Organisms are made up of cells. Most organisms are multicellular and have cells that are specialised to do a particular job. Microscopes are needed to study cells in detail.
Almost all animals and plants are made up of cells.
Animal cells have a basic structure. Below the basic structure is shown in the same animal cell, on the left viewed with the light microscope, and on the right with the transmission electron microscope.
mitochondriaStructures in the cytoplasm of all cells where aerobic respiration takes place (singular is mitochondrion). are visible with the light microscope but can’t be seen in detail.ribosomeThe site of protein synthesis. are only visible with the electron microscope.
Cell structures and their functions
Function
Cytoplasm
A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.
Nucleus
Contains genetic material, including DNA, which controls the cell’s activities.
Cell membrane
Its structure is permeable to some substances but not to others.
It therefore controls the movement of substances in and out of the cell.
Mitochondria
Organelles that contain the enzymes for respiration, and where most energy is released in respiration.
Ribosomes
Tiny structures where protein synthesis occurs.
Cytoplasm
Function
A jelly-like material that contains dissolved nutrients and salts and structures called organelles. It is where many of the chemical reactions happen.
Nucleus
Function
Contains genetic material, including DNA, which controls the cell’s activities.
Cell membrane
Function
Its structure is permeable to some substances but not to others.
It therefore controls the movement of substances in and out of the cell.
Mitochondria
Function
Organelles that contain the enzymes for respiration, and where most energy is released in respiration.
Ribosomes
Function
Tiny structures where protein synthesis occurs.
Most cells are specialised and are adapted for their function. Animals and plants therefore consist of many different types of cell working together.