Module 6: Energy Centers

Question 1

Mitochondria = the powerhouse of the cell

Answer 1

One of the other locations in the cell that contains DNA besides the nucleus
Produces most of the energy needed for the cell’s various function
Several important reactions that take place w/in it: the electron transport chain and the Krebs cycle

Question 2

Endosymbiotic theory

Answer 2

Mitochondrias and chloroplasts = originally prokaryotes that were engulfed by eukaryotes
When these prokaryotes were swallowed by larger eukaryotic cells → both organisms received an advantage

Question 3

Endosymbiotic theory: the advantage for both the prokaryotic and eukaryotic cells

Answer 3

Eukaryotic cells didn’t have to rely on anaerobic metabolism (I.e. glycolysis) alone anymore for energy
Prokaryotic cells now had a safe home to stay in and not be destroyed

Question 4

General structure of the mitochondria

Answer 4

Cylindrical organelle containing an outer membrane, inner membrane, and two intermembrane spaces
Variety of proteins are in the 2 membranes → necessary for the different functions of the membranes
Inner membrane → contains cristae = many infoldings
Intermembrane space = located between the 2 membranes
Matrix = is separated from the rest of the organelle by the inner membrane

Question 5

Special features of the mitochondrial membranes

Answer 5

Cardiolipin → special lipid in these membranes → especially prominent in the inner membrane
Many transport proteins → make both membranes selectively permeable to specific molecules (fatty acids, carnitine, etc
Inner membrane also has the proteins needed for the electron transport chain

Question 6

Main functions of the mitochondria

Answer 6

The conduction of the Krebs cycle and the electron transport chain

Question 7

Krebs cycle

Answer 7

Uses the pyruvate that’s made from glycolysis → turns it into acetyl CoA → used to generate ATP and NADH & FADH2 (the electron carriers)
The electron carriers are then used in the electron transport chain

Question 8

Electron transport chain

Answer 8

Uses the electron carriers (NADH and FADH2) generated from the Krebs cycle
This process uses a protein gradient and electron transfer between the chain’s different complexes → generate energy for the cell → via oxidative phosphorylation

Question 9

Oxidative phosphorylation

Answer 9

Generation of ATP via the use of oxidized electron carriers

Question 10

Structures used in the electron transport chain

Answer 10

Needs complexes 1,2,3, and 4 (ATP synthase)
Each complex contains cytochromes
Some complexes create a proton gradient → used at the end by ATP synthase → form ATP

Question 11

Complexes 1,2,3 and 4 (ATP synthase): importance

Answer 11

Required for the ETC to produce ATP from NADH and FADH2 (the electron carriers generated by the Krebs cycle)
Each complex contains cytochromes

Question 12

Cytochromes

Answer 12

A family of colorful proteins that contain an iron atom that can accept electrons
Aid in the transfer of electrons from NADH and FADH2 → to lower energy levels → to generate ATP

Question 13

Proton gradient

Answer 13

Created between the mitochondrial matrix and the intermembrane space due to H+ being pumped into the intermembrane space by some of the complexes
Proton gradient is used at the end of the electron transport by ATP synthase → forms ATP

Question 14

Efficiency of the ETC