G11 Biology Term 3 Exam Review

The organelle responsible for modifying, sorting, and packaging proteins is

• Mitochondria

• Golgi Apparatus

• Ribosome

• Nucleus

Answer explanation

What does the Golgi apparatus do?

It modifies, sorts, and packages proteins made by the ribosomes. Think of it as the post office of the cell—it processes and ships proteins to their correct destinations.

How does it work?

Proteins are first made by the ribosomes and sent to the endoplasmic reticulum (ER). The Golgi apparatus receives these proteins, modifies them (like adding sugars or cutting them), and sends them where they are needed (inside or outside the cell).

Which of the following is NOT a function of the plasma membrane?

• Regulating the movement of materials into and out of the cell

• Providing structural support

• Controlling cellular respiration

• Allowing cell communication

Answer explanation

The plasma membrane (also called the cell membrane) has three main functions:

-Regulating what enters and leaves the cell (like a security gate).

-Providing structural support to keep the cell intact.

-Allowing cell communication by sending and receiving signals.

However, cellular respiration (making energy/ATP) happens in the mitochondria, not the plasma membrane.

In cellular respiration, the majority of ATP is produced during

• Glycolysis

• The Citric Acid Cycle

• Oxidative Phosphorylation

• Pyruvate Oxidation

Answer explanation

Cellular respiration has three main stages:

Glycolysis – Breaks down glucose, produces 2 ATP.

Citric Acid Cycle (Krebs Cycle) – Generates electron carriers (NADH, FADH₂), produces 2 ATP.

Oxidative Phosphorylation – Uses electron transport chain (ETC) to make about 34 ATP.

Since most ATP (about 34 out of 38 total ATP) comes from oxidative phosphorylation, this is the correct answer.

Which of the following molecules is the final electron acceptor in oxidative

phosphorylation?

• NADH

• ATP

• Oxygen

• Carbon dioxide

Answer explanation

During oxidative phosphorylation (the last step of cellular respiration), electrons move through the electron transport chain (ETC). At the end of the chain, these electrons need a final acceptor to complete the process.

Oxygen (O₂) is the final electron acceptor.

It combines with electrons and hydrogen ions to form water (H₂O).

This process helps drive ATP production by creating a proton gradient.

Which type of signaling involves hormones traveling through the bloodstream to

reach target cells?

• Paracrine

• Endocrine

• Autocrine

• Synaptic

Answer explanation

Endocrine signaling uses hormones that travel through the bloodstream to reach target cells in different parts of the body.

For Example: Insulin is released by the pancreas and travels through the blood to regulate blood sugar in different organs.

The process in which glucose is broken down to pyruvate in the cytoplasm is

called

• Glycolysis

• The Calvin cycle

• The Krebs cycle

• Oxidative phosphorylation

Answer explanation

Glycolysis is the first step of cellular respiration.

It breaks down glucose (C₆H₁₂O₆) into two pyruvate (C₃H₄O₃) molecules in the cytoplasm.

This process does not require oxygen (anaerobic) and produces a net gain of 2 ATP.

What happens to an animal cell in a hypertonic solution?

• It swells and bursts

• It stays the same

• It shrinks

• It undergoes mitosis

Answer explanation

A hypertonic solution has more solutes (salt, sugar, etc.) than the inside of the cell.

Water moves out of the cell by osmosis to balance the concentration.

As a result, the cell shrinks and becomes dehydrated (crenation in animal cells).

The main function of ribosomes is

• Energy production

• Lipid synthesis

• Protein synthesis

• DNA replication

Answer explanation

Ribosomes are tiny structures found in all cells.

Their main job is to assemble amino acids into proteins based on the instructions from mRNA (messenger RNA).

They can be free-floating in the cytoplasm or attached to the rough endoplasmic reticulum (RER).

Which of the following organelles contains hydrolytic enzymes to break down

waste and cellular debris?

• Golgi apparatus

• Lysosome

• Ribosome

• Mitochondria

Answer explanation

Lysosomes are membrane-bound organelles filled with hydrolytic enzymes that break down waste, old cell parts, and cellular debris.

They act as the cell’s recycling center, digesting unwanted materials and recycling useful components.

They also play a role in defense by breaking down bacteria or harmful substances.

10. A ligand binds to a receptor, triggering a signal transduction pathway. This is an

example of:

• Passive transport

• Cell communication

• Cellular respiration

• DNA replication

Answer explanation

A ligand is a signaling molecule that binds to a receptor protein on a cell’s surface or inside the cell.

This activates a signal transduction pathway, where the signal is relayed and amplified inside the cell, leading to a specific response (such as gene expression or enzyme activation).

This process is a key part of cell communication and is used in hormone signaling, immune responses, and nervous system function.