Microbial Nutrients and Nutrient Uptake Flashcards
(23 cards)
What is metabolism?
Metabolism is the set of life-sustaining chemical reactions in organisms.
What seven elements are essential for all microbes?
The seven essential elements for all microbes are C, H, O, N, P, S, and K.
Which four elements combine for over 95% of a cell’s dry weight?
C, H, O, and N combine for over 95% of a cell’s dry weight.
What are the two basic sources of C used by microbes?
The two basic sources of C used by microbes are organic compounds and carbon dioxide.
What are the three basic sources of N used by microbes?
The three basic sources of N used by microbes are ammonia, nitrate, and organic nitrogen.
Microbes require P, S, K, and Mg for what purposes?
Microbes require P for nucleic acids, S for amino acids, K for enzyme function, and Mg for stabilizing structures.
Why is Fe the most important microbial micronutrient?
Fe is crucial for many enzymatic processes and electron transport.
What are growth factors? Recall several examples.
Growth factors are organic compounds required for growth. Examples include vitamins, amino acids, and purines.
Most vitamins are used for what purpose?
Most vitamins are used as coenzymes in metabolic reactions.
What is active transport?
Active transport is the movement of molecules across a membrane against their concentration gradient, requiring energy.
What three basic mechanisms of active transport are found in prokaryotic cells?
The three mechanisms are simple transport, group transport, and ABC transport.
What proteins or components are used in each mechanism of active transport?
Simple transport uses transport proteins, group transport uses phosphotransferase systems, and ABC transport uses ATP-binding cassette proteins.
What is the basic structure of the transmembrane component of most transport mechanisms?
The basic structure is typically a protein that spans the membrane.
What energy source powers simple transport?
Simple transport is powered by the proton motive force.
What energy source powers group transport?
Group transport is powered by the phosphorylation of substrates.
What energy source powers ABC transport?
ABC transport is powered by ATP hydrolysis.
What is the difference between symport and antiport reactions?
Symport reactions transport two substances in the same direction, while antiport reactions transport them in opposite directions.
How does the lac permease work?
Lac permease is a symporter that transports lactose into the cell along with protons.
How does group transport differ from simple transport?
Group transport modifies the substrate during transport, while simple transport does not.
How does the phosphotransferase system work?
The phosphotransferase system transfers a phosphate group from PEP to the substrate during transport.
How do ABC transport systems work?
ABC transport systems use ATP to transport substrates across the membrane.
What is a characteristic property of periplasmic binding proteins?
Periplasmic binding proteins have high affinity for their substrates, which aids in transport efficiency.
How are the ABC transport systems of gram-positive bacteria different from those of gram-negative bacteria?
Gram-positive bacteria have a simpler ABC transport system that lacks an outer membrane.
