Chapter 6: Nutrition & Growth Flashcards by Elizabeth Lopez

Define: photoautotroph

Microorganism that requires light energy and uses carbon dioxide as a carbon source

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Define: chemoautotroph

Microorganism that uses carbon dioxide as a carbon source and catabolizes organic molecules for energy

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Define: photoheterotroph

Microorganism that requires light energy and gains nutrients via catabolism of organic compounds

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Define: chemoheterotroph

Microorganism that uses organic compounds for both energy and carbon

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Define: obligate
aerobe

require oxygen for metabolism

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Define: microaerophile

“small amt. of oxygen liking”
Use oxygen in metabolism but not always required
Can only tolerate oxygen in amt. less than atmospheric concentration 3-10%

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Define: facultative anaerobe

Grow best in oxygen but can survive without oxygen

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Define: obligate anaerobe

“require no oxygen”
killed by oxygen

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Define: aerotolerant anaerobe

No aerobic metabolism but can tolerate oxygen

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Define: psychrophile

Optimum 10℃ (cold loving)
never cause disease in human live in snow

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Define: mesophile

Optimum 20℃- 40℃
many live in animals/humans=pathogens & normal flora
Think →refrigeration & cooking

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Define: thermophile

Optimum is 40℃-80℃ (heat loving)
live in compost pile, hot springs( water heated by earth)

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Define: hyperthermophile

Optimum is above 80℃
live in hot springs, mostly archaea some bacteria, membrane, nucleic acids, enzymes are unique to allow survival @ high temps.

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Define: neutrophile

Neutral pH (6.5-7.5)
food industry to prevent unwanted microbial growth
using microbes to kill microbes (yogurt, cheese, pickles aka fermentation)

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Define: acidophile

grow best in acidic environment; often times produce acid (2)
Obligate acidophiles: require acidic environment (hot springs water runoff from mines)
Acid-tolerant: can tolerate acidic environment, many used in food industry (fermentation)

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Define:
alkalinophile

grow best in alkaline environment; found in soil & water environment up to pH 11.5

Define: halophile

grow best in hypertonic environment (up to 30% salt) will explode in freshwater
Facultative halophiles: do not require salty environment but can tolerate high salt ex: Staphylococcus auerus can survive on fresh shower skin and sweating salty skin

Define: barophile

live at very high pressure @ the bottom of the ocean
require high pressure to maintain membrane & enzyme structure

Define: biofilm

many species living together in a layer(surrounded by glycocalyx; slime layer/capsule) attached to a surface

Define: quorum sensing

Change in physiology in response to the number of microbes present (roll call)

Define: generation time

the times to completes binary fission (cell grows then divides to produce two cells)

Describe the differences between photoautotrophs, chemoautotrophs, photoheterotrophs,
chemoheterotrophs.

o Carbon source? Energy source?

Photoautotroph: ENERGY from light CARBON from carbon dioxide
Chemoautotrophs: ENERGY from breaking down organic compounds CARBON from carbon dioxide
Photoheterotrophs: ENERGY from light CARBON from organic compounds other than CO2
Chemoheterotroph: Energy from breaking down organic compounds CARBON from organic compounds other than CO2
Troph- means to feed

Describe the carbon cycle

Describe how energy flows among organisms in an ecosystem

Explain the importance of phototrophs and autotrophs to all life. (Hint: your answer has nothing to do with oxygen!)

phototrophs get their energy from light autotrophs can make their own organic carbon from inorganic compound They both happen during photosynthesis (green plants, algae, cyanobacteria)

Why can’t some organisms tolerate oxygen? (i.e. What do the aerobes have that the anaerobes do not?) o What is it about oxygen that makes it toxic to some organisms?

Aerobes are able to detoxify: 1) superoxide radical: O2 (dismutase) 2) peroxide: O2- (peroxidase) 3) hydroxyl radical: OH- (catalase) 4)Singlet oxygen:1O2 (catenoid) Organisms that survive in oxygen have enzymes or antioxidants (vitamin C & E) to destroy toxic oxygen Since oxygen is electronegative it can take electrons from dif. part of cell and cause irreversible damage

Nitrogen is typically the growth-limiting nutrient. (Know what this sentence means!) o Why is this the case? (How is nitrogen usually found in the environment – is that what organisms can use?) o What is nitrogen fixation? What type of organism does this? (Be specific, don’t just a say “a nitrogen fixer”!) o Explain the importance of organisms that use nitrogen fixation to all life.

NO MORE NITROGEN NO MORE GROWTH - Nitrogen in atmosphere as N2(gas). Organisms can only use NH3 (ammonia), NH4+(ammonium) -Nitrogen Fixation N2????? -Nitrogen Fixation essential for life on the planet, basis for crop rotation -Rhizobium & some cyanobacteria use nitrogen fixation (??? why important to these organisms)

Understand what “optimum growth temperature” means. o How does temperature affect microbes? o What temperature-related term would be used to describe a human pathogen?

TEMP WHICH GROW BEST: ENZYMES WORK EFFICENTLY & MEMBRANE LIPDS ARE INTACT (good barrier shape) -Microbes are all different they grow better in dif. temp. -Mesophiles: many live on animals/ humans = pathogens & normal flora (20℃-40℃)

How does pH affect microbes? o What pH-related term would be used to describe a human pathogen?

Changes in acidity= changes in concentration of H+ & OH- can interfere with H bonding in proteins & nucleic acids -NuertalPhill?????? Human pathogen

How does the concentration of a solution affect microbes? (Remember osmosis!) o What is a halophile? Facultative halophile?

Osmolarity: difference in the amt. of salt you have inside the cell vs. outside of cell has an effect on osmosis which is the movement of water across the semi-permeable cell membrane -HAROPILE: grow best in hypertonic environment (up to 30% salt) will explode in freshwater -Facultative halophiles: do not require salty environment but can tolerate high salt ex: Staphylococcus auerus can survive on fresh shower skin and sweating salty skin

What is a barophile? Where might you find one?

Water exerts pressure in proportion to its depth (1atm of pressure for every 10 meters) Barophile live at very high pressure Can find at bottom of the ocean

How do biofilms help microbes? Why are they important to people?

Organisms are protected from environment (Drying, antibiotics don't' penetrate through biofilm, UV, Chemicals) ???why impoertant to people????

Describe the four phases of microbial growth

LAG Phase: no increase in cell # preparing for growth by making enzymes (to break down nutrients) LOG Phase: exponential growth, lots of nutrients very low waste (toxic to cell) gives more dividing cells than dying/ cell wall intact(do gram stain) antibiotics that effect metabolism have more effect now STATIONARY Phase: no increase in cell #. culture capped capacity. limiting nutrients & build up waste/ cells dividing= cells dying DEATH Phase: out of nutrients & lots of wastes=toxic more cells dying than dividing