Exam #3 Flashcards
This chapter is about one thing…it’s about how cells make ___.
ATP
Most life on earth acquires energy through ___________, followed by ________ _________.
photosynthesis, cellular respiration
Our energy comes from the sun. It is harnessed by plants. The chloroplast converts that light energy into _______ energy, in the form of organic molecules.
Photosynthesis requires some starting material, and that would be ___ and ____.
chemical
CO2 and H20
What is the most efficient way to do catabolism?
Respiration
Cellular respiration is a ________ breakdown
complete
Fermentation is an ________ breakdown
incomplete
The whole point of catabolism is to provide ________ for the manufacturing of ATP. ALL ABOUT MAKING ATP
energy
Organic fuel is oxidized, what does that mean?
It means the removal of electrons
If something is oxidized, it’s _______ its electrons.
losing
Reduction is the ______ of electrons
gain
If something is oxidized and loses its electrons, something else is reduced and _____ those electrons
gains
What kind of bond does CH4 have?
non-polar covalent bond
What does non-polar covalent bond mean, in terms of electrons?
Electrons are all shared equally
What kind of bond does CO2 have?
polar-covalent bond
What does polar covalent bond mean, in terms of electrons?
Electrons are not shared equally, oxygen is pulling on the electrons
Rule of thumb: watch the ________ !
HYDROGENS!
Electrons are transferred along with protons…what is a proton? A hydrogen atom. So if we’re transferring protons, we’re transferring hydrogens. Does Carbon gain or lose hydrogen’s in this reaction?
It lost all of them
Does the oxygen gain or lose hydrogens in the reaction?
It gained them, which means reduction
If you lose hydrogens, you’re ________
If you gain hydrogens, you’re ________
oxidized
reduced
It’s the _______ in methane that have the energy
electrons
In non-polar covalent bonds, electrons are ____ from the nucleus and have more energy
far
In polar covalent bonds, electrons are _____ to the nucleus and have less energy
close
What about electrons in glucose? Energy poor or energy rich?
Energy rich, non-polar covalent bonds
Glucose and fats are biologicals fuels…we consume them and drain them of their energy…BY WHAT?
OXIDATION. It’s the electrons that have the energy, we’re going to oxidize the heck out of them, get all those electrons!
This is the reaction that attaches an inorganic phosphate to ADP to make ATP. This is called _________.
phosphorylation
When you join a phosphate to something, it’s called __________.
phosphorylation
ATP synthesis is _________.
Endergonic
What is the equation or “process” for cellular respiration?
C6H12O6 + 6O2 –> 6CO2 + 6 H20 + energy (ATP+heat)
What is the delta G for cellular respiration?
Delta G = -686 kcal/mole
How much energy is released when glucose is catabolized?
-686 kcal/mole
How does aerobic glucose catabolism compare with processes like the combustion of methane? How is it different?
They’re similar in that, glucose catabolism and combustion of methane are both…
Exergonic…
Organic fuel is oxidized (CH4 and C6H12O6)…
And oxygen is the oxidizing agent.
That said, this is not combustion. It’s not even a single reaction. Glucose catabolism is a process.
Also, unlike the combustion of methane, glucose catabolism is going to have many reactions. Steps. Glucose catabolism.
The words electrons and ________ are used interchangeably
hydrogens
H’s are eventually transferred to O2, but are FIRST transferred to chemicals known as _________, which will hold them for a time…hold them…
coenzymes
What are coenzymes?
Small molecules required by some enzymes.
Are coenzymes enzymes?
NO, THEY ARE NOT ENZYMES
Coenzymes are like a substrate of an enzyme. They will _____ to the enzyme. Like the substrate, they will be chemically _______ in the reaction.
bind, altered
Coenzymes have a very specific purpose, which is to serve as a molecular _____.
handle
Why are we taking the H’s from glucose?
They have ENERGY!
You take the H, you don’t want to lose track of the H…it’s so small…you need to chemically/covalently attach it to something that can serve as a _____ to carry the H to where it can be utilized for its energy content.
handle
What are three common coenzymes?
NAD+, FAD, Coenzyme A
Which of the three doesn’t carry H?
Coenzyme A
What is the main coenzyme?
NAD+
To be more specific, NAD+ carries one complete __ and one ______.
hydrogen, electron
EXAM QUESTION:
When NAD+ is reduced, what does it carry?
2e- and 1 p+
What is the reduced form of NAD+?
NADH
What is the difference between NAD+ and NADH?
The H, which is one electron and one proton.
Where is the other electron? Ah, there’s a charge…a charge where?
NAD+
NAD+ is an electron carrier that keeps the electrons _______.
energetic
How much energy is lost as we transfer electrons from glucose to NAD+?
Very little energy is lost
What is NAD+ specifically?
Two nucleotides join together…
Nicotinamide adenine dinucleotide
In NAD+, the two nucleotides are joined together by their __________.
phosphates
What’s important about NAD+?
It carries hydrogens
What kind of agent is NAD+?
Oxidizing agent
If you have a chemical with H’s, you can strip them away with _____.
NAD+
**Once NAD+ strips away the H’s, that chemical is ________, and NAD+ is _________.
oxidized, reduced
NAD+ does not carry both protons…it carries two ______ and one ______. So the other proton from that H goes into the _______.
two electrons, one proton.
solution
Start out with NAD+…NAD+ is _______…it delivers its electrons…NADH is ______.
NAD+ is _______, then NADH is ______…it goes back and forth
reduced, oxidized
reduce, oxidized
Who is the ultimate electron acceptor?
Oxygen
Who is the ultimate oxidizing agent?
Oxygen
EXAM QUESTION:
Who does NADH reduce?
Who does NADH give its electrons to?
THE ELECTRON TRANSPORT CHAIN
What are the four stages of cellular respiration?
Glycolysis
Pyruvate oxidation
Citric acid cycle
Electron transport chain
The first _____ stages of cellular respiration are going to catabolize glucose completely.
three. By the end of step 3, glucose will be completely catabolized.
Catabolism will occur through ________.
Oxidation
We’re going to _______ in glycolysis.
We’re going to _______ in pyruvate oxidation.
We’re going to _______ in the citric acid cycle
OXIDIZE, OXIDIZE, OXIDZE.
Stripping away electrons.
Many NAD+ are going to be _______.
Many NADH’s will be generated…
reduced
What happens in step 4? In step 4, _____ delivers those electrons to the….
NADH, electron transport chain.
When NADH delivers electrons to the ETC, NADH will become ________
oxidized, then back to NAD+
When do we make the ATP? Which stages?
1 and 3.
Literally Glycolysis and citric acid cycle
Which stage does not really make ATP?
Pyruvate oxidation
Which stage makes the most ATP?
Stage 4, ETC
It’s all about transferring those electrons…
We ____ the electrons in stage 1, we ____ the electrons i stage 2, we ____ the electrons in stage 3, and then _______ the electrons in stage 4 and that’s where ATP is finally made.
took, took, took, delivered
Where do these processes happen?
Cellular respiration beings in the _______. That’s where glycolysis happens. The product of glycolysis is imported into the __________. Everything else happens in the mitochondria. Stage 2 - pyruvate oxidation, stage 3 - citric acid cycle, stage 4 - ETC. So most of these things happen in the mitochondria. Glycolysis happens in the cytosol.
cytosol. mitochondria.
What’s the point of each stage? We’re _______ the sugar, creating the _______ coenzyme _____.
oxidizing, reduced, NADH
90% of ATP is made in stage __.
4
Glycolysis is a __ step pathway.
10
Glycolysis is run by __ enzymes.
10
Glycolysis means “sweet split.” The splitting of a sugar molecule. Glycolysis breaks glucose into __ smaller molecules.
2
In step 1, glucose is converted into the first _______ of glycolysis
intermediate
What is the other reactant, in addition to glucose, in this reaction?
ATP
What’s the other product?
ADP
So ATP was hydrolyzed. It’s phosphate was removed. Notice that the phosphate has become part of the glucose.
By burning and ATP to make the phosphate there, we’re making the sugar even more _______.
reactive. Even more energy rich…it’s got a phosphate now
Step 2 is a _________. Or isomerization.
Rearrangement. It rearranges the atoms and the sugar.
Step 3, something familiar happens…what? Another ATP is invested…to make our sugar even more _______. It’s got another phosphate now! It’s now got 2 phosphates! Even more ______!
reactive, reactive!
Step 3 is the first step I would like you to know specifically…
EXAM:
Step 3 is catalyzed by the enzyme ______________.
Phosphofructokinase (PFK)
What enzyme catalyzes step 3?
PFK
Through___, we control a large part of cellular respiration.
PFK
Step 4 _____ the sugar.
splits. glucose has 6 carbons, so it’s split right down the middle, 3 carbons and 3 carbons.
EXAM QUESTION:
In stage 4, the sugar is split into 2 smaller sugars, which are ___ and ___.
DHP and G3P
Step 5 converts ___ into a second ___
DHP into a second G3P
We now have two ____.
G3P’s
From from here to the rest of catabolism, everything is going to happen ______.
twice
Everything happens twice now because we ….?
Split the sugar
What happens in step 6?
It’s an oxidation reaction! It’s the first one! IT HAPPENS IN STEP 6!!!
Which step has the first oxidation reaction?
Step 6.
In step 6, G3P is ________ by NAD+, generating _____.
oxidized, NADH
What does step 7 do, finally?
Makes ATP
Which step in glycolysis is ATP first made in cellular respiration?
STEP 7!
How many NADH do we have and why?
2 NADH because we have 2 G3P
How many ATP do we make?
2! Everything happens twice
What happens in step 10?
2 more ATP is made
What is the final product in glycolysis?
Pyruvate
Glycolysis is split into 5 and 5. Recognize that the first half, we invested some _____. The second half, we saw the payoff into the form of ___.
energy, ATP
How many NADH were produced in glycolysis and in what step?
2 NADH were produced, in step 6
ATP was made twice! Once in step __ and once in step __
7 and 10
How much total ATP does glycolysis produce?
4
ATP synthesis is ________.
endergonic
Where did the energy come from?
The substrate
Enzymes don’t change the _____ __, but they DO enable _______.
coupling
Substrate level phosphorylation: making ___ by transferring a ______ from an organic ______ to ___, which makes ATP.
ATP, phosphate, substrate ADP
This happened twice…twice in step _ and then twice in step _, which is the 4 ATP.
7 and 10
Glycolysis can be divided into two parts.
The first part of glycolysis deals with ________ energy, to make the sugar even more energetic and reactive.
The second part of glycolysis, really beginning in step 6, is an energy _______. When we use the invested energy to produce a product. To make ATP, step 7. To make ATP, step 10. And also, to make _____. PLEASE, THIS IS MORE IMPORTANT THAN THIS LITTLE AMOUNT OF ATP. This is more important because we’ve established that’s the way we’re going to strip electrons away from glucose, that’s the way we’re ultimately going to derive energy as ATP.
investing, payoff, NADH
At the end of glycolysis, how many pyruvate are produced?
2
In glycolysis, we make _ ATP.
4
_ ATP produced per G3P
_ ATP produced per glucose
**NET of _ ATP per glucose. **
2
4
2
Why a net of 2 ATP per glucose?
We put in 2 ATP, so 4-2 = 2
_ NADH per glucose
2
The energy is coming from the sugar, to make ATP, to make ____
NADH
The final product of glycolysis, pyruvate, is transported to the _________ _____
mitocondrial matrix
Pyruvate oxidation is a _ step pathway, requiring _ enzymes.
3
The enzymes are bound to one another to form a multi-enzyme _______. This is a very efficient way to run a pathway.
complex
What is step 1?
Removing CO2 from pyruvate. CO2 is held together by polar covalent bonds. It has no energy. Get rid of it.
Where is the first CO2 of cellular respiration produced?
Step 1 of pyruvate oxidation
What is step 2?
Oxidation!
NAD+ is going to strip H’s away from pyruvate and the result is NADH.
What is step 3?
Attaching what’s left to a coenzyme
So attaching an acetyl group to coenzyme A, you get a chemical called **Acetyl Coenzyme A*
Pyruvate oxidation, tabulate per glucose…
_ CO2 have been made, of the 6
_ NADH have been made, which you can add to the two made from glycolysis (2)
_ Acetyl Coenzyme A have been made
2
2
2
The citric acid cycle is an _ step pathway, involving _ enzymes
8
It’s a cycle, what does that mean?
One of the initial reactants is recycled at the end of the pathway
There are _ reactants in the first reaction
2
One of those reactants reappears….it’s recycled at the end of the pathway…and so if you use it and produce it again…in effect, the pathway forms a _____.
cycle
This pathway ______ catabolizes the sugar
completely
The citric acid cycle is sometimes referred to as the ______ cycle
Krebs
The coenzyme A is holding the acetyl group and is now delivering it…who does it deliver it to?
Oxaloacetate
There are two reactants in this first reaction…
The first reactant is _______ _______ _, and the other is _________.
acetyl coenzyme A
Oxaloacetate
The coenzyme’s job is done, so the coenzyme goes away, and the result is this chemical here…what is this chemical called?
Citrate…aka citric acid
The citric acid cycle is named for the first product of the pathway, which is _______.
citrate
How many CO2 are made per cycle? PER ONE CYCLE
2
How many NADH are made? PER ONE CYCLE
How many ATP are made? PER ONE CYCLE
How many FADH2 are made? PER ONE CYCLE
3
1
1
What is the most energy harvesting process in cellular respiration?
The citric acid cycle. You generate the most products
Is this single cycle tabulating back to our original glucose?
No! We have 2 acetyl coenzyme A…that will complete this cycle. Everything happening here will happen **TWICE!
** Ohhh, so we made _ CO2!
4 CO2
We made _ CO2 in pyruvate oxidation, _ in citric acid cycle, that’s 6 CO2! We’re done with catabolism!
We made _ NADH! We made _ FADH2 and _ ATP
2, 4
6, 2, 2
Folks, we have now completely catabolized glucose.
Glucose has 6 carbons, all 6 have been realized as ___.
CO2
We’ve made _ ATP.
_ in glycolysis and _ in the citric acid cycle.
We’ve made 4 ATP
2 in glycolysis, 2 in the citric acid cycle
How much total NADH have we made?
_ in glycolysis, _ in pyruvate oxidation, _ in citric acid cycle.
How much total FADH2 have we made?
10
2, 2, 6
2
EXAM, KNOW THIS
I want you to know that pyruvate oxidation is an ________, so you make _____. It begins the production of ___, so you make CO2. And it produces a product of ______ _______ _, which carries the acetyl group into the citric acid cycle.
oxidation, NADH, CO2, acetyl coenzyme A
EXAM, KNOW THIS
I want you to know that the ______ _____ _____ completes catabolism and you make the remaining ___ there. The citric acid cycle oxidizes the heck out of the sugar in completing that catabolism. So you make _ NADH there, you make _ FADH2 there, you make _ ATP.
citric acid cycle, CO2
6, 2, 2
Most of the harvested energy in glucose is now in _____.
NADH
EXAM QUESTION:
NADH is now ________ by an electron transport chain
oxidized, passing on its electrons to the electron transport chain
The electron transport is a ‘chain’ of proteins within the _____ ________. These proteins are joined together to form ____ complexes.
inner membrane, four
Which protein is embedded in the inner membrane of the mitochondria?
ATP synthase
In order for the ATP synthase to produce ATP, its rotor has to rotate. That rotation causes a conformational change in this domain of the protein, which produces ____.
ATP.
The inner membrane is highly ______, that’s where the ETC is.
folded
What does ‘transport’ mean? Electron ‘transport’…
Electron transport means is simply that the chain is adapting to accepting electrons and then passing them along. That’s what it does. If you give it electrons, it passes it along within the components of the transport chain.
The chain does _____.
redox
The chain is oxidized by _______.
oxygen
Where do the electrons go?
Oxygen
______ is the terminal electron acceptor.
Oxygen
In the fourth complex…
Oxygen + protons + electrons = ____
H20. That’s the H20 that’s produced in cellular respiration
For 1 NADH, _ electrons are carried
So for 1 NADH, you make _ H20
2
1
For 2 NADH, _ electrons are carried
So for 2 NADH, you make _ H20
4
2
What happens to the electrons energy over the course of this chain? Increases or decreases?
Decreases
Electronegativity _______ as you go down the chain
increases
How is ATP going to be generated?
In order to generate ATP, we need to turn the rotor on the ATP synthase
The chain proteins transport electrons, but that’s a misnomer…when they do redox, they also harness the energy of the electrons passing through, and use that energy to move ______ across the inner membrane.
protons
They’re moving protons across the inner membrane. What does that do? What happens if you keep moving protons from the matrix to the inner membrane space? If you’re moving protons on one side of the membrane…you’re creating a _______.
gradient
Gradients store ________! So the train transforms energy from electron energy into GRADIENT ENERGY in the form of a proton gradient.
Energy
**The chain proteins establish a ______ gradient, which stores energy! **
proton
ATP synthase is also a proton ________.
channel
Cellular respiration is endergonic or exergonic?
exergonic
Using a proton gradient to make ATP is called ___________.
chemiosmosis
EXAM:
The process that makes ATP in stage 1 and 3 is called _______ ______ _________.
Substrate level phosphorylation.
The key is to recognize, what’s the source of energy?
Making ATP is exergonic or endergonic?
Endergonic. You need energy to make energy
What is the oxidizing agent of NADH?
ETC
The purpose of the redox of the ETC is to move ______ across a membrane…which membrane?
protons, inner membrane
What’s the enzyme that makes ATP?
ATP synthase
It does so because not only is this an enzyme, but it’s also a _______ protein. It’s specific to transporting _______. When proteins go through it, they turn the rotor, creating ATP.
transport, protons
ATP synthase _______ exergonic with endergonic so ATP can be made
couples
What is chemiosmosis?
Using a proton gradient to make ATP
Making ATP from ADP and inorganic phosphate powered by redox of an electron transport chain is called _________ _________.
oxidative phosphorylation
________ _______ means making ATP using the electron transport chain. What’s the source of energy?
oxidative phosphorylation, proton gradient
Final ATP tabulation (per glucose) Glycolysis: _ ATP Citric Acid Cycle: _ ATP Oxidative phosphorylation: \_\_ or \_\_ ATP Total: _ ATP
2
2
26 or 28
30 or 32
Efficiency of cellular respiration…32%
Is this efficient?
Yeah, pretty efficient. We’ll always lose some energy as heat (2nd Law)
The ETC is oxidized by _______.
Oxygen
What would happen if you no longer had the oxygen to be that terminal electron acceptor?
The ETC will have nobody to give its electrons to. It will back will back up with electrons, and then NADH will back up with electrons, and we’ll have nobody to give our electrons to.
What if O2 is unavailable?
1) The chain fills up with electrons and stops functioning
2) NADH has no oxidizing agent
What’s the solution?
Fermentation
Fermentation is a type of catabolism without _______.
oxygen
Fermentation is not going to completely breakdown sugar…it’s a partial breakdown. We’re going to do _______, and that’s about it.
glycolysis
How will we accomplish glycolysis without NAD+? All the NAD+ has been converted into NADH in the absence of O2
The final solution to this problem:
We’re going to oxidize NADH using _______.
pyruvate. Using the final product of glycolysis
If you oxidize NADH with pyruvate, the pyruvate becomes ______ _______.
Lactic acid, or “lactate”
Hence the name, lactic acid _________.
fermentation
Do bacteria do fermentation or cellular respiration?
BOTH
It is across the ____ ________ that bacteria generate the proton gradient, and at that cell membrane where bacteria make ___.
cell membrane, ATP
Single celled life also run aerobic ________ _________, including bacteria and yeast.
cellular respiration
Who is the oxidizing agent in fermentation?
NAD+
Recall, the function of carbs, lipids, protein is to…? Two things
1) store energy
2) carbon source
Intermediates are used for _________ pathways. (Arrows going in and out)
anabolic
Cellular respiration is regulated through the enzyme ___.
PFK
PFK catalyzes the _____ step of glycolysis
third
PFK has ________ sites
allosteric
PFK can be turned __ or turned ___, depending on who binds where.
on, off
PFK is controlled by _________ inhibition.
feedback
PFK is turned off when ___ binds to it.
ATP
ADP and AMP can bind to ___ and stimulate it…turn it on.
PFK
Citrate also regulates ___.
PFK
_____ binds to PFK and turns it off.
Citrate
