cell bio 2a

output: ATP and CO2, input: O2, fats and carbohydrates

cytosol

NADH, whose electrons are stripped by the electron transport chain

each protein has higher affinity than the next for electrons

• NADH dehydrogenase complex, cytochrome b-c1 complex, and cytochrome oxidase complex
• carriers: ubiquinone and cytochrome c

acetyl CoA goes in, FADH2 and NADH and Co2 goes out

flagellar motor movement

inner bacterial membrane and in the space below the peptidoglycan layer

use amino acids to fuel ATP production

remove excess NADH from cytosol to further speed glycolysis

supply cytosol with excess citrate for synthesis of fatty acids and sterols, or supply cytosol with reducing power (as NADPH) for biosynthesis using excess mito reducing power

use energy in light to fuel production of sugar and other molecules needed by the cells

• input water to replenish electron supply and Co2
• output o2, and carbohydrate molecules from carbon-fixation cycle

chloroplasts contains thousands of light absorbing chlorophylls, energy of one chlorophyl bumps into another unti lit hits reaction center; energy causes electron to jump to a higher energy level, initiates a series of electron transfers (neighboring electrons accepts, while another donates low energy e to a deficient chlorophyll molecule, then this low energy chlorophyl receives e from water); need happen 4 times

when light bumps e out of photosystem, e is transported to carrier molecules; the diffusable e brings energy to pump h+ across membrane

photosystem II, cytochrome comples, photosystem I and NADP reductase, which drives NADP to NADPH to liberate oxygen from 2 molecules of water

extracellular environment

happens regularly

peripheral membrane, nuclear, chloroplast and cytosolic

integral, secreted, lipids

continuous with the outer nuclear membrane, anastrosomes: meshwork of 3-D interconnected membrane sheet 

• signal hypothesis (secreted and integral membrane proteins, 6-15 nonpolar a.a.s, cotranslationsl)
• SRP-7SRNA
• Signal peptidase
• chaperone
• glycosylation

• ribosomes can recognize sequence of translative protein-that's got a signal sequence. Tell ribosome to dock at specific place in ER and docking mechanism allows for translocation to middle of docking station and lumen of ER (secreted) or membrane protein to be released to membrane
• SRP has RNA that recognizes a.a.s, halts translation, brings it to ER (receptor), and docks it to porin and translation resumes, protein snakes into lumen, signal cut with signal peptidase. Chaperone BiP drags it in and folds it

when ribosome engaged with translocon

signal recognition particle binds signal sequence on protein

folding and prevents backsliding