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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. 

Onderwerp en thema
Form 1
Biology
Cell structure and organisation
Concept of cells
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2015
Schepper/Auteur
Sal Khan
Trefwoord
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).

Onderwerp en thema
Form 1
Biology
Cell structure and organisation
Concept of cells
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2022
Schepper/Auteur
Khan Academy
Trefwoord
Cells

Factorising Quadratics

In this video we’re going to discover how to factorise quadratics that don’t have 1 as the coefficient of the x-squared term. These are called non-monic quadratics. We can do it by trial and error and just spotting the factors, but this takes a lot of trial an error. Luckily there is a different method we can use instead, which we will looks at in this video.

Onderwerp en thema
Form 2
Mathematics
Quadriatic equations
Solving equations
Type bron
Video
Taal
English
Uitgever
Fuseschool- Global Educations
Publicatiedatum
2017
Bron
Trefwoord
Factorisation

Introduction to the cell

Introduction to the cell.

Onderwerp en thema
Form 1
Biology
Cell structure and organisation
Concept of cells
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2017
Schepper/Auteur
Sal Khan
Trefwoord
Cells

More on Newton's third law

An elaboration on some of the common misconceptions in dealing with Newton's Third Law. He also shows how to correctly and reliably identify Third Law force pairs.

Onderwerp en thema
Form 2
Physics
Newton's law of motion
3rd law of motion
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2016
Schepper/Auteur
David SantoPietro
Trefwoord
Third Law of Motion
Laws of motion
Newton

Newton's third law of motion

Learn about Newton's third law of motion, which states that for every action there is an equal and opposite reaction. Look at multiple examples that illustrate this law, including pushing a block on ice, pushing against a desk, walking on sand, how rockets work, and how an astronaut could save themselves from drifting in space.

Onderwerp en thema
Form 2
Physics
Newton's law of motion
3rd law of motion
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2012
Schepper/Auteur
Sal Khan
Trefwoord
Third Law of Motion
Laws of motion
Motion
Newton

Quadratic equations

Outcomes

In this course you will learn how to:

  1. Solve quadratic equations by factorisation.
  2. Solve quadratic equations by using the quadratic formula.
  3. Solve simultaneous equations involving quadratic equations
  4. Solve word problems involving quadratic equations.
Onderwerp en thema
Form 2
Mathematics
Quadriatic equations
Solving equations
Type bron
Cursus
Taal
English
Publicatiedatum
2023

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.

Onderwerp en thema
Form 1
Biology
Cell structure and organisation
Concept of cells
Type bron
Video
Taal
English
Uitgever
Khan Academy
Publicatiedatum
2015
Schepper/Auteur
Sal Khan
Trefwoord
Cells

Solve Linear and Quadratic Equations

By the end of this unit you will be able to:

  • Solve equations with a single variable which are called linear equations
  • Solve equations with a single variable that is squared (quadratic equations) by factorisation.
Onderwerp en thema
Form 2
Mathematics
Quadriatic equations
Solving equations
Type bron
Cursus
Taal
English
Uitgever
National Curriculum Vocational Mathematics Level 2
Publicatiedatum
No date
Schepper/Auteur
Dylan Busa
Trefwoord
Linear equations
Quadratic equations

Solve Quadratic Equations by Completing the Square

By the end of this unit you will be able to:

  • Solve a quadratic equation by completing the square.
Onderwerp en thema
Form 2
Mathematics
Quadriatic equations
Solving equations
Type bron
Cursus
Taal
English
Uitgever
Pressbooks
Publicatiedatum
No date
Schepper/Auteur
Dylan Busa
Trefwoord
Quadratic equations
Completing the square