Functions of

Cells

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.

For ExampleWhat 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.

Skin Cells

How does the shape of skin cells help the cells do their task?

Cover and protect your body

Nerve Cells

How does the shape of nerve cells help the cells function?

long, narrow - so that it can carry messages to many cells

Blood Cells

How does the shape of blood cells help the cells function?

bowl shape - so they can easily travel through the veins.

Muscle Cells

How does the shape of muscle cells help the cells function?

long and thin - allows them to contract

White blood cellsJob: 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

Link

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

VorticellaLives 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.

Amebalives 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.

Cells VaryCells 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

Other DifferencesThe 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.

Muscle Cells

Must contract quickly as you stand, walk, and run

It contains more energy-producing mitochondria than other cells

Heart Cells or Skin Cells

Which would have more mitochondria?

heart cells, because they are always active

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?)

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.

Quiz - True or False1. A cell’s shape helps it perform its

specific function.

2. The job of white blood cells is to find and destroy bacteria

3. All one-celled organisms are similar to one another.

4. An ameba moves by pushing out cytoplasm into pouches called pseudopods.

Quiz - True or False5. As you grow taller, your individual

cells grow bigger.

6. Heart cells that beat constantly have more mitochondria.

7. Cilia are extensions of animal cells that move rapidly.

8. All cilia are used to help animal cells find food.

9. All animal cells have the same number of organelles.

The Answers

Quiz - True or False1. A cell’s shape helps it perform its

specific function. True

2. The job of white blood cells is to find and destroy bacteria True

3. All one-celled organisms are similar to one another. False

4. An ameba moves by pushing out cytoplasm into pouches called pseudopods. True

Quiz - True or False5. As you grow taller, your individual

cells grow bigger. False

6. Heart cells that beat constantly have more mitochondria. True

7. Cilia are extensions of animal cells that move rapidly. True

8. All cilia are used to help animal cells find food. False

9. All animal cells have the same number of organelles. False

ActivityWrite 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

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