Chapter 8: 8.1 Introduction to Metabolism Flashcards
What provides most of the energy for metabolic reactions?
Electron transfers
Many biological molecules need to be…
Reduced
What is the mnemonic for oxidation/reduction?
OIL RIG
* Oxidation Is Loss (of an electron) - more bonds to oxygen (an electronegative atom), where applicable
* Reduction Is Gain (of an electron)
What are pairs of compounds in which one compound is readily oxidized/reduced called?
Redox pairs
Give examples of redox pairs
NADH and NAD+
NAPDH and NADP+
What is the reducing power of NADH important for?
ATP synthesis
Describe:
NAD
Nictoinamide Adenine Dinucelotide
* Carries electrons on the nicotinamide group
How many electrons can NAD+ accept?
Two electrons in the form of a hydride anion (H atom with 2 electrons)
Describe:
NADP
Nicotinamide Adenine Dinucleotide Phosphate
What is NADPH important in?
Reducing power of NADPH is important in biosynthesis of bio-molecules (e.g. lipids, cholesterol, etc.)
Define:
Metabolism
Describes the combined processes of energy production and utilization within living organisms
What are the two phases/processes of metabolism?
- Catabolism
- Anabolism
Define:
Catabolism
The conversion of high energy nutrients to low energy products
Catabolism is a ——— process where ATP is ——-
- Oxidative
- Created
Anabolism is a ——— process where ATP is ——–
- Reductive
- Utilized
What kind of process is catabolism?
An exergonic (spontaneous) process
* Results in the loss of energy from starting material
What kind of process is anabolism?
An endergonic (non-spontaneous) process
* Results in disordered and free floating small molecules being converted into ordered macromolecules
Define:
Phototrophs
Utilize light energy
Define:
Chemotrophs
Utilize energy from oxidized electron donors
Define:
Autotrophs
Use CO2 as their source of carbon
Define:
Heterotrophs
External organic sources of carbon
Define:
Photoautotrophs
Utilize light energy and CO2 as a carbon source
Define:
Chemoautotrophs
Utilize energy from oxidized electron donors and CO2 as a carbon source
Define:
Photoheterotrophs
Utilize light energy but can not utilize CO2 as a carbon source
Define:
Chemoheterotrophs
Utilize energy from oxidized electron donors and but can not utilize CO2 as a carbon source
What are the Metabolic Classifications?
- Phototrophs
- Chemotrophs
- Autotrophs
- Heterotrophs
- Photoautotrophs
- Photoheterotrophs
- Chemoautotrophs
- Chemoheterotrophs
——- are responsible for carrying out metabolic pathways
Enzymes
Metabolic pathways can be regulated at any point, how can the enzymes be regulated?
- Competitively
- Non-competitively
- Allosterically
State the formula for:
Gibbs Free Energy Change
ΔG = ΔG’^o +RTln(P/S)
State the formula for:
Standard Free Energy Change
ΔG’^o = -RTln(Keq’)
State how the reaction progresses if:
- Keq = 1, ΔG’^o = 0
- Keq < 1, ΔG’^o > 0
- Keq > 1, ΔG’^o < 0
- The reaction is at equilibrium
- The reverse reaction is spontaneous
- The forward reaction is spontaneous
Unfavourable reactions can be coupled with favourable reactions if…
The sum of the standard free energy is a negative value
Define:
Flux
The conversion metabolites through the enzymes involved in the metabolic pathway
Define:
High Energy Intermediates
Molecules that can be broken down to release large amounts of energy
What does the difference in free energy upon bond breakage depend on?
Stabilization
How do we determine the amount of energy released?
The more stable the product, the greater the energy released
List:
How to identify a highly stable product
- Elimination of bond strain
- Stabilization by ionization
- Isomerization
- Resonance stabilization
ATP can accept or donate…
Phosphates
What pathways is ATP involved in?
Involved in both:
* Catabolism and Anabolism pathways
Other than ATP, what are some other high energy intermediates?
- Mixed anhydrides
- Enol phosphates
- Thioesters
- Phosphocreatine
Describe:
Phosphocreatine
A way of storing high energy phosphates
* ΔG’^o = -43 kJ/mol allows it to be cleaved to produce ATP in a favourable reaction
