CELLS - HISTO LEC Flashcards
Two Basic Parts of the Cell:
- Cytoplasm
2. Nucleus
- metabolically active structures or complexes, with or without membranes, in the cytoplasm of eukaryotic cells
Organelles
outermost component of the cell
-separates cytoplasm from extracellular environment
PLASMA MEMBRANE
- defines the outer limit of the cell
- continuum exists between extracellular and intracellular macromolecules
PLASMA MEMBRANE
- contains integrins
- made of phospholipids, cholesterol, proteins, oligosaccharide chains
PLASMA MEMBRANE
- a selective barrier regulating passage of materials into and out of the cell
- facilitates transport of molecules
PLASMA MEMBRANE
- range from 7.5 to 10 nm in thickness
- visible only in electron microscope
PLASMA MEMBRANE
consisting of two nonpolar long-chain fatty acids linked to a charged polar head bearing a phosphate group
Amphipathic –
*Phospholipids are most stable when organized into a
double layer (hydrophobic toward the middle).
*Phospholipids in each half of the bilayer are
different.
restricts movement of phospholipid fatty acids; stabilizes lipid bilayer
Cholesterol –
areas of less movement
-have higher concentrations of cholesterol and saturated fatty acids
Lipid rafts -
proteins/linkages which produce a continuous exchange of influences, in both directions, between ECM and cytoplasm
Integrins –
– fluid component of cytoplasm
Cytosol
– proteins which determine the shape and motility of eukaryotic cells
Cytoskeleton
minor cytoplasmic structures which are generally deposits of carbohydrates, lipids, or pigments
Inclusions –
outer lipids which include oligosaccharide chains that extend outward from the cell surface
-contribute to glycocalyx
Glycolipids –
– delicate cell surface coating formed by glycolipids
Glycocalyx
major constituent of membranes
Proteins –
TYPES OF PROTEINS
- Integral
- Peripheral
- Multipass Transmembrane
– small electron-dense particles
- all have 2 subunits of different sizes
- act to catalyze the process of protein translation
Ribosomes
– extends from the surface of the nucleus to the cell membrane
- encloses a cisternae
- SINGLE MEMBRANE
Endoplasmic Reticulum
series of intercommunicating channels and sacs
Cisterna –
Functions of Endoplasmic Reticulum
1. Synthesis • SER – lipid synthesis and carbohydrate metabolism • RER – protein synthesis 2. Transport 3. Storage 4. Detoxification
specialized for protein secretion
- synthesizes and segregates proteins not destined for cytosol
- initial glycosylation of glycoproteins
- assembly of mutlichain proteins
- granular, basophilic cytoplasmic surface due to the presence of polysomes
Rough Endoplasmic Reticulum –
not basophilic; best seen with TEM
- More tubular
- phospholipid synthesis
- steroid synthesis
- abundant in many liver cells
- sequesters and releases Ca2+ (sarcoplasmic reticulum)
- has enzymes for lipid and glycogen metabolism
Smooth Endoplasmic Reticulum –
– completes posttranslational modifications of proteins synthesized in the RER
-packages and addresses these proteins to proper destinations
Golgi Apparatus or Golgi complex