1. Cells: the basic units of life This show is about types of cells and cell organelles and their functions. by Linda Moore
2. There are two types of cells in nature: Prokaryotic cells have no membranes around their cell parts or nuclei. Bacteria and some algae are prokaryotic cells. Scientists consider these cells to be the ancestors of all cells. bacteria cells
3. Eukaryotic cells each have a nucleus surrounded by a membrane that separates the cells into two regions: the nucleus and the cytoplasm. The cells parts in the cytoplasm also have membranes. We will focus on animal and plant cells. human cheek cells with nuclei onion cells with nuclei
4. Plant and animals cells have a lot in common, but there are three very important differences. Do you remember that plants are producers (make their own food)? The cells of plant leaves and stems have many chloroplasts. The chloroplasts are filled with a green liquid called chlorophyll. Chlorophyll captures sunlight to produce food for plants. plant cells with chloroplasts filled with chlorophyll
5. Animal cells do not have chloroplasts. Animals are consumers not producers. Animals are not green! Another difference between animals and plant cells is that plants cells have cells walls made of cellulose. All cells have cell membranes, but only plant cells have cell walls! portion of plant cell wall made of cellulose
6. thth The third big difference between plant and animals cells is that plant cells have vacuoles. The large central vacuole (above picture) stores food, water and waste. The central vacuole is like a water balloon in the center of a plant cell.
7. Now, let’s focus on the cell parts that plant and animal cells have in common. All cells have cell membranes. The cell membrane controls what enters or leaves a cell. If something is too large, it cannot get through the cell membrane. The cell allows in what it wants and gets rid of what it doesn’t want.
8. The nucleus controls most of a cell’s activities. The chromosomes are in the nucleus. The chromosomes contain the instructions for cell activities. chromosome Humans have 46 chromosomes in most of the cells of our bodies.
9. Powerhouses of Cells: mitochondria Mitochondria release energy from glucose for all of the life processes of living things. Why do you think muscle cells have more mitochondria than skin cells?
10. The endoplasmic reticulum (ER) and ribosomes are important for making proteins and taking the proteins where they are needed. Proteins are very important to organisms. Muscles and enzymes are made of proteins. There are 1000s of different proteins in the bodies of living things. The tubes are the ER, and the ribosomes are the round structures attached to the ER. Ribosomes are where proteins are made. Then, they travel through the cells in the ER tubes.
11. Golgi bodies are saclike structures used for storing and packaging substances made by the cell that will be transported out of the cell. This picture shows the Golgi bodies, the ER with attached ribosomes. Did you know that Golgi bodies were first discovered in the eyeball cells of owls?
12. Last, but not least, I’ll bet you have been wondering if there is a cell part for destroying and getting rid of unwanted stuff inside a cell. Well, wonder no more! The lysosomes do these important jobs.
13. Here’s what an artist thought plant and animal cells might look like:
14. I hope that you will enjoy learning about cells and their parts. Remember: All living things are made of cells. All of life’s activities are done by cells. All new cells come from other cells.
15. Here are some human body cells as they would appear under a microscope. nerve cell muscle cells white blood cells red blood cells
