Exam 2 - Chapter 8 Flashcards
What is metabolism?
sum total of chemical reactions of biosynthesis and energy-harvesting
What two fundamental tasks must cells accomplish in order to grow?
-synthesize new components(biosynthesis)
-harvest energy
What are the two components of metabolism?
Anabolism and Catabolism
What type of reactions are catabolism? (how is energy made)
Degradative, produces energy from breaking down large molecules
What type of reactions are Anabolism?
Synthesis of cell components; require energy from catabolic reactions
What are the two types in which energy can exist?
Potential (stored) and Kinetic (motion)
True or false: Energy can be converted from one form to another
True. vice versa as well
Energy is always lost what what form?
Heat
Free energy =
released energy that is available to do work
Proton pumps are membrane proteins that
actively transport H+ across the membrane
creating a concentration gradient. What type
of energy does this concentration gradient
represent?
1. Kinetic energy
2. Potential energy
3. Heat energy
4. Free energy
- Potential energy [gradient]
Exergonic reaction
Reactants have more free energy than products, energy is released
Endergonic reaction
Products have more energy than reactants, energy is consumed
What initial input of energy is required to break chemical bonds?
Activation Energy
What are catalysts?
Substances that lower the activation energy of reaction (not consumed in the reaction)
Biological catalysts are called:
Enzymes
Name some properties of Enzymes
-Very Specific(will only act with one or a limited number of substrates)
-Do not alter reactants or products of a chemical reaction
- end in -ase
What is a substrate? What is formed?
The specific substance on which the enzyme acts; products are formed
Cofactor
Non-protein component reacting with enzyme
Coenzyme
Organic cofactors; NAD+,FAD+,NADP+
What factors affect enzyme activity?
Temperature = speed of reaction
pH = function best above 7
NaCl concentration = low preferred
Competitive inhibition
Inhibitor competes for active site with substrate and is structurally similar
Non-competitive inhibition
Inhibitor and substract act on different enzyme sites
Allosteric inhibition
Regulates product production, modifies enzyme affinity to substrate
Feedback inhibition
End product of pathway acts on allosteric site of enzyme and shuts down pathway
Oxidation-reduction reactions
reactions in which one or more electrons is transferred from one substance to another
Compounds that LOSE electrons are:
Oxidized
Compounds that GAIN electrons are:
Reduced
True or false: Electron carriers can be fixed OR diffusible
True
Energy currency of the cell
ATP (Adenosine triphosphate)
What is ATP composed of?
Negatively charged phosphate groups attached to an adenosine molecule; creating an unstable, energy releasing bond
What properties of ATP make it so well-
suited to serving as the energy currency of
the cell?
The high-energy unstable negative bonds release energy when broken.
What three mechanisms create ATP?
Substrate phosphorylation
Oxidative phosphorylation
Photophosphorylation
Substrate phosphorylation
Uses chemical energy to add phosphate ion to molecule of ADP
Oxidative phosphorylation
Uses energy from proton motive force to add phosphate ion to ADP
Photophosphorylation
Utilizing radiant energy from sun to phosphorylate ADP to ATP
Fermentation
Living systems that used pyruvate as a final electron acceptor; main goal is to reoxidize NADH to NAD+
Fermentation pathways (2)
Alcoholic and lactic
How is ATP usually produced in fermentation? Max yield?
Substrate phosphorylation; 2 ATP(glycolysis)
Cellular Respiration
Metabolic pathway that generates ATP via oxidative phosphorylation
How is ATP usually produced in Cellular Respiration?
Oxidative phosphorylation
Glycolysis definition
Breakdown of Glucose
Common fermentation pathway, (also called Embden-Meyerhof pathway
Redox Reactions
oxidation-reduction reactions, where oxidation and reduction occur in tandem
Fermentation vs Respiration
F = End products varied; small amount ATP produced
F = Occurs in absence of oxygen(anaerobic)
R = Occurs in presence of oxygen(aerobic)
R = End products are consistent; large amount ATP produced
Glycolysis requires what in order to continue
NADH must be oxidized to regenerate NAD+
Glycolysis; broadly:
Glucose consumed; pyruvate produced
2NADH produced, only to regenerate NAD+
2ATP Produced; (whole point)
Glycolysis end products
Alcohol/Wine/Cheese/Butane
What 4 components does a standard respiration pathway involve?
Glycolysis
Pyruvate Oxidation
Tricarboxylic Acid Cycle (TCA)
ETC, Electron transport chain
Pyruvate Oxidation function
Modifies 3-C Pyruvate from glycolysis to 2-C acetyl CoA
NAD+ is reduced to NADH
Tricarboxylic Acid Cycle function
Completes oxidation of glucose
Takes acetyl CoA, releases CO2
2 ATP
4 CO2
6 NADH2
2 FADH2
Electron Transport Chain
Group of membrane-embedded electron carriers; their arrangement aids in production of proton motive force = ATP harnessed from movement
ETC Products
10 Protons pumped out per NADH
One NADH = 3 ATP
6 Protons pumped out per FADH
One FADH = 2 ATP
How much ATP produced through Substrate Phosphorylation?
4
How much ATP produced through Oxidative Phosphorylation?
Eukaryotic = 38 ATP
Prokaryotic= 24 ATP
Anaerobic Respiration
Oxygen does not act as final Electron acceptor/Less efficient/Nitrate Reduction
Chemolithotrophs functions
-oxidize inorganic chemicals as source of energy
-generate ATP through oxidative phosphorylation
Chemolithotroph groups (4)
Hydrogen Bacteria’’
Sulfur Bacteria’’
Iron Bacteria’’
Nitrifying Bacteria’’
Photosynthesis
Organisms use to harvest energy from light
Carbs from CO2
Two distinct stages(types) of photosynthesis
Light dependent = light –> chemical energy
Light independent = light reactions –> chemical compounds
Photosystems
Protein complexes containing pigments
Photosystems locations in: Cyanobacteria/plants/p+g bacteria
Cyanobacteria: embedded in membranes; thylakoid
Plants: thylakoids within chloroplasts
P+G: cytoplasmic membrane
Two tasks that light dependent reactions accomplish
Synthesis of ATP thorough photophosphorylation
Generate reducing power to fix CO2
Photosystem I - Cyclic
When only ATP is needed
Photosystem I + II - Noncyclic
When ATP and reducing power are needed; NADP+ reduced to NADPH; system I is left oxidized
Three stages of Calvin Cycle
-CO2 –> Organic compound
-Reduction of resulting molecules
-Regeneration of starting compound
T or F; Noncyclic is anaerobic
FALSE
T or F; Anoxygenic bacteria use water as an electron donor
False; use hydrogen gas, hydrogen sulfide, or organic compounds
Light Independent Reaction term for converting CO2 into organic carbon
Carbon Fixation
Most common pathway of carbon fixation
Calvin cycle
Where did the carbon found throughout the cell of a cyanobacterium originate?
Soil
Water
Air
Light
Air
Where are carbon skeletons for amino acid synthesis found?
From glycolysis intermediates or TCA
Synthesis of what requires nitrogen bases to be constructed atom by atom from other sources?
Nucleotide Synthesis
What acids are synthesized two carbons at a time?
Fatty(Lipid synthesis)
What holds the growing lipid synthesis chain in place?
acyl carrier proteins (ACP)
Ecology definition
The study of relationships between organisms to each other and the environment
Community definition (biology)
Organisms in a given area
An ecosystem is
communities interacting with each other and non-living environment
Trophic level =
Food source of organism
Three general trophic levels
Primary producers
Consumers
Decomposers
What cycles are cyclical paths that elements take as they flow through living and nonliving components of the ecosystem?
Biogeochemical Cycles
Three general purposes that elements play in an organism’s metabolism
Biomass production
Energy source
Terminal electron acceptor
Carbon Cycle Steps
Carbon fixation
Respiration/Fermentation
Combustion
Carbon reduction
Methane oxidation
Nitrogen cycle steps
Nitrogen fixation
Ammonification
Nitrification
Denitrification
Nitrogen fixation
process by which nitrogen gas is reduced to form ammonia
Ammonification
decomposition process that converts organic nitrogen into ammonia
Nitrification
process that oxidizes ammonium to nitrate
Denitrification
process that converts nitrate to gaseous nitrogen
Sulfur cycle
Sulfur oxidation
Sulfur reduction
