Metabolism Flashcards
What is the difference between catabolic and anabolic reactions
Catabolic: All metabolic pathways that consume energy to syntesize complex molecules from simpler molecules. Anabolic: All metabolic pathways that consume energy to syntesize complex molecules from simpler molecules
What is metabolism
The totality of an organism’s chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.
What are the 4 types of energy and what does each term mean
Kinetic energy: Energy associated with the relative motion of objects.
Chemical energy: Energy available in molecules for release in a chemical reaction (= potential energy)
Thermal energy: Kinetic energy due to the random motion of atoms and molecules (=heat)
Potential energy: Energy that matter possesses as a result of its location or spatial arrangement
What are the 2 laws of thermodynamics
The energy of the universe is constant. Energy can be transferred and transformed, but it cannot be created or destroyed -> Principle of conservation of energy.
Every energy transfer or transformation increases the entropy (disorder) of the universe. > any chemical reaction is accompanied by the loss of unusable energy… heat
Describe nutritional requirements of plants
Energy source: light
Carbon Source: inorganic compound (CO2)
Describe nutritional requirements of Photohetrotrophs
Energy Source: light
Carbon Source: organic compounds (glucose)
Describe nutritional requirements of Chemoautotrophs
Energy Source: chemical compound
Carbon Source: inorganic compound (CO2)
Describe nutritional requirements of Chemoheterotrophs
Energy Source: chemical compound
Carbon source: organic compounds (glucose)
how much energy is lost from one trophic level to the next
90% is lost.
What is Gibbs Free Energy
amount of energy available to do work in a system when the temperature and pressure are uniform
How to calculate Gibbs free energy?
Delta G = G final state - G initial state
What does exergonic mean
reaction releases energy (G < 0)
what does endergonic mean
reaction requires energy (G > 0)
When a reaction is exergonic, the reaction product has a ______ free energy level
lower
When a reaction is endergonic, the reaction product has a _____ free energy level than the substrate
higher
A spontaneous reaction is ____
exergonic
What is an open system
Living cells are never at equilibrium, they constantly acquire and transfer energy and material
What does ATP stand for
adenosine triphosphate
What is the structure of ATP
1 adenosine (nitrogenous base) + 1 ribose (sugar) + 3 phosphate groups
What is chemical work
enzymes can couple two reactions (endergonic and exogonic) to produce a Gibbs energy,
What is transport work
the hydrolysis of ATP can lead to the change in the shape of protein (activate). ATP can power the movement of molecules against their concentration gradients
What is mechanical work
The hydrolysis of ATP can lead to the change in the shape of a protein. It is preformed by an activated motor protein
How can ATP be regenerated
through the phosphorylation of ADP using substrate level phosphorylation
What is activation energy
the energy required to start a reaction and break the bonds
What do enzymes do to activation energy
lower it
What does an active site contain
specific amino acids that establish hydrogen and ionic bonds with the reactancts before it is transformed into products
what are 4 things the rate of the reaction depend on?
- the concentration of substrate
- the number of enzymes with free active site
- the temperature
- the pH
What are the 6 categories of enzymes and what are their functions
- Oxidoreductase: transfers an e from one molecule (reductant) to another (oxidant
- Tranferase: transfers a functional group
- Hydrolase: uses water to break down a chemical bond
- Lyase: breaks a chemical bond (other than through hydrolysis)
- Ligase: joining large molecules
- Isomerase: converts a molecule from one isomer to another
What is metabolic regulation
A cell can regulate its metabolism by switching on/off genes that encode specific enzymes and also by regulating enzymatic activity
What is a cofactor
inorganic molecule that helps the enzymes catalytic function
What is a coenzyme
organic molecule that helps the enzymes catalytic function
What are two types of enzyme inhibition?
Competitive Inhibition
Non-competitive inhibition
What is competitive inhibition?
Resemble the normal substrate molecule and competed with it for the active site. It blocks substrates from entering active sites, decreasing rate of reaction
What are non-competitive inhibitors
binds to the enzyme at a site other than the active site. it changes its shape (conformation) and decreases the catalytic efficiency at active site
What is allosteric regulation
regulate enzyme activity by binding to another site on the protein, causing them to alternate between active and inactive form.
What does an allosteric activator do
stabilizes the active shape of the protein complex
What does an allosteric inhibitor do
Stabilizes the inactive shape of the protein complex
What is cooperativity
the binding to one subunit in an allosteric protein can increase the affinity of other subunits to that substrate.
What is feedback inhibition?
The product that is produced by a metabolic pathway goes back and acts as a competitive inhibitor in order to regulate its own production (usually regulates first enzyme)
How does ATP synthesis regulation work
higher ATP presence decreases affinity of enzyme, lower ATP presence increases affinity of enzyme: Catabolism
tWhat is Reduction-Oxidation
energy tranferred from a reductant (electron donor) to an oxidant (electron acceptor)
What is aerobic respiration
oxidation of glucose into CO2 + reduction of O2 into H2O
What is anaroebic respiration
uses final electron acceptors other than O2
What is LEO says GER
LEO: lose an electron is oxidation
GER: gain an electron is reduction
What is cellular respiration and how many ATP does it produce
Catabolic pathways of aerobic and anaerobic respiration which break down organic molecules to produce 32 ATP
What are the 4 parts of cellular respiration
Glycolysis, Oxidation of pyruvate, Citric acid Cycle, and Oxidative Phosphorylation
Where does glycolysis occur
cytosol of cell
where does oxidative phosphorylation and citric acid cycle occur
mitochondria
where does oxidative phosphorylation occur
mitochondria
What is glycolysis and what does it produce
a molecule of glucose is broken into 2 pyruvate molecules. This produces 2 pyruvate molecules and 2 ATP
What is pyruvate oxidation and what does it produce
CO2 is removed. NAD+ is reduced to NADH, and coenzyme A binds. This produces 2 Acetyl-CoA, 2 CO2, and 2 NADH
What is the citric acid cycle and what does it product
Coenzyme A is recycled. Produces 3 NADH, 1 FADH2, 2CO2, and 1 ATP
What is oxidative phosphorylation and what does it produce
Electron transport chain: creates a proton gradient which ATP synthase uses to convert ADP to ATP. Produces 28 ATP
What is an isolated system?
What is an open system? List an example of open systems.
- Isolated systems: are unable to exchange energy or matter to its surroundings. Reaches an equilibrium and cannot perform any work.
- Open systems: Never at equilibrium, there is a constant flow of energy and material.
- Cells constantly acquire and transfer energy and material, any metabolic reactions are coupled to allow the exvhange of energy between molecules in a specific direction.
What is chemioosmosis
An energy coupling mechanism that uses potential energy (H+ concentraion gradient)
-> powers the synthesis of ATP (phoshporylation of ADP with Pi)
-> ATP synthase conversion into chemical energy
Describe the flow of energy during cellular respiration
Glucose, NADH, Electron Transport Chain, Proton-motive force, ATP
In the absense of oxygen, anaerobe organisms can do either ______ or _______
anaerobic respiration or fermentation
How is anaerobic respiration different than aerobic
includes glycolysis and krebs cycle, but is less efficient. Also, ETC is very different as O2 is not the last electron acceptor
What is fermentation
A process that enables glycolysis to continue to make ATP (substrate level phosphorylation) in the absence of O2
How is fermentation different from cellular respiration
No oxidative phosphyrlation, No ETC, no krebs cycle
What are the two types of fermentation?
- alcoholic (where the final e acceptor is acetaldehyde)
- lactic (where the final e acceptor is pyruvate)
What is photosynthesis
conversion of light energy to chemical energy that is stored in sugars to other organic compounds
What does the light reaction of photosynthesis produce
ATP and NADPD
WHat does the calvin cycle produce
produces carbohydrates using CO2
After excitation by light, electrons have a natural tendency to move toward
the ______ possible state of ______
lowest, potential energy
How are the citric acid cycle and calvin cycle different
Citric Acid Cycle:
-Catabolic
-Oxidizing acetyl CoA
-Using energy to synthesize ATP
Calvin Cycle:
-Anabolic
-Synthesizing carbohydrates
-Consuming ATP
