What is a Cell?
The cell is the basic unit of life. It the structural and functional of all living organisms. If you've ever wondered what you are made up of, well, all humans are made up of trillions of cells on the inside that are microscopic and not visible to the naked eye.
THE Cell theory
What is the cell theory?
The cell theory is one of the basic principles of biology.
The cell theory is:
1. All organisms compose of one or more cells
2. All cells come from pre-existing cells.
3. The cell is the basic structure and organisation in organisms.
ABOUT ANIMAL CELLS:
Animal cells are eukaryotic cells, or cells with a membrane bound nucleus. As opposed to prokaryotic cells animal cells have DNA stored within the nucleus. Animal cells also contain other membrane-bound organelles, or tiny cellular structures, that carry out specific functions necessary for normal cellular operation. Each organelle has a different assigned responsibility to help the cell function.
diagram of a general animal cell
HOW DOES AN ANIMAL CELL FUNCTION?
Different cells function in different ways, for example although animal and plant cells have some corresponding organelles (parts of a cell) they do not function the same. Cells can be thought of as a factory, each organelle factory workers with separate responsibilities.
The three main parts of a cell are; the plasma/cell membrane, nucleus and cytoplasm.
The cell/plasma membrane is the outer shell like part surrounding the cell, its function is to allow materials to enter and exit the cell.
The nucleus is one of the out two organelles (the other being mitochondrion) that has a double membrane. It is considered the power house of the cell. The nucleus's job is to control cell activity, and is the only part of the cell that contains DNA.
The cytoplasm is essentially the jelly-like substance that fills the cell. It is made 80% up of water and is usually clear/colourless. Its function is to help dissolve solutes and move materials around.
OTHER ORGANELLES IN THE ANIMAL CELL:
Nucleoplasm - suspension substance for organelles in the nucleus.
Nucleolus - creates ribosomes.
Ribosomes - makes proteins (amino acids).
- Rough ER - receives ribosomes from the nucleus, is a tunnel system for protein making ribosomes.
- Smooth ER- makes fats breaks down toxins. (Is not covered in ribosomes unlike rough ER)
Golgi Apparatus - sorts and packages proteins sent from ribosomes, exports finished proteins in a vesicle.
Mitochondria - Creates ATP in a process called, cellular respiration.
Lysosome - breaks down food, kills pathogens.
Like animal cells, plant cells are also a type of eukaryotic cells which are found in organisms within the plant kingdom. Also like an animal cell, plant cells contain a variety of organelles that help the cell function, however not all the same.
HOW DOES A PLANT CELL FUNCTION?
Although plant and animal cells are different cells, they still have many similarities, however the two cells still do not function completely the same.
ANIMAL & PLANT CELL SIMILARITIES
Corresponding organelles between the two cells include:
- Cell/plasma membrane.
- Golgi apparatus
- Rough ER
- Smooth ER
- Nuclear membrane
PLANT CELL ONLY
However there are certain organelles that plant cells contain that animal cells do not/usually do not include. These are:
Cell wall - this is the outermost layer of plant, fungi and bacteria cells and other than these no other organisms contain it. Its function is to protect and add support for growth.
Vacuole - this is often the largest organelle in the cell, its function is to hold materials and wastes.
vacuole within plant cell
Chloroplast - this is a plastid in green plant cells and contain chlorophyll. Its function is to perform photosynthesis.