Cell Organelles and Features

Organelles Plasma Membrane (Cell membrane) Centrioles Chloroplasts Nucleus Nuclear envelope Nucleolus Mitochondria Ribosomes Rough Endoplasmic Reticulum (RER) Smooth Endoplasmic Reticulum (SER) Golgi Apparatus Vesicles Lysosomes Peroxisomes Cytoskeleton Centrioles Chloroplasts

Plasma Membrane/Cell Membrane Consists of a phospholipid bilayer and membrane proteins embedded within the phospholipid bilayer Function: Physically separates the cell from the environment Acts as a barrier to allow only certain things to pass It is comparable in function to human skin

Plasma Membrane/Cell Membrane

Cell Wall Rigid layer that lies outside the cell’s plasma membrane Plant cell walls contain a carbohydrate called cellulose Cellulose is embedded in a matrix of proteins and other carbohydrates Pores in the cell wall allow water ions, and some molecules to enter and exit

Cell Wall

Cytoplasm Region of the cell within the plasma membrane Includes the fluid portion of the cell and all of the organelles Part of the cytoplasm that includes molecules and small particles but not membrane bound organelles is the CYTOSOL

Nucleus Control Center for the cell Most functions for a cell are determined here House’s and protects the cells genetic information DNA Site where DNA is transcribed into RNA

Nuclear Envelope Double membrane that surrounds the nucleus Made up of two phospholipid bilayers Protects the nucleus

Nucleolus Denser area inside the nucleus Site where DNA is concentrated when it is in the process of making ribosomal RNA

Nucleus and Its Many Parts

Mitochondria Tiny organelle that transfer energy from organic molecules to adenosine triphosphate (ATP) ATP powers most of the cell’s chemical reactions Has an inner and outer phospholipid membrane Outer membrane separate the mitochondrion from the cytosol Inner membrane has many folds called cristae

Mitochondria

Ribosomes Small, roughly spherical organelles Responsible for building proteins Made up of protein and RNA molecules Some ribosomes are free in the cytosol and others are attached to the rough endoplasmic reticulum

Ribosomes

Endoplasmic Reticulum (ER) Sytem of membranous tubes and sacs, called cisternae ER functions primarily as an intracellular highway Two Types Rough Endoplasmic Reticulum (RER) Smooth Endoplasmic Reticulum (SER)

Rough Endoplasmic Reticulum (RER) System of interconnected, flattened sacs covered with ribosomes Rough ER produces phospholipids and proteins Ex) Digestive Enzymes and anti-body producing agents

Smooth Endoplasmic Reticulum (SER) Lacks ribosomes Most cells contain very little Smooth ER Produces the steroid hormones estrogen and testosterone Releases calcium, helps detoxify drugs and poisons

Golgi Apparatus/Bodies Another system of flattened, membranous sacs Processes and packages macromolecules such as proteins and lipids that are synthesized by the cell More particular, the processing of proteins for secretion

Vacuole Large, fluid filled organelle that stores not only water but also enzymes, metabolic wastes, and other materials Can make up to 90% of a plant cell’s volume Considered to be like a reservoir that stores large amounts of water

Vessicles Small, spherically shaped sacs that are surrounded by a single membrane and are classified by their contents Often migrate to and merge with plasma membrane As they do, they release their contents to the outside of the cell

Lysosomes Vesicles that bud from the Golgi Apparatus and that contain digestive enzymes In liver, lysosomes break down glycogen in order to release glucose into the blood stream Breaks down cells when it is time for them to die

Peroxisomes Similar to lysosomes but contain different enzymes and are not produced by the Golgi Apparatus Neutralize free radicals (oxygen ions that can damage the cell) and detoxify alcohol and other drugs Also break down fatty acids, which the mitochondria use for energy sources

Cytoskeleton Network of thin tubes and filaments that crisscross the cytosol Give shape to the cell from the inside in the same way tent poles support the shape of a tent Consist of Microtubules, Microfilaments, and Intermediate Filaments

Cytoskeleton

Centrioles Consist of two short cylinders of microtubules at right angles to each other Situated in the cytoplasm near the nuclear envelope Occur in animal cells but not in plant cells Organize the microtubules of the cytoskeleton during cell division

Chloroplasts Use light energy to make carbohydrates from carbon dioxide and water Composed of membrane bound sacs called thylakoids Thylakoids contain a green pigment called chlorophyll Found in plants and in a wide variety of eukaryotic algae

Chloroplast

Cilia Organelle found in eukaryote cells Hair-like structures that extend 5-10 micrometers from the cell body Functions for movement or as a sensory appendage

Flagella Tail-like structure that projects from the cell body of certain prokaryote and eukaryote cells Main function is for movement

Nucleoid Found in prokaryotes Irregularly shaped region where the genetic material is located