MCB 2610: Exam 3 pt. 8

catabolism

breakdown of molecules for energy, reducing potential and building blocks

cells produce ATP in three basic pathways

substrate level phosphorylation, photophosphorylation and oxidative phosphorylation

what pathway produces low levels of ATP?

substrate level phosphorylation

what pathway produces lots of ATP?

oxidative phosphorylation

photophosphorylation is performed by those that can?

use light to generate ATP

oxidative phosphorylation is used by those that use?

chemicals to make ATP

substrate level phosphorylation can occur in both?

presence/absence of oxygen because it doesn't use it

substrate-level phosphorylation can be used across?

all 3 domains

sunstate-level phosphorylation is an enzymatically?

coupled reaction producing ATP

substrate level phosphorylation is the transfer of a phosphate group from?

a reactive intermediate generated during catabolism to ADP

in cells substrate level phosphorylation occurs in?

heterotrophs in cytoplasm - aerobic and anaerobic

what energy source are we using the majority of the time?

glucose

other energy sources

polysaccharides, proteins or phospholipids

why is glucose used the majority of the time

because polysaccharides, proteins or phospholipids all break down into glucose or other intermediaries of the glycolytic pathways and everything funnels into the same pathways

why is it important that everything gets funneled into the same pathway?

we can save on raw materials and genetic storage space

bacteria has a ton of catabolic pathways and can catabolize

inorganic/organic things

catabolic pathways

breaking down macromolecules into smaller things, releasing energy and storing it in ATP

catabolic pathways are enzyme catalyzed reactions whereby the product of one reaction serves as?

the substrate for the next

catabolic pathways also provide materials for?

biosynthesis

amphibolic pathways

run in catabolic and anabolic direction due to amphibolic enzymes

anabolic pathways takes what we made in catabolic pathways and put them together to make?

larger macromolecules

important amphibolic pathways

embden-meyerhof pathway and pentose phosphate pathway

why are amphibolic pathways important?

save on genetic space by not having lots of different enzymes

why is it important to have some non-amphibolic pathways?

you want to be able to independently regulate pathways based on needs of cell

glyconeogenesis

pyruvate to glucose

respiration should be associated with what?

using an ETC

aerobic respiration terminal electron receptor

oxygen

aerobic respiration

process that can completely catabolize an organic energy source to CO2 energy

3 ways to do aerobic respiration

glycolytic pathways (glycolysis), TCA cycle and electron transport chain with oxygen as final electron acceptor

aerobic respiration produces?

ATP and high energy electron carriers

anytime you use an electron transport chain do you make more or less ATP than when using substrate-level phosphorylation?

more ATP

3 different glycolysis pathways

embden meyerhof, pentose phosphate, entner doudoroff

what is the most common glycolysis pathway

Embden-Meyerhof pathway

when do you use pentose phosphate pathway

in fermentation

entner doudoroff pathway is associated with?

gram-negative bacteria

all 3 pathways for glycolysis are used in all 3?

domains

embden meyerhof pathway occurs in?

cytoplasmic matrix of all major groups of microorganisms, plants and animals

can the embden meyerhof pathway function in the presence or absence of O2?

both

two phases of embden meyerhof pathway

energy investment phase (6 carbon phase) and production phase (3 carbon phase)

embden meyerhof pathway - addition of phosphates...

primes the pump

embden meyerhof pathway - oxidation step generates?

NADH

embden meyerhof pathway - high energy molecules used to synthesize ATP by?

substrate level phosphorylation

glycolysis starts with?

glucose, 2 ADP and 2 NAD+

glycolysis ends with?

2 pyruvate, 2ATP and 2NADH

what do we have to do after glycolysis and why?

TCA cycle because energy is still stuck in pyruvate

TCA cycle is common in?

bacteria, archaea, different eukarya, aerobic bacteria, free-living protozoa, most algae and fungi

TCA cycle major role

source of carbon skeletons and electron carriers for biosynthesis

in eukaryotes TCA cycle occurs in the?

mitochondrion

in prokaryotes TCA cycle occurs in the?

cytoplasm

redox reaction to generate electron carrier occurs when?

pyruvate turns to acetyl CoA

pyruvate conversion to acetyl coA is mediated by enzyme?

dehydrogenaze

is converting pyruvate to acetyl coA a reversible action?

no

in the TCA cycle we are generating lots of electron carriers to be funneled into the ETC, do we generate a lot of ATP?

no

for every acetyl-CoA molecule oxidized, the TCA cycle produces?

2 molecules of CO2, 3 molecules of NADH, one FADH, one GTP

per every starting molecule of glucose how many acetyl-CoA are produced?

twp

NADH and FADH are examples of?

electron carriers

or organisms that use ETC the TCA cycle is where they make the majority of ATP, they have to have a way to what?

shut TCA cycle down if organism isn't using ATP

TCA cycle regulation

allosteric regulation - isocitrate dehydrogenase

allosteric regulation - isocitrate dehydrogenase is the point of regulation and where TCA cycle first interacts with ETC -> 2 things

feedback inhibition (ATP/NADH) and precursor activation (ADP/NAD)

ATP and NADH go up what happens?

cell is not using ATP or electron carriers, enzyme shuts TCA cycle down

ATP goes down and NADH goes down what happens?

they will bind to isocitrate dehydrogenase and activate enzyme to increase its affinity for its substrate and help TCA cycle start up again

is regulating the TCA cycle important?

yes