Cell Respiration

Question 1

Why did cell resp evolve

Question 2

What are the pos and neg feedback loops

Answer 2

Usually have to do with the amount of ATP, if there is a lot of ATP then it will bind to some of the enzymes and inhibit them
if there not a lot of ADP then it will cause the enzymes to increase production

Question 3

Which steps in cell resp can be shut down and which ones continue regardless

Answer 3

Glycolysis will continue regardless
the others will shut down

Question 4

When and whyuse fermentation

Answer 4

when pyruvate accepts the electron from NADH made in glycolysis instead of O2
Allows the glucose to still be processed and make ATP when there not enough final electron receptor(Oxygen) for the for the electron transport chains
converts Nadh back into Nad+
only makes 2 ATP, very inefficient

Question 5

What are the 2 types of fermenation

Answer 5

lactic acid fermentation - pyr accepts elect from NADH, makes NAD+ and lactate. NAD+ is used again in glyc
For mammals, more common
alcohol fermenation - pyr is converted into acetaldehyde and CO2
Acetaldehyde accepts elect from NADH
Ethanol and NAD+ are produced
for orgs like yeast, unicellular moulds
NAD+ is oxidized in fermentation

Question 6

What are the 4 main steps of cell resp

Answer 6

glycolysis - gluc broken down into pyr
pyruvate oxidation - pyr processed to make acetyl-Coa
krebs cycle - Acetyl-Coa is processed to CO2
electron transport chain - has oxidative phosphorylation

Question 7

How does the location change througout cell resp

Answer 7

Glycolysis into pyruvate happens in cytosol
pyr goes into mitochondria, through its 2 memb, into cytosol of mitochondria
krebs happens in the cytosol of mitochondria
etc happens in the inner memb of mito

Question 8

make analogy of atp and NADH in cell resp

Answer 8

like money,
atp is the base currency
NADH is another currency that needs ot be converted into ATP to be of use.
same with FADH2

Question 9

what is oxidation of glucose vs oxidative phosphorylation

Answer 9

the first 3 steps in cell resp are ox of glucose (glycolysis, pyr ox, krebs)
etc + atp synthase is oxidative phosphorylation

Question 10

Why do things use starch to store sugars, why is this important to use

Answer 10

It is insoluble in water
storage capacity for glucose doesn’t degrade in the presence of water which is really important
humans eat the foods like potatos that use starch to store sugars.

Question 11

Summary of glycolysis

Answer 11

10 chem reactions
makes 2, 3 carbon molec called pyruvate
NAD+ is reduced to NADH
has net 2 ATP (uses up 2, makes 4)
has net 2 NADH
regulated with neg feedback loo

Question 12

How is glycolysis regualted

Answer 12

with neg feedback loop
high levels of ATP inhibit enz used in glyc
ATP can also bind to the active site but if there is high conct of ATP some will bind to regulatory site and slow it down
If you have too much ATP then you don’t need to run the second half of glyc, enz is in step 4

Question 13

Summary of pyruvate ox

Answer 13

In the presence of ox it becomes Acetyl-coa
Acetyl Coa is 2 carbon molec, pyr is 3
One of the carbon atoms from pyr is lost as CO2
Takes place in mitochondrial matrix, and then Acetyl-Coa goes into mitochondria
Makes CO2 an NADH
has Pos and Neg feedback

Question 14

Where does pyr ox happen in bact and archaea

Answer 14

If the bact or arch is just the mitochondria then it would just happen on the inside of the bact
Happnes in the cytosol of the bacteria and archaea

Question 15

How is pyr ox positive and negative feedback

Answer 15

if there is high ATP levels then it does negative feedback
also if there is not a lot of NAD+ it slows down so that it doesnt get depleted
NADH is used as positive feedback

Question 16

Summary of krebs

Answer 16

Third and final step in oxidation of glucose
Acetyl Coa is oxidiced into 2 CO2
8 molecs are used but none of them are used up
makes 3NADH and1 FADH2 and 1ATP
happens in mitochondrial matrix
has neg feedback loop, regulated by ATP and NADH levels

Question 17

Summary of electron chain transport

Answer 17

electrons in NADH and FADH2 are decreased in redox reactions
uses protiens in the innber memb of mitochondria, makes up etc
etc used to pump protons accros memb, makeing electrochem gradiant
electrons end up at O2
Uses proton motive force to drive atp synthase

Question 18

How is proton motive force generated

Answer 18

protein complexes in the mito memb reduce the NADH and FADH and push the protons into the intermemb space
keeps conct high so that they are trying to get in through the atp synth