chapter 6.2 Flashcards
forms of oxygen that are highly reactive and behave like oxidizing agents, stealing electrons from chemicals
toxic forms of oxygen
when a molecule loses electrons during a chemical reaction
oxidization
when a molecule gains electrons during a chemical reaction
reduction
a molecule that strips electrons from other molecules
oxidizing agent
four toxic forms of oxygen
- singlet oxygen
- superoxide radical
- peroxide anion
- hydroxyl radical
an enzyme that some aerobes have that converts Hydrogen Peroxide into water and oxygen
catalase
hydrogen peroxide naturally converts to what unless there is catalase present
peroxide anions or hyrdroxyl radicals
protect against oxidizing agents from stealing electrons through donating electrons to oxidizing agents which quenches their thirst for electrons
antioxidants
nitrogen is needed to synthesize
proteins and nucleic acids
where is nitrogen found
- amino group of amino acids
- nucleotides that make up DNA/RNA
low levels of lack of nitrogen do what
limit growth of microbe since DNA and proteins are required to grow in size or reproduce through cell division
needed for synthesis of nucleic acids and ATP
phosphorous
energy currency in cells
ATP
phosphate backbone of DNA
nucleic acids
element found in some amino acids
sulfur
sulfur allows for
3D structures and protein folding
elements that are required in very small amounts, but still essential
trace elements
organic chemicals that cannot be synthesized by certain microorganisms that boost growth
growth factors
important physical factor in microbial growth because it affects protein structure and plasma membrane structure
temperature
protein that unfolds and works uncorrectly
denaturing
if the temp is too low the plasma membrane becomes
too rigid/fragile, close together and will shatter
if temp is too high the plasma membrane
becomes too fluid like, moves away from eachother
generally grow best below 15 degrees and are found in cold water ice and snowfields, cannot infect humans
psychrophiles
generally grow best between 20-40 degrees celsius and are found in most environments, pathogenic to humans
mesophiles
this bacteria grows in extreme heat which include boiling water of hot springs
thermophiles/hyperthermophiles
how can thermophiles/hyperthermophiles survive in their envrionment
avoid denaturing and damage as they often have extra hydrogen and covalent bonds that maintain structure
the lowest temp the bacteria will grow at, growth is slow
minimum temp
highest temp the bacteria will grow at, growth is slow
maximum temp
growth of bacteria is the fastest at this temp
optimal temp
what happens to the bacteria cell when it is at a temp higher than its maximum temp
- plasma membrane melts causing vital chemicals to leak out
- proteins denature or unfold, proteins not native in shape will not work
what happens to a bacteria cell when it is at a temp lower than it minimum temp
- plasma membrane becomes rigid and shatters
- metabolism slows down, reproduces slows
microorganisms that grow in a narrow pH range that is close to neutral
neutrophiles
thrive in environments with a pH less than 5
acidophiles
live in alkaline soils and water up to pH 11.5
alkalinophiles
pH below 7
acid
pH above 7
basic
movement of water across a semipermeable from high concentration to low concentration
osmosis
solutions have low solute concentration or high water concentration compared to the inside of the bacteria cell, bacteria will burst
hypotonic
solutions have high solute concentration or low water concentration compared to the inside of a bacteria cell, will shrink
hypertonic
Biofilm functions:
- allow bacteria to adhere to the environment or other bacteria better
- sequesters or takes in additional water and nutrients
- serves as a physical form of protection from other microorganisms or harmful toxins
(make microorganisms more harmful or pathogenic)
how biofilm is produced
- bacteria cells secrete quorum sensing molecules
- quorum sensing molecules detect the presence of other individuals
- quorum sensing molecules then activate genes involved in the production of biofilms
- channels develop in biofilm that allow for the transport of water
