Cell Metabolism

Question 1

Warburg Effect

Answer 1

Cancer cells use a lot of sugar but choose to run fermentation rather than respiration

Question 2

Metabolism

Answer 2

sum total of chemical reactions happening in a living cell

Question 3

Laws of Conservation

Answer 3

1st- energy cannot be created or destroyed, just changed from one form to another
2nd- entropy always increases and released heat causes a net entropy in the universe

Question 4

Glycolysis start

Answer 4

1 glucose with 6 carbons, chemical energy (glycolysis takes place in cytosol)

Question 5

Electron transport chain

Answer 5

takes place in mitochondrial inner membrane, chemical energy is transformed into potential energy as energy from electrons is used to pump protons generating a PMF

Question 5

Proton motive force

Answer 5

potential energy from the steep concentration gradient of protons across a membrane, protons are pumped by ETC into mitochondrial inter-membrane space (electrochemical gradient making inter-membrane space more positive than mitochondrial matrix)

Question 6

ATP synthesis by ATP synthase

Answer 6

ATP synthase uses potential energy from PMF to make ATP, takes place in mitochondrial matrix, potential (PMF)->mechanical (ATP synthase)->chemical energy (ATP), respiration generates lots of ATP

Question 7

Fermentation start

Answer 7

1 pyruvate with 3 carbons and 2 NADH (both are chemical energy with chemical bonds and/or high energy electrons), fermentation can run without mitochondria and oxygen in cytosol

Question 8

ATP

Answer 8

energy intermediate, carries energy in chemical bonds (high energy phosphate bonds)

Question 9

NAD+ and NADH

Answer 9

energy intermediates, NADH carries energy in form of high energy (excited) electrons, 2-3x as much energy as ATP and NAD+ is the oxidized form of NADH when its electrons are given away

Question 10

NAD+ problem

Answer 10

if only glycolysis is run, the cell runs out of NAD+ to generate NADH and glycolysis grinds to a halt (need fermentation and respiration to regenerate NAD+)

Question 11

Pyruvate oxidation and TCA cycle

Answer 11

part 1 of respiration, start with one 3 carbon pyruvate that carries chemical energy/electrons and is used to generate 3 CO2 (1 from pyruvate oxidation and 2 from TCA cycle), 4 NADH (1 from po and 3 from TCA), 1 FADH2 and 1 GTP, takes place in the mitochondrial matrix

Question 12

Oxidative phosphorylation

Answer 12

part 2 of respiration, takes place in and around mitochondrial inner membrane, start with chemical energy of high energy electrons in NADH and FADH2, these electrons are donated to an ETC which regenerates NAD+ and FAD and electrons travel through the ETC to the final electron acceptor, O2, which is then reduced to H2O

Question 13

glycolysis end

Answer 13

2 pyruvates have been generated with 3 carbons each as well as 2 ATP and 2 NADH all with chemical energy (technically 4 ATP, but 2 were invested earlier in glycolysis, so only net yield of 2)

Question 14

substrate-level phosphorylation

Answer 14

during glycolysis, ATP is generated when high energy phosphate is transferred to ADP and is catalyzed by pyruvate kinase (is a chemical energy to chemical energy process)

Question 15

fermentation end

Answer 15

electrons from NADH are transferred back to pyruvate which yields lactate and regenerates NAD+ (one pyruvate yields one lactate), energy is now chemical energy of lactate (fermentation yields no ATP itself)