ALLCBTs

Senior Secondary School Biology Questions.

Published on Jul 22, 2025 • Education

Introduction

Good day, everyone!
My name is Ade Banke, and I’ll be your biology tutor for today’s session. In this tutorial, we’ll be tackling key senior secondary school biology questions, focusing on DNA replication and bacterial survival mechanisms. These topics are commonly featured in WAEC, NECO, and JAMB exams.

Let’s dive straight into the questions and explain them step by step for deeper understanding.

You can watch the full class in the video below:

Question 1: What Process Allows Prokaryotes to Survive Harsh Conditions?

Question:
Which process allows prokaryotes to survive harsh conditions by forming a tough, protective wall?

• A. Budding
• B. Binary fission
• C. Endospore formation
• D. Sporulation

Explanation:

This question explores the adaptation of prokaryotes (like bacteria) to extreme environments such as high heat, dehydration, or nutrient deficiency.

• Option A: Budding – This is a form of asexual reproduction, not a survival mechanism.
• Option B: Binary fission – This is how cells divide, not how they survive stress.
• Option C: Endospore formation – Correct! Endospore formation is a special method bacteria use to encase themselves in a durable structure to resist unfavorable conditions.
• Option D: Sporulation – This refers more generally to spore formation in plants and fungi, not prokaryotes.

Correct Answer: C. Endospore formation

Question 2: Which Enzyme Is Responsible for Unzipping DNA Strands During Replication?

Understanding DNA Replication:

DNA is a double-stranded helical molecule, often compared to a twisted ladder. For DNA replication to occur, the strands must first separate or "unzip" to allow the creation of a complementary copy—just like making a photocopy of a textbook.

• A. DNA ligase
• B. DNA helicase
• C. DNA polymerase
• D. RNA primase

Explanation:

Each of these enzymes has a specific role in DNA replication:

• DNA Ligase acts like glue, joining Okazaki fragments on the lagging strand.
• DNA Helicase is like a scissors or unzipper, breaking hydrogen bonds between base pairs to unwind the double helix.
• DNA Polymerase adds new nucleotides to build the new strand.
• RNA Primase lays the initial RNA primer for DNA polymerase to start copying.

Correct Answer: B. DNA helicase

Remember:

Think of helicase as a molecular "zip opener" that starts the replication process by unwinding the helix.

Watch more educational videos and past questions: https://youtube.com/@allcbts

Conclusion

Today’s biology lesson helped clarify:

• How bacteria use endospore formation as a survival strategy
• The function of helicase in DNA replication
• These concepts form the foundation for more advanced biology topics and are frequently asked in exams. Make sure to:
• Understand definitions and functions of biological processes
• Practice related multiple-choice questions
• Use diagrams to visualize processes like replication and cell structure

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