1. Microbial growth Flashcards
What two ways do eukaryotic cells divide?
mitosis and meiosis
Define mitosis
diploid division of cell creating an exact copy
Define meiosis
Haploid division of cell
What are the two ways prokaryotes divide?
binary fission and budding
Define binary fission
asexual cell division following enlargement of a cell to twice its minimum size
Define budding
unequal asexual division to form daughter cell
What is the only type of asexual reproduction that is unequal?
budding
What environmental factors can affect the cell?
temp
pH
osmotic pressure/moisture
substrate availability
What is a positive change in relation to the environment affecting the cell?
increase in growth
What is a negative change in relation to the environment affecting the cell?
decrease in growth; death
What is stage one of a negative change?
unstable proteins, fluidity of membrane, and stability of nucleic acids
Which stage can’t cells come back from in a negative change?
stage two
What is stage two in relation to a negative change
denatured protein, disrupted membrane, denature nucleic acids
What happens at a microbes minimum optimal temperature?
membrane gelling, and transport processes slow down and growth stops
What happens at a microbes maximum optimal temperature?
protein denaturation and collapse of cytoplasmic membrane
At what temp are bacterial pathogens optimally growing?
37C
How does cold affect micrboes?
doesn’t kill them, but saves them for later
What are acidophiles?
microorganisms that like an acidic environment
What are alkaliphiles?
microorganisms that like a basic environment
What two gases have the most influence on microbial growth?
O2 and Co2
How have cells adapted to live with oxygen?
enzymes to neutralize toxic oxygen species and break them down to nontoxic components
What is an obligate aerobe?
requires gaseous oxygen in its metabolism
What is a facultative organism?
aerobe that doesn’t always need oxygen for its metabolism and can grow without it
What is a microaerophile?
doesn’t grow at normal atmospheric concentrations of oxygen but still needs a small amount of it
How do strict and obligate anaerobes relate to oxygen?
doesn’t use it in it metabolism
How do aerotolerant anaerobes relate to oxygen?
Doesn’t use oxygen in its metabolism
What are osmophiles?
live in habitats with a high solute concentration
What are xerophiles?
live in dry environements
What are halophiles?
live in habitats with high salt concentrations
How are cells able to live in hypertonic environments?
pump solutes into cell
synthesize cytoplasmic solutes
How do bacteria adapt to hypotonic environments?
cell wall protects them form bursting
How do amoeba adapt to hypotonic environments?
water vacuole moves excess water out of the cell
What are the two levels growth happens on?
cells grow in size
number of cells increases
