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How are Amino Acids linked and what do they form?
Linked by peptide bonds and form polypeptides (PROs)
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Describe Nucleotide Structure.
- Nitrogenous Base ( A, C, G, T, U)
- Ribose
- Phosphates
- Linked by phosphodiester bonds
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Which nitrogenous bases are purines and which are pyrimidines?
- Purines: Adenine and Guanine
- Pyrimidines: Thymine, Cytosine, and Uracil
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What is the structure of DNA?
- Usually double stranded
- Strong Covalent Bonds
- Base Pairing
- H-bonds between bases form helixs
- Phosphodiester bonds
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What are the functions of Nucleic Acids?
- Passes parent to offspring as genetic info
- Information for protein synthesis (DNA - long term storage info, RNA - ss info storage during protein synthesis)
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All cells contain both DNA and RNA. ___________ contain ________ DNA or RNA. ATP energy currency.
Viruses, either
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ATP has a _______ structure.
Nucleotide
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What is anabolism?
Synthesis, bond formation, requires energy
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What is catabolism?
Bonds broken, energy released
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What are reduced molecules?
Contain electrons and potential energy (e.g. CHO, lipids)
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What are oxidized molecules?
Contain fewer electrons and less energy
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What are prokaryotic cells?
- Cell wall
- Bacteria (no small organelles)
- High Surface area : volume ratio, allows for survival without specialized organelles
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What is Eukaryotic cells?
- Animals, plants, fungi, and protozoa
- Large nucleus, other organelles
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What are the typical prokaryotic morphologies?
- Coccus - Sphere
- Coccobacillus - elongated sphere
- Vibrio - banana
- Bacillus - Rod
- Spirillum - wave
- Spirochete (corkscrew, almost always motile)
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Describe bacterial arrangements.
- Single-celled arrangement very common
- Diplo: Two joined
- Strepto: Chains
- Staphylo: Clusters
- Tetrads: Four Cells
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Describe the cell membrane of a prokaryotic cell.
- Exterior to cell membrane, complex, semi-rigid
- Borders cytoplasm
- Composed of phospholipid bilayer + proteins(act as bilayer in and out)
- No sterols (e.g. cholesterol)
- Barrier
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What are the functions of the cell wall?
- Determines shape
- Protects cell membrane from osmotic pressure changes
- Composed of peptidoglycan lattic
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What is the structure of peptidoglycan lattice?
- Carbohydrate, backbone of NAG-NAM disaccharide repeats
- Peptide chains + cross-bridges (4 AA)- cross-link and strengthen CHO backbone
- CHO backbones can be 30-40 thick
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Describe the peptidoglycam in gram positive and in gram negative.
- Gm (+): Thick layer of peptidoglycam, Teichioic acids , no outer membrane
- Gram (-): Thin peptidoglycam, Outer membrane contains LPS or endotoxin(which stimulate immune response), periplasmic space - between cell membrane and cell wall, metabolically active, hydrolysis of organic nutrients
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How are AA linked in peptidoglycan lattice?
AA linked together by stable peptide bonds
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What can inhibit cross-link formation?
Cell wall synthesis inhibitors (e.g. penicillin)
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What is gram stain procedure?
Based on cell wall differences, is critical to bacterial identification
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What is the importance of the nuclear region of the cell?
- Contain a singular chromosome
- Other nucleic acid: Plasmids
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What are plasmids?
- Small circular extrachromosomal DNA molecules
- Common location of antibiotic resistance genes
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What are ribosomes?
- Structurally distinct from eukaryotic
- Antibiotic target
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What are endospores?
- Resistant structures produced by some (not all) bacteria
- Can survive in extreme conditions
- Dehydrated, metabolically inert, comped of core, cortex, spore coat layers
- Not for reproduction (1 per bacteria)
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How are endospores produced?
Vegetative (active) cell produced endospore under stress
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How is an endospore activated?
Germination: Endospore activates, enters vegetative cycle
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What are the layers of an endospore?
- Endospore
- Spore Coat
- Cortex
- Core
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During endospore formation, what occurs during "good times" and what occurs during "bad times" or stress?
- Vegitative cycle: Good times
- Sporulation: Bad times
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What are the external structures located outside of the cell?
- Flagella: Motility
- Basal Body: Anchors flagella to plasma membrane/cell wall
- Taxis: Response to stimuli
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What are the different kinds of taxis>
- Chemo: Attracted to or away from a chemical
- Phototaxis: Maintain themselves in the upper layer of the water / ability to move towards a light source
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What is Pili? What are the two types?
- Pili: Attachment, not motility
- Attachment pili: Allow attachment to surfaces (key virulence factor for some pathogens)
- Conjugation pili (sex pili): Allow transfer of DNA (conjugation), Usually a plasmid from one cell to the next
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What is the Glycocalyx?
- Enternal to cell wall
- Usually composed of polysaccharides, provides 'slippery' outer layer
- Prevents desiccation, acts as virulence factor by protecting cell from phagocytosis, can also aid in attachment
- Not thick
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