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Mycoplasma sp
Uses sterols in the cellular membrane to help stabilize the cell and fortify the membrane |
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Cell membrane
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Phospholipid bilayer
Function: Acts like a barrier / Gatekeeper Generation of energy through oxidative phosphorylation in bacteria Synthesis of cell wall components Synthesis of phospholipids in the membrane Permease activity Active transport of molecules Breakdown of large food molecules Segregation of daughter chromosomes |
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What is the largest molecular weight of molecules that can pass through the cell membrane?
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1000 Daltons MW
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Where does oxidative phosphorylation occur in bacteria?
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In the cell membrane because there are no mitochondria
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What is the protein phospholipid composition of bacterial cell membrane
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75% protein and 25% phospholipid
(50-50 in eukaryotic cells) |
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Mesosomes
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Invagination of cell membrane
Increases surface area |
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Septum
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Invagination of the cell wall and cell membrane
Formed at the site of cell division |
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Bactoprenol
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AKA lipid carrier/ undecaprenol
55-carbon lipid found in the cell membrane of bacterial cell Aid in the synthesis of the cell wall by transporting cell wall components from inside the cell to the peptidoglycan cell wall structure outside |
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Function of cell wall
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Protects cell from bursting due to rigid structural components
Provides shape to bacterial cell Protects bacterium from chemicals |
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Peptidoglycan
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Major component of the cell wall of bacteria
A meshwork is made around the cell with Monomer units made up with peptide and glycan portions |
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Peptide portion of Peptidoglycan
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Composed of
D-alanine, D-glutamic acid, DAP/lysine, L-alanine |
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What are the novel amino acids that can be found in peptidoglycan?
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D-alanine
DAP (diaminopimelic acid) |
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D-alanine
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Novel amino acid found only in the peptidoglycan cell wall of bacteria
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Diaminopimelic acid
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AKA DAP
Novel amino acid found only in the peptidoglycan cell wall of bacteria Similar in structure to lysine but contains an extra carboxyl group |
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Glycan portion of peptidoglycan
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Composed of 2 amino sugars called
N-acetyl glucosamine (Glutamic acid) N-acetyl muramic acid |
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What are the novel amino sugars that can be found in peptidoglycan?
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N-acetyl muramic acid
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N-acetyl muramic acid
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Novel amino sugar found only in the peptidoglycan cell wall of bacteria
Similar in structure to N-acetyl glutamic acid but has lactic acid attached in addition |
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What makes up the backbone of the peptidoglycan?
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Two amino sugars
N-acetyl glutamic acid N-acetyl muramic acid |
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What type of linkage is between the 2 amino sugars in the peptidoglycan?
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Beta-1,4 linkage
Glycosidic link |
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What is the order of amino acids on the tetrapeptide?
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1. L-alanine
2. D-isoglutamamide / glutamic acid 3. L-lysine or DAP 4. D-alanine |
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What is the bond that links up different strands of peptidoglycan?
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Peptide bond between 3.DAP of one strand and 4.D-alanine of another strand
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What effect does Penicillin have on bacteria?
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Prevents cross-bridging
It inhibits transpeptidation, when the peptide bond is formed between different amino acids on different peptidoglycan strands It causes the cell to burst because the cell wall is no longer stopping growth and preventing lysing |
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Peptidoglycan of Staph aureus
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Peptidoglycan contains an extra 5 glycine residues called penta-glycine bridge to which the D-alanine from other strands attach to
Therefore the order of amino acids are 1. L-alanine 2. Glutamic acid 3. Lysine or DAP -> +5-glycine --> attachment to other strand here 4. D-alanine |
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Penta-glycine bridge
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In the peptidoglycan of Staph aureus bacteria
An extra 5 residues added on to the tetrapeptide to the Lysine at the 3 position |
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Transpeptidation
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Step that connects the amino acids from different peptidoglycan strands together
Inhibited by penicillin |
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Lysozyme
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Attacks the glycosidic bond between the two amino sugars making up the backbone of peptidoglycan in bacterial cell walls
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