Metabolism Flashcards
Metabolism
all of organ’s chemical reactions
Metabolic Pathway
begins with specific molecule and ends with product
Anabolic Pathway
consume energy to build complex molecules from simpler ones
Ex of Anabolic Pathway
synthesis of protein from amino acids
Bioenergetics
the study of how energy flows through living organisms.
Energy
capacity to cause change
Thermodynamics
the study of energy transformations
Open System
energy and matter can be transferred between the system and its surroundings (this is what organisms use)
First Law of Thermodynamics
Energy can be transferred and transformed, but it cannot be created or destroyed
Entropy
a measure of molecular disorder, or randomness ; also refers to energy loss in the form of heat!
Second Law
During every energy transfer or transformation, some energy is unusable and is often lost as heat or entropy
Relation between Entropy in Surrounding and Organism
Entropy (disorder) may decrease in a particular system, such as an organism, as long as the total entropy of the system and surroundings increases
Exergonic Reaction
proceed with net release of free energy and spontaneous
Endergonic Reactions
need extra energy so they are nonspontaneous
Free Energy
energy that can do work ; a measure of a system’s instability
Delta G and spontaneous Processes
DeltaG is negative for all spontaneous processes
How do cells manage energy?
Energy Coupling
Energy Coupling
the use of an exergonic process to drive an endergonic one (catabolic to anabolic) - utilizes by ATP
ATP
energy shuttle
Catalyst
speed up a reaction w/o being used
How is more ATP made?
by hydrolysis
Sucrase
breaks sucrose
- ase means enzymes
How do catalysts make reactions quicker? *4
- orient substrates correctly
- strain substrate bonds
- provide a favorable environment
- covalently bonds to a substrate
Substrate
- reactant that an enzyme acts on
Active Site
The region on the enzyme where the substrate binds
Induced Fit
both the substrate and the active site of the enzyme change in conformation until the substrate is completely bound to the enzyme
What factors influence enzyme acitivity?
temperature and PH or chemicals
Cofactors
non-protein enzyme helpers
- can be inorganic
Coenzymes
- organic co-factor
- includes vitamins
Competitive inhibitors
bind to the active site
of an enzyme, competing with the substrate
Noncompetitive Inhibitors
bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective
Examples of Inhibitors
toxins, poisons, pesticides, and antibiotics
Competitive vs Noncompetitive
- competitive binds to active site
- in competitive, the issue can be fixed by adding more substrate, but not in noncompetitive.
Energy *Source and stuff
Energy flows into an ecosystem as sunlight and leaves as heat
Aerobic Respiration
- consumes organic molecules and needs oxygen to yield ATP
Fermentation
a partial degradation of sugars that occurs without oxygen
Redox Reactions
Chemical reactions that transfer electrons between reactants are called oxidation-reduction reactions, or redox reactions
Oxidation
a substance loses electrons, or is oxidized
Reduction
a substance gains electrons, or is reduced (the amount of positive charge is reduced)
Reducing Agent
The electron donor
Oxidizing Agent
electron receptor
Example of Redox Reaction
An example is the reaction between methane and oxygen
Glycolysis
breaks down glucose into two molecules of pyruvate when oxygen is not present
NAD+
- oxidizing agent during first step of cellular respiration (glycolysis)
- charged carriers
- electron acceptor
What does glycolysis do to NAD+
This process reduces the co-factor NAD+ to NADH
Oxidative phosphorylation
accounts for most of the ATP synthesis
What is Oxidative phosphorylation powered by?
redox reactions
Two Major Phases of Glycolysis
Energy investment phase
Energy payoff phase
Where does glycolysis occur?
cytoplasm
Reactants for Glycolysis
Glucose and two ATP
NET Products of Glycolysis
2 pyruvates, 2 NADH, and 2 ATP
Pyruvate Oxidation Location
Mitochondria
Pyruvate Oxidation *steps
- The pyruvate molecule is oxidized, losing two electrons and a hydrogen molecule.
- The oxidation results in the creation of a NADH molecule and the loss of CO2.
- Pyruvate is made into acetyl coA
What are products of pyruvate oxidation
create acetyl CoA and NADHA (2)
acetyl COA
when pyruvate is converted into a two-carbon molecule bound to Coenzyme A, known as acetyl CoA in pyruvate oxidation
Citric Cycle Location
Mitochondria
Citric Acid Cycle *2 Steps
- Acetyl-CoA will first be bonded to a four carbon molecule called oxaloacetate which will create citric acid
- electrons and hydrogen ions are removed from the citric acid molecule and added to form NADH and FADH2
Citric Acid Cycle Reactants
acetyl CoA (usually done twice so double this)
Citric Acid Cycle Products
1 ATP, 3 NADH, and
1 FADH (this is usually done twice so double this: 6 NADH, 2 FADH2, 2 ATP)
What do you do with NADH and FADH2 from the Citric Acid Cycle?
these become electron carriers who donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation
Where is the electron transport chain?
inner membrane (cristae) of the mitochondrion
Oxidative phosphorylation/ Electron Transport Chain *4 steps
-step that generates most ATP
- The first step of the electron chain is when one of the electron carriers *NADH or FADH
will release an electron. - The electron will be taken by a different carrier that will move through three different membrane proton pump proteins which forms a gradient
- Protons flow back into the matrix through an enzyme called ATP synthase, making ATP.
- oxygen accepts electrons and takes up protons to form water.
Function of Cytochromes
Electrons are passed through a number of proteins including cytochromes (each with an iron atom)
END PRODUCTS OF CELLUALR RESPRIATION
6CO2, 6H2O and 38 ATP molecules *technically 32 since 4 are lost in heat
Why do you need oxygen in the electron transport chain?
unloads electron transport chain ; terminal electron receptor at the end of chain
Two types of Fermentation
- Alcohol Fermentation
- Lactic Acid Fermentation
Lactic Acid Fermentation
- human muscles use this to generate ATP when oxygen is scarce
Obligate anaerobes
carry out fermentation or anaerobic respiration ; cannot survive without oxygen
facultative anaerobes
they can survive using either fermentation or cellular respiration