The Animal Cell

The building blocks for all animals

Animal Cell

We will be discussing 9 organelles

of the animal cell:

Wonders of the Cell

Cell Membrane

When you think about a membrane, imagine it is like a big plastic bag with some tiny holes. That bag holds all of the cell pieces and fluids inside the cell and keeps any nasty things outside the cell. The holes are there to let some things move in and out of the cell. The cell membrane is not one solid piece. Everything in life is made of smaller pieces and a membrane

is no different.

Cell Membrane

Nucleus

The cell nucleus is like the brains of the cell. It helps control eating, movement and reproduction. If it happens in a cell, chances are the nucleus knows about it. The nucleus is not always in the center of the cell. You probably won't find it near the edge of a cell because that might be a dangerous place for the nucleus to be. It will be a big dark spot somewhere in the middle of all of the cytoplasm. The cytoplasm is the fluid that fills cells, it is a complex mixture of water, gasses, wastes, nutrients which supply the cells needs.

Nucleus

Endoplasmic ReticulumAnother organelle in the cell is the endoplasmic reticulum (ER). In the same way that the nucleus acts as the cell brain, the ER works as a packaging system. It does not work alone. ER works closely with the Golgi apparatus, ribosomes, RNA, mRNA, and tRNA. It creates a network of membranes throughout the entire cell. The ER may also look different from

cell to cell, depending on the cell's function. There is rough ER and smooth ER .

Smooth ER has its purpose in the cell. It acts as a storage organelle. It is important in the creation and storage of steroids. Rough ER are very important in the synthesis (making) and packaging of proteins.

Endoplasmic Reticulum

MitochondriaThe mitochondria are known as the powerhouses of the cell. They are the organelles that act like a stomach and small intestine which take in nutrients, breaks them down, and creates energy for the cell. The process of creating that energy is known as cellular respiration. The mitochondria is shaped perfectly to maximize its efforts. Mitochondria are very small organelles. You might find cells with several thousand mitochondria. If the purpose of the cell is to transmit nerve impulses there will be fewer mitochondria than in a muscle cell that needs loads of energy. If the cell feels it is not getting enough energy to survive, more mitochondria can be created.

Mitochondria

Ribosomes

Cells need to make proteins. Those proteins might be used as enzymes or as support for other cell functions. When you need to make proteins, you look for ribosomes. Ribosomes are the protein builders or the protein synthesizers of the cell. They are like construction guys who take one amino acid at a time and build long protein chains. You might find them floating in the cytoplasm. Those floating ribosomes make proteins that will be used inside of the cell. Other ribosomes are found on the endoplasmic reticulum. Those attached ribosomes make proteins that will be used inside the cell and proteins made for

export (outside the cell).

Ribosomes

Golgi ComplexThe Golgi apparatus or Golgi complex is found in most cells. It is another packaging organelle like the endoplasmic reticulum. While layers of membranes may look like the rough ER, they have a very different function. The Golgi complex gathers simple molecules and combines them to make molecules that are more complex. It then takes those big molecules, packages them in vesicles and either stores them for later use or sends them out of the cell. It is also the organelle that builds lysosomes.

Golgi Complex

LysosomesYou will find organelles called lysosomes in nearly every animal-like cell. They exist in the cell to digest. They might be used to digest food or break down the

cell when it dies. A lysosome is basically a specialized vesicle holding a variety of enzymes. The enzyme proteins are first created in the rough ER. Those proteins are packaged in a vesicle and sent to the Golgi apparatus. The Golgi then does its final work to create the digestive enzymes and pinches off a small, very specific vesicle. That vesicle is a lysosome. From there the lysosomes float in the cytoplasm until they

are needed.

Lysosomes

CytoplasmCytoplasm is the fluid that fills a cell. Scientists used to call the fluid protoplasm. The organelles of the cell are suspended in the cytosol. While you will discover that the microfilaments and microtubules set up a "skeleton" of the cell, the cytosol fills the spaces. The cytoplasm has many different molecules dissolved in solution. You may discover enzymes, fatty acids, sugars, and amino acids that are used to keep the cell working. Waste products are also dissolved before they are taken in by vacuoles or sent out of the cell.

Cytoplasm

Food VacuoleVacuoles are storage bubbles that are found in cells. They are found in both animal and plant cells but are much larger in plant cells. Vacuoles might store food or any variety of nutrients the cell would need to survive. They might even store waste products so that the rest of the cell is protected from contamination. Eventually

those waste products would be sent out of the cell.

Vacuole