12: Mitochondria and E Generation CBIO

What is cellular respiration?

breaks glucose into ATP

What are the ways to get E or ATP?

1. Substrate Level Phosphorylation

2. Oxidative Phosphorylation

What is SUbstrate Level Phosphorylation? examples?

E favorable breakdown of molecules coupled to E unfavourable by adding phosphate to ADP

1. glycolysis

2. TCA cycle or Krebs cycle or Citric Acid cycle

What is Oxidative Phosphorylation? Example?

Uses E from activated carriers to make ATP

• ETC (NADH, FADH2, FAD+, NAD+)

Which activated carriers are used for AEROBIC ?

NADH and FADH2

Where is the 50% or E stored? wheres the rest of the E?

stored in glucose of ATP bonds

remaining E is released as heat

What is catabolism?

breakdown of big to small (pro to aa)

What happens in digestion?

large polymers into monomers

• intestines abosrbs it all and lysosomes break em down

What is glycolysis? where does it happen

1 glucose (6 carbons) split into 2 pyruvate (6 carbons) (1 py = 3 carbs)

• making 2 NADH and 2 ATP

• occurs in cytosol

What are the process of glycolysis? explain them all. explain net gate

Energy investment - invests 2 ATP to get:

Energy pay off phase = 4 ATP and 2 NADH out of it

since we 4 and used 2 and got 2 we get a total of 2 ATP

net gain: 2 ATP, 2 NADH

4-2 = 2 ATP

Explain the intermediate step or pyruvate oxidation. where does it occur for euks and bac

Pyruvate (3 C) turns into CO2 and acetyl-COA (2 C)

• euk = mitochondrial matrix

• bac = cytosol

What is citric acid cycle aka? explain what happens

• TCA cycle, krebs cycle

• Acetyl-COA oxidized to CO2 generating 3 NADH, 1 FADH2, 1 ATP

  • releases 2 carbons or 2 CO2

What are the diff enzymes of glycolysis

1. kinase

2. isomerase

3. dehydrogenase

4. Mutase

What is kinase? ex?

adds phosphate group to a molecule

• step 1 of glycolysis hexokinase

What is isomerase?

rearragnges bonds by same chemical formula but diff stucture of moelcule

Wat is dehydrogenase? example?

oxidation occurs because H and e- is removed replaced with O

• NAD+ to NADH

Whats a mutase?

shifts chemical group from 1 position to another within a moelcule

ex. swaps phosphate group with hydroxyl group

Explain coupling oxidation to E storage in activated carriers

last steps of glycolysis

• oxidation of the aldehyde in G3P is coupled to a high-E 1,3-biphosphoglycerate molecule

• then 1,3-biphosphoglycerate is consumed to release enough free E to attach a phosphate group to ADP to make ATP

  • not a huge burst of free E change but js enough = -12.5 KJ/mole

What is fermentation? goal?

breaks sugar without O2

• provides an alternative (bc need O2 at the end of ETC for oxidative phosphorylation) where NADH can drop(lose) its e- and regenerate or oxidizes into NAD+ to cycle through glycolysis

• Glycolysis requires NAD+ to convert glucose into pyruvate. In this step, NAD+ is reduced to NADH.

• When oxygen is unavailable, the cell must quickly recycle the accumulated NADH back to NAD+ to keep glycolysis running and produce a small amount of ATP (NAD+ is the "limiting reagent").

explain lactose fermentation

will go thru glycolysis so glucose splits into 2 pyruvates and then NADH is oxidized to NAD+

• pyruvate is reduced into lactate

• NADH is oxidized to NAD+.

What is anaerobic respiration?

a molecule besides O2 is used as a terminal e- acceptor in the ETC

• NADH and FADH2 drops e- in ETC, gets passed from carrier to carrier, at the end (w/ aerobic) we have O2 and will combine to e- and protons producing H2O as a byproduct

  • NOW, we have other molecules like sulphate with e- = sulphude

  • nitrate = ammonia

  • CO2 = methane

What is the intermediate step (pyruvate oxidation) and the generation of Acetyl-CoA

1. decarboxylation (remoes carboxyl group COOH)

• 3 enzymes from pyruvate dehydrogenase complex makes CO2, NADH, and Acetyl-CoA

2. FA (hydrocarbon chains- bunch of carbons in a row attached to H) broken down into acetyl-CoA

• linked to CoA

• cuts 2 carbons off the carboxyl end of hydrocarbon

• will produce NADH and FADH2 which will go thru ETC

3. Aa can convert to acetyl-CoA and intermediates in the CAC

what does coenzyme mean? what does conezyme A mean?

organical molecule helps enzyme functions

• helps TCA by adding on to acetyl to make acetyl coa

What is the citric acid cycle, kreb cycle, TCA cycle?

completes oxidation of the acetyl groups of acetyl-CoA or sugar into acetyl coa

1. acetyl coA (2 C) + oxaloacetate (4 C)= citric acid

2. CA oxidized to release CO2, which its E is stored to produce NADH and FADH2

• NAD+ reduced to NADH and FAD reduced to FADH2

1. we get O2 that makes CO2 from water splitting

What are the products of CAC?

per 1 acetyl coa is:

• 2 CO2

• 1 GTP

• 3 NADH

• 1 FADH2

what is GTP?

high E molecule

• stores E in TCA which will go thru secondary messengers to generate ATP

• Guanasine triphosphate

What is the product of CAC for 1 glucose that enetered cellular respiration?

1 glucose makes 2 py so cycle will go 2x

• 4 CO2

• 2 GTP

• 6 NADH

• 2 FADH2

what is biosynthetic pathways? what are metabolites?

intermediates from glycolysis and the CAC are used in anabolic pathways (build things)

metabolites - precursors to annabolic pathways

what are control mechanisms? example?

• regulate and coordinate the activty of enzymes (metabolite shld go catoblic or anabolic pathway)

  • enhance of inhibits an enzyme

    • regulation of glyolysis and glucogenesis

What is glucogenesis?

creates glucose from pyruvate consuming 4 ATP and 2 GTP

• consumes more E than what we get out of glycolysis

• Everything this way or that way so we don’t lose E

  • Don’t go back and forth w no regulation as we would release heat and consume E

What are enzymes that bypass the irrevresible rections from glycolysis for glyco and gluconeogenesis

glyco - phoshofructoKINASE phosphorylates fructose-6-phosphate to produce 1,6-biphosphate

gluconeo- fructose 1,6-biPHOSPHATASE removes a phosphate to produce fructose-6-phosphate

diff with phosphofructokinase and fructose 1,6-biphosphatase? similarity?

phosphofructokinase activated by ADP, AMP, phosphate

• ATP inhibits

• low amounts of ATP = glycolksis

fructose 1,6-biphosphatase activated by ATP

• ADP, AMP, phosphate inhibits

• low armounts of ^ = gluconeogeneiss

• controlled by feedbakc regulation (products regulate the eearly ones)

stages of Oxidative phosphorylation?

1. ETC

   1. chemiosmotic coupling

What is ETC? goal? location in euks and prok?

high E e- transferred thru a series of e- carriers

• generate proton motive force

euks - inner mitochondrial membrane ((folded so have lots of SA = cristae = more e- TC shoved to create very big pmf)

prok - cell or plasma membrane

how does ETC generate an electrochemical proton graident?

releases E to power pump proteins

• First carrier moelcule will be reduced as it gets e- then passes its on so

  • Redox release lil E which pumps e- across the membrane against [graident]

• Pumps = tranpsoetr molecuels used in active transport

• Terminal acceptor, last thing to accept so that its reduced to O2 (required in aerobic, if anerobic we'd have sulfphate..)

Goal of chemiosotmic coupling? how?

• USES proton motive force

• protons flow down their electrochemicla gradient thru ATP synthase, which releases E and..

• makes high amojunts of ATP from ADP and phosphate

What is the mitochondroia? made up of?

• production of ATP site

• can adjust its location, shape, and number to suit the needs of the cells

  • forms elongated tubular networks

• inner and outer membrane

whats the outer membrane of a mitochondria like? and inner like?

outer

• has many porin proteins - beta barells that lets things in and out

inner mem

• has cristae folds

• where ETC is

• has many trnaport proteins as most substances are impermeable (CHOOSE SI ATE)

What are the enzyme complexes of ETC? describe em

3 transmembrane complexes

1 peripheral complex

• NADH dehydrogenase complex

• cytochrome c reducyase complex

• cytochrome c oxidase complex

• each complex will have metals (mg and fe) and other chemical grops that allows movement of e- through the complex (one complex to the other)

• complexes forms large supercomplex whcih are assembled in a nice row to move e- easily

exmplain ETC’s complexes? it goes from where to were

• I to ubiq to III to cyrotchorm c to IV to terminal acceptor

complex I

• NADH transfer e- to ubiquinone of complex II

• also NADH oxidizes into NAD+

‘complex II

• has ubiquinone

Complex III

• Reduces cytochrom c when it passes e- to cyto c

Complex IV

• oxidizes cytochrome c when receives e- 

• from mitochondrial matrix to intermembrane space

How many 

1 NADH = pumps 10 protons agaisnt [gradient]

 

• FADH2 drops off at complex II

  • Instead at I it does it at^

  • So e- from FADH2 will pass to 2 -> ubiq -> III -> cyto c -> IV ->

  • Will nto pump anything in complex I

  • So FADH2 pumps 6 protons across membrane

    • NADH holds more E e- than FADH2

• HIGH TO LOW E state