Cells to Systems
OB43 draw one example each of an animal cell and a plant cell, identifying the nucleus, cytoplasm and cell wall (plant cell), and indicate the position of the cell membrane
Nucleus Contains chromosomes which control the cell
Cytoplasm A liquid in which many cell reactions take place
Cell Membrane Holds the cytoplasm in place and allows certain substances into and out of the cell
Chloroplasts Carries out photosynthesis*
Vacuole Stores materials in water and supports the cell, animal cells can have vacuoles too, but they are less common and much smaller
Cell Wall Provides strength and support
*Photosynthesis is when a plant makes food from Carbon Dioxide in light.
All living organisms (the official way to say living things) are made up of cells. The most basic organisms have only one cell but most of the organisms you know are multicelled (they have more than one cell).
So you should notice that all cells have
- a nucleus, this contains genes and DNA
- a cell membrane
they all carry out the processes of living things such as
Cells are very small, many times smaller than a grain of sand....
how many grains of sand would you need to make a model of a human
so you would need many more cells to make you
OB41 living things are made up of
cells, tissues, organs and systems,
relationship between cells, tissues, organs and systems
There are many different types of cells in living things, there are skin cells, blood cells, muscle cells ......
When the cells act together they are called a tissue
We are made up of billions of cells, as one cell is so small that we need a microscope to see it you can see that these cells must work together. Similiar cells all join to form tissue.
For example we are covered in skin, this skin is made up of billions of cells but all these cells are similiar to each other.
Under the skin, we have blood, bones and muscles these are all different substances, they too are made from cells, but the cells in bone and muscle are different.
When cells work together we call this tissue.
Each type of cell has its own function (job) in large multicelled organisms, here are a few examples of
the functions that cells carry out,
When different sets of tissues act together they are called an Organ
Kidney, Heart, Lungs, Skin, Brain, Intestines, Liver, Bladder, Stomach, Spleen, Appendix, Eyes.
When different Organs, Tissues and Cells work together they are called Systems.
- Respiratory System
- Circulatory System
- Urinary System
- Sensory System
- Digestive System
- Reproductive System
In this course we will deal with many different types of systems. Check the biology index page for examples of the different systems that the body needs to survive.
and when different systems work together it is an organism
and understand that growth results from cell division
You can see examples of organs and systems on the BBC site.
Test yourself again, probably more in keeping with your JC course
The details of what happens inside the nucleus come later in the section on genetics