Basic Cell Structure

Cell Membranea thin layer of lipid and protein that separates the cells contents (insides) from its environment (outsides).

**The cell membrane controls what enters and leaves the cell.

Also called the plasma membrane.

Cytoplasm • a semi-fluid substance

made mostly of water and organic compounds that is found between the cell membrane and the nucleus.

• Organelles are suspended in the cytoplasm.

Organelles

• Structures that perform specific functions within a cell

• “little organs”

Cytoskeleton

• a network of protein fibers and tubes that extend throughout the cytoplasm. This network gives the cell support and helps to maintain or change its shape.

Nucleus• The control center of a

cell. It is the most easily seen of the cells organelles.

• The nucleus contains most of the cells genetic material.

• It is surrounded by a double membrane called a nuclear membrane or nuclear envelope.

Chromosomes – located in the nucleus, the cells genetic information – DNA (nucleic acids)

Nucleolus – a dense portion of the nucleus where ribosomes are made.

Ribosomes• Small organelles that help assemble amino acids

into protein chains. They are found floating in the cytoplasm and attached to membranes.

• Both eukaryotes and prokaryotes have ribosomes.

Endoplasmic reticulum (ER)• A large network of membranes that

produce materials for the cell

There are TWO types of Endoplasmic reticulum

• Rough ER – has ribosomes on its surface and functions in the synthesis (making) of proteins

• Smooth ER – Makes lipids, processes carbohydrates and toxic waste.

Golgi Apparatus• a series of flat,

membrane-bound sacs that sorts, packages, and transports substances in the cell.

• Vesicle = sac containing manufactured materials

Mitochondria

• Energy producing organelles. They change energy stored in food compounds into energy usable by the cell (ATP).

Lysosomes

• Saclike organelles that contain digestive enzymes to break down macromolecules (such as proteins) or old organelles.

• Mostly found in animal cells

Cilia

• short, hair-like projections that are found in large numbers on the surface of certain cells.

• Function in movement

Flagella

•A long, tail-like projection used in movement.

Put it all together!

Plant vs Animal Cells

Cell Wall• Plant cells have a cell wall that

is a tough rigid outer covering that protects the plant cell and helps it maintain its shape. It is composed mostly of cellulose. Fungi, algae, and bacteria also have cell walls.

• **Animal cells DO NOT have cell walls.

Chloroplast• structures that enable the plant to make sugar

through photosynthesis. Contain chlorophyll (a pigment) that gives the plant cell its green color.

Vacuole• All plant cells contain a large

central vacuole – a membrane bound compartment that serves many functions. The main function is the absorption of water, but they also may store proteins, ions and waste products.

• Animal cells may have vacuoles, but they are very small.

Centriole• Animal cells also

have centrioles – small cylinder shaped organelles that help move chromosomes during cell division.

• NOT found in plants