cellular respiration

ap bio

what is respiration

breaking down foods to convert stored energy into ATP which is the form of energy our cells use

organisms lose body mass because of the loss of carbon dioxide

glycolysis —> citric acid ( krebs ) cycle —> electron transport chain —> chemiosmosis

endotherms

increase metabolic processes ( like respiration) to generate heat to maintain homeostasis body temperature

ectotherms

rely on surrounding to maintain homeostasis

fermentation

a partial degration of sugars that occur w/out O2

aerobic respiration

consumes organic molecules and O2 and yeilds ATP ( needs oxygen )

anaerobic respiration

similar to aerobic but consumes things other than O2 ( doesnt need O2 )

redox reactions

transfer electrons between reactants

oxidation

losing electrons / oxygen

reduction

gaining electrons / oxygen ( positive charged REDUCED )

electron donor

reducing agent ( gains electrons )

electron acceptor

oxidizing agent ( loses electrons )

IN CELLULAR RESPIRATION….

glucose is OXIDIZED ( loses electrons)

and O2 is REDUCED ( gains electrons )

oxidative phosphorylation

production of ATP made by breaking down ( oxidation) of molecules during electron transport chain

happens in the elc transport chain

substrate level phosphorylation

production of ATP made when an an enzyme removes a phosphate group from a substrate molecule and transfers it to ADP

happens in the krebs cycle and glycolisis

glycolysis ( first step )

rearranges the bonds in glucose which releases free energy in the form of ATP ( substrate level phosphorylation) and makes a pyruvate

where does glycolysis occur

outside of the cell in the cytosol and happens with or without oxygen

stars with one glucose molecule

what does glycolysis produce

2 ATP

2 NADH

2 pyruvates

if O2 is present in the pyruvate….

it enters the mitochondria and is used in aerobic respiration

if O2 is NOT present in the pyruvate….

the pyruvate enters fermentation

what is fermentation

an extension of glycolisis that makes a small amount of ATP from pyruvate when there is no oxygen

• regenerates NAD+ so that glycolysis can happen again

• anaerobic process

• takes place in the cytosol

lactic acid fermentation

converts pyruvic acid ( from glycolysis ) into lactic acid

• NAD+ is generated for glycolysis to continue

• examples : muscle cell during strenuous activity ,yogurt,cheese

alcohol fermentation

converts pyruvic acid ( from glycolysis ) into ethanol

• NAD+ is regenerated

• examples : alcohol, wine, beer, bread, yeast

aerobic respiration

1. pyruvate enters mitcho and is converted to acetyl and NADH

• reaction occurs twice since 2 pyruvates are made

• (total of 2 acetyl CoA and 2 NADH )

citric acid cycle ( second step )

1.both acytcl CoA molecules enter the krebs clycle in the mitochondrial matrix

• since theres two, the cycle goes around twice for each glucose molecule

• 8 steps that break down acetyl

final products of krebs cycle

2 ATP ( substrate level phosphorylation )

6 NADH

2 NADH2

• NADH and NADH2 act as energy carriers and transfer energy to the electron transport chain

electron transport chain ( third step )

series of proteins that transport electron which relase energy used to make ATP

• in the inner membrane of mitoch

• DOES NOT MAKE ANY ATP DIRECTLY

steps of elec transport chain

1.NADH and FADH get oxidized ( broken down ) and electrons are transported to the chain

2.electrons are passed down the chain until they reach the final electron acceptor ( oxygen )

• electrons pick up H+ to make water

• oxygen is a electron acceptor that functions as an energy capturing molecule.

3.movement of electrons releases free energy

4. the energy is used to power chemiosmosis ( which makes ATP )

chemiosmosis ( fourth and final step )

energy coupling reaction that uses energy stored in the form of a proton gradient to make ATP

steps of chemiosmosis

1. energy released from the electron transport chain is used to pump H+ from the matrix into the intermembrane space

   • results in a proton gradient

   • rate of proton pumping is LOWER if oxygen is NOT present

2. H+ protons are diffused back across the inner mitochondrial membrane through ATP synthase ( which makes ATP )

each molecule of NADH that enters electron transport chain makes…

3 ATPS

each molecule of FADH2 that enters electron transport chain makes…

2 ATPS

energy flow in a sequence

glucose —> NADH —> electron transport chain —> proton pradient —> ATP

electron transport chain and chemiosmosis are ____ because _____

coupled, they work together to make ATP

uncoupling proteins

in the mitochondria and dissipates the proton gradient before it can be used for ATP and instead that energy is made to generate heat (form of thermoregulation)