Oxidative phosphorylation, fermentation

Question 0

Does FADH2 and NADH donate an equivalent number of electrons?

Answer 0

yes a number of 2 electrons for oxygen reduction, the electron transport chain provides about one-third less energy for ATP synthesis when the electron donor is FADH2 rather than NADH.

Question 1

whats the difference between FADH2 and NADH

Answer 1

FADH2 adds its electrons to the electron transport chain from within complex II, at a lower energy level than NADH does.

Question 2

Electrons from NADH passed among proteins of the ETC with the help of…

Answer 2

coenzyme Q and cytochromes (iron atom) to O2

Question 3

Does ETC generate ATP directly?

Answer 3

NO

Question 4

Cytochromes

Answer 4

• most of the remaining electron carriers between ubiquinone and oxygen are proteins called cytochromes.
• their prosthetic group called a heme group has an iron atom that accepts and donates electrons.

Question 5

Electron transport chains has several types of cytochromes…

Answer 5

each a different protein with a slightly different electron carrying heme group

Question 6

chemiosmosis

Answer 6

process, in which energy stored in the form of a hydrogen ion gradient across a membrane is used to drive cellular work such as the synthesis of ATP
-use of a H+ gradient to drive work

Question 7

Osmosis

Answer 7

flow of H+ across a membrane

Question 8

ETC + Chemiosmosis =

Answer 8

oxidative phosphorylation

Question 9

ETC Chemiosmosis summary

Answer 9

• NADH( glycolysis and TCA) and FADH2 (TCA) transfer electrons to ETC
• ETC complexes located on the mitochondrial inner membrane
• series of redox reactions transfers electrons
• H+ pumped into inter-membrane space
• electrons delivered to 1/2 O2

Question 10

Proton motive force (inter membrane space-> mitochondrial matrix)..

Answer 10

drives ATP synthesis

Question 11

Most ATP is produced by….

Answer 11

oxidative phosphorylation is the mitochondrion

Question 12

Supply of pyruvate to mitochondria

Answer 12

supply can limit rate of oxidative phosphorylation (production of NADH, FADH2 by Krebs cycle)

Question 13

Transport protein

Answer 13

mitochondrial pyruvate carrier (MPC)

yeast->mammals

Question 14

normal chemiosmosis

Answer 14

protons re-enter the mitochondrial matrix through ATP synthase, generating ATP
-the are coupled (mitochondria)

Question 15

uncoupled mitochondria

Answer 15

in some situations/species/tissues:

proton gradient “uncoupled from ATP synthesis”

Question 16

Chemiosmosis is an energy-coupling mechanism…

Answer 16

that used energy stored in the form of and H+ gradient across a membrane to drive cellular work
ex. in mitochondria it comes from exergonic redox reactions and ATP synthesis is the work performed

Question 17

uncoupling protein

Answer 17

a mitochondrial inner membrane protein that can dissipate the proton gradient before it can be used to provide the energy for oxidative phosphorylation
also called leaky mitochondria.

Question 18

brown fat (Uncoupled)

Answer 18

• in neonates and hibernators, brown from high density of mitochondria
• high density of UCP in mito. inner membrane
• generate heat without shivering

Question 19

what does uncoupled mitochondria do?

Answer 19

• oxidize NADH from glycolysis and TCA but produce no ATP
• only 4 (from glycolysis and Krebs cycle)/32 possible ATP from glucose molecule
• inefficiency in conversions of ingested macromolecules to energy

Question 20

any given amount of food generates less ATP…

Answer 20

Less excess energy to be stored

Question 21

some poisons uncouple mitochondria

Answer 21

malonate-make the inner membrane permeable to ions including protons
eg. 2,4 dinitrophenol

Question 22

Rotenone

Answer 22

blocks NADH dehydrogenase

Question 23

reactive oxygen species

Answer 23

chemically reactive molecules containing oxygen.

ex. oxygen ions and peroxides

Question 24

catabolism of other substrates

Answer 24

other organic molecules can be the source of electrons for cellular reparations

Question 25

catabolism of other substrates: carbohydrates

Answer 25

glycolysis accepts a wide range of carbohydrates

Question 26

catabolism of other substrates: proteins

Answer 26

- digested to amino acids - feed glycolysis or the citric acid cycle - ammonia produced- nitrogenous waste

Question 27

catabolism of other substrates: fats/lipids

Answer 27

-digested to glycerol and generates acetyl CoA by beta oxidation

Question 28

Anabolism (biosynthesis)

Answer 28

use of small molecules to build other substance - directly from food - from glycolysis - from the citric acid cycle

Question 29

some organisms that normally use oxidative phosphorylation..

Answer 29

can produce some ATP in the absence of oxygen