Back to: Botany 100 Level
Hello, my brilliant Afrilearn scholar! Have you ever thought about what makes a city work? A city has different departments—electricity, transport, security, and waste management—all working together to keep things running smoothly. In the same way, a cell has tiny structures called organelles, each with a special job to keep the cell alive and functioning.
Today, we’ll look at the different organelles found in eukaryotic cells and what makes each one important!
Overview Of Cell Organelles In Eukaryotic Cells
What are Eukaryotic Cells?
Before we talk about organelles, let’s quickly understand eukaryotic cells. These are cells that have a nucleus and other complex organelles. They are found in plants, animals, fungi, and protists.
Eukaryotic cells are different from prokaryotic cells (like bacteria), which do not have a nucleus or complex organelles.
Major Organelles in Eukaryotic Cells and Their Functions
Just like different parts of a city have different jobs, each organelle inside a eukaryotic cell has a specific role:
1. Nucleus – The Control Centre
The nucleus is the “brain” of the cell.
It contains DNA, which holds genetic instructions for growth and reproduction.
It directs all activities in the cell, just like a governor manages a city.
2. Cell Membrane – The Security Gate
The cell membrane surrounds the cell and controls what goes in and out.
It acts like a security gate, allowing useful substances like oxygen in while keeping harmful substances out.
3. Cytoplasm – The Work Area
The cytoplasm is the jelly-like substance that fills the cell.
It holds all the organelles and allows movement of materials within the cell.
4. Mitochondria – The Powerhouse
The mitochondria produce energy by breaking down food (glucose).
Just like a power station supplies electricity to a city, mitochondria provide energy for the cell to function.
5. Endoplasmic Reticulum (ER) – The Transport System
The endoplasmic reticulum (ER) is a network of tunnels that transports materials around the cell.
It comes in two types:
Rough ER (has ribosomes) – Helps in protein production.
Smooth ER (no ribosomes) – Helps in making lipids (fats) and detoxifying harmful substances.
6. Ribosomes – The Protein Factories
Ribosomes are small structures that make proteins, which are needed for growth and repair.
They can be found floating in the cytoplasm or attached to the rough ER.
7. Golgi Apparatus – The Packaging Centre
The Golgi apparatus modifies, sorts, and packages proteins for transport.
It works like a post office, ensuring proteins reach their correct destination.
8. Vacuole – The Storage Tank
Vacuoles store water, food, and waste.
In plant cells, the vacuole is large and helps maintain the cell’s shape.
In animal cells, vacuoles are smaller but still important for storage.
9. Lysosomes – The Waste Disposal (Mainly in Animal Cells)
Lysosomes contain digestive enzymes that break down waste and old cell parts.
They act like the garbage disposal system of a city, keeping the cell clean.
10. Chloroplasts – The Food Factory (Only in Plant Cells)
Chloroplasts are found in plant cells and contain chlorophyll, which makes plants green.
They carry out photosynthesis, converting sunlight into food for the plant.
11. Cell Wall – The Support Structure (Only in Plant Cells)
The cell wall is a strong outer layer found only in plant cells.
It provides support and protection, just like a fence around a compound.
Key Differences Between Plant and Animal Cells
Feature
Plant Cell
Animal Cell
Cell Wall
Present
Absent
Chloroplasts
Present
Absent
Vacuole
Large and central
Small and scattered
Lysosomes
Rare
Common
Why Are Organelles Important?
Without organelles, a cell would not function properly. Each organelle:
Helps the cell grow, move, and survive.
Produces energy and nutrients.
Removes waste to keep the cell healthy.
In the same way that a city cannot run without electricity, water, and transportation, a cell cannot function without organelles!
Summary
Eukaryotic cells are complex cells with a nucleus and organelles.
Each organelle has a specific function, like running a city.
The nucleus controls the cell, mitochondria provide energy, ribosomes make proteins, and the Golgi apparatus packages materials.
Chloroplasts and cell walls are found only in plant cells.
Organelles work together to keep the cell alive and functioning properly.
Evaluation
- What is the function of the nucleus in a eukaryotic cell?
- Which organelle is known as the “powerhouse” of the cell, and why?
- What is the main difference between rough ER and smooth ER?
- Why do plant cells have chloroplasts, but animal cells do not?
- What is the role of the Golgi apparatus in the cell?
You are doing an incredible job! Cells may be tiny, but they have a whole world inside them! Keep up the great learning, and I’ll see you in the next lesson!
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