Compartmentalization Flashcards
3 distinct sub cellular regions
Cell membrane (plasma membrane)
Nucleous
Cytoplasm
__% of bodily fluid is in the inside of cells
60%
Function of the cell membrane
Control what exits the cell and leaves the cell (selectively permeable)
What can/can’t move freely through the cell membrane
Can: Small, non-polar, lipid or fat soluble uncharged molecules (move by passive/simple diffusion)
Can’t: Large, uncharged, polar or water soluble and charged molecules need hep (Facilitated by proteins)
Hydrophobic
Water hating, non-polar
Hydrophilic
Water loving, polar
Amphipathic molecule
A molecule with both hydrophobic and hydrophilic portions
Very important in forming the lipid bilayer
How does cholesterol affect the plasma membrane
Cholesterol decreases fluidity/increases rigidity. This decreases permeability since the bilayer is rigid.
Less cholesterol will increase fluidity and permeability.
Integral proteins (intrinsic)
Have at least 1 hydrophobic region that anchors them to the hydrophobic core of the lipid bilayer. The hydrophilic portion associates with aqueous fluid either outside or inside the cell.
Some stick only partway into the membrane and others span the entire width (transmembrane protein)
Transmembrane protein
Protein that spans the entire width of the membrane
Peripheral proteins (extrinsic)
Surface protein (can be on either side of the membrane) that is temporary. Attached to integral proteins or the hydrophilic heads of phospholipids. They do not associate with the hydrophobic core
Difference between integral (intrinsic) proteins and peripheral (extrinsic) proteins
Integral proteins anchor themselves to the hydrophilic core, either only on one side, or spanning the entire membrane.
Peripheral proteins attach to the integral proteins on either side of the membrane and do not associate with the hydrophilic core. They are temporary.
Function of carbohydrates on the cell surface
They are usually attached to proteins (glycoproteins) or lipids (glycolipids) and provide cushioning/protection, involved in cell recognition and connect/join two cells together.
2 examples of extracellular fluids
Intercellular/interstitial or intravascular
Fluid within the cell
Intravascular
Nuclear envelope consists of
2 lipid bilayer membranes
Top layer- Outer lipid bilayer that is continuous with the rough endoplasmic reticulum.
Inner layer- Inner lipid bilayer that is lined by the nuclear lamina, which is protein that organizes DNA
Job of nuclear lamina
Protein that organizes DNA found in the inner layer of the lipid bilayer within the nuclear envelope.
Semifluid matrix found inside the nucleus
Nuceloplasm
Chromatin
DNA + protein within the nucleoplasm
Nucleolous
Within the nucleoplasm, site of rRNA and ribosome synthesis
Fibrous proteins found in the cytoskeleton
Microtubules
Actin filaments
Intermediate filaments
Role of the cytoskeleton
Provides structure and support inside the cell. Helps materials inside the cell move by kinesin and or dyneine
Ribosome subunits
large subunit (60s) and small subunit (40s)
Only composed of rRNA and proteins. Does not have a surrounding membrane (not membrane bound)
Cisternae
a series of tubules and flattened sacs. Found in the endoplasmic reticulum and golgi apparatus
Role of the smooth ER
- lacks ribosomes
- Lipid processing center. Turns toxic lipid/fats into water soluble substances
- High presence in liver (detoxifies drugs/alc)
- Uses Ca2+ from the cytosol
What is the golgi apparatus made of
Cisternae (tubules and flattened sacs) and the membrane is a lipid bilayer.
Role of the golgi apparatus
Modiefies proteins received from the ER. Glycosylation.
Cis and trans sides of the golgi
Cis- receiving side (longer) and trans- shipping side (smaller)
What is the mitochondria composed of
Double membrane, mitochondrial matrix and circular DNA from mom. (can synthesize rRNA, tRNA, and mRNA)
Inner membrane forms many deep folds (Cristae) with fluid inside and the outer is the surface.
Which organelle plays a role in apoptosis
mitochondria
pH of lysosome
Acidic ~5.
Contains enzymes that break down old cellular components or foreign particles.
Lysosome role
Recycle/trash.
Surrounded by a membrane
Contains enzymes to break down particles
pH ~5
Peroxisomes
- Surrounded by lipid bilayer (good bc selective permeability)
- Involved in a variety of reactions such as fatty acid oxidation, neutralizing free radicals, myelin synthesis, and cholesterol synthesis.
