Principles Biochemistry Flashcards
What is rRNA?
Ribosomal RNA.
What is the function of rRNA?
rRNA combines with proteins to form ribosomes, where protein synthesis takes place.
Define a redox reaction
A redox reaction is the transfer of electrons from one molecule to another.
Define an oxidation reaction.
An oxidation reaction results in the loss of electrons.
Define a reduction reaction.
A reduction reaction results in the gain of electrons.
Name 3 major classes of molecules.
- Peptides
- Proteins
- Lipids.
- Nucleic acids.
- Carbohydrates.
Give a function of a biomolecule.
- DNA
- Structural (bones, teeth, cartilage).
- Recognition/communication/specificity as hormones/receptors/enzymes.
- Energy currency/storage as ATP.
Give an example of a carbohydrate.
Monosaccharide, disaccharide, polysaccharide (cellulose and glycogen).
What is the First law of thermodynamics?
Energy is neither created nor destroyed.
What is the Second Law of thermodynamics?
As energy is converted from one form to another, some of the energy becomes unavailable to do work.
How may the free energy change (ΔG) be calculated?
Energy of products - energy of reactants.
Describe an exergonic reaction.
An exergonic reaction is one in which the total free energy of the products is less than that of the reactants. ΔG is NEGATIVE.
Can an exergonic reaction occur spontaneously or not?
Yes. Exergonic reactions may occur spontaneously.
Describe an endergonic reaction.
Reactions in which the total free energy of the products is greater than that of the reactants. ΔG is POSITIVE.
Can an endergonic reaction occur spontaneously?
No. they require an input of energy in order to proceed.
ΔG values near zero are characteristic of which type of reaction?
Readily reversible reactions.
What does ΔG = 0 indicate about the system?
It indicated the system is at equilibrium.
Phosphoglucomutase catalyses which reaction?
Glucose-6-phosphate Glucose-1-phosphate.
Glucose-6-phosphate Glucose-1-phosphate.
What are the forward and backward reactions involved in?
Forward: glycogen synthesis.
Backward: glycogen breakdown.
How may unfavourable cellular processes be driven?
By coupling them to highly favourable processes.
What is ATP used for?
It is a universal energy currency for driving many different cellular processes.
Is ATP stored in cells in large amounts?
No, it is constantly regenerated.
How may ATP be regenerated?
Using creatine phosphate.
What type of energy bonds do anhydride bonds possess?
High energy bonds.