Organelles Flashcards
Non membranous organelles
No membrane •
Direct contact with cytosol •
Include the cytoskeleton, microvilli, centrioles, cilia,
ribosomes, and proteasomes
Membranous organelles
Covered with phospholipid membrane
• Isolated from cytosol
• Include the nucleus, endoplasmic reticulum (ER), the
Golgi apparatus, lysosomes, peroxisomes, nucleus, and mitochondria
Cilia
Primary cilia- has sensory function, sends signals to inside of cells
Motile cilia- moves fluids/itself
Ribosomes
Build polypeptides in protein synthesis
2 types
-free ribosomes= in the cytoplasm, Manufacture proteins for the cytosol
-fixed ribosomes= in the ER, Manufacture proteins for places other than the cytosol
Proteasomes
Contain enzymes (proteases) • Disassemble damaged proteins for recycling
Nucleus
Cell control center and largest organelle
Nuclear envelope
•Double membrane around the nucleus
Perinuclear space
•Between the two layers of the nuclear envelope Nuclear pores
•Communication passages
Contents of the nucleus
DNA
•All information to build and run organisms
Nucleoplasm
•Fluid containing ions, enzymes, nucleotides,
and some RNA
Nuclear matrix
•Support filaments
Nucleoli
•Are related to protein production
•Are made of RNA, enzymes, and histones
•Synthesize rRNA and ribosomal subunits
Cisternae
storage chambers within membranes
Functions of the ER
1) Synthesis of proteins, carbohydrates, and lipids
2) Storage of synthesized molecules and materials 3. Transport of materials within the ER
4. Detoxification of drugs or toxins
Smooth ER
No ribosomes attached
• Synthesizes lipids, fatty acids, and carbohydrates
• Phospholipids and cholesterol (membranes)
• Steroid hormones (reproductive system)
• Glycerides (liver cells and fat cells)
• Glycogen (skeletal muscle and liver cells)
Rough ER
Surface covered with ribosomes
• Active in protein and glycoprotein synthesis
• Folds polypeptide protein structures
• Encloses products in transport vesicles
Golgi Aparatus
Vesicles enter forming face and exit maturing face
-Functions
1. Modifies and packages secretions
• Hormones or enzymes
• Released through exocytosis
2. Renews or modifies the plasma membrane
3. Packages special enzymes within vesicles for use
in the cytoplasm
Lysosomes
Powerful enzyme containing vesicles
Primary-
Formed by Golgi apparatus
• Contains inactive enzymes
Secondary-
Lysosome fused with damaged organelle,
digestive enzymes activated
Autolysis
Auto- = self, lysis = break Self-destruction of damaged cells •Lysosome membranes break down •Digestive enzymes released •Cell decomposes •Cellular materials recycle
Peroxisomes
Are enzyme-containing vesicles - Peroxisomes contain at least 50 different enzymes
• Formed by endoplasmic reticulum
• Break down oxidative substrates: fatty acids, amino acids, and uric
acid
• Produce hydrogen peroxide (HO) as a product of oxidative
reactions
• contain the enzyme catalase converting hydrogen peroxide to water and
oxygen
• Invovled in lipid biosynthesis
• In liver cells involved in synthesis of bile acids
