cell energetics

catabolic

large molecule broken down

exergonic

energy exits a process

anabolic

building large molecules

endergonic

energy enters a process

endotherms

heat comes from within, consume large amnts of food to generate heat 

ecotherms

heat comes from outside the body

homeotherms

maintain homeostasis for body temp

poikilotherms

body temp varies 

oxidation

lose e-

adding oxygen, removing hydrogen, release energy exergonic

reduction

gain e-

removing oxygen, adding hydrogen, stores energy endergonic

phosphorylation

phosphate broken off attaches to another molecule which transfers energy to that molecule

endosymbiotic theory

mitochondria and chloroplasts were once free living organisms engulfed by larger cells; double membrane, own DNA and ribosomes

cristae

folded inner mitochondrial membrane 

intermembrane space

fluid filled space between membranes

matrix

inner fluid filled space; DNA, ribosomes, and enzymes free here

cell respiration

breaking down organic molecules to produce ATP; catabolic as glucose is broken down in small rxns, e- shuttled by NADH down ETC through glycolysis, pyruvate oxidation, Krebs/ Citric Acid cycle, and ETC

redox rxn

electrons transferred between reactants; one substance is oxidized and the other is reduced

glycolysis

occurs in cytoplasm/ cytosol with or without oxygen to break sugar into pyruvate by partially oxidizing glucose; endergonic w/ glucose and 2 ATP exergonic w/ 2 ATP and 2NADH; 6C (C6H12O6) to 2 pyruvates when 2 G3P (3 carbon 1 phosphate, glyceraldehyde 3 phosphate) through phosphorylation by PEP ADP- ATP and NAD-NADH to make finished 3 carbon pyruvate

fermentation

regenerate NAD by oxidation to keep glycolysis going without oxygen; oxidized when NADH accepts e- after pyruvate in glycolysis is converted to ethanol (w/ CO2) or lactic acid net gain of 2 ATP

pyruvate oxidation

oxygen present and occurs in mitochondrial matrix, carboxyl group removed from pyruvate, remaining 2 C are oxidized and released e- to NAD then NADH and this fragment (acetate) attaches to CoA to become acetyl-CoA; link between glycolysis and Krebs

Krebs/ citric acid

mitochondrial matrix gains 2 ATP by substrate level phosphorylation and 6 NADH 2 FADH2 and CO2, need to reduce carriers and regenerate 4 C compound; oxaloacetate 4 C acceptor regen. in each turn and acetyl CoA w/ 2C loses one to be CoA then forms 6C citrate w/ oxaloacetate, 1C lost as CO2 when NAD-NADH (5C), then another lost NAD-NADH (4C), GDP phosphorylized to GTP, FAD phosphorylized to FADH2, NAD to NADH regen. oxaloacetate

electron transport chain

along cristae in inner membrane, H+ pumped across inner membrane for proton gradient then diffuse through ATP synthase to make ATP, start with 10 NADH 4 from glycolysis 6 from Krebs and 2 FADH2 from Krebs where H cleaved off FADH and NADH so e- stripped from H to become protons and e- passed by carriers in membrane then protein pumps move protons into membrane space

electron transport carriers

final acceptor is oxygen in water, each carrier is more electronegative than the next and each step is oxidation/ exergonic as heat is released when e- move

ATP synthase

proton gradient facilitated diffusion as ions move high to low, high H+ in intermembrane space low H+ in matrix, ADP-ATP by chemiosmosis (ions moving across mem.) and as H= flows through ATP synthase enzyme spins causing part to shift and ADP and P fit into active site during oxidative phosphorylation (E released during oxidation of e- donor)

photosynthesis

light energy to chemical energy; Co2 & sunlight + H2O= O2 + C6H12O6, endergonic redox rxn water split e- trans w H+ to CO2- sugar

mesophyll

middle of leaf in whose cells most chloroplasts are found

stomata

pores in leaf (CO2 enter, O2 exit)

thylakoid

where light rxns occur, store chlorophyll and store sunlight energy in chloroplast

grana

stacks of thylakoids in chloroplast

stroma

fluid surrounding thylakoids containing ribosomes and chloroplast DNA

light rxns

(thylakoid mem.) light energy absorbed by chlorophyll photosystems (PS2 680) excites e- and diverts to ETC, e- lost in PS2 to ETC replaced by photolysis (water splitting) O2 released to atmosphere, e- move along ETC some E used to pump H+ from stroma into thylakoid to create proton gradient diffusing high to low and diffusing H+ out into stroma for ATP synthase to be used in Calvin

non cyclic

one direction, PS2 to NADPH making ATP and NADPH

cyclic

e- recycled around PS1 regenerating only ATP to balance NADPH/ATP

light rxn pt.2

denergized e- move to PS1 chlorophyll PS1 absorb light energy and e- passed to NADP+ H = NADPH- Calvin

PS2

Photons energized the electrons in chlorophyll and picked up by an electron carrier in the chain

Water is split: electrons replace those lost by PS2 chlorophyll, release oxygen to atmosphere, and protons in thylakoid lumen to help establish gradient

cytochrome complex

Light energy captured by chlorophyll to go to cytochrome complex, No matter change, But carrier protein in complex carries leftover electrons  to PS1, Some energy from electrons used to transport additional protons from lumen to the cytochrome complex; electrons drained

PS1

Photons excite chlorophyll electrons, move to next electron carrier in the chain, eventually the electrons move to NADP (final electron acceptor) then becomes NADPH; also losing electrons and replaced by cytochrome complex, all E captured as ATP and NADPH

Calvin Cycle

carbon fixation, reduction, regeneration

Carbon fixation

Inorganic carbon (carbon dioxide from the air) incorporated into organic molecules in fixation. 3 molecules of carbon dioxide react with ribose biophosphate to produce six molecules of a three-cabon molecule 3-PGA all catalyzed by rubisco.

Fixed with RuBP

reduction

Organic molecules accept electrons when 6 molecules of 3-PGA use 6 molecules of ATP and 6 molecules of NADPH. This stores energy from the light reactions to generate 6 molecules of G3P which is higher in potential energy than 3-PGA. One G3P exits to make other organic molecules 

ATP and NADPH used to connect 3 GPA into 3GP precursor to making glucose 

regeneration

Large set of reactions use the other 5 molecules of G3P and energy from 3 ATP to produce 3 RuPB (ribose biophophate) to restart the process.

More ATP than NADPH so switch to cyclic 

Rearrange G3P into RuBP