Match the terms in Column II with the descriptions in Column I. Also, state the importance of DNA replication and the monomers of DNA.

• Altricial refers to young that are born or hatched helpless and require extensive parental care.
• Precocial refers to young that are relatively mature and mobile at birth or hatching, requiring less parental care.

The description "A reproductive strategy where the young is independent of their parents" directly matches the definition of precocial.

The correct answer is B ONLY.

Question 1.3.2

DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule.

• A: "Doubles genetic material" is a direct outcome and importance of DNA replication, ensuring that each daughter cell receives a complete set of chromosomes during cell division.
• B: "Formation of mRNA" is the process of transcription, where DNA is used as a template to synthesize mRNA, which is distinct from DNA replication.

The importance of DNA replication is to double the genetic material.

The correct answer is A ONLY.

Question 1.4.1

a) The monomers (building blocks) of a DNA strand are nucleotides.

b) The type of sugar found in an mRNA strand is ribose.

Question 1.4.2

To answer this, we first need to complete the table using the given information that both the DNA strand and mRNA strand are 18 nitrogenous bases long, and applying base pairing rules (A-T in DNA, A-U in mRNA, C-G in both).

Given:

• Total bases in DNA strand = 18
• Total bases in mRNA strand = 18

Initial table:

• If DNA Guanine (G) = 5, then mRNA Cytosine (C) = 5.
• If DNA Thymine (T) = 2, then mRNA Adenine (A) = 2.
• If mRNA Guanine (G) = 8, then DNA Cytosine (C) = 8.

For the DNA STRAND:

• Known bases: Thymine (2) + Guanine (5) + Cytosine (8) = 15
• Remaining bases for Adenine = 18 - 15 = 3
  • So, DNA Adenine = 3

For the mRNA STRAND:

• Known bases: Adenine (2) + Cytosine (5) + Guanine (8) = 15
• Remaining bases for Uracil = 18 - 15 = 3
  • So, mRNA Uracil = 3

Completed table:

a) From the completed table, the number of Adenine bases present in the DNA strand is 3.

b) From the completed table, the number of Cytosine bases present in the mRNA strand is 5.

Question 1.4.3

DNA contains the nitrogenous bases Adenine, Guanine, Cytosine, and Thymine. Uracil is found in RNA, replacing Thymine.

Based on the composition of DNA, uracil is not present in a DNA strand.

The percentage of uracil in the DNA strand is 0%.