final: ch 11

heterotrophs use a

carbon source

autotrophs use a

carbon source

heterotrophs use

organic molecules

autotrophs use

a single carbon molecule

photoautotrophs use an

energy source

chemotrophs use an

energy source

phototrophs use

light

chemotrophs obtain energy from

oxidation of chemical compounds

lithotrophs use a

electron source

organotrophs use a

electron source

lithotrophs use

reduced inorganic substances

organotrophs use

organic compounds

chemoorganotrophs can do

• fermentation

• aerobic respiration

• anaerobic respiration

chemolithotrophs can only do

• aerobic respiration

• anaerobic respiration

respiration involves the use of

the electron transport chain (ETC)

fermentation uses an

endogenous electron acceptor such as pyruvate

fermentation does not use

the electron transport chain (ETC) or proton motive force (PMF)

substrate level phosphorylation (SLP)

does not require oxygen

there are many different energy sources such as

proteins, polysaccharides, phospholipids

most pathways generate

glucose or glucose intermediates

pathways

must still synthesize the glycolytic intermediates

carbon skeletons from the EMP (glycolysis)

• glucose-6-phosphate

• fructose-6-phosphate

• glyceraldehyde-3-phosphate

• 3-phosphoglycerate

• phosphoenolpyruvate (PEP)

• pyruvate

the central metabolic pathways

provide the precursor metabolites to all other pathways

EMP, EED and PPP

convert glucose to glyceraldehyde-3-phosphate

glyceraldehyde-3-phosphate is oxidized to pyruvate

products of the EMP (glycolysis)

2 ATP, 2 NADH

products of the ED

ATP, NADH, NADPH

the next yield for EMP (glycolysis) is

2 pyruvate

the net yield for ED is

2 pyruvate

the carbon skeletons from the PPP are

• erythrose-4-phosphate

• ribose-5-phosphate

the carbon skeletons from the TCA are

• acetyl CoA

• alpha-ketoglutarate

• succinyl CoA

• oxaloacetate

tricarboxylic acid (TCA) cycle, citric acid, krebs

fully oxidizes glucose and occurs partially during fermentation

products of the TCA, citric acid, krebs cycle

• 6 CO2

• 8 NADH

• 2 FADH2

• 2 GTP → ATP

the ETC

makes most of ATP as NADH and FADH2 are re-oxidized

proteins exist in a multiprotein complex called

oxidoreductases or oxidase

the ETC is a

series of e- carriers from more negative to most positive

these mitochondrial ETC’s are coupling sites

• complex I

• complex III

• complex IV

where is the ETC located in eukaryotes

mito IMM

where is the ETC located in prokaryotes

cell membrane

differences between prokaryotic and eukaryotic ETC

• location

• different electron carriers

• may be branched

• may be shorter

• may have lower P/O ratio

fermentation pathways are named after

the major acid or alcohol produced

mixed acid fermenters

• metabolize pyruvate into numerous products

• results in acetic, lactic and formic acids

butanediol fermenters

• 2,3-butanediol is the major end product

• produces ethanol

alcoholic acid fermenters

ferments sugars to ethanol to CO2 via alcohol dehydrogenase

fermentation includes products that

• lead to food spoilage

• making of alcoholic beverages, yogurt, cheese, bread and fuel

most common type of fermentation

lactic acid fermentation

lactic acid fermentation

reduction of pyruvate to lactate

chemolithotrophy

eating rocks

many chemolithotrophs are also

autotrophs

chemolithotrophs must use

reverse electron flow due to more positive reduction potentials