Plant Cells

Lesson Plan - Get It!

Audio:

So now that you know some of the differences, take a few minutes to draw a Venn diagram (the two overlapping circles) and write all of the unique characteristics of plant cells on one side and all the shared characteristics in the center where the two circles overlap.

Don't worry about the animal cell circle yet. You can take a closer look at animal cells in another lesson. (That means you should hang on to this paper). You can replay the song as many times as needed until you feel ready to move on.

Ok, so you may not know all the unique characteristics, but here are some things you should have learned from that mighty fine scientific rhyme.

• Plants cells are usually larger than animal cells.
• Plant cells have only one large vacuole. (Animal cells have many smaller ones).
• Plant cells have organelles called chloroplast and chlorophyll.
• Plant cells are usually square or rectangular in shape.

Now, take a look at a plant cell and its organelles. An organelle is a tiny structure in the cytoplasm of a cell that performs a specific job or function.

Take a look at the thick green layer all around the cell. That's the cell wall. The cell wall is a tough, non-living material that acts as a barrier for each plant cell. Cell walls give support, strength, and shape to plant cells.

Think of the cell wall as your skin. It helps to protect your insides, gives you a form, absorbs nutrients, and excretes waste (like skin excretes waste through pores, like sweat, or pimples, for example).

Once you pass the cell wall, you get to the real factory-like processes.

First is the cell membrane, which holds the parts of the cell together and controls the movement of materials into and out of the cell.

Next you have the cytoplasm, that jelly-like substance that protects all the organelles and keeps them floating in place. Once you start poking around the cytoplasm, here's what you'll find.

• Chloroplasts make sugar using carbon dioxide, water, and energy from sunlight.
• They are green and egg-shaped.
• Chloroplasts contain chlorophyll, which traps energy from the sun.
• Chlorophyll is inside chloroplasts and is what makes plants green.
• Chloroplasts are very important.

Since chloroplasts house chlorophyll, they play a huge role in the way plants make energy. There is a special process called photosynthesis where plants convert sunlight, water, and carbon dioxide into food energy (sugars and starches), oxygen, and water. Plants need chlorophyll to complete this process.

Watch this video to learn all about the process of photosynthesis.

 Mitochondria are organelles where food and oxygen react to release energy.

• The mitochondria make food for the cell.
• Mitochondria are called the powerhouse of the cell.
• The more active a cell is, the more energy it needs, and the more energy it needs, the more food it needs.

Think about the human body.

• Do you play a sport? If you do, think about when you practice really hard.
• You get super hungry, don't you? That's because your body is using extra energy, and you need to eat more to regain energy.

Vacuoles are sac-like organelles used for storing material.

• Vacuoles store nutrients and water as well as waste material.
• Water inside vacuoles helps keep plant cells firm.

The endoplasmic reticulum (ER) is an organelle that transports materials inside the cell.

• The ER looks like a series of channels or roadways.
• Some parts of the ER are covered by tiny structures called ribosomes.

Ribosomes are the protein manufacturing plants for the cell.

The Golgi body (also called the Golgi apparatus or Golgi complex) is a flattened, layered, sac-like organelle that looks like a stack of pancakes. You can usually find it hanging out with the nucleus. Its job is to package proteins and carbohydrates into little packages, so they can be transported out of the cell to another nearby cell.

The nucleus is the brains of the operation. This spherical-shaped organelle actually contains a bunch of other organelles, including the nucleolus, which is home to DNA and RNA. The nucleus controls most cellular functions. In fact, it is so important, it has its own membrane for protection.

You may notice that little purple swirly amyloplast in the upper-right corner of the cell.

This is a special organelle that is only found in tubers, or plants that grow underground, such as potatoes, beets, and onions. Since these plants grow underground, they can't get as much (if any) energy from the sun, so they have little or no chloroplasts.

Think about a carrot. Only the part that is above ground is green, right? But in most cases, there isn't enough of the plant exposed to sunlight, so these plants need a different way to make energy. That's where amyloplasts play a role.

Amyloplasts are non-pigmented (colorless) organelles responsible for the synthesis and storage of starch granules through the polymerization of glucose.

• What does that mean?

Basically, it means that it turns the sugars into starch. They also store the starch so it can be converted back into sugar when the plant needs energy. That's why potatoes, which are vegetables, are categorized with rice and other starch-filled foods rather than with vegetables on the food pyramid.

Here's a little peek at amyloplasts in a potato exposed to iodine and viewed under a microscope.

Now you know all about the basic structure and function of plant cells! Continue on to the Got It? section to use your new knowledge!