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Cell theory

Introduction to cell theory--the idea that 1) all living things are made of one or more cells, 2) cells are the basic unit of life and 3) all cells come from other cells. Explore the roles that Hooke, Leeuwenhoek and others played in developing cell theory.

Hooke and Leeuwenhoek were two of the first scientists to use microscopes to study the microscopic world of cells. Hooke coined the term "cell" after observing the tiny compartments in cork, while Leeuwenhoek discovered a variety of living creatures in pond water, blood, and other samples. They contributed to the cell theory by suggesting that cells are the fundamental units of life and structure, and that all living things consist of one or more cells that originate from other cells by division. 

Subject and Topic
Form 1
Biology
Cell structure and organisation
Concept of cells
Resource Type
Video
Language
English
Publisher
Khan Academy
Publication Date
2015
Creator/Author
Sal Khan
Keyword
Cells

Cells and organisms

All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular).

Subject and Topic
Form 1
Biology
Cell structure and organisation
Concept of cells
Resource Type
Video
Language
English
Publisher
Khan Academy
Publication Date
2022
Creator/Author
Khan Academy
Keyword
Cells

Comparing animal and plant cells

Plant cells have a cell wall in addition to a cell membrane, whereas animal cells have only a cell membrane. Plants use cell walls to provide structure to the plant. Plant cells contain organelles called chloroplasts, while animal cells do not. Chloroplasts allow plants to make the food they need to live using photosynthesis.

Subject and Topic
Form 1
Biology
Cell structure and organisation
Plant and animal cells
Resource Type
Video
Language
English
Publisher
Khan Academy
Publication Date
2022
Creator/Author
Khan Academy
Keyword
Animal cell
Plant cell

The concept of mechanical advantage

The amount of effort saved when using machines is called mechanical advantage (MA). Simple machines use mechanical advantage as a key property to their functionality, helping humans perform tasks that would require more force than a person could produce. We will use the lever as an example of a simple machine to illustrate the concept of mechanical advantage.

Subject and Topic
Form 2
Physics
Simple machines
Concept of simple machines
Resource Type
Werkbladen en klassikale activiteiten
Language
English
Publisher
Department of Higher Education
Publication Date
No date
Creator/Author
Leigh Kleynhans
Contributor
Michael Atkinson
Keyword
Effort Force
Resistance Force
Mechanical Advantage

Introduction to the cell

Introduction to the cell.

Subject and Topic
Form 1
Biology
Cell structure and organisation
Concept of cells
Resource Type
Video
Language
English
Publisher
Khan Academy
Publication Date
2017
Creator/Author
Sal Khan
Keyword
Cells

Mechanical advantage of simple machines

In this unit we will learn how these factors can affect the output of a simple machine. We will also learn about the difference between ideal mechanical advantage (IMA) and actual mechanical advantage (AMA), and how to apply your knowledge to calculate the efficiency of various simple machines.

Subject and Topic
Form 2
Physics
Simple machines
Concept of simple machines
Resource Type
Studieboeken
Language
English
Publisher
Department of Higher Education
Publication Date
No date
Creator/Author
Leigh Kleynhans
Contributor
Michael Atkinson
Keyword
Lever
Inclined plane
Vectors
Effort Force

Overview of animal and plant cells

Overview of animal and plant cells. Topics include cell walls, vacuoles, chloroplasts, peroxisomes, lysosomes, mitochondria, etc.

Subject and Topic
Form 1
Biology
Cell structure and organisation
Plant and animal cells
Resource Type
Video
Language
English
Publisher
Khan Academy
Publication Date
2015
Creator/Author
Sal Khan
Keyword
Animal cell
Plant cell

pH Scale

Outcomes:

  • Determine if a liquid is acidic, basic, or neutral
  • Place acids or bases in relative order
  • Describe on a molecular scale, with illustrations, how the water equilibrium varies with pH
  • Determine concentration of hydroxide, hydronium and water at a given pH
  • Relate liquid color to pH
  • Predict (qualitatively and quantitatively) how dilution and volume will affect the pH and concentration of hydroxide, hydronium and water
Subject and Topic
Form 1
Biology
Introduction to biology
The biology laboratory
Resource Type
Simulatie
Language
English
Publisher
pHET Interactive Simulations
Publication Date
No date
Creator/Author
Yuen-ying Carpenter (lead)
Keyword
pH
Dilution
Concentration
Acids
Bases

Scale of cells

Even though molecules, proteins, viruses, and cells are all tiny, there are significant size differences between them. The diameter of a water molecule is roughly 0.28 nanometers. The diameter of the protein hemoglobin is roughly 5 nanometers. The diameter of the HIV virus is roughly 120 nanometers. A red blood cell is 6-8 micrometers.

Subject and Topic
Form 1
Biology
Cell structure and organisation
Concept of cells
Resource Type
Video
Language
English
Publisher
Khan Academy
Publication Date
2015
Creator/Author
Sal Khan
Keyword
Cells

Simple Machines

What are simple machines? Simple machines are tools that make work easier. They have few or no moving parts. These machines use energy to do work with one movement. They make our work easier by letting us use less mechanical effort to move an object.

Subject and Topic
Form 2
Physics
Simple machines
Concept of simple machines
Resource Type
Studieboeken
Language
English
Publisher
Department of Higher Education
Publication Date
No date
Creator/Author
Leigh Kleynhans
Contributor
Michael Atkinson
Keyword
Lever
Pulley
Inclined plane
Wedge