Flashcards in Lecture 16 - Carbon Cycling Deck (68)
What are the 4 nutrient cycles microorganisms use?
carbon, iron, nitrogen, sulfur (CINS)
Which nutrient cycle is the most important for microbes?
What are the 3 man-made things that contribute to the carbon in the atmosphere and results in the increase of atmospheric CO2?
fossil fuels, deforestation, cement production
What is carbonated rock? What is a rule with this carbon source?
oceanic earth's crust/fossil fuel source, should be inactive | should NOT be cycled, but it us used anyways
Which is the largest carbon reservoir in the planet?
Which is the smallest carbon reservoir in the planet?
Which carbon reservoir is the most actively cycled?
What is due to the drastic increase in atmospheric CO2?
past 100 years = industrialization
What are the 2 carbon reservoirs in the ocean?
carbonate rock and dissolved/particulate organic material (DOM/POM)
What are the 4 carbon reservoirs on land?
land plants (biota), humus, fossil fuels and earth's crust
How do carbon reservoirs relate to the issue of global warming?
CO2 and CH4 = high levels in sky = traps heat and doesn't let it escape
Microorganisms may play a role in more than one nutrient cycle (ex: can fix both nitrogen and carbon). How does this overlap affect the microbe community?
can drive how these organisms are structured within the community
By how much (%) has atmospheric CO2 increased in the past century?
What are autotrophs?
takes up CO2 >>> carbon fixation
What are heterotrophs?
takes organic carbon >>> carbon respiration >>> produce CO2
What is the primary productivity of our planet a result of? (50% what and 50% what?)
50-plants | 50: cyano-b, algae, microbes (CAM)
What cycle uses carbon anaerobically?
What are the 4 predominant forms of organic carbon in the environment?
peptidoglycan, chitin, plant polymers, insect exoskeleton
Why are organic polymers important?
help support heterotrophic activity
What are the 3 different components that make up a plant? (order them from which makes up most of the plant to least)
cellulose, hemicellulose, lignin
Where does the environment get peptidoglycan from?
bacterial cell wall
Where does the environment get chitin from?
fungal cell wall
What is cellulose?
homogenous molecule - glucose subunit repeats connected via beta-1,4-glycosidic linkage
How is cellulose a problem for microbes?
large molecule and insoluble in water
How do microbes get a large insoluble molecule across their cell walls?
secretes enzymes to break it down into smaller pieces
What is cellulase?
NOT one enzyme, CLASS of enzymes that break down cellulose
What are the 3 major enzymes that play a role in the breakdown of cellulose?
B1,4-endoglucanase, B1,4-exoglucanase, cellobiase (B1,4-glucosidase)
What is beta1,4-endoglucanase?
randomly breaks up cellulose into shorter pieces by targeting glycosidic (beta 1,4) linkage
What is beta1,4-exoglucanase?
more specific = goes at end of cellulose and breaks bond at every 2 subunits == produces di-glucose