Unit 3 Zoom & Lab Q Flashcards
Why do organisms need carbon?
For macromolecules
Why do organisms need hydrogen?
water, energy, macromolecules
Why do organisms need oxygen?
water, macromolecules
Why do organisms need nitrogen?
nucleic acid, proteins, NADH
Why do organisms need phosphorus?
ATP, nucleic acids, lipids
Why do organisms need sulfur?
proteins, cofactors
Why do organisms need calcium?
signal transduction, transport
Why do organisms need iron?
cofactors, DNA synthesis
Why do organisms need magnesium?
cofactors, energy, ion regulation
A microbe grows on the surface of skin and breaks down organic molecules in sebum (oily substance from glands in skin), using only fermentation (not aerobic respiration). What growth/nutrition terms describe this microbe?
- Halophile: salt-loving (skin)
- Chemoorganoheterotroph: Chemotroph: energy: chemical (organic or inorganic), Organotroph: electrons; organic, Heterotroph: carbon; organic
- Aerotolerant: can survive in the presence of oxygen but does not use it for metabolism.
- Mesophile; thrives in body/room temp
Can you think of some reasons why the number of cells doesn’t increase immediately? (microbial growth curve)
Cells are adapting to the new environment.
Enzymes and proteins needed for growth are being made.
Cells might repair any damage from past conditions.
Nutrients are being absorbed by the cells.
After this, they start growing rapidly in the log phase.
Is it possible that cell division is occurring during the lag phase?
No, cell division typically does not occur during the lag phase;
In this phase, cells are focusing on adapting to the new environment, synthesizing necessary enzymes and proteins, and preparing for growth
What sorts of things that might cause a broth culture to move from the log phase into the stationary phase?
Nutrients run out.
Toxic waste builds up.
Oxygen gets used up (for aerobic bacteria).
Too many cells competing for space and resources.
pH changes make the environment less favorable.
Stationary phase: cells stop growing, and number of new cells = number of dying cells.
What type of O2 requirements have the enzyme Catalase?
Obligate aerobe (21%)
Facultative anaerobe (0-21%)
some microaerophiles (2-10%)
What type of O2 requirements have the enzyme Superoxide dismutase (SOD)?
Obligate aerobe (21%)
Facultative anaerobe (0-21%)
Microaerophiles (2-10%)
some Aerotolerant (0%)
What type of O2 requirements have the enzyme peroxidase?
Aerotolerant (0%)
some Obligate aerobe (21%)
What type of O2 requirements perform fermentation?
Facultative anaerobe (0-21%)
Aerotolerant (0%)
Obligate anaerobe (0%)
What type of O2 requirements perform aerobic respiration?
Facultative anaerobe (0-21%)
Obligate aerobe (21%)
Microaerophiles (2-10%)
What type of O2 requirements perform anaerobic respiration?
Facultative anaerobe (0-21%)
Obligate anaerobe (0%)
Step 1 of biofilm development:
Free-swimming microbes are vulnerable to environmental stresses
Step 2 of biofilm development:
Some microbes land on a surface, such as a tooth, and attach
Step 3 of biofilm development:
The cells begin producing an extracellular matrix and secrete quorum-sensing molecules
Step 4 of biofilm development:
Quorum sensing triggers cell to change their biochemistry and shape
Step 5 of biofilm development:
New cells arrive, possible including new species, and water channels form in the biofilm