Functions of Cells

1. Functions of Cells

2. Things to Know • The shape and size of a cell are related to its function. • What does that mean? • The shape of the cell helps it perform its task.

3. For Example • What are do plant cells have around them that animal cells don’t? • Cell Wall • What is the shape of the cell wall? • Close together • What task (function) does the cell wall perform? • protects the cell • How does the shape relate to the function? • The cell wall fits tightly to protect the cell.

4. Skin Cells • How does the shape of skin cells help the cells do their task? • Cover and protect your body

5. Nerve Cells • How does the shape of nerve cells help the cells function? • long, narrow - so that it can carry messages to many cells

6. Blood Cells • How does the shape of blood cells help the cells function? • bowl shape - so they can easily travel through the veins.

7. Muscle Cells • How does the shape of muscle cells help the cells function? • long and thin - allows them to contract

8. White blood cells Link • Job: find and destroy invaders • Shape: irregular • How does their shape help them do their job? • allows them to slip through the thin walls of blood vessels and move among your muscle cells and other tissues

9. One-Celled Organism • Must carry out the same jobs that are carried out by many celled organisms! • Their different shapes help them survive • The following slides will introduce you to some single-celled organisms

10. Vorticella • Lives in ponds and attaches to solid objects such as twigs • It is funnel shaped • It has small hair-like structures called cilia which beat near the funnel. This creates a whirlpool. • What do you think happens then? • food particles are swept into the funnel and eaten by the vorticella.

11. Ameba • lives on the bottom of bodies of water • has no definite shape • moves by pushing out its cytoplasm into thin pouches in the cell membrane called pseudopods • the pseudopod surrounds the food and the ameba digests it.

12. Cells Vary • Cells vary in size and shape. Does that mean that larger animals have larger cells? • not always • Cells do come in many shapes and sizes, but bodies grow bigger by having MORE cells, not bigger cells. • The largest single cell is and ostrich egg. • The smallest cell is bacteria

13. Other Differences • The function (task or job) determines the kind of organelles it has, and the number of organelles it has. • What is an organelle again? • tiny structure in cytoplasm that performs a special job. • What are some examples of organelles? • nucleus, mitochondria, vacuole, etc.

14. Muscle Cells • Must contract quickly as you stand, walk, and run • It contains more energy-producing mitochondria than other cells

15. Heart Cells or Skin Cells • Which would have more mitochondria? • heart cells, because they are always active

16. Special outgrowths • Some cells have pieces growing out of them to help them function. • Flagella extend from the volvox and help them move • The Vorticella has hairlike structures called cilia at the top of its funnel. (Remember?)

17. Special outgrowths • The cells that line your breathing passage, lungs, and nose have hundreds of cilia to keep your air passages clean. • The paramecium have cilia to help it move in the water.

18. Quiz - True or False • A cell’s shape helps it perform its specific function. • The job of white blood cells is to find and destroy bacteria • All one-celled organisms are similar to one another. • An ameba moves by pushing out cytoplasm into pouches called pseudopods.

19. Quiz - True or False • As you grow taller, your individual cells grow bigger. • Heart cells that beat constantly have more mitochondria. • Cilia are extensions of animal cells that move rapidly. • All cilia are used to help animal cells find food. • All animal cells have the same number of organelles.

20. The Answers

21. Quiz - True or False • A cell’s shape helps it perform its specific function. True • The job of white blood cells is to find and destroy bacteria True • All one-celled organisms are similar to one another. False • An ameba moves by pushing out cytoplasm into pouches called pseudopods. True

22. Quiz - True or False • As you grow taller, your individual cells grow bigger. False • Heart cells that beat constantly have more mitochondria. True • Cilia are extensions of animal cells that move rapidly. True • All cilia are used to help animal cells find food. False • All animal cells have the same number of organelles. False

23. Activity • Write a script for a skit in which a person interviews different kinds of cells about their: • size & shape • functions they perform • Why the size & shape helps their function • Each person in the skit must say something • You will hand in your group script

24. Kinds of cells you could use • different human body cells: • muscle, nerve, blood, heart, skin, etc. • plant cells • single-celled organisms: • vorticella, ameba, volvox, bacteria, paramecium