Membranous Organelles Flashcards
Mitochondria (function)
Produces ATP (adenosine triphosphate) - available energy for cell processes.
Membranous organelles
Mitochondria
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Peroxisomes
Mitochondria (structure)
Composed of an outer membrane and an inner membrane.
Cristae
Folds projected by the inner membrane into the interior of the mitochondrion, increasing surface area.
Matrix
Fluid inside the mitochondria
Intermembrane space
The gap between the two membranes
The number of mitochondria in a cell
It is related to the cell’s energy needs
The outer membrane (structure)
Contains many transmembrane proteins called porines that form channels through which small molecules pass to enter the intermembrane space from the cytoplasm.
Mitochondrial deficiency diseases characterized by
Muscular disfunction
Drooping of the upper eyelid
Difficulties in swallowing
Limb weakness
Endoplasmic reticulum (structure)
Continuous network of membrane tubules and cisternae
Endoplasmic reticulum (types)
Rough ER
Smooth ER
Rough ER (structure)
Ribosomes on the tubules, attached to the ER membrane.
Rough ER (function)
Production (by ribosomes) of proteins made for exportation and of lysosomal enzymes.
Smooth ER (structure)
No ribosomes on the ER membrane.
Smooth ER (function)
Lipid metabolism
Golgi apparatus (structure)
Cytoplasmic organelle composed of a stack of smooth membranous saccules and associated vesicles. Usually found near the rough ER in the cell.
It has two faces: cis (receiving or entry) and trans (maturing or exit).
Golgi apparatus (function)
Modification, sorting and transport (shipping) of proteins.
Produces enzymes sorted into lysosomes, to degrade proteins and organelles.
Plays a role in retrieving and recycling proteins.
Mechanism of protein shipping
Once the proteins are produced by the rough ER, they pass into sack-like cisternae that are the main part of the Golgi body. These proteins are then squeezed of into the little belbs which drift off into the cytoplasm.
Protein shipping problems
If the Golgi complex makes a mistake in shipping the proteins to the right address, certain functions in the cell may stop.
Lysosomes (structure)
Single-membrane organelles nicknamed “suicide sacs”.
They are specialized vesicles holding a variety of enzymes capable of digesting or breaking down all organic materials.
Lysosome (formation)
The enzyme proteins are first created in the rough ER.
Those proteins are packaged in a vesicle and sent to the Golgi apparatus.
The Golgi apparatus does its final work to create the digestive enzymes and pinches off a specific vesicle, the lysosome.
From there the lysosomes float in the cytoplasm until they are needed.
Primary lysosomes
Produced by the Golgi apparatus.
Secondary lysosomes
Formed by the fusion of primary lysosomes with other membrane-bound vesicles in the cytoplasm. These vesicles either contain extracellular material that has entered the cell by phagocytosis and requires digesting, or organelles that require degrading because they have reached the end of their active life.
They contain around 40 different types of hydrolytic enzymes.
Peroxisomes (structure)
Enzyme-containing membrane-bound vesicles.
