Cell Types and Cell Structure

Prokaryotic vs. Eukaryotic nucleus membrane enclosed organelle chromosomes in pairs streaming in the cytoplasm cell division by mitosis complex flagella larger ribosomes complex cytoskeleton cellulose in cell walls DNA bound to histone proteins no nucleus no membrane enclosed organelles single chromosome no streaming in the cytoplasm cell division without mitosis simple flagella smaller ribosomes simple cytoskeleton no cellulose in cell walls no histone proteins

Prokaryotic vs. Eukaryotic Examples: Bacteria Examples: Plant cells Animal cells Fungi Protists

Cell Characteristics Eukaryotic cells have a complex, highly organized internal structure that enables them to perform specific cellular processes. Several organelles work together to make and process proteins. Other organelles, such as the mitochondria and chloroplasts, supply energy for cells.

Cell membrane Also known as the plasma membrane Made of a double layer of phospholipids with proteins embedded to assist with the transportation of molecules Forms a boundary between the cytoplasm and the outside of a cell and controls what enters and exits the cell

Cytoskeleton A network of fibers that provides internal structure and support for a cell. There are three main types of fibers which form the cytoskeleton. These fibers are made of proteins. The three types of fibers are: Microtubules – long hollow tubes that give a cell its shape Intermediate filaments – small fibers that give a cell its strength Microfilaments – tiny threads that allow a cell to move and divide

Cytoplasm Jelly-like substance inside a cell that contains the cell organelles. It is made mostly of water. The fluid filled part of the cytoplasm is known as the cytosol.

Stores and protects the genetic information, or DNA, of a cell. Nucleus Stores and protects the genetic information, or DNA, of a cell. DNA is located in chromosomes inside the nucleus. Is surrounded by a nuclear envelope, or nuclear membrane, that contains pores that allow molecules to travel in and out of the nucleus. Contains the nucleolus which produces ribosomes for the cell.

Endoplasmic reticulum (ER) The Endoplasmic Reticulum (ER) is a network of thin folded membranes that assists in the processing and transportation of proteins and lipids. Rough ER – Transports proteins (roughness is the attached ribosomes) Smooth ER – Processes and transports lipids

Ribosomes The site of protein synthesis (production). Ribosomes are made in the nucleolus and can be found floating freely in the cytoplasm or attached to the Rough ER. Ribosomes are responsible for linking amino acids together to form proteins.

Golgi Apparatus (Golgi Bodies, Golgi Complex) Closely layered stacks of membrane-enclosed spaces The spaces within the Golgi apparatus are where proteins are processed, sorted and packaged.

Vesicles Small membrane-bound sacs that isolate and transport specific molecules

Mitochondria Bean-shaped organelle made of an inner membrane, comprised of many folds, and an outer membrane Supplies energy for the cell in the form of ATP Mitochondria have their own ribosomes and DNA, which make them a unique organelle

Vacuole Fluid-filled sac used for the storage of water, food molecules and enzymes. Animal cells contain multiple small vacuoles and plant cells contain one large central vacuole which helps support the cell. Vacuoles

Lysosomes Organelle that contains enzymes that break down damaged or worn-out cell parts, breakdown large molecules, and protect cells from invading bacteria and viruses. They are found in large numbers in animal cells.

Centrioles Cylinder-shaped organelles made of short microtubules arranged in a circle. The centrioles are perpendicular to each other and divide DNA during cell division. Centrioles also organize microtubules to form cilia and flagella (structures used for movement).

Chloroplasts Organelles that contain an outer membrane, as well as an inner membrane that contains stacks of disc-shaped sacs called thylakoids. The thylakoids contain chlorophyll and perform photosynthesis.

Cell Wall A rigid layer found in plant cells that provides protection, support and shape to the cell. In plants and algae the cell wall is made of cellulose (polysaccharide). In fungi the cell wall is made of chitin.

Comparison: Plant cells Animal cells Large, central vacuole Chloroplasts Rigid cell wall outside of cell membrane No large, central vacuole No chloroplasts No rigid cell wall