IB Biology HL Paper 1 Questions

Get ready to challenge your understanding of IB Biology HL with our latest set of practice questions! Covering Genetics, Human Physiology, and Ecology, these questions are designed to test and reinforce key concepts crucial for your success in the exam. Following the questions, you'll find detailed solutions that explain the reasoning behind each answer, helping you solidify your knowledge.

Let's dive into these questions and enhance your biology expertise!

Practice Questions

1. Question 1:

   • Topic: Genetics and Evolution

   • Question: What is the main purpose of polymerase chain reaction (PCR) in genetic engineering?

     • A) To cut DNA into fragments

     • B) To amplify specific DNA sequences

     • C) To introduce DNA into host cells

     • D) To seal DNA fragments together

2. Question 2:

   • Topic: Human Health and Physiology

   • Question: Which part of the human brain is primarily responsible for coordination and balance?

     • A) Cerebrum

     • B) Cerebellum

     • C) Medulla oblongata

     • D) Hypothalamus

3. Question 3:

   • Topic: Ecology

   • Question: Which process is primarily responsible for the transfer of energy from autotrophs to heterotrophs in an ecosystem?

     • A) Photosynthesis

     • B) Respiration

     • C) Decomposition

     • D) Consumption

Worked Solutions

1. Solution to Question 1:

   • PCR (Polymerase Chain Reaction) is a technique used in molecular biology.

   • It is not used for cutting DNA into fragments (that's the role of restriction enzymes) or for introducing DNA into host cells.

   • PCR is also not used for sealing DNA fragments together; that's the function of DNA ligase.

   • The primary purpose of PCR is to make millions of copies of a specific DNA sequence, thus amplifying it.

   • Answer: B) To amplify specific DNA sequences

2. Solution to Question 2:

   • The human brain has different parts responsible for various functions.

   • The cerebrum is involved in higher brain functions like thought and action.

   • The cerebellum is known for its role in coordinating movement and balance.

   • The medulla oblongata controls automatic functions like breathing and heart rate.

   • The hypothalamus is responsible for hormonal control and regulation of body temperature.

   • Therefore, the part responsible for coordination and balance is the cerebellum.

   • Answer: B) Cerebellum

3. Solution to Question 3:

   • In an ecosystem, energy transfer is a key process.

   • Photosynthesis is how autotrophs (like plants) capture energy from the sun, but it is not how energy is transferred to heterotrophs.

   • Respiration releases energy from food, but it's not the method of energy transfer from autotrophs to heterotrophs.

   • Decomposition breaks down organic matter, but it's not the primary method of energy transfer to heterotrophs.

   • Consumption, where heterotrophs (like animals) eat autotrophs or other heterotrophs, is the primary way energy is transferred in an ecosystem.

   • Answer: D) Consumption

These questions and solutions are aimed at reinforcing key concepts in the IB Biology HL syllabus, providing a clear and concise understanding of each topic.