Structure of Plant Cells
Cell Wall
Plant cells are eukaryotic cells, but unlike animal cells which have a cell membrane, plant cells have cell walls.
Plants have a rigid cell wall that surrounds the plasma membrane.
The cell wall is made of cellulose and lignin, which are strong and tough compounds.
Plant Cells Labelled
Plastids and Chloroplasts
Plants make their own food through photosynthesis.
Plant cells have plastids, which animal cells don’t. Plastids are organelles used to make and store needed compounds.
Chloroplasts are the most important of plastids.
They convert light energy from the sun into sugar and oxygen.
The most exposed parts of the plants to the sun, tending to be the most green, are filled with chloroplasts, which are making food and oxygen for the plant.
Central Vacuole
Vacuoles have a very important role in plant cells compared to others, which is why only some animal cells have vacuoles, and even then, their vacuoles don’t have as big a role.
Plant cells can push water into vacuoles. They provide turgor pressure inside the cell, which reinforces the plant.
When the plant loses water, the turgor pressure drops, and the plant wilts.
The vacuole is a storage container not only for water for other compounds. It can contain and export things that the cell doesn’t need.
Endoplasmic Reticulum
The endoplasmic reticulum(s) are organelles that create a network of membranes that transport substances around the cell.
They have phospholipid bilayers. There are two types: the rough ER, and the smooth ER The rough endoplasmic reticulum is rough because it has ribosomes (which I will explain later) attached to it.
It helps in the synthesis and packaging of proteins. The smooth endoplasmic reticulum doesn’t have ribosomes attached.
It contains enzymes that help with the creation of important lipids.
It has a role in the process of cell detox.
The smooth ER adds a carboxyl group to noxious substances, making them soluble in water.
Ribosomes
Ribosomes create proteins.
They can float freely in the cytoplasm or can be attached to the nuclear envelope.
They create proteins by assembling amino acids into polypeptides.
As the ribosomes build an amino acid chain, the chain is pushed into the endoplasmic reticulum.
When the protein chain is complete, the endoplasmic reticulum pinches it off and sends it to the Golgi apparatus.
Golgi Apparatus
The Golgi apparatus focuses on protein processing and packaging.
Golgi bodies are the Golgi apparatus’s layers.
Golgi bodies cut up large proteins into smaller hormones.
They can combine proteins with carbohydrates to make various molecules.
They then package these products into sacs called vesicles, which will ship the products of the Golgi body to other parts of the cell, and outside the cell as well.
Lysosomes
Lysosomes are enzyme sacs that break down cellular waste – they process cell digestion.
They can take substances from outside of the cell and cellular waste and turn them into simple compounds.
The compounds are then transferred into the cytoplasm where they can be used as a cell building material
Nucleus
The nucleus is a highly specialized organelle that lives in its own double membrane with the nucleolus.
The nucleus stores the cell’s DNA and holds all the information the cell needs to do its job.
Chromatin is a web-like substance that holds the nucleus’s DNA.
Chromatin gathers into rod-shaped chromosomes that hold DNA molecules when the cell is ready to split during cell division.
The nucleolus lives inside the nucleus and is the only organelle that is not enveloped by its own membrane.
It makes ribosomal RNA, rRNA, which is important during protein synthesis.
Ribosomal RNA or rRNA combines with proteins to form the basic units of ribosomes.
When the units are done, the nucleus spits them out of the nuclear envelope, where they are assembled into ribosomes.
The nucleus sends orders in the form of messenger RNA, or mRNA.
The messages are sent to ribosomes, which carry out the orders in the rest of the cell.
Mitochondria
The mitochondria is the “power plant” of the cell.
This is where cellular respiration takes place.
During this, energy is derived and converted into ATP from fats, carbohydrates, and other fuels.
Mitochondria almost act as their own organism and have their very own DNA which is an exact replication of the mother’s DNA
Plant Cells Citations
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