1. Those part of the DNA or gene that contribute to the mRNA product is called _________
a) Introns
b) Intervening sequences
c) Exons
d) Split genes
Explanation: Intervening sequences, also called introns are the portions of DNA excluded during transcription and thus are not there in the mRNA product. Exons are the part of DNA transcribed to form mRNA. The genes with intervening sequences are called split genes.
2. Which of the following disaccharides have beta (1->4) bond?
a) Maltose and Sucrose
b) Maltose and Isomaltose
c) Lactose and Cellobiose
d) Sucrose and Cellobiose
Explanation: Among the disaccharides, sucrose, maltose and isomaltose have alpha(1->4) glycosidic bond. However, lactose, lactulose and sucrose have beta(1->4) glycosidic linkage.
3. An example of polar but uncharged amino acid is ___________
a) Lysine
b) Aspartate
c) Serine
d) Arginine
Explanation: Lysine and Arginine are polar and positively charged amino acids. While Aspartate is a polar and negatively charged amino acid. Serine is a polar and uncharged amino acid.
4. Example of a polar amino acid is ____________
a) Glutamine
b) Alanine
c) Methionine
d) Valine
Explanation: Glutamine is a polar but non-charged amino acid. Alanine, Valine and Methionine, on the other hand, are non-polar amino acids.
5. Reactions that lose heat are termed as _____________
a) endothermic
b) exothermic
c) chemical
d) physical
Explanation: Energy can neither be created nor be destroyed. It is only transduced from one form into another. Heat is also a form of energy; reactions in which heat is lost to the surroundings are termed as exothermic reactions and those in which heat is gained from the system are termed as endothermic reactions.
6. According to laws of thermodynamics, the energy of the Universe is _________ whereas the entropy ______________
a) constant, increases
b) constant, decreases
c) increases, remains constant
d) decreases, remains constant
Explanation: According to the first and second laws of thermodynamics, the energy of the universe remains constant however the entropy increases owing to the randomness.
7. Exergonic processes are thermodynamically unfavorable.
a) true
b) false
Explanation: The processes having negative Gibbs free energy (-ΔG) are termed as exergonic; are thermodynamically favored and are spontaneous in nature. Processes having +ΔG are endergonic, thermodynamically unfavorable and non-spontaneous.
8. Hydrolysis of ATP is which type of reaction?
a) Physical
b) Mechanical
c) Endergonic
d) Exergonic
Explanation: Hydrolysis of ATP is the most important chemical reaction in a living cell. It is highly favorable and exergonic with a standard free energy (ΔG⁰’) between reactants and products equal to -7.3 kcal/mol.
9. Cellular metabolism is a non-equilibrium metabolism.
a) true
b) false
Explanation: Cellular metabolism is essentially a non-equilibrium metabolism; that is the ratio of reactants to products is maintained in a non-equilibrium state. This makes most of the reactions irreversible.
10. Which of the following are responsible virtually for every reaction that takes place inside a cell?
a) Carbohydrates
b) ADP
c) Nucleic acids
d) Enzymes
Explanation: Enzymes are the catalysts responsible for virtually everything that takes place inside a cell. Without these catalysts the cellular metabolism and bioenergetics would be imperceptible.