Exam 2 (7-9) Flashcards
What bond forms between molecules of water in a beaker of water?
Hydrogen bonds
What is the building block of polymers?
Monomers
What is the site on an enzyme where enzymes bind?
Active site
What is the purpose of fermentation?
Regenerate NAD+
What is metabolism?
All the reactions in a cell/organism
What is a pthway that breaks down glucose to make pyruvate in certain microbes?
Entner-Doudoroff (ED) pathway
When does substrate level phosphorylation occur?
Glycolysis, Kreb’s cycle
What is the definition of chemiosmosis?
Movement of hydorgen ions through ATP synthase
Does anaerobic respiration involve the reduction of an organic final electron receptor?
No (it’s for aerobic)
What are the 4 categories of microbes based on temperature?
- Psychrophile (-10 to 20) - fridge is 4
- Mesophile (20 to 45) - internal body is 37
- Thermophile (40 to 70)
- Hyperthermophile (65 to 110)
What are the ways pH and temperature affect metabolic functions and how might it be overcome? (4)
PROTEIN ACTIVITY (Temp/pH) - denaturation
* Alter protein structure (thermophiles: increase secondary bonds for rididity; psychorophiles: use hydrophobic residues to exclude water and avoid freezing)
MEMBRANE (Temp) - fluidity/rigidity
* Alter phospholipid structure (psychrohpiles: use unsaturated lipids; thermophiles: use saturated lipids)
NUCLEIC ACID ACTIVITY (Temp/pH) - DNA denaturation
* Increase GC content
ETC PRODUCTION (pH) - H+ gradient
* Active transport (proton pumps) and use different ions (Na+)
Optimal pH ranges of organisms (3)
- Acidophile: low pH
- Neutrophile: around pH 7
- Alkaliphile: high pH
What are the 5 categories of microbes based on O2 requirements?
- Obligate aerobe: requires O2
- Microaerophile: requires low O2
- Facultative anaerobe: doesn’t need O2, but grows better
- Aerotolerant anerobe: tolerates O2
- Obligant anaerobe: killed in O2
What are the enzymes a microbe can use to detoxify oxygen and the chemical reactions involved? (3)
- Catalase: H2O2=H2O+O2
- Peroxidase: H2O2+H=H2O
- Superoxide dismutase: O2+H=H2O+O2
What are the different types of of media used to grow microbes? (4)
- Chemically defined: exact composition is known
- Complex: exact composition is unknown
- Selective: encourage some, supress others
- Differential: distinguishes different colonies
What are the 4 phases of microbial growth?
- Lag: preparation
- Log: exponential growth
- Stationary: plateau, running out of space/nutrients
- Death: exponential decrease
What is a biofilm?
- Clusters of microbes attached to surface and encased on matrix
- Provides protection, keeps cells together, and has division of labor
- Wound, teeth, rocks, etc
What is quorum sensing?
- Mechanism where microbes coordinate gene expression based on cell density
- Signaling peptides/hormones (more signal = more population)
Oxygen is a strong […] agent
Oxidizing (steals electrons) – can be very damaging
What are the different bonds? (5)
- Covalent: 2 or more atoms share electrons
- Polar covalent: unequal sharing
- Nonpolar: equal sharing
- Hydrogen: very weak bonds between polar molecules (e.g. H2O, DNA base pairing)
- Ionic: between ions of opposite charge (cations/ions)
Condensation vs hydrolysis
- Condensation makes bonds and has H2O in the end products (synthesis/anabolism)
- Hyrolysis uses water to break bonds (decomposition/catabolism)
Acid vs bases
- Acids release H+ ions (lower pH)
- Basics release OH- ions (higher pH - basic)
What are the 4 levels of protein structure?
- Primary: AA squence, peptide bonds
- Secondary: bending/coiling, H bonds
- Tertiary: 3D shape, R group interactions
- Quaternary: 2+ polypeptides, subunit attraction
Redox, oxidation & reduction
- Oxidation: loss of electrons
- Reduction: gain of electrons
- Redox: pairing of oxidation + reduction (moving of e- and protons at same time, carried by H)
What are the 3 mechanisms of how ATP can be generated?
- Substrate level phosphorylation: glycolysis, Krebs
- Oxidatative of phosphorylation: ETC
- Photophosphorylation: photosynthesis
Enzyme sites and inhibitors (5)
- Active site: where substrate binds
- Allosteric site: site other than active site that regulates activity
- Competitive inhibtor: binds to active site (blocks acitivity)
- Noncompletitve inhibtor: binds to allosteric site inducing shape change
- Feedback inhibtor: enzyme end product ends on 1st enzyme and shuts down pathway (slows down production for homeostasis)
Apoenzyme, cofactor, and holoenzyme
- Apoenzyme: protein portion of enzyme that is inactive
- Cofactor: nonprotein components needed for activity
- Holoenzyme: apoenzyme + cofactor (active)
Where is prokaryotic respiration?
Cytoplasm, cell membrane
Steps to respiration
- Glycolysis (energy investment, payoff)
- Intermediate Pathway (convert pyruvate to acetyl coA)
- Krebs Cycle (ADP>ATP, NADH+FADH2)
- ETC (H+ gradient, ATP synthase, ATP, final acceptor is O2)
Alternatives to glycolysis
PPP: used when cells need to make nucleic acids alongside glycolysis
ED: replaces glycolysis, not in eukaryotes (G-)
