Lecture 2A Flashcards
are required in large amounts (in culture
media, usually represented in gram-amounts)
Macronutrients
are required in minute amounts (in
culture media, usually represented in milligram-amounts)
Micronutrients
Examples of Macronutrients
O and H, usually from H2O
Other macronutrients needed by cells (but typically in smaller amounts)
Phosphorus
Suflur
Potassium
Magnesium
Calcium and sodium
for nucleic acids and phospholipids; usually incorporated as phosphate
Phosphorus
in the amino acids cysteine and methionine and also in several vitamins,
including thiamine, biotin, and lipoic acid
Sulfur
Sulfur is commonly incorpated as
- Sulfate
- Sulfide
- Organic sulfur compounds
required for the activity of several enzymes
Potassium (K)
stabilizes ribosomes, membranes and nucleic acids and
also required for the activity of many enzymes.
Magnesium (Mg)
are essential nutrients for only a few organisms,
such as the NaCl requirement of most marine microorganisms.
Sodium and Chloride
What does magnesium stabilizes?
- Membrane
- Nucelic acid
- Proteins
is needed in the largest amount (50% of a cell’s dry
weight)
C (Carbon)
are next (combined, 25% of dry weight), and N follows (13%).
O and H
Elements that are essential to microorganisms
- H, C, N, O, P, S, Se
Essential cations/aniones
- Na, Cl, K, Mg, Ca
At least ______ other elements either are required by one or
more microorganisms or, if not required, are still metabolized in some way
50
Carbon source from ____ compounds for most prokaryotes
Organic
the breakdown of polymeric substances
Catabolism
Bulk of nitrogen available in nature is as
- Ammonia
- NH3
- NO3
- N
Metals needed in _____________ amounts
very small
is primary micronutrient because of role in ________________
Fe
Trace metals (metallic) serve as enzyme ____
cofactors
_____ of the cell membrane serves as a challenge for nutrient transport.
Impermeability
GLUT
Glucose-facilitated diffusion transporter
Steps of GLUT-1
- Glucose binds to site
- Transport protein shifts
- Glucose is relased inside, protein returns to original conformation
types of Potassium channels
- Calcium-activated potassium channel
- Inwardly rectifying potassium channel
- Tandem pore domain potassium channel
- Voltage-gated potassium channel
used for signaling pathwat (nerve impulses/AP)
Sodium channel
Toxins that block sodium channel
- TTX (Tetrodotoxin)
- STX (Saxitoxin)
Has on effect on sodium but not on potassium
TTX
produces dinoflagellato (shellfish)
- potent natural toxin
STX
bind to external binding site making it toxic
TTX and STX
first to identfiied aquaporin
Dr. peter agre
a type of protein that helps move water, glycerol, and other small molecules across cell membranes
Aquaglycerolprotein
ion bearer
- usually microbial origin
- transport ion down the chemical gradient
Ionphores
Two basic type of ionphores
Channel formers
Mobile carriers
Representative examples of Ionophores
- valinomycin
- 2,4-dinitrophenol
- 18-crown-6
- nystatin
- 12-unit (dodeca) depsipeptide where amino acid
peptide bonds are alternated with amino alcohol ester bonds
Valinomycin
enantiomers that is composed by valinomycin
D- and L-valine
- channel-forming ionophore that creates a hydrophobic
pore across a membrane - allow for the rapid facilitated diffusion of various ions that depend on the
dimensions of the pore.
Nystatin
Nystatin binds to ____, thus targeting fungi in the presence of animal cells
Ergosterol
Kþ ionophore
Valinomycin
proton ionophore
2,4-dinitrophenol
synthetic crown
ether 18-crown-6
the channel forming
ionophore
nystatin
utilizes energy, often in the form of ATP, to drive solute uptake against its gradient resulting in a net accumulation of the solute
active transport
Basic mechanisms cell membrane transport in prokaryotic cell
Simple transport
Group translocation
ABC transport systems
consist only of one transmembrane transport protein
simple transport
employs a series of proteins in the transport event
group translocation
components of ABC transport systems
- substrate binding proteins
- Transmembrane transporter
- ATP hydrolyzing protein
Transmembrane component of all transport systems is composed of a
__________ that weave back and forth through the membrane to form a channel
Polypeptide containing 12 domains
Transport is linked to a _______________ in this transmembrane protein
conformational change
Drives chemical translocation
PEP
PEP
Phosphoenolpyruvate
Simple active transport reactions (secondary active transport) are driven by the energy inherent in the
Proton motive force (PMF)
electro-chemical difference created by protons
Proton motive force
Different way that group translocation differs from simple transport
- Transported susbtance is chemically modified
- Energy-rich organic compounds
Components of glucose transport system
- Enzyme (Enz) I
- Enzymes IIa
IIb and IIc - HPr
Steps of phosphotranferase system in E. coli
PE-P -> Hpr -> Enzyme II a -> Enzyme II b -> Enzyme II c
Where does phosphate comes from
PE-P activation of glucose
- Transport systems that employ a periplasmic binding protein along with transmembrane and ATP-hydrolyzing components are called
ABC transport systems
Structural feature of proteins that bind ATP
ATP-binding proteins
Other mechanisms of moving solutes in and Out of the cell (in eukaryotes)
Pinocytosos
Phagocytosis
Exocytosis
