Lecture 22 - Energy Balances in Cells and Organisms Flashcards
What is the first law of thermodynamics?
- The total energy within a system is constant
- Energy cannot be created or destroyed
- Energy can be converted between forms
What does biochemistry rely on?
energy conversions
What happens during Anabolism?
Adding - Energy is used to make bigger molecules (fuel molecules)
What happens during catabolism?
Cutting - Respiration Energy released when large molecules broken down
What is the energy from ATP hydrolysis used for?
cellular work
Where is energy stored?
In chemical bonds and is released upon the breaking of the bond
What are the high energy bonds in ATP?
phosphoanhydride bonds
What is hydrolysis?
- reaction where a chemical bond is broken using water
- water molecule is consumed in the separation of a larger molecule into smaller parts
What is ATP?
the major energy intermediate (currency) of the cell
What are carbohydrates broken down into?
Monosaccharides
What are proteins broken down into?
amino acids
What are fats broken down into?
fatty acids
What are nucleic acids broken down into?
Nucleotides
What does digestion involve?
- Hydrolysis of bonds connecting monomer units
- Absorption from gastrointestinal tract into body
What are monomers used in the body for?
Catabolism (fuel molecules) – breaking molecules down
and energy conversion into ATP
What are minerals?
inorganic elements in the diet
What is the term for minerals needed in greater abundance in the body?
Major (macro) minerals
What is the term for minerals in very low concentrations in the body?
Minor (trace) minerals
What are some examples of major minerals?
Ca, P, Mg, Na, K, Cl
What are some examples of minor minerals?
Fe, Zn, Se, I, Cu, Cr, Mn, Mo
What are vitamins?
Organic substances usually essential in diet
How can vitamins be classified?
water or fat soluble
Can fat soluble vitamins be stored?
yes
Can water soluble vitamins be stored?
no
What do minerals and vitamins often function as?
Cofactors
What are cofactors?
small molecules required for the activity of an associated
enzyme and have a range of mechanisms
What is a coenzyme?
type of cofactor, organic, often derived from vitamins
What are key features of coenzymes in the pathways?
- low concentration in cells
- act as carriers (transfer things)
- have two forms
What does change of gibbs free energy tell us?
tell us about the amount of energy stored in the chemical bonds of the products and
substrates
Is ATP hydrolysis or ATP synthesis energetically favourable?
ATP hydrolysis (synthesis is unfavourable)
How is energy released from fuel molecules?
Oxidation reactions
What is oxidation?
When the chemical loses an electron
What is reduction?
When the chemical gains an electron
What is the reducing agent?
The chemical that is oxidised, as it being oxidised provides reducing power
What is the oxidising agent?
The chemical that is reduced as it provides oxidising power
What do biological redox reactions often involve the transfer of?
Hydrogen atoms (as well as e-)
What can hydrogen be referred to in redox?
A reducing equivalent
What enzymes often catalyse biological redox reactions?
Dehydrogenases
What is stepwise oxidation of fuel molecules?
The more gradual oxidation in steps, rather than all at once allowing for the energy to be captured for ATP production
