Plant cells are eukaryotic cells, sharing many of the same subcellular organelles with animal cells. However, they also have chloroplasts, a vacuole and a cell wall made of cellulose. There are many different types of plant cells, such as xylem cells and phloem cells.
Under an electron microscope, plant cells would look something similar to the diagram below.
Animal and plant cells share the following sub-cellular structures:
|Nucleus||Contains the genetic information of the cell in the form of DNA.|
A gene is a functional unit of DNA. Information about every feature of the cell and the whole organism can be found in the genes.
The nucleus also controls the activities that occur within the cell e.g. the substances that the cell produces and what goes in and out of the cell.
|Cytoplasm||A jelly-like material where most of the chemical reactions in the cell occur.|
The organelles of the cell move around in this substance. Important molecules, such as enzymes (which catalyse many metabolic reactions), are also found in the cytoplasm.
|Mitochondria||Organelles found within the cytoplasm, which are responsible for providing energy, by carrying out aerobic respiration.|
The enzymes for respiration are found in the mitochondria.
|Ribosomes||Very small organelles that are responsible for the synthesis (production) of proteins such as enzymes.|
There are millions of ribosomes located in the cell.
|Cell membrane||Every cell has a cell membrane which controls what moves in and out of the cell.|
It is the boundary between the cell cytoplasm and the cell’s surroundings, keeping the cell’s cytoplasm and the cell’s organelles locked within the cell.
There are different ways that substances can move across the cell membrane, such as diffusion and active transport.
Some sub-cellular structures are unique to plant cells:
|Cell wall||Plant cells are all surrounded by this tough cell well, made of cellulose. It strengthens and supports the cell, which defines its shape.|
Cell walls make it easy to spot a plant cell under a light microscope.
|Permanent vacuole||A large section at the centre of the cell that is filled with cell sap (a watery fluid). The cell sap helps keep the cell turgid. It does this by pushing the cytoplasm outwards against the cell wall.|
These large permanent vacuoles are primarily found in plant cells, although animal cells may sometimes contain small vacuoles.
|Chloroplast||These green, disc-shaped organelles are the site of photosynthesis. They contain a green pigment, called chlorophyll, which absorbs light energy for photosynthesis.|
It is actually chlorophyll that gives plants their green colour.