Chloroplast (plastid)

http://138.192.68.68/bio/Courses/biochem2/Photosynthesis/PhotosynthesisResources/Chloroplast.gif

Structure:

-Outer membrane, on the outside of the chloroplast, a phospholipid bilayer

-Inner membrane, inside the outer membrane, also a phospholipid bilayer

-Stroma, a fluid which contains DNA and ribosomes

-Thylakoids, comprised of space (called lumen), a membrane, and the pigment chlorophyll

-Grana, stacks of thylakoids

-Stroma lamellae, which connect the grana in a chloroplast

Function (photosynthesis):

-Used in plant cells, algae (protists), and some bacteria

-Converts 6 H₂O and 6 CO₂ into C₆H₁₂O₆ and 6 O₂ with light

-Uses  chlorophyll, a protein which reacts to light

-3 components: photosystem I, photosystem II, and Calvin cycle

-Uses and produces the high-energy compounds ATP and NADPH

 

Mitochondrion

http://www.cartage.org.lb/en/themes/sciences/zoology/AnimalPhysiology/Anatomy/AnimalCellStructure/Mitochondria/Mitochondria.htm

Structure:

-Outer membrane

-Inner membrane

-Cristae, folds in the inner membrane

-Matrix, on the inside of the inner membrane

-Mitochondrial DNA, in the matrix

Function:

-Krebs Cycle

            -synthesizes ATP

            -occurs in the matrix

-Electron Transport Chain

            -synthesizes ATP

            -occurs on the cristae

-Source of energy for the cell

 

 

Cytoskeleton

 

Structure:

-Actin Filaments: near outside of cell, strong, made of two chains

-Intermediate filaments: thicker than actin filaments but similar structure; used closer to the inside of the cell

-Microtubules: hollow tubes made of several small filaments; can expand and contract and are polarized

 

-MTOCs (microtubule organization centers)

-Centriole: the MTOC in animal cells, made of 2 perpendicular centrosomes (groups of microtubules), found at the center of the cell

-Basal Bodies: MTOCs in cells with cilia or flagella

Function:

-Maintains cell shape

-Protects the cell

-Moves certain cells

-Forms organelles such as cilia, flagella, and lamellipodia

-Cell division (cytokinesis)

-Transports other organelles with motor proteins                                                                                                   Part of a Cell's Cytoskeleton.

 

-Interacts with motor proteins to move vesicles

-Allows motor proteins to move along the polarized surface

-Grows its microtubules with its MTOC

 http://en.wikipedia.org/wiki/Image:FluorescentCells.jpg

 

Endomembrane System

The endomembrane system includes all of the membranes which form organelles inside the cell. The components of the endomembrane system are:

-The plasma membrane

-The nuclear membrane

-The endoplasmic reticulum

-The Golgi apparatus

-Ribosomes

-Lysosomes

-Vacuoles

-Vesicles

 

Plasma Membrane

 

http://www.molecularexpressions.com/cells/plasmamembrane/plasmamembrane.html

Structure:

-Phospholipid bilayer

-Hydrophilic areas

-Hydrophobic area

-Embedded proteins

Function:

-Protects the cell

-Allows certain substances to enter through proteins

 

Nuclear Membrane

http://en.wikipedia.org/wiki/Nuclear_membrane

Structure:

-2 Phospholipid bilayers

-Surrounds the nucleus

-Contains pores

-Contains ribosomes

-Connected to the rough endoplasmic reticulum

Function:

-Separate nucleus from cytoplasm

-Allow certain substances to pass through pores

 

Endoplasmic Reticulum 

Structure:

-Membranes

-Rough Endoplasmic Reticulum (contains ribosomes)

-Smooth Endoplasmic Reticulum

-Cisternae (membrane folds)

-Cisternal space (lumen)

-Supported by the cytoskeleton

Function:

-Folds Proteins

-Transports proteins

-Detoxifies some substances

-Synthesizes lipids

-Stores enzymes and minerals

-Metabolizes carbohydrates

 http://micro.magnet.fsu.edu/cells/endoplasmicreticulum/endoplasmicreticulum.html

 

 

 

Golgi Apparatus

 

Structure:

-Cis Face, near the endoplasmic reticulum

-Trans Face, near the cell membrane

-Cisternae, elongated phospholipid membrane sacs

-Cisternal space (lumen)

Function:

-Accepts proteins from the endoplasmic reticulum

-Modifies proteins

-Synthesizes carbohydrates

-Transports lipids

-Creates lysosomes

 

 http://micro.magnet.fsu.edu/cells/golgi/golgiapparatus.html

 

 

 

 

Ribosome 

Structure:

-50S (prokaryote) or 60S (eukaryote) large subunit

-30S (prokaryote) or 40S (eukaryote) subunit

-Proteins

-Nucleotides (RNA)

Function: translation of mRNA into protein. This is a multi-step process. The steps involved are as follows:

-The mRNA is copied from a portion of the DNA.

-The ribosome moves the mRNA through molecules of tRNA.

-Each molecule of tRNA contains 3 nucleotides, which correspond to 3 nucleotides on the mRNA, and 1 amino acid. The amino acid is specific to the nucleotide sequence.

-The sequence of amino acids on the tRNA molecules forms a polypeptide chain. This folds into a protein on its own.

 Left: 30S ribosome component       Right: 50S ribosome component

 

 

http://www.molgen.mpg.de/~ag_ribo/ag_franceschi/30S_50S.jpg

 

 

Lysosome (my choice)

Structure:

-Digestive enzymes

-Phospholipid membrane

Function: Digestion of external substances. This process works as follows:

-An external substance is taken in through endocytosis.

-The substance is contained in a vacuole.

-The lysosome binds to the vacuole and opens to release its enzymes.

-The enzymes break down the contents of the vacuole.

When the contents are digested, the components can be either used by the cell or removed using exocytosis.

Alternatively, the lysosome could digest a malfunctioning organelle.

 

Vacuole

Structure:

-Internal space

-Membrane

Function:

-Removing undesirable substances from the cell

-Maintaining internal pressure

-Storage

-Regulating pH of a cell

 

 

Extracellular Fluid

Extracellular fluid is a term for any fluid in the body that is not found within cells. There are three types of extracellular fluid:

-Interstitial fluid (a solution containing an organism’s cells)

-Blood plasma (the liquid component of the blood)

-Transcellular fluid (such as digestive fluid, joint fluid, and urine)

Extracellular fluid contains several ions, including sodium, potassium, calcium, chloride, and bicarbonate. Its pH is usually close to neutral. 

 

 

Exocytosis/Endocytosis

Exocytosis: The process of a cell expelling an internal substance in a vesicle from the cell. There are several steps involved in this process.

-The movement of the vesicle towards the plasma membrane with the help of a portion of the cytoskeleton and a motor protein

-The positioning of the vesicle near the membrane

-The orientation of the vesicle

-Proteins prepare the vesicle to bind to the membrane (in nerve cells only)

-The binding of the vesicle to the membrane, opening the vesicle and releasing its contents

The transmission of nerve impulses involves exocytosis.

Endocytosis: The process of a cell taking in an external substance or a smaller cell. There are two types of endocytosis.

-Phagocytosis, the process of taking in a small cell and enclosing it in a vacuole

-Pinocytosis, the process of taking in a solute or protein

This process is integral for taking in nutrients which cannot fit through any of the transport proteins.