Chapter 6 notes


Organisms that utilize an inorganic source of carbon (that is, carbon dioxide) as their sole source of carbon. Autotrophs make organic compounds from CO2 and does not need to get carbon from organic compounds in other organism


Catabolize reduced organic molecules (such as proteins, carbohydrates, amino acids, and fatty acids) they acquire from other organism

Organisms can be catagorized according to whether they use chemicals or light as their energy source for such cellular processes as

anabolism, intracellular transport, and motility


Organisms that acquire energy from redox reactions involving inorganic and organic chemicals which are anerobic aerobic respiration or fermentation.


are organism that use light as their energy source

Organisms can be catagorized into 4 four basic groups based on their carbon and energy sources.

1.Photoautotrophs - energy source light, Carbon source CO2
2. Chemoautoptrophs - energy source Chemical compounds, Carbon source CO@
3. Photoheterotrophs - energy source light, Carbon source organic compounds
4. Chemoheterotrophs - energy source chemical

Hydrogen importance

All organisms cells require electrons or hydrogen atoms for redox reductions. Hydrogen is the most common chemical element in cells. Metabolism is never interupted by a lack of Hydrogens, they are that common.

Obligate aerobes

prokaryotes that need oxygen to live, Must have O2 for cellular respiration, in contrast oxygen is a deadly poison for anaerobes.

electron acceptor

A chemical entity that accepts electrons transferred to it from another compound

four toxic forms of oxygen

1. Singlet oxygen 1O2
2. Superoxide radical O2-
3. Peroxide anion O2 2-
4 Hydroxyl radical OH

Singlet oxygen

a molecular oxygen with electons, is a normal molecular oxygen that has been boosted into a higher-energy state and is extremely reactive
certain human white blood cells use it to oxidize pathogens.

Superoxide radical

formed during an incomplete reduction of O2 during electron transport in aerobes and during metabolism by anaerobes in the presence of oxygen. Superoxide radicals are so toxic and reactive that aerobic organisms must produce superoxide dismutase to detoxi

Anaerobes die from oxygen why?

They are unable to produce superoxide dismutase. so superoxide radicals are formed which kills them.

Peroxide anion

toxic; microbes have developed enzymes to neutralize it- catalase converts it into oxygen and water; when added to colony of bacteria cells producing catalase, oxygen bubbles are released; peroxidase also breaks down but does not produce oxygen


enzyme found in most plant and animal cells that functions as an oxidative catalyst

Anaerobes lack?

catalase or have only very small amounts, so they can be harmed by the toxic action of hydrogen peroxide.

Hydroxyl radicals

are the most reactive of the four toxic forms of oxygen, but because hydrogen peroxide does not accumulate in aeorbic cells (due to peroxidase and catalase hydroxyl radicals are virtually eliminated in aerobic cells.

facultative anaerobes

An organism that makes ATP by aerobic respiration if oxygen is present but that switches to fermentation under anaerobic conditions. ex Escherichia coli

Aerotolerant anaerobes

do not use Aerobic Metabolism, but do have some enzymes that detoxify oxygen's poisonous forms, so can grow in its presence

What growth medium is used to identify the oxygen requirements of organisms

Liquid thioglycollate growth medium


microbes by this name are aerobic but can only grow in places where the oxygen content is lower than in pure air due to their own production of toxins when exposed to atmospheric air.

nitrogen fixation

The assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that can be directly used by plants.

trace elements

basic chemical substance needed in small amounts; many are important parts of enzymes

growth factors

organic chemicals that cannot be synthesized by certain organisms (Vitamins, Essential Amino Acids, Purines, Pyrimidines, Cholesterol, NADH, and Heme)


plays an important role in microbila life through its effects on the three deminsional configurations of biological molecules.

Lowest / highest temp a microb can conduct metabolism is called

minimum / maximum growth temp...optimum growth temp - is the temp the microb metabolises the best.

The 4 catagories microbs can be put in due to temp

phychrophiles, -10 to 20 degrees celcius
Mesophiles 10 to 40 degrees celcius
thermophiles 40 to 80 degrees celcius
hyperthophiles 70 to 100 degrees celcius

Explain how extremes in temperature, pH and osmotic and hydrostatic pressure limit microbial growth

Temperature- p170
Osmotic Pressure-pg172-173
Hydrostatic Pressure-pg173
All organisms have a range of temp, pH and osmotic/hydrostatic pressure that they prefer and can tolerate.
Temperature- Effects the three-dimensional configurations of bi

Describe how quorum sensing can lead to formation of a biofilm

p 172
Biofilms are examples of complex relationships among numerous microorganisms, often different species, attached to a surface (ie. plaque on teeth). In Quorum Sensing microorganisms respond to the density of other microorganisms nearby. Cells secrete

Describe methods for collecting clinical specimens

p 175- table 6.2
Skin, Accessible Membranes (eyes, ears, vagina, throat, mouth, nose, open wounds, etc.) -Sterile swab on surface.
Blood- needle aspiration from vein. Anti-coagulants are in specimen tube.
Cerebrospinal fluid- Needle aspiration from subara

Describe the two most common methods by which microorganisms can be isolated for culture

Streak Plate- most common. Sterile inoculating loop or needle spreads inoculum across surface of a solid medium in petri dishes. The loop streaks a pattern so that CFU's (colony forming units) are separated and not together. Incubation occurs and col

Describe media based on chemical make-up (synthetic or complex) and physical characteristics (liquid, semi-solid, solid)

Nutrient Broth- contains powered beef extract and peptones. It is dissolved in water- LIQUID.
Nutrient agar- You can add 15% agar into hot broth to make it SOLID.
Agar- ia a COMPLEX polysaccharide derived from the cell walls of certain red algae.

Describe functional types of media (selective, differential, anaerobic, transport)

Selective-typically contain substances that favor growth of particular microorganisms or inhibit the growth of unwanted ones. For example, Eosin/Methylene blue/Crystal violet/bile salts are included in media to inhibit growth of Gram+ bacteria wi

Describe the use of special culture techniques (animal and cell cultures, low-oxygen cultures, enrichment cultures)

Animal and Cell- Used when artificial media are inadequate for growing microbes. Grown in animals or if needed, in live cells, such as bird eggs or cultures of living cells.
Low Oxygen- Since many organisms prefer oxygen conditions that are inter

Contrast refrigeration, deep freezing, and lyophilization as methods for preserving cultures of microbes

To store living cells, a scientist must slow the cell's metabolism to prevent excessive accumulation of waste and exhaustion of nutrients in a medium.
Refrigeration: best for short period storage
Deep Freezing: Long term storage. Can be restored year

Describe the events of binary fission

Binary Fission- process by which the cell doubles in size and then divides in half to produce 2 daughter cells of equal size. Most unicellular microorganisms reproduce in this way.
1. When the DNA molecule replicates, it results in the formation of t

Describe logarithmic growth

The growth of binary fission. 1 cell divides and equals two. Two then divide and equal 4. 2 divides and equals 8. Etc. One would have to factor in the amount of time (generation time) the growth takes for each new cell but each time, the cells wo

Explain what is meant by the generation time of bacteria

The time required for a bacterial cell to grow and divide. It varies according to the bacteria and is dependent on its chemical and physical conditions

Draw and label a growth curve; describe what occurs at each phase

Log Phase- Cells are adjusting to their new environment. They actively synthesize enzymes to utilize nutrients available to them.
Log Phase- When exponential growth occurs. Reproductive rate reaches a constant as DNA and protein synthesis are max

Compare and contrast direct and indirect methods of measuring bacterial growth

Direct- Requiring Incubation:
Serial Dilution and viable plate count- used if number of cells in a sample is TOO GREAT TO COUNT. Dilution of a liquid culture, then count the colonies on plates with 25-250 visible colonies and then multiply that n

Compare and contrast the genomes of prokaryotes and eukaryotes