The anticodon for the amino acid tryptophan is ACC.
What shows a template DNA sequence that includes the DNA triplet for tryptophan?
▶️ Answer/Explanation
Ans: D
Given the tRNA anticodon ACC, the mRNA codon would be UGG (complementary). The template DNA strand must be ACC (complementary to mRNA). Option D contains ACC in the middle sequence (CCT ACC CAT), making it correct. Remember DNA uses T instead of U.
Which processes occur during the formation of messenger RNA?
- condensation
- polymerisation
- replication
- transcription
▶️ Answer/Explanation
Ans: B
During mRNA formation: condensation (1) links nucleotides, polymerisation (2) builds the RNA chain, and transcription (4) copies DNA to RNA. Replication (3) is for DNA copying, not RNA synthesis. Thus, the correct processes are 1, 2, and 4 (B).
Which strand of DNA does RNA polymerase bind to?
▶️ Answer/Explanation
Ans: D
RNA polymerase binds to the template strand (D) during transcription. This strand provides the complementary sequence for mRNA synthesis. The terms “lagging strand” (A) and “leading strand” (B) relate to DNA replication, while “non-transcribed strand” (C) is the opposite of the template strand.
Which properties of water are dependent on hydrogen bonding between water molecules?
▶️ Answer/Explanation
Ans: B
Hydrogen bonding in water is responsible for:
- High surface tension (cohesion between water molecules at the surface).
- High specific heat capacity (energy needed to break hydrogen bonds before temperature rises).
- Solvent properties (polarity from hydrogen bonding enables dissolving ionic/polar substances).
Option B correctly includes these properties. Density and freezing (not in B) are less directly dependent on hydrogen bonding.