L4: Principles of Cell Biology Flashcards
plasma membrane
- 7.5 nm thick
- lipid bilayer with 2 leaflets
e face
- extracellular face
p face
- protoplasmic face
lipids make up how much of plasma membrane
- 35%
- phospholipids
- glycolipids
- cholesterol
proteins make up how much of plasma membrane
- 60%
- integral proteins
- peripheral proteins
carbs make up how much of plasma membrane
- 5%
plasma membrane fluidity
- fluidity for exocytosis, endocytosis, membrane trafficking, and membrane biogenesis
integral proteins
- embedded in lipid bilayer
- transmembrane proteins
- composed of hydrophilic and hydrophobic amino acids
- folded; multipass
- serve as receptors, cell adhesion molecules, cell recognition proteins, signal transduction, transport
peripheral proteins
- usually located on cytoplasmic aspect of inner leaflet
- bind to phospholipids or integral proteins
- serve as electron carriers, part of cytoskeleton, part of 2nd messenger system
nuclear envelope structure
- formed by outer and inner nuclear membranes
- the 2 membranes fuse to form 80 nm nuclear pores
- outer nuclear membrane continuous with RER
nucleolus structure
- nuclear inclusion but not surrounded by a membrane
- observed in interphase cells that are synthesizing proteins
- contains mostly rRNA and protein as well as DNA
function of nucleus
- contains genetic material encoded in DNA
- synthesizes all forms of RNA
ribosomes
- formed by small and large subunits of rRNA and proteins
two types of ribosomes
- free ribosomes in cytosol
- membrane-bound ribosomes
rough ER
- system of membrane free sacs
- outer surface covered in ribosomes
- continuous with outer nuclear membrane
- location where membrane-packaged proteins are synthesized
smooth ER
- network of tubules, vesicles, and sacs (cistern)
- varies in amount, distribution, and complexity based on cell type/fxn
- smooth-surfaced membranes
- function varies by cell
smooth ER function hepatocytes
- carbohydrate metabolism - glycogen -> glucose
- degradation of lipid-soluble drugs and alcohol (via cyt P450)
smooth ER function steroid secreting cells
- ovary, testis, adrenal
- lipid and lipoprotein synthesis
smooth ER function muscle cells
- smooth ER = sarcoplasmic reticulum
- calcium ion regulation
Mitochondria membranes
- outer membrane
- inner membrane (invaginating to form cristae)
mitochondria spaces
- intermembrane compartment - between outer and inner membrane
- inner matrix compartment - flows all within cristae
mitochondria
- ATP synthesis via the Krebs cycle (most enzymes in the matrix)
- contains DNA and RNA for coding some mitochondrial proteins (although many mitochondrial proteins are coded by nuclear DNA)
- produce heat (rather than energy) in brown fat cells
where does the Krebs cycle occur
- mitochondrial matrix
where the ETC occur
- inner mitochondrial membrane
cytochrome c oxidase
- important component of the electron transport chain
- defects result in severe metabolic disorders
- don’t confuse with C450 in smooth ER
Golgi apparatus
- membrane bound cisternae (saccules) arranged in irregular-looking sacs
- two faces
cis face of golgi
- toward nuclear next to RER