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MH1010 Biochemistry Exam Questions With
Correct Answers
How are peptide bonds formed? - answer✔They are formed by the condensation of the alpha
carboxyl of one amino acid and the amino group of another
Define biochemistry - answer✔Biochemistry is the study of chemical substances and processes
occurring in living organisms
Define PH
What is the ionic product of water? - answer✔PH = -log[H+]
kw = [H+][OH-]
[H+] = [OH-]
Describe the PH scale - answer✔Acid - PH of less than 7
Base - PH of more than 7
Neutral - PH of 7
What is the normal PH of blood?
What happens if there is changes in this PH? - answer✔The PH of blood should be 7.35 - 7.4
If PH drops below 6.8 - acidosis
If PH goes above 7.8 - alkalosis
How does ATP carry energy? - answer✔Phosphoryl groups are added via two
phosphoanhydride and one phosphoester bond
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When these bonds are broken by the process of hydrolysis, energy is released
What is the difference between exergonic and endergonic? - answer✔Exergonic - energy
releasing
Endergonic - energy requiring
Define the first law of thermodynamics - answer✔Energy is conserved, it can neither be created
nor destroyed
Define the second law of thermodynamics - answer✔In any closed system, the entropy of the
system will either remain constant or increase
Define enthalpy - answer✔Enthalpy is the internal energy in a system - H
Define entropy - answer✔Entropy is the randomness or disorder in a system - S
Define Gibbs Free Energy - answer✔This expresses the amount of energy capable of doing work
during a reaction at a constant temperature and pressure - G
Write the equation for gibbs free energy - answer✔Delta G - change in free energy
Delta H - change in enthalpy
Delta S - change in entropy
T - absolute temperature
What does a negative delta G mean in terms of gibbs free energy? - answer✔- Energy is
released, exergonic
- Tend to occur spontaneously
What does a positive delta G mean in terms of gibbs free energy? - answer✔- Energy is
consumed, endergonic
- Will not occur unless energy is supplied
What are the bonds found in each type of biomolecule? - answer✔- Carbohydrates - glycosidic
bonds
- Proteins - peptide bonds
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- Nucleic acids - phosphodiester bonds
What are stereoisomers? - answer✔Stereoisomers are two chemicals that have the same
chemical and structural formulas but the geometrical positioning of the functional groups in
space differs
What are enantiomers? - answer✔These are stereoisomers that mirror one another and as a
result cannot be superimposed on one another
What are essential amino acids? - answer✔Histidine - H
Valine - V
Tryptophan - W
Threonine - T
Phenylalanine - F
Methionine - M
Isoleucine - I
Leucine - L
Lysine - K
What is transcription? - answer✔This is the DNA dependant synthesis of RNA
What is translation? - answer✔This is the process where mRNA sequence is used to order and
join amino acids into a polypeptide chain
Give the functions of the three different types of RNA - answer✔rRNA - found in the ribosome -
plays a role in protein synthesis
mRNA - carries genetic information from the nucleus to the cytoplasm during protein synthesis
tRNA - translates a sequence of mRNA into amino acids
What is the general structure of an amino acid? - answer✔Amino acids consist of ;
- An amino group, NH3+
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