CELLS

06/18/12

What is a cell?

• The Cell Theory:1. All living things are composed of cells2. Cells are the basic units of structure and functions in living things.

- Bone cells make up bones.- Nerve cells transmit signals from brain to

rest of body. 3. All cells come from preexisting cells.

- Cells replicate to form other cells.

Types of Cells

• Nerve Cells: They are responsible for relaying information from your brain to your muscles, organs, and other parts of your body.

• Muscle Cell: Important for the contraction of muscles.

• Skin Cell: Builds your skin. Protects from the outside world

• What other cells can you think of?

Nerve Cells

Onion Root Skin Cells

Organelles

• Organelles are the organs of cells. “Little organs”.– There are many different organelles, all having a

specific function.

Remember to take good notes! WE WILL LEARN A LOT OF ORGANELLES

Basic Cell Structure

Cell Membrane:

Serves as the outer boundary of the cell. It regulates what can and cannot enter the cell.

Cytoplasm:

The space between the nucleus and the cell membrane. Contains many different organelles.

Nucleus:

Main control center. Directs all activities of the cell. This is where the DNA is.

Mitochondria

• This is the “power plant”.

• This is where the carbohydrates and lipids are broken down to release their energy.

Ribosomes

• Among the smallest of organelles.

• There are many of these in a cell.

• This is where protein is made.

Endoplasmic Reticulum (ER)

• Looks like a long tunnel system.• Can either be rough or smooth– Rough if ribosomes are attached to it.

• The ER transports materials through the inside of the cell. – Transports the proteins!

Golgi Apparatus

• This is the “shipping” organelle.– The post office for proteins

• Looks like a stack of pancakes. • The Golgi modifies proteins,

much like we modify cars, and then sends them to other parts of the cell where they can do specific functions.

Lysosomes

• Contain chemicals and proteins (enzymes) necessary for digesting certain materials in the cell.

• The “clean-up crew”

• Formed from Golgi

Vacuoles

• Store materials such as water, salts, proteins, and carbohydrates.

• Think of a refrigerator or a pantry that stores food.

• They look like small sacs.

Nucleolus

• The nucleolus is within the nucleus.

• Recall, the nucleus contains the DNA and is the command center of the cell.

• The nucleolus is where ribosomes are made.

Let’s put this all together

Making your own Cell Analogy!

• First complete the handout.• Then get into groups of 3.• Obtain a large sheet of paper from Caitlin, Saydie, or

me.• Make your own cell analogy representing the

organelles. Draw it and color it.– Ex. Shoe factory is the ribosome and shoes are proteins.

• Your cell analogy can be anything! Just as long as the cell analogy’s parts represent organelles and their functions.

Animals vs. Plants

• Plants have much larger vacuoles• Plants have an extra layer beyond the cell

membrane called the cell wall. – Important for structure and rigidity.

• Plants do not have lysosomes.• Plants have organelles called chloroplasts.– Responsible for converting light energy from the

sun into chemical energy in sugars.

Eukaryotes vs. Prokaryotes

• Eukaryotes have eukaryotic cells. – Animal cells and Plant Cells

• Prokaryotes have prokaryotic cells.– Bacteria