Copyright Pearson Prentice Hall
Part 2: Eukaryotic Cell Structures
Cytoplasm• Location / Structure: The region of a cell
between the cell membrane and the nucleus; made of a jelly-like watery fluid called the cytosol
• Function: “cushions” the organelles
Cell MembraneLocation / Structure:•Also called the plasma membrane•A barrier that surrounds the cytoplasm •Separates the inside of cells from the outside environment Function: •Regulates passage of materials into and out of the cell
NucleusLocation / Structure:
• Found at the center of the cell
• Contains DNA
• Surrounded by a double-membrane with holes (aka pores) to allow passage of materials (not DNA) into and out of the nucleus
Function: Controls the activities of the cell
Nucleolus
Location / Structure:
• A spherical structure found at the center of the nucleus
Function: Creates (synthesizes) ribosomes… see next slide for a description of ribosomes
Ribosomes
Location / Structure:• Found floating in the cytoplasm and
attached to the rough ER• Very small• Made of RNA and protein
Function:• Make proteins
Rough Endoplasmic Reticulum
Location / Structure:
•Tubes and sacs made of membrane
•Has ribosomes on its surface
Function:
•Make proteins (due to ribosomes)
•Transport materials (like proteins) around the cell… it is the highway of the cell!
Smooth Endoplasmic Reticulum
Location / Structure:
•Tubes and sacs made of membrane
•Does not have ribosomes on its surface
•Attached to the Rough ER, farther out from the nucleus
Function:
•Makes lipids
•Breaks down toxins
Golgi ApparatusLocation / Structure:•Another system of tubes and sacs made of membrane close to the cell membrane
Function: •Vesicles (spheres of membrane) carry materials (ex: proteins from the Rough ER) to the Golgi and from the Golgi to release materials at the membrane•Called the “post office” because it repackages materials and sends them out of the cell
LysosomesLocation /Structure: •small, spherical organelles that contain enzymes•float in the cytoplasm
Function: •enzymes can digest carbs, lipids, DNA, RNA, old organelles, viruses, bacteria•Only found in animal cells
Mitochondria
Location / Structure: Has a double membrane, inner membrane is folded
Function: powerhouse of the cell; produces energy!
Question: In what types of cells would mitochondria be the most numerous?
ChloroplastsLocation / Structure:•only found in plant cells•double membrane•stacks of “disks” inside inner membrane•green due to pigment “chlorophyll”
Function: •Sunlight energy is captured by chlorophyll and converted to energy stored in sugars like glucose during photosynthesis
Vacuole
Location / Structure•Floating in the cytoplasm, sphere of membrane surrounding fluid•Found in plants and animals, but large and in the middle of the cell in plants
Function: Stores waste, water, food, etc.
Cell Wall
Location / Structure:
•Outer barrier on plant cells
•Made of cellulose, a tough polysaccharide
Function: supports and protects the cell
Cytoskeleton• Location / Structure: a
“mesh” of three types of long protein strands located in the cytoplasm
• Function: a structure to maintain the shape and size of cells (like our skeletons!)
Cilia / FlagellaLocation / Structure: •hair-like organelles that extend from the surface of the cell•cilia are shorter and more numerous•flagella are longer and less numerous
Function: •Movement
CentriolesLocation / Structure: •Made of the same types of proteins found in the cytoskeleton arranged in cylinders (look like “churros”)•Found only in animal cells
Function: •Assist with cell division