Lecture 1: Introduction Flashcards
(36 cards)
Describe Autotrophs. Where do they get their carbon from?
Autotrophs can synthesise energy-containing organic molecules, from inorganic sources, using basic energy sources such as sunlight. They get their carbon from inorganic forms such as CO2.
Describe Heterotrophs.
Cannot synthesis their own food, so rely on other organisms for nutrition - from which they also acquire a reduced volume of carbon.
Define biomass,
The total weight of all living organisms.
Define Productivity.
The rate of carbon fixed from CO2 to organic material in an area.
What is the difference between net and gross photosynthesis?
Gross photosynthesis is the total rate of CO2 fixation, whilst net photosynthesis is this value - CO2 released in respiration.
Describe soluble organic molecules compared to soluble inorganic molecules.
Soluble organic - Excretory / breakdown products
Soluble inorganic - Chemical or biological derivation (DIC = carbon dioxide, bicarbonate anions, carbonic acid, carbonate)
Describe insoluble organic and insoluble inorganic molecules.
Insoluble organic - Living or dead biomass
Insoluble inorganic - non biological particles
In nutrient cycling, describe the respective roles of Autotrophic microbes and Heterotrophic bacteria in terms of uptake and conversion.
Autotrophs uptake inorganic matter, whilst Heterotrophs uptake organic and inorganic matter after which it is converted to particulate organic biomass.
Nutrients are cycled through the food chain, but describe how they are released back into the environment.
Released as either dissolved organic forms, or dissolved inorganic forms (REMINERALIZATION)
Give the equation for the carbon cycle.
CO2 + H20 organic carbon + O2
By which process do funghi contribute to the carbon cycle?
They respire, as they are decomposers
What is the largest store of carbon in the carbon cycle?
Rock 70,000,000 GtC
Describe the difference between DIN and DON.
DIN = gas (N2), anion (NO3-, N02-) or cation NH4+ DON = A heterogenous group of organic compounds, ranging from well defined constituents such as urea and amino acids, to more complex compounds such as humic and fulvic acids.
What does the following equation represent?
N2 + 8H —> NH3 + H2
Nitrogen fixation
What is the chemical conversion that occurs in denitrification and nitrification?
De = NH4+ ---> NO3 - Nitri = NO3- ---> N2
What type of nitrogen is converted to ammonia in Ammonification?
organic
What compounds is carbon found in as a macronutrient, and what is its biological role?
DOC, CO2, CO3^2-, HCO3- used in cell material, photosynthesis and controlling the pH of water.
What compounds is Phosphorus found in as a macronutrient, and what is its biological role?
Ortho- (PO4-) and poly- phosphates. It is a component of nucleotides DNA, RNA and ATP
What compounds is nitrogen found in as a macronutrient, and what is its biological role?
DON, N2, NO3-, NO2- and NH4+. It is used as a component of amino acids and proteins.
Name the four growth factors for microbes.
Vitamins, amino acids, purines, pyrimidines.
What differentiates a typical macronutrient from a microntrient?
Macronutrients = microbes need in excess, whereas micronutrients they only need a very small amount of, so tend not to be limiting.
Prokaryotes include which two groups of microorganisms?
Bacteria and Archae
What comes under Eukaryotes in the phylogentic tree?
Eukarya, includes animals, plants and funghi
Which of the following processes are carried out by Archae, Bacteria and Eukaryotes respectively:
- Nitrification
- Denitrification
- Nitrogen fixation
Archae and Bacteria both nitrogen fix and denitrify which Eukaryotes dont. Bacteria are the only ones to nitrify.
