The cell was first discovered in 1665 by an English scientist named Robert Hooke. He observed tiny boxes when examining the bark from an oak tree, and he called these boxes cells.
Plant cells form the basic unit of life in organisms of the Plantae kingdom and are classified as eukaryotic cells meaning their nucleus is within a nuclear envelope.
Eukaryotes are organisms, such as plants, composed of large and complex cells.
Despite cells differing in size and complexity, all cells are composed of the same substances and serve similar life functions, such as growth, metabolism, and reproduction.
The distinctive features of a plant cell are a cell wall composed of cellulose, a large vacuole, chloroplast, and cytoplasm.
The plant cell wall is primarily made up of the carbohydrates molecules cellulose and lignin. Cellulose is a key ingredient in the making of paper.
This is what a plant cell looks like:
Parts of a plant cell:
- Nucleus – contains the cell DNA and controls what the cell does
- Cell Wall – a tough outer case made of cellulose that helps support the plant and gives the cell a rigid structure
- Cell Membrane – Acts like a barrier to control the movement of substances in and out of the cell
- Cytoplasm – a jelly-like substance where many vital chemical reactions take place
- Chloroplast – contains chlorophyll – a green substance that allows the plant to make its food through photosynthesis which happens inside the chloroplast
- Large Vacuole – a large sack-like feature that contains cell sap and helps support the plant
- Mitochondria – the powerhouse of the cell and where respiration takes place
Specialized parts of cells, such as the above, are known as organelles. Organelles are tiny structures inside cells with a specific role.
Cellulose in our clothes?
Cellulose is found in the cell wall and is important for keeping the cell stiff and strong! However, it’s an important substance for making other things and can be found in everyday products such as paper and clothes.
Plants such as cotton have even more cellulose than other plants, which is why cotton is found in many clothes!
Cellulose is a molecule of hundreds and sometimes thousands of carbon, hydrogen, and oxygen atoms. Humans cannot digest cellulose, but it is important in the diet as fiber.
Animals such as cows, sheep, and horses can digest cellulose, which can be found in grass. Therefore, those animals can get the nutrients they need by eating grass.
Cellulose is an example of a natural polymer – a long and repeating chain of the same molecule stuck together. This is important for helping the plant grow stronger.
Differences between plant and animal cells
- Animal cells are typically an irregular shape, whereas plant cells are more regular
- Plant cells contain a cell wall, which supports the structure of the cell
- Plant cells have vacuole, which contains tree sap
- Plant cells also contain chloroplasts, which produce chlorophyll for photosynthesis
- This means that ultimately the plant cells are bigger than animal cells because of all their additional specialized organelles
Specialized Plant Cells:
There are many different types of cells in plants, each with its unique job. Each specialized cell is equipped with features that help it do its job, and together they ensure the plant functions as a whole.
Here are some examples of specialized plant cells:
Root Hair Cells – root hair cells have large surface areas to provide contact with soil water. It also has thin walls so as not to prevent the movement of water.
Xylem Cells – Xylem cells look like long tubes. They have no top or bottom walls between xylem vessels, so water can run continuously through them. Their walls become thick and wood-like to help support the plant.
Phloem – Phloem help to transport amino acids and dissolved sugars up and down the stem. Energy is transported to the phloem through companion cells.