Cell Biology: Chapter 12

mitochondrial matrix

where does Beta oxidation occur?

the matrix to be oxidized

Fatty acids must enter

catalyze activation of long chain fatty acids, esterifying them to coenzyme A.

Acyl-CoA Synthases (Thiokinases) of ER & outer mitochondrial membranes

ATP-dependent, & occurs in 2 steps

Fatty Acid activation is

Acyl-CoA Sythases

There aer different ___ ___ for fatty acids of different chain lengths

carnitine

Transfer of fatty acid across the inner mitochondrial membrane involves

outer mitochondrial membrane; cannot penetrate the inner membrane

Fatty acyl-CoA formed outside can pass through the ___ ___ ___, but

cyclic

the b-oxidation pathway is

b-oxidation

first of three stages of fatty acid oxidation

butyryl-CoA is converted to 2 molecules of acetyl-CoA

If the fatty acid contains an even number of C atoms, the final reaction cycle

reoxidized by transfer of electrons to respiratory chain

FADH2 and NADH produced during fatty acid oxidation are

ATP

Transfer of electrons in the respiratory chain leads to production of

Krebs cycle, yielding additional NADH, FADH2, and ATP

Acetyl-CoA can enter

cell ATP

Fatty acid oxidation is a major source

photosynthesis

• a redox reaction

• highly endergonic

• 18 ATP, 12 NADPH per 6 carbons fixed

• ΔG = +686 kcal/mole

Thylakoid Reactions

light-dependent reactions

stroma reactions

does not need light to occur

discrete amounts

atoms/matter absorb and emit energy only in

blue photons

excited electrons to an even higher energy state

red photons

excite electrons to a high-energy state

chlorophyll

the msot abundant pigment in the chloroplast

chlorophyll a and chlorophyll b

all eurkaryotic photosynthetic organisms contain both

cartenoids

transfer energy from photons to chlorophyll

free radicals

Cartenoids can quench ___ ___ by accepting or stabilizing unpaired electrons and so protect chlorophyll molecules

“head” region

when a photon strikes, its energy can be transferred to an electron in the

raised to a higher electron shell, with greater potential energy

when an electron is excited, it is

blue and red light

chlorophylls absorb

green light

chlorophylls transmit

blue and green light

cartenoids absorb

yellow, orange, or red light

cartenoids transmit

reaction center

The excited-state energy of pigments increases with distance from the

closer; lower

pigments ___ to the reaction center are ___ in energy than those farther from it.

energetically favorable and that transfer back out to the peripheral portions of the antenna is energetically favorable

The energy gradients ensures that excitation transfer toward the reaction center is

excited electrons feed an electron transport chain

In photosystem II,

Pheophytin

has the structure of chlorophyll but without the Mg in the porphyrin-like ring and acts as an electron acceptor

plastoquinone (PQ)

electrons that reach pheophytin are transferred to

the electron binds to pheophytin and the reaction center chlorophyll is oxidized

when an electron in the reaction center chlorophyll is excited energetically,

ETC that Pumps Protons

Photosystem II Feeds a(n)

protons to the inside of thylakoids, creating a proton-motive force.

plastoquinone carries

a series of reduction-oxidation reactions that results in protons being pumed from stroma to thylakoid lumen

passage of electrons along the chain involves

5

the pH of the lumen reaches

8

the pH of the stroma is around

1000 times higher

the concentration of H+ is ___ ___ ___ in the lumen than the stroma

electron from the excited chlorophyll.

An essential component of the Photosystem II is the physical transfer of theT

~picoseconds

The transfer takes

photosystem II

electrons come out from water, break down water and take two electrons. this is where ocygen come from.

photosystem I

Production of ATP and NADH