Fundamentals Of Microbiology - Cells, Metabolism, and Growth Flashcards
What characteristics distinguish living organisms?
- Responsiveness
- Growth
- Reproduction
- Metabolism
- Movement
- Excretion
- Cell
What are Prokaryotes?
Bacteria + Archaea
What distinguishes prokaryotes from eukaryotes?
- No nuclear membrane
- No membrane bound organelles
- No cell nucleus
- Ribosomes - protein synthesis, not really an organelle
How small are prokaryotes?
Smaller (0.5 - 5 micrometers)
What distinguishes a eukaryote cell from a prokaryote?
- Nucleolus
- Vesicle
- Endoplasmic reticulum
- Golgi apparatus
- Centrioles
- Algae and plants contain organelles (chloroplasts) for photosynthesis with coloured pigments to trap sunlight energy
What do cells need for growth?
- Energy
- Electrons
- Matter - carbon, substrates, minerals
What is catabolism?
Catabolism = cellular energy production → energy release
- creates simple molecules
What is anabolism?
Anabolism = assimilation, growth, and repair → energy consumption
- new cellular materials are made larger
What allows metabolism to take place?
Metabolism = catabolism + anabolism + enzyme catalysts
What are some characteristics of catabolism?
- Produce simple waste
- Energy temporarily conserved as ATP
What are some characteristics of anabolism?
Anabolism is characterized by energy consumption, the synthesis of complex molecules from simpler ones, and its role in growth and repair of body tissues.
What are autotrophs?
Cells that use inorganic carbon - CO2 - autotrophic
What are chemoautotrophs?
An organism, typically a bacterium, which derives energy from the oxidation of inorganic compounds
What are Photoautotrophs?
Organisms that carry out photosynthesis. Use light as an energy source
What are heterotrophs?
Consume organic matter and break it up
What are chemoheterotrophs?
Microbes that get their energy from organic chemicals and mainly use organic compounds for carbon (fungi+animals)
What are photoheterotrophs?
Group of microorganisms acquires energy from sunlight - purple nonsulfur bacteria
What does ATP stand for?
Adenosine triphosphate
What is the first thing that happens to glucose molecule in catabolism and energy production?
Glycolysis - no oxygen need
What comes after glycolysis?
Pyruvate
What happens in the presence of oxygen in the process of catabolism and energy production?
- Taken into mitochondria
- Where it goes through the Kreb cycle and more ATP created
What creates more ATP?
The electron transport chain
What happens in anaerobic conditions in catabolism and energy production?
Fermentation which causes lactate
What happens in the Kreb cycle?
A series of reactions releasing ATP from citric acid breakdown
What happens in the electron transport chain?
Couples a series of chemical reactions between an electron donor (e.g., NADH) and an electron acceptor (e.g., O2); H+ ions and electrons are used to produce ATP
What must cells do when oxygen absent?
Must use an alternative terminal electron acceptor to complete the catabolic process
How can H+ ions travel from high con to low con?
ATP Synthase
What causes new growth in cells
Substrate and enzyme production
What is the specific growth constant?
mu
When does growth rate decline to zero?
As substrate exhausted
How does cell division happen in prokaryotes?
- Prokaryotes - binary fission → no spindle apparatus for dividing chromosomes
- Divide every 20 - 30 min
- Similar to asexual mitosis
What cell division happens in eukaryotes?
Mitosis and Meiosis
How can pH affect growth?
Effects enzyme activity and protein
structure
What are the different types of organism which can survive different pHs?
Acidophiles, Alkaliphiles, Neutrophiles
What are the different types of organisms which can tolerate different temps?
- Thermophile tolerate highest temperatures (40-80 degrees)
- Mesophile
- Psychrophile
What are facultative anaerobes?
- Do not require free O2 for growth, but grow better in its presence
- Have genes for both respiration + fermentation
What are obligate aerobes?
Can only grow in the presence of O2
What are obligate anaerobes?
- Cannot tolerate the presence of O2 and die when exposed to it
- Only use alternative electron acceptors
How does water affect growth?
- Cells sensitive to changes in osmotic potential
- Cell walls maintain cell integrity
- Salinity or drying prevent microbial growth
What is osmosis?
Water molecules move from region of high kinetic energy to lower kinetic energy, randomly passing through the semi-permeable membrane; solute molecules are too large to pass through the semi permeable membrane
