2-BIO 221: Energy, Enzymes, and Respirations

ATP

molecule that stores and transfers energy in cells

3 ways ATP is made

photophosphorylation, substrate level phosphorylation, and oxidative phosphorylation

Photophosphorylation

sunlight is absorbed and releases e- into the ETC which leads to PMF and ATP synthesis

Substrate level phosphorylation

organic molecules bonded with a phosphate react with ADP leading to ATP synthesis

Oxidative phosphorylation

organic molecules with energy rich e- are oxidized and the e- are used in PMF and ATP synthesis

How e- are transferred in redox reactions

e- are transferred from a donor becoming oxidized and an acceptor becoming reduced

Does the electron donor become oxidized or reduced when it donates electrons in redox reactions

oxidized because it lost an e-

Does the electron acceptor become oxidized or reduced when it accepts electrons in redox reactions

reduced because it gains an e-

Function of electron carriers in redox rxn

they carry electrons after being reduced to their destination to create PMF, becoming oxidized after dropping of e-

What pathways produce and use precursor metabolites

catabolic pathways make them, and anabolic pathways use them as starting points

electron carrier definition

accept an e- from donor and brings to/starts ETC

Oxidized forms of electron carriers

NAD+, FAD, NADP+

NAD+, FAD, and NADP+ convert to what in redox rxns

NADH, FADH2, NADPH

Reduced forms of electron carriers

NADH, FADH2, NADPH

Reducing power

electrons in carriers used to do work within cells

function of reducing powers NADH and FADH2

create PMF

function of reducing power NADPH

used in anabolic reactions and biosynthesis

aerobic respiration harvests ____ to create ____ by doing what

energy, PMF, breaking down glucose to gain energy rich e-

Summary of glycolysis

break down glucose into 2 ATP, 2 NADH, and 2 pyruvate

Glycolysis function

begin oxidation of glucose, make ATP through SLP, and source precursor metabolites

Phases of glycolysis

energy investment puts in energy, cleavage splits up Fructose 1,6-biphosphate, energy liberation adds phosphate to liberate energy

What is the beginning substrate for glycolysis

glucose

What is occurring during the energy investment phase of glycolysis

starts with glucose, invest energy (2ATP) to produce 1,6 biphosphate

What is occurring during the cleavage phase of glycolysis

Break 6 carbon into 2 glyceraldehyde-3 phosphate

What is occurring during the energy liberation phase of glycolysis?

End in production of 2 pyruvate, total of 4 ATP

Where does glycolysis occur

eukaryotes and prokaryotes both have it occur in the cytoplasm/cytosol

Is ATP produced in glycolysis? If so, by what process is it produced?

Yes, substrate level phosphorylation (SLP)

Why is the net ATP of glycolysis 2 ATP

2 are used to start glycolysis, 4 are put in to finish the process, 2 are whats left after the rxn

Into what organic compound is glucose converted after glycolysis is complete?

Pyruvate

What can regulate glycolysis

ATP in excess can bind to allosteric sites preventing glycolysis

Transition step between glycolysis and CAC

2 pyruvates are broken down into 2 ATP, 2 CO2, 2 NADH, and 2 ACoA

What enzyme catalyzes pyruvates

pyruvate dehydrogenase

Where does the transition step occur

Eukaryotes occur in the mitochondrial matrix and prokaryotes occur in the cytosol

How does pyruvate get into the mitochondria

enter through symport transporters in the membrane using PMF

Function of the citric acid cycle (CAC)

final step in aerobic metabolism turning ACoA into ATP and precursor metabolites, completes oxidation of glucose

What occurs during CAC reactions

2 carbon acetyl-CoA molecule is completely oxidized

What is the beginning substrate of the CAC

2 carbon acetyl

What are the products of CAC

4 CO2, 6 NADH, 2 FADH2, 2 ATP (2 full cycles)

Why does the CAC need 2 turns to oxidize glucose

each glucose produces 2 ACoA, one cycle for each ACoA

Where does CAC occur

eukaryotes occur in the mitochondria and prokaryotes occur in the cell membrane

How can CAC be regulated

Feedback inhibition of isocitrate dehydrogenase due to an excess of ATP and NADH

What are the full yeild of 1 glucose

6 CO2, 4 ATP, 10 NADH, 2 FADH2

What pathways produce ATP directly

glycolysis, citric acid cycle, oxidative phosphorylation

what does reducing power do

create PMF

proton motive force (PMF)

potential energy stored across cell membranes due to diffrence in proton concentration

Oxidation of glucose creating PMF

transferring e- through the ETC causes the membrane to pump H+ ions across the membrane

Eukaryotes use PMF for

synthesizing ATP and powering symports to transfer pyruvate into the mitochondria

Prokaryotes use PMF for

trasnfering e- across the cell membrane where much of PMF and ATP are generated

What happens to e- as they are passed through ETC

they lose energy which goes into the system creating PMF

Terminal electron acceptor (aerobic respiration)

Oxygen (O2)

Terminal electron acceptor (anaerobic respiration)

inorganic molecules that arent O2 (nitrate and sulfate)

How does PMF create ATP

PMF pushes H+ ions into ATP synthase between protein A and C which power protein B to spin combinging ADP + P into ATP

What is ATP syntheis in non-photosynthetic organisms called

Oxidative phosphorylation

Why is there a difference between the theoretical yield and reality

ATP is used for many things in the body so the theoretical of 30-40 never comes true

Fermentation

a process that breaks down glucose without O2 or ETC

Products of fermentation

more NAD+ from NADH for glycolysis to make more ATP

How nutrients other than glucose is catabolized for energy

catabolism breaks down molecules/subunits into useable material for the metabolic pathways

Components needed for anabolic pathways

precursor metabolits, ATP, enzymes, reducing power (e- carriers)

What catabolic pathway does aerobic respiration use to make precursor metabolites

glycolysis

What catabolic pathways produce precursor metabolites

glycolysis, CAC, pentose phosphate pathway