The Cell As A “City”

Each organelle has a job---your cells run like a little city with many jobs to

be done.

Lets take each organelle and put it’s job into a “life” situation. . . .

• Nucleus—basically like the boss, mayor, principal, chairman of the board—get the picture?

• Job—to direct all the cell’s activities, even reproduction.

Surrounding the city is the . . .

• Cell membrane—this acts like a fence or gate. Why?-it allows some things in and keeps other things out. It can bring things in or throw them out and uses energy to do so.

There is more to the nucleus. . .

• Remember the nucleus is the “control center”• The nucleus is surrounded by a membrane

called the nuclear envelope. This is a protection for the nucleus. Envelopes protect the letter inside—in this case the nuclear membrane protects the nucleus.

The nuclear envelope has “PORES”

• Materials pass in and out of the nucleus through the pores in the nuclear envelope.

Think of the traveling/jumping through the pore to deliver or remove substances.

Chromatin is in the nucleus---?

• What is it? • Genetic material (DNA)• SO----?!?! • The genetic material contains the instructions for directing the

cell’s activities!• This ensures that a leaf cell grows and divides to form more

leaf cells.

Nucleolus• This structure is inside the nucleus and

produces ribosomes.

Mitochondria• These appear as jelly-bean shaped; their job is to take thefood that the organism ingests and convert it into energy. The nicknamefor the mitochondria is “The

Powerhouse”

Endoplasmic Reticulum (ER)• The highway of the cell.They appear as mazes ofpassageways. Proteins andother materials are carried from one area ofcell to the other.

Ribosomes• These can be attached to the ER itself or freely

floating out in the cytoplasm. Ribosomes are small, grain-like bodies. They are factories that produce proteins for the cell. Most proteins are then sent to the Golgi bodies.

Cytoplasm• This is the jelly-like substance that all

organelles float in. Cytoplasm actually helps the organelles move (stream) around in the cell.

• Cytoplasm is basically clear.• This slide has been stained-------

Golgi Body

• This is like the packing/shipping department.

• Proteins are sent here and packaged up to be sent out to other parts of the cell. Materials can also be sent outside the cell.

Vacuoles• These are storage areas in the cell. They may

contain food, water and also waste. The vacuole is large in a plant cell and small or even absent in an animal cell.

Lysosomes

• Small, round structures which contain chemicals to break down certain materials—you can think of lysosomes as a clean-up crew. The contents are enzymes, acids, etc.

Chloroplasts—only in Plants!!!

• Otherwise we would be. . . . . . .

• Green People!

Seriously—a chloroplast is for. . .

• Photosynthesis—In this process, plants make the food for the themselves by using CO2, water and sunlight.

So-------

• Plant lots of trees so we have lots of fresh oxygen!!!

Mitochondria –vs- chloroplast

• They do not really look the same!!!

WOW—do you have all that now?• Remember—think of the cell as a mini-city where each organelle

has a job to do—• Nucleus-boss/control center-remember the nucleolus and the

nuclear membrane• Cytoplasm-something soft to sit in• Ribosome-makes proteins• Lysosome-cleanup crew/janitor• Endoplasmic reticulum-highway to travel on• Golgi body—packing/shipping department• Vacuole-storage area• Mitochondria-powerhouse for energy needs• Cell membrane-like a gate to let things in and out