Bacterial Adaptation & Metabolism

Question 1

What does bacterial metabolism refer to?

Answer 1

• all biochemical reaction occurring in organisms
• diversity in both substrate and mechanism
• fundamental feature is hydrogen transfer
• use the high energy phosphate bond (ATP) as primary energy source

Question 2

Microbial nutrient uptake by passive diffusion, facilitated diffusion, active transport and group translocation. Explain each one.

Answer 2

1) Passive diffusion
- high conc to low conc. only small molecules such as H2O and CO2 (non polar) can movie across by passive diffusion. does not involve carrier proteins, along the concentration gradient, no metabolic energy is required, if conc gradient disappears then net inward movement ceases, reversible movement, no specificity since there’s no carrier proteins, slow, shows saturation.
2) Facilitated diffusion

• carrier proteins
• rate of diffusion increases with conc gradient
• intrinsic proteins
• small polar molecules
• glycerol is transported by f. diffusion in bacteria
• involves use of permeases

3) active transport

• transport of solute molecules to higher conc with the input of metabolic energy
• permeases used
• against conc grad
• shows saturation
• irreversible

4) group translocation
- process in which a molecule is chemically modified as it is brought into the cell. it is a type of active transport since it utilises metabolic energy during the uptake of the molecule.

Question 3

Bacterial Adaptations to Temperature.

Answer 3

Hot

• chemotrophic - inorganic energy source
• autotrophic - CO2 is carbon source
• changes in membrane hydrocarbon composition - maintains membrane fluidity
• membrane lipids with minimal permeability
• increase in GC base pair content

Cold

• changes in membrane hydrocarbon composition - membrane fluidity maintained
• increased large lipid groups
• anti-freeze proteins bind to ice crystals
• enzymes show a reduction in ion pairs, hydrogen bonding and hydrophobic interactions