Cell Organelles Flashcards
Prokaryotes
Unicellular organisms that lack membrane bound nuclei or specialized organelles. They have no genetic diversity due to cytokinesis
Nucleoid
Location of DNA in the nucleus of a prokaryote
Eukaryote
Multicellular organisms that contain specialized organelles and a nuclear membrane
3 Domains of Life
Eubacteria, Archea, Eukarya
Eukarya
Animals, Fungi, Plants
Archaea
Bacteria that was invaded by eubacteria to form a eukaryotic organism
Phospholipid molecules (cell membrane)
Head groups are polar and hydrophilic. Inside is non-polar and hydrophobic.
Integral (transmembrane) proteins
pores and receptors
Peripheral (extrinsic) membrane
accessory proteins
Saccharides (cell membrane)
attached glycolipids and glycoproteins (glycocalyx)
Nuclear Envelope
Selectively permeable barrier that is a continuation of the ribonucleic membrane
Nuclear Pores
Control what goes in and out of cell. Small molecules pass easily, but larger molecules need transport proteins to pass (chaperones)
Nucleolus
Site of RNA synthesis
Pars fibrosa
Area in the nucleolus that consist of primary rRNA transcripts
Pars granulosa
Area in the nucleolus where maturing ribosomal subunits accumulate
Pars amorpha
Nuclear organizer region of the nucleolus that consists of DNA sequences coding for rRNA.
Heterochromatin
heavy stained DNA
Euchromatin
light stained DNA
Chromatin
DNA, Protein (histones, transcription factors)
Histones
Level of DNA packaging where DNA is bundled up in the nucleus
Cytokinesis
The cytoplasmic division of a cell at the end of mitosis or meiosis.
Ribosomes
Site of protein synthesis
Nascent Protein
A protein before it folds into its active shape.
Free ribosomes
Synthesis for cytosolic and cytoskeletal proteins and proteins for import into the nucleus, mitochondria, and peroxisomes
Ribosomal components of the RER
Require further processing before incorporation into membranes.
Endoplasmic Reticulum
Cleaves single peptides, protein folding, and attachment of oligosaccharides.
Smooth ER
Synthesizes phospholipids, fats, and steroids
Contains enzymes for detoxification
Proteosomes
Destroys proteins that can not be folded
Cystic Fibrosis
Example of protein misfolding
Golgi Apparatus
Modifies, sorts, packages, and targets proteins to to organelles from there ER to the plasma membrane
Cis face
Forming face. Site of protein synthesis and phosphorylation of sugars and lysosomal proteins
Trans face
Maturing face. Site of protein sorting and distribution of lysosomes and secretory vesicles towards the plasma membrane.
Coat protein (COP) II
Promotes forward movement of vesicles
Coat protein (COP) I
Promotes retrograde movement of vesicles
KDEL receptor
Mediates the retrieval of misfolded proteins from the Golgi back to the ER
Lysosome
Contains an acidic environment that degrades debris from the cell.
Mannose-6-phosphate receptor (M6P)
Sorted by the Golgi. Targets proteins to lysosomal vesicles.
Multi vesicular body
2 primary lysosomes fused together
Secondary lysosome
A phagocytic vesicle fused with a lysosome
Peroxisome
Produces hydrogen peroxide to break down harmful substances. Detoxifies alcohol and other harmful chemicals.
Peroxisomal enzyme
Perform B-oxidation of long chain fatty acids (first step of catabolism)
Mitochondria
Synthesize ATP during aerobic respiration and sequester excess cytoplasmic calcium. Formed from an symbiotic relationship with bacteria.
Lipofuscin
Membrane bound lipid contains residues of lysosomal digestion (tertiary lysosome)
Glycogen
Not membrane bound. Stores of glycogen are an energy source
Glycogenolysis
degrades glycogen into glucose
Lipids
Not membrane bound triglycerides (fat cells) in storage form
Microfilaments
Smallest unit of cytoskeleton responsible for structure and support. Ex/ actin
Actin
Responsible for intracellular movement and muscle contraction.
Consist of globular monomers that assemble in the presence of K+ and Mg2+. They form a double helix.
Stress fibers
play a role in contractibility and motility of the entire cell and organelles within the cell
Terminal web
Structure that microvilli and stereocilia anchor into. Attached to the zona adherens
Filopodia
Active, motile finger-like projections of actin in migrating cells. They sense locomotion and cell-cell interactions.
Microtubules
Membrane structures that exist in individual fibers, cilia, or in centrioles. Heterodimer of a and B subunits
Axoneme
doublets of microtubules in the core of cilia (9+2 arrangement)
Centriole
triplets of microtubules that form centrosomes and basal bodies (nucleates the axoneme of cilia)
Mitotic organizing center (MTOC)
pairs of centrioles form this. They nucleate the mitotic spindle
Nuclear lamins
Intermediate filaments that make up that makes a mesh between the nuclear envelope and chromatin in the nucleus.
Vimentinlike proteins
Intermediate filament proteins that are located in muscle, neurons, glial cells.
Neuronal intermediate filaments
Neurons
Keratins
Intermediate filament that attaches with desmosomes (adhesion cells) to form a framework within the cytoplasm in the epidermis.
Zonula Occludens
Tight junctions. Prevent material from passing from the lumen to intercellular space of cells.
Zonula Adherens
Intermediate junctions. They anchor cells together and form a belt between cells.
Macula Adherens
Desmosomes, adhesion cells. They form “spot welds” for the attachment of cells to each other. They contain cadherin
Hemi-desmosome
Anchors the basal cytoplasm to the basal lamina. Contains integrin
Communicating Junctions
Gap junctions that mediate rapid communication between cells. They allow small molecules (Na, K, Cl) to pass through rapidly to mediate signal transduction for coordinated function.
