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Cell Membrane Notes

Site: ShuleniHub E-Learning
Course: Grade 8 Integrated Science - Materials in and out of the cell - Cell Membrane
Book: Cell Membrane Notes
Printed by: Guest user
Date: Friday, 19 September 2025, 6:53 AM

Table of contents

1. Comparing animal and plant cells

Plant and Animal Cells

Chapter 3: Cell Biology

Plant and animal cells have slight differences in their internal structures while some features are common in both. The figures below show the components of both plant and animal cells as seen under a light microscope.

Plant Cell

Cell Wall
Cell Membrane
Nucleus
Chloroplast
Vacuole

Diagram showing plant cell structure

Animal Cell

Cell Membrane
Nucleus
Mitochondria
Small Vacuoles

Diagram showing animal cell structure

Complete Comparison Table

Feature Plant Cell Animal Cell
Size Large in size (10-100 micrometers) Small compared to plant cells (10-30 micrometers)
Cell Wall Present - made of cellulose Absent - no cell wall
Cell Membrane Present Present
Nucleus Present - controls cell activities Present - controls cell activities
Chloroplasts Present - contain chlorophyll for photosynthesis Absent - no chloroplasts
Vacuoles Large permanent vacuole - stores water and maintains pressure Small temporary vacuoles or none - for storage and transport
Mitochondria Present - cellular respiration Present - powerhouse of the cell
Shape Fixed rectangular/square shape due to cell wall Variable round/irregular shape
Main Function Photosynthesis and food production Movement, feeding, and rapid response

P Plant Cell Unique Features

  • Size: They are large in size.
  • Cell Wall: It has a cell wall made of cellulose.
  • Chloroplasts: Some plant cells have chloroplasts that give the plant its green colour.
  • Vacuole: Plant cells have a permanent vacuole that occupies a large part of the cell.

A Animal Cell Unique Features

  • Size: They are small compared to plant cells.
  • Cell Wall: It does not have a cell wall.
  • Chloroplasts: It lacks chloroplasts.
  • Vacuole: Animal cells usually do not have vacuoles, however, small temporary vacuoles may occur.

✓ Similarities between Plant and Animal Cells

Cell Membrane: They both have the cell membrane.

Nucleus: Both have nucleus within them.

2. Functions of Cell Structures

Functions of Cell Structures

Chapter 3: Cell Biology - Part B

Understanding the specific functions of cellular structures helps us appreciate how cells maintain life processes. Each organelle and structure has evolved to perform specialized tasks essential for cell survival and function.

Plant Cell - Functional Overview

Protection & Shape
Controls Entry/Exit
Control Center
Photosynthesis
Storage & Support

Animal Cell - Functional Overview

Controls Entry/Exit
Control Center
Energy Production
Temporary Storage

Detailed Functions of Cell Structures

Part/Structure Function Found in
Vacuole
 It is the space that has a watery fluid (cell sap) that contains dissolved water, mineral salts and waste products. In plants: Large permanent vacuole maintains cell pressure and provides structural support. In animals: Small temporary vacuoles assist in storage and transport of materials. Both plant and animal cells
Cell Membrane
 Cell membrane is a thin layer around the cell that holds the cell together. It acts like a fence and controls what goes in and out of the cell. Therefore, the cell can take in substances it needs and get rid of waste products. This selective permeability is essential for maintaining cell homeostasis. Both plant and animal cells
Cytoplasm
 It is a jelly-like liquid that fills inside the cell. The cytoplasm is where chemical reactions of the cell take place. It also contains small structures called organelles which have special functions. The cytoplasm provides a medium for organelle movement and nutrient transport. Both plant and animal cells
Nucleus
 The nucleus carries genetic information and controls what happens or all the activities of the cell. It contains DNA which provides instructions for protein synthesis, cell division, and inheritance. Often called the "brain" or "control center" of the cell. Both plant and animal cells
Cell Wall
 It is a thick, tough layer made from cellulose found on the outside of the cell. It covers the cell membrane in plant cells. Cell wall helps the cell to keep its shape. It protects the cell from mechanical damages and provides structural support to the entire plant. Plant cells only
Chloroplast
 It is an organelle in the cytoplasm of plant cells. Chloroplast contain green pigment called chlorophyll. Chlorophyll absorbs light that is used by plants to make their own food through photosynthesis. This process converts light energy, carbon dioxide, and water into glucose and oxygen. Plant cells only

🔬 Key Takeaways

Universal Structures

Cell membrane, cytoplasm, nucleus, and vacuoles are found in both plant and animal cells, each performing essential life functions.

Plant Specializations

Cell walls provide structure and protection, while chloroplasts enable photosynthesis - making plants autotrophic organisms.

Functional Integration

All cell structures work together as an integrated system to maintain life, with each organelle contributing to overall cell function.

Page 46 | Cell Biology Textbook