Metabolism Flashcards
Fill in the blank:
All living cells need _____ to move and grow, which comes from ______ ________.
Energy
Chemical Reactions
What is catabolism?
A type of metabolism that breaks down complex molecules into smaller ones to RELEASE ENERGY, which can be used in anabolism.
What is anabolism?
A type of metabolism; reactions that build larger molecules from small molecules that REQUIRES ENERGY.
(T/F) All of the energy released in catabolism is used for anabolism.
False! Some of it is released as heat.
(T/F) Every form of life uses energy.
True!
Match the following terms to their definitions:
1) Energy
2) Entropy
A) Measure of the disorder or randomness of a system
B) Ability to do work
Energy - ability to do work
Entropy - measure of the disorder or randomness of a system
What does a cell require to continue growth?
- Continual gain of energy
- Continual radiation of heat
(T/F) Cells use energy to assemble simple, ordered molecules into complex, disordered molecules.
False! Cells use energy to assemble simple, disordered molecules into complex, ordered molecules.
(T/F) Like cells, on earth, the total metabolism of all life-forms must ultimately dissipate most energy as heat.
True!
What does the Earth’s biosphere behave as? Why?
GIANT THERMAL REACTOR.
Because it allows for reactions that dissipate most energy as heat.
In earth’s biosphere, energy is gained and the order ______, while outside earth, energy is dissipated and the order _______.
Increases; decreases
Where do trees get their mass from?
Air
*they get carbon dioxide from the air for photosynthesis, the O2 leaves and the carbon remains to make glucose.
Match the following terms for prefixes regarding carbon source for biomass:
1. Auto
2. Hetero
A. OUTSOURCED; performed organic molecules are acquired and assembled into new organic molecules
B. MAKE YOUR OWN; carbon dioxide is fixed and assembled into organic molecules
- Auto - MAKE YOUR OWN; carbon dioxide is fixed and assembled into organic molecules
- Hetero - OUTSOURCED; performed organic molecules are acquired and assembled into new organic molecules
*plants are autotroph (they make their own food) while humans are heterotroph (eat the organic molecules made by plants).
Match the following terms for prefixes regarding energy source:
1. Photo
2. Chemo
A. CHEMICAL reactions (electron transfer between chemicals) yield energy without absorbing light
B. LIGHT absorption captures energy
- Photo - LIGHT absorption captures energy
- Chemo - CHEMICAL reactions yield energy without absorbing light (oxidize inorganic organic compounds - transfer electrons)
*autotrophs are usually phototrophs, they use energy from light to produce their own food
Match the following terms for prefixes regarding electron source:
1. Litho
2. Organo
A. INORGANIC molecules (metal, salts, single elements, no C-H bond) donate electrons
B. ORGANIC molecules (lipids/sugars) donate electrons
- Litho - INORGANIC molecules (metal, salts, single elements, no C-H bond) donate electrons
- Organo - ORGANIC molecules (lipids/sugars) donate electrons
(T/F) Multicellular organisms use more diverse energy sources than microbes.
False! Microbes use more diverse energy sources than multicellular organisms, collectively.
Match the terms with their definitions:
1. Chemoorganotrophy
2. Chemolithotrophy
3. Photoautotrophy
4. Photoheterotrophy
A) Use INORGANIC compounds as a source of electrons for energy
B) Light absorption without Carbon Dioxide fixation
C) Uses ORGANIC compounds as a source of electrons for energy
D) Light absorption drives Carbon Dioxide fixation.
- Chemoorganotrophy - Uses ORGANIC compounds as a source of electrons for energy
- Chemolithotrophy - Use INORGANIC compounds as a source of electrons for energy
- Photoautotrophy - Light absorption drives Carbon Dioxide fixation.
- Photoheterotrophy - Light absorption without Carbon Dioxide fixation.
Which of theses is true for chemolithoautotroph?
a) inorganic molecules as energy sources and inorganic carbon as a carbon source.
b) organic molecules as electron sources and inorganic carbon as a carbon source.
c) organic molecules as energy sources and organic carbon as a carbon source.
d) inorganic molecules as electron sources and organic carbon as a carbon source.
e) inorganic molecules as energy sources and organic carbon as a carbon source.
a!
inorganic molecules as energy sources and inorganic carbon as a carbon source
Cyanobacteria carry out oxygenic photosynthesis, producing oxygen as a by-product from the oxidation of water, which serves as the electron donor for the light-dependent reactions. How would cyanobacteria be classified?
Photosynthesis - AUTOTROPH + PHOTOTROPH
Oxidation of water (inorganic molecule) - LITHOTROPH
Hence, it will be a photolithoautotroph!
(T/F) For humans, oxygen accepts electrons and protons, passed through the electron transport chain, and becomes water. Oxygen is not the only electron acceptor, especially for anaerobic organisms.
True!
What are ENERGY CARRIERS? What are three examples of them?
Molecules that gain or release SMALL amounts of energy in REVERSIBLE reactions.
NADH, ATP, and PEP are the three examples of energy carriers.
Some energy carriers can transfer electrons, what agent is an electron donor and an electron acceptor?
Electron donor; reducing agent
Electron acceptor; oxidizing agent
LEO the lion says GER
- > Loss of electrons; oxidization; done by a reducing agent
- > Gain of electrons; reduction; done by an oxidizing agent
Microbes catalyze many substrates. Match the following terms into what they are catalyzed to:
A. Polysaccharides
B. Pyruvate + intermediary products
C. Lipids + amino acids
D. Aromatic compounds
- Acetate through various pathways such as the Catechol Pathway
- Disaccharides –> monosaccharides (sugars & amines/acids sugars) –> pyruvate
- Fermented OR further catabolized to CO2, H2O via the TCA/Krebs cycle
- Glycerol and acetate + other metabolic intermediates
A. Polysaccharides –> disaccharides –> monosaccharides (sugars & amines/acids sugars) –> pyruvate
B. Pyruvate + intermediary products –> fermented OR further catabolized to CO2, H2O via the TCA/Krebs cycle
C. Lipids + amino acids –> glycerol and acetate + other metabolic intermediates
D. Aromatic compounds –> Acetate through various pathways such as the Catechol Pathway
*all funnelled through pyruvate or acetyl-coA to go through cell respiration or fermentation
What are the three main catabolic pathways?
- Fermentation
- Respiration
- Photoheterotrophy
Match the following terms to their definitions:
1. Fermentation
2. Respiration
3. Photoheterotrophy
A. Catabolism is conduced with a “boost” from light (ex. bacteriorhodopsin)
B. Partial breakdown of organic food without net electron transfer to an inorganic terminal electron acceptor
C. Complete breakdown of organic molecules with electron transfer to a terminal electron acceptor such as O2
- Fermentation - partial breakdown of organic food without net electron transfer to an inorganic terminal electron acceptor
- Respiration - complete breakdown of organic molecules with electron transfer to a terminal electron acceptor such as O2
- Photoheterotrophy - Catabolism is conduced with a “boost” from light (ex. bacteriorhodopsin)
What are the differences and similarities between photoheterotrophy and photoautotrophy?
Similarities:
- Source of energy is both from the sun
- Electron acceptor is H2 for both
- Both are anaerobe
Differences:
- Source of carbon: organic ompounds for heterotrophs and fixing carbon for autotrophs
- Source of electrons: organic compounds for photoheterotrophy, thiosulfate and Fe2+ for photoautotrophy.
Which organisms do glucose fermentation and respiration?
CHEMORGANOTROPHY
or Chemoheterotrophes
but not others!
What are the three main routes that bacteria and archaea use to catabolize glucose?
- Glycolysis, or the Embden-Meyerhold-Parnas (EMP) pathway
- Entner-Doudoroff (ED) pathway
- Pentose phosphate pathway (PPP), aka pentose phosphate shunt
(T/F) While Glycolysis and Entner-Doudroff pathways produce pyruvates to undergo TCA or fermentation from glucose and sugar acids, respectively, pentose phosphate pathway results in biosynthesis of substances like nucleic acid needed for cell division. The sources of food can shuffle between these 3 pathways depending on the needs of the cell.
True!
Briefly explain how cell respiration works for eukaryotes. Make sure to include all of its 4 stages.
Stage 1: Sugar is turned into pyruvate in glycolysis in the cytosol
Stage 2: Pyruvate is funnelled into the TCA cycle in the mitochondria
Stage 3: The electrons produced through the NADH molecules of the TCA cycle are funnelled through the electron transport chain, generating a proton motive force
Stage 4: The proton motive force powers ATP synthase and ATP is produced!
What is the electron acceptor of the electron transport chain for cellular respiration? What does it produce?
Oxygen is the electron acceptor, it produces water!
*for aerobes!
Briefly explain how Photosynthesis works in eukaryotes. Make sure to include all of its 4 stages.
Stage 1: Energy is absorbed by pigments and directly transfer to electrons.
Stage 2: Electrons are funnelled through the ELECTRON TRANSPORT CHAIN, generating a PROTON MOTIVE FORCE
Stage 3: The proton motive force activates ATP SYNTHASE and ATP is produced.
Stage 4: ATP is used for CARBON FIXATION and sugar is produced.
*all steps in the chloroplast
What is the electron acceptor of the electron transport chain for photosynthesis? What does it produce?
Water is the electron acceptor of the ETC and it produces O2!
While sunlight is the energy source for photosynthesis, _____ ___ is the energy source for cellular respiration.
Chemical bond
What is the difference between metabolism (photosynthesis / cellular respiration) in eukaryotes and bacteria?
*not including fermentation
Bacteria do not have a mitochondria for cellular respiration or a chloroplast for photosynthesis.
However, they can use sun or chemical bonds (carbon source) to generate a proton motive force through the ETC the same way as eukaryotes to produce ATP.
(T/F) While the proton motive force is outside the inner membrane in mitochondria and outside the plasma membrane of a bacterium, it is in the inside (thylakoid space) of chloroplast.
True!
What can the proton motive force generated by the electron transport system in bacteria be used for?
ATP synthesis, flagella rotation, and nutrient transport
What is fermentation?
Completion of catabolism without the ETC and an exogenous terminal electron acceptor.
Glucose turns into Pyruvate through glycolysis, producing 2 ATPs and it does not undergo TCH or ETC, resulting in an end metabolite (alcohol, lactate, etc).
2 NADH are formed when pyruvate is turned into the end metabolite (reducing the NAD+ used in glycolysis).
(T/F) Most fermentations do not generate ATP beyond that produced by SUBSTRATE LEVEL PHOSPHORYLTATION (transfer of phosphate group from a substrate to make ADP into ATP)
True! Not as efficient as cellular respiration (OXIDATIVE PHOSPHORYLATION) but is faster!
How do microbes compensate for the low efficiency of fermentation?
Microbes consume large quantities of substrates and excrete large quantities of products.
(T/F) Both chemorganotrophes and chemolithotrophes can undergo fermentation and cellular respiration.
False! Chemolithotropes can’t undergo fermentation! Their electron sources are INORGANIC, while fermentation requires ORGANIC compounds.
Chemoorganotrophes can undergo cellular respiration and fermentation.
Match the following terms to their definitions:
1) Bioremediation
2) Bioaugmentation
3) Biostimulation
A. Adding microbes SELECTED FOR GROWTH on a certain pollutant or GENETICALLY MODIFIED BACTERIA that are specially adapted to metabolize the pollutant.
B. The use of microbes to remove pollutants or xenobiotics, such as the aromatic compounds in oil spills. Includes Bioaugmentation and Biostimulation.
C. Addition of fertilizers with nitrogen and phosphorus or electron acceptors/donors to stimulate naturally occurring microbial populations in the contaminated area
Bioremediation - The use of microbes to remove pollutants or xenobiotics, such as the aromatic compounds in oil spills. Includes Bioaugmentation and Biostimulation
Bioaugmentation - Adding microbes SELECTED FOR GROWTH on a certain pollutant or GENETICALLY MODIFIED BACTERIA that are specially adapted to metabolize the pollutant
Biostimulation - Addition of fertilizers with nitrogen and phosphorus or electron acceptors/donors to stimulate naturally occurring microbial populations in the contaminated area
Bioremediation occurs naturally as microbes attack the petroleum if the conditions are _______.
Aerobic
Why are fertilizers used in biostimulation (esp to get rid of petroleum) rich in nitrogen and phosphorus?
Microbes usually obtain their nutrients in aqueous solutions, whereas petroleum (oil-based) is relatively non-soluble.
Though the microbes can digest the hydrocarbons of petroleum, they are deficient in nitrogen and phosphorus, essential for microbial growth.
By providing fertilizers with these elements, we provide microbes with the missing elements and more food. This allows microbes to digest the petroleum quickly.
Provide a drawback for both bioaugmentation and biostimulation.
Bioaugmentation - introduced (exogenous) microbes can not be established in the environment and rarely survive. (can also mess up the ecosystem)
Biostimulation - due to the contaminant toxicity, the existing microbial population may not be enough for the biodegradation process
Which of the following groups is responsible for the vast majority of primary production on the planet?
A. chemoautotrophs
B. photoautotrophs
C. photoheterotrophs
D. chemoheterotrophs
PHOTOAUTOTROPHS
*primary production is the synthesis of organic compounds from carbon dioxide
The use of anything other than O2 as the terminal electron acceptor in the ETC is known as ________ _______.
Anaerobic respiration