Question 1: Define DNA and describe its primary function in living organisms.

Answer: DNA (Deoxyribonucleic Acid) is the molecule that stores genetic information in all living organisms and provides the instructions needed for growth, development, and reproduction.

Question 2: What are the four types of nitrogenous bases found in DNA?

Answer: Adenine, Thymine, Cytosine, and Guanine.

Question 3: Explain the significance of the double-helix structure of DNA.

Answer: The double-helix structure allows DNA to be very stable and compact, and it enables the molecule to replicate accurately during cell division. The complementary base pairing (A with T, C with G) facilitates precise copying of genetic information.

Question 4: Which component of DNA makes up the backbone of the molecule?

Answer: The sugar-phosphate backbone.

Question 5: Fill in the blank: In DNA, adenine pairs with __________, and cytosine pairs with __________.

Answer: Thymine, Guanine

Question 6: Calculate the total number of hydrogen bonds formed between 10 pairs of adenine-thymine bases and 10 pairs of cytosine-guanine bases.

Answer: A-T pairs form 2 hydrogen bonds each; C-G pairs form 3 hydrogen bonds each. Total bonds = (10 × 2) + (10 × 3) = 20 + 30 = 50 hydrogen bonds.

Question 7: Multiple Choice: Which part of the nucleotide differs among the four types of bases in DNA?

Answer:

Question 8: Describe the process by which DNA replicates itself before cell division.

Answer: DNA replication involves the unwinding of the double helix, separation of the two strands, and complementary base pairing where each original strand serves as a template for a new strand. DNA polymerase enzymes facilitate the addition of new nucleotides, resulting in two identical DNA molecules.

Question 9: Identify the role of hydrogen bonds in maintaining the structure of DNA.

Answer: Hydrogen bonds between complementary bases hold the two strands of DNA together, stabilizing the double-helix structure.

Question 10: Explain why DNA's structure is suitable for its function in storing genetic information.

Answer: DNA's stable double-helix structure, with complementary base pairing, allows it to reliably store and transmit genetic information across generations. Its compact form fits within the nucleus and can be accurately copied during cell division.

Question 11: In modern biotechnology, how is understanding DNA structure utilized in DNA fingerprinting?

Answer: Knowing the structure of DNA allows scientists to analyze specific sequences through techniques like PCR and gel electrophoresis, which are used in DNA fingerprinting to identify individuals based on genetic differences.