lecture 5: Kreb’s cycle and the electron transport chain (ETC)

Question 1

what is the first product that enters in the Krebs cycle and how many of them are they

Answer 1

acetyl coa

2

Question 2

what are 2 other named for the kreb cycle

Answer 2

Citric acid cycle

tricarboxylic acid cycle

Question 3

what substance links glycolysis and kreb cycle

Answer 3

acetyle coa

Question 4

true or false, you only lose CO2 in pyruvate oxidation

Answer 4

false, you lose 2 CO2 on kreb cycle

Question 5

what are the 2 co enzymes of the kreb cycle

Answer 5

FADH2 and NADH

Question 6

what is FAD

Answer 6

flavin adenine dinucelotide

Question 7

what does FAD reduce to

Answer 7

FADH2

Question 8

explain the reduction of the FAD

Answer 8

it can be reduced to FADH2 when it accepts 2 H+ and 2 electron

Question 9

what is the structure of FAD

Answer 9

has two nitrogen groups to accept the Hydrogens and electrons
contains ADP and a riboflavin

Question 10

how many carbons are in acetyl CoA

Answer 10

2

Question 11

how many carbons are in oxaloacetate

Answer 11

4

Question 12

how does the kreb cycle start (ie how is citrate formed)

Answer 12

the 4 carbon oxaloacetate merges with the 2 carbon acetyl coa and you get citrate being formed

Question 13

Explain the Krebs cycle

Answer 13

1) Acetyle coa merges with oxaloacetate to form citrate
2) There are a series of metabolic reactions to get the 6 carbon citrate down to a 4 carbon succinyl coa
3) the two carbons that are lost become CO2 and are expired at the lungs
4) At many stages you get NAD+ being reduced to NADH by accepting electrons and hydrogen from the substates of the cycle
5) You also get reduced of FAD to FADH2 by the same manor
6) This cycle also generates 1 ATP by hydolysis of GTP which phosphorylates ADP to ATP
7) cycle will continue until succinyl coa is turned into oxaloacetate again

Question 14

for every turn of the Kreb cycle, how many NADH+h are formed

Answer 14

3

Question 15

for every turn of the Kreb cycle, how many FADH2 are formed

Answer 15

1

Question 16

for every turn of the kreb cycle, how many co2 formed

Answer 16

2

Question 17

for every turn of the kreb cycle, how many atp is formed

Answer 17

1

Question 18

how many turns of the kreb cycle happen for the pyruvates coming down from pyruvate oxidation

Answer 18

2 total times (2 molecules of acetyle coa)

Question 19

what is needed for the cycle to continue

Answer 19

acetyl coa

Question 20

in total, what are the yields for 1 turn of the kreb cycle

Answer 20

3 nadh
1 fadh2
1 atp
2 carbon dioxide

Question 21

how is atp formed in the kreb cycle

Answer 21

GTP (guanine triphosphate) gets hydolized and donates its phosphate to ADP to become ATP

Question 22

where is Fad and NADh located

Answer 22

in the mitochondira

Question 23

where is pyruvate located

Answer 23

in the cytosol and gets transported through the membrane by protein carriers

Question 24

where is the kreb cycle performed

Answer 24

matrix

Question 25

why is acetyl CoA an important biomechanical junction

Answer 25

many substances (proteins, pyruvates, fatty acids) can be transromed into acetyl coa and enter the kreb cycle

Question 26

where are the 3 main places atp are formed

Answer 26

glycolysis kreb ETC

Question 27

Where do the cofactors for ETC come from>

Answer 27

NADH comes from either kreb cycle (3) OR glycolysis (2) under aerobbic conditions FADH2 kreb cycle

Question 28

when will the NADH go to the ETC from glycolsysi

Answer 28

2 NADH will come if it is not being used for lactate (only in aerbocib or resting conditions)

Question 29

Where is the NADH from the glycolysis found

Answer 29

in the cytosol and needs to go into tbe. matrix for ETC

Question 30

True or false: the NADH and FADH2 that go to the ETC only come from kreb cycle

Answer 30

false they also can come from glycolysis under the proper conditions

Question 31

how much ATP and NADH is formed from glycolysis

Answer 31

``` 2 atp (net 2 nadh (from glyceradhyde 3 phosphate) ```

Question 32

Does glycolysis happen in the mitochondrial matrix, the inner mitochondrial membrane or the cytosol

Answer 32

cytosol

Question 33

Does kreb happen in the mitochondrial matrix, the inner mitochondrial membrane or the cytosol

Answer 33

matrix

Question 34

Does ETC happen in the mitochondrial matrix, the inner mitochondrial membrane or the cytosol

Answer 34

inner mitochondiral membrane

Question 35

True or false: the ETC is a single segment of proteins in the inner mitochondrial matrix

Answer 35

false, there are many proteins that rpeat themselves over and over

Question 36

true or false: the ETC happens in the outer mitochondrial membrane only

Answer 36

false, | in the inner membrane only

Question 37

what is the space between the two mitochondrial membranes called

Answer 37

the intermembrane space

Question 38

what does a complex mean (ETC)

Answer 38

a series of proteins attached | with an enxyme

Question 39

what are the complexed of the ETC

Answer 39

COmplex 1, 2, 3, 4

Question 40

what are the carries of the ETC (carrie the electrons)

Answer 40

CoQ and CytC

Question 41

What complex does NADH come into contact with first

Answer 41

complex 1

Question 42

what complex does FADH2 come into contact with first

Answer 42

complex 2

Question 43

explain the electron transportation for NADH

Answer 43

1) NADH contacts at complex once and gets reduced to NAD 2) electrons are released and flow through the complex and to the COq 3) This energy allows the Hydrogen to flow through the complex 1 into the intermmebrane space 4) electron travels with Coq to complex 3 and another hydrogen moves up complex 3 5) electron is bound to Ctc and goes to complex 4 allowing another hydrogen to move through complex 4 6) electron is transfered to oxygen

Question 44

do the electrons from NADH skip or pass through complex 2

Answer 44

skip it

Question 45

is the coq for NADH mobile or immobile

Answer 45

mobile

Question 46

is the coq for FAD mobile or immobile

Answer 46

immobile

Question 47

where are the 3 places that the hydrogens are pumped through

Answer 47

complex 1, 3 and 4

Question 48

where do the hydrogens get pumped from and to

Answer 48

pumped from matrix | pumped to intermmebrane space

Question 49

explain electron transport from FADH

Answer 49

1) FADH2 comes into complex 2 and loses its 2 electrons and hydrogens to become FAD 2) electrons travels through COq and go to complex 3 which allows hydrogens to pas through complex 3 3) electrons nbind to cyt C and pass through complex 4 allowing hydrogens to move through complex 4 4) electrons get bound to oxygen

Question 50

what is the final electron acceptor

Answer 50

oxygen

Question 51

how do hydrogens get pumped into the intermembrane space?

Answer 51

the electon pairs donate energy (since they have a charge) to allow the hydrogen to move through the complex

Question 52

explain the oxygen as the final hydrogen acceptor

Answer 52

the elcetrons from the ETC bind onto the oxygen moleucle and form water

Question 53

why is oxygen so important to the ETC

Answer 53

it accepts electrons therefore with more oxygen, bind more elcetrons, then NADH and FADH2 can continue to donate electrons with inadqurate oxygenation consumption, electrons have no where to bind and ETC will slow

Question 54

what is the last protein of the ETC

Answer 54

ATP synthase protein

Question 55

what is the ATP synthase protein

Answer 55

it is an intramembrane enzyme that helps the speed of hydrogen proteins going through it pumps the hydrogens back to the matrix

Question 56

true or false: ALL the complexes are considered to be intramembrane enzymes

Answer 56

false, complex 2 is only in the matrix

Question 57

What happens as hydrogens pass through the intramembrane atp synthase

Answer 57

Hydrogens passing thoreugh have a lot of kinetic energy build up therefore it imparts chemical energy to the ADP which allows a free phosphate to bind to ADP and form ATP

Question 58

True of false: for every hydrogen that passes through, you form atp

Answer 58

true

Question 59

the hydrogens from NADH get taken up through complex...

Answer 59

1,3,4

Question 60

the hydrogens of FADH2 go through the complex...

Answer 60

complex 3 and 4

Question 61

for every molecule of NADH how many hydrogens and therefore how many atp is formed

Answer 61

1 molecule NADH=3 hydrogens=3 atp

Question 62

for every molecule of FADH2, how many hydrogens and therefore how many atp are formed

Answer 62

1 molecule FADH2= 2 hydrogens = 2 atp

Question 63

true or false: the matrix has a positive charge

Answer 63

false | it has a negative charge which creates an electrocheimical gradient

Question 64

what is the reason hydrogens want to flow back into the matrix through ATP synthase protein>

Answer 64

There is a buildup of negative charge in the matrix of the mitochondira (since they are being pumped out) therefore this electrochemical attraction/gradient will cause the hydrogens to diffuse back into the matrix through atp synthase which will give you energy

Question 65

what is another name for the COq transporter

Answer 65

ubiquinone

Question 66

what is another name for complex three

Answer 66

cytocochrome b-c1 complex

Question 67

what is the name for CT c

Answer 67

cytochrome c

Question 68

what is another name for the 4th complex

Answer 68

cytcohome oxidase complex

Question 69

true or false: only Coq is mobile?

Answer 69

false, cyt c is also mobile

Question 70

does complex 2 promote any hydrogen pumping/movement

Answer 70

no

Question 71

without oxygen what happens (full picture)

Answer 71

wihout oxygen, cannot bind electrons therefore the metabolic process will be backed up hydrogen movement will decrease electron transport activity will decrease (NADH and FADH2 will start to increase) kreb cycle will shut down pyruvate to acetyle (which goes to kreb) will stop Pyruvate will go to lactic acid instead of actyl coa

Question 72

ETC and chemiosmosis together is called..

Answer 72

oxidative phosphorylation

Question 73

what is the part of the ETC that produces energy called (the part that allows protons to travel back into the ATP synthase for ATP)

Answer 73

chemiosmosis