The cell
Cells come in many shape and sizes. The size and shape of a cell relates to its job
or function. Ex. red blood cells are small size and disk shape to pass easily through
the smallest vessels.
Cell Membrane
Although different types of cells perform different functions, all cells have some
structures in common. Every cell is surrounded by a protective covering called
cell membrane that protects that inside of the cell from outside environment.
Cell membrane is mostly made up of two different macromolecules-proteins and
a type of lipid called phospholipids.
Cell Wall
- A stiff structure outside the cell membrane that protects a cell from
attack by viruses & other harmful organisms. Plant cells, fungal cells,
bacteria, and some types of protists have cell walls.
Cell Appendages
Cell appendages are often used for movement. Flagella are long, tall-like
appendages that whip back and forth to move a cell. Cilia are short, hair
like structures that can move a cell or molecules away from a cell.
Cytoplasm & Cytoskeleton
Water is the main ingredient in a cell. Most of the water is in the
cytoplasm, a fluid inside a cell that contains salts and other molecules.
The cytoskeleton is a network of threadlike proteins that are joined
together. The cytoskeleton framework gives a cell its shape and helps it
move.
Cell types
Prokaryotic Cells(small)
Most prokaryotic cells are unicellular organisms called prokaryotes. The
genetic material in a prokaryotic cell is NOT surrounded by a membrane.
Eukaryotic Cells(large)
Each eukaryotic cell has genetic material that is surrounded by a
membrane. Plants, animals, fungi, and protists are all made of eukaryotic
cells.
Cell Organelles
Organelles enable cells to carry out different functions at the same time.
Nucleus
- The largest organelle
- Directs all cell activities
- Stores DNA
Manufacturing Molecules
Proteins are made on small structures called ribosomes. Ribosomes can
be floating around the cytoplasm or attached to the web like structure
called Rough Endoplasmic Reticulum(site of protein production). The
endoplasmic reticulum without ribosomes is called Smooth Endoplasmic
Reticulum. It makes Lipids & helps remove harmful substances from a cell.
Processing Energy
All living things require energy in order to survive. Energy is released during
chemical reactions that occur in the mitochondria. This energy is stored in
high molecules called ATP(fuel). In plant cells, there is a organelle called
chloroplast use light to make food(glucose) from water and carbon
dioxide in a process known as photosynthesis.