The Cell 2.2

Cell Shape and Movement The size and shape of a cell relates to its job or function. Ex. Blood cells are small so it can easily pas through the smallest blood vessels. Structures of a cell also have unique functions.

Cell Membrane All cells have a cell membrane. A cell membrane is a flexible covering that protects the inside of a cell from the environment outside a cell. Cell membranes are mostly made of phospholipids and proteins. Most cell membranes are selectively permeable. (decides what enters and exits the cell)

Cell Wall A stiff structure outside the cell membrane. NOT ALL CELLS HAVE A CELL WALL Plant cells and fungi cells have a cell wall. Protects a cell from the attack by viruses and other harmful organisms. Also, helps maintain the shape and gives structural support.

Cell Appendages Cell appendages are used for movement. 1. Flagella – are long, tail-like appendage that whips back and forth and move a cell. 2. Cilia- short hair-like structure that helps with movement and capturing food.

Cytoplasm and Cytoskeleton Cytoplasm is the fluid inside a cell that contains salts and other molecules. All cells have a cytoplasm. Cytoskeleton is a network of threadlike proteins that are joined together. Cytoskeleton gives a cell its shape and helps it move.

Cell Types Prokaryotic cells contain DNA found in the cytoplasm. Most Prokaryotic cells are unicellular organisms. Ex. Bacteria

Eukaryotic Cells Eukaryotic cells have a nucleus which contains DNA. Eukaryotic cells also have other organelles which have specialized functions. Most organelles are surrounded by membranes. Ex. Plants, animals, fungi and protists are made of eukaryotic cells.

Cell Organelles Organelles are structures found in eukaryotic cells. Enable cells to carry out different functions at the same time. Can obtain energy, store information, make macromolecules and get rid of waste materials.

Nucleus Normally the largest organelle in eukaryotic cells Directs all cell activities and contain genetic information stored in DNA. DNA is organized into chromosomes. Different species have different number of chromosomes. Contains the nucleolus (large dark spot in the nucleus).

Nucleus Nucleolus make ribosomes (organelles involved in the production of proteins). Nuclear envelope are two membranes that surround the nucleus. Nuclear envelope contains pores.

Manufacturing Molecules Proteins are made on ribosomes. Ribosomes are NOT surrounded by a membrane. Ribosomes are found floating in the cytoplasm and attached to the Rough Endoplasmic Reticulum. Endoplasmic Reticulum (ER)- are a weblike organelle that spreads from the nucleus throughout the cytoplasm. 2 types of ER- Rough ER that has ribosomes and is the site of protein production. Smooth ER does not have ribosomes. Smooth ER makes cholesterol and remove harmful substances from the cell.

Processing Energy All living things require energy to survive. Mitochondria releases energy during chemical reactions. Energy is stored as Adenosine triphosphate (ATP). ATP is the fuel for cellular processes: growth, cell division, and material transport. Mitochondria is surrounded by two membranes.

Chloroplasts Plant cells and some protists contain chloroplast. Are membrane bound organelle that use light energy and make food. Photosynthesis occurs in the chloroplast. During photosynthesis, glucose (sugar) is made from water and carbon dioxide.

Processing, Transporting, and Storing Molecules Golgi Apparatus prepares proteins for their specific jobs. Golgi Apparatus packages the proteins in vesicles. Vesicles are organelles that transport substances from one area of the cell to the next. Lysosomes contain substances that help break down and recycle cell parts. Vacuoles are saclike parts that store food, water, and waste material. Plant cells have one large vacuole, whereas animal cells have small vacuoles.