Chapter 6 Flashcards
Which enzyme helps the using up of stored ATP?
ATPase
Is energy produced when breaking down ATP to ADP? What is it used for?
Yes, used to power all forms of biologic work
In the presence of _____, phosphocreatine will create ATP.
ADP
Where did the ADP come from to help phosphocreatine?
From the breaking down of ATP. (1st equation)
Which enzyme helps PCr and ADP to form ATP?
creatine phosphate kinase
Which enzyme aids in the equation involving ADP + ADP?
Adenylate kinase
Which of the three equations is the one that makes energy used for biologic work?
1st equation of stored ATP
Which enzyme speeds up the reaction of glucose by charging it with a high energy phosphate bond and turning it into G6P?
Hexokinase
Where did the addition phosphase bond come from that charges the glucose?
It came from using stored ATP and breaking it down to ADP.
Glucose then changes form. What does it become and with which enzyme?
It becomes a fructose molecule (F6P), with the help of glucose-phosphate isomerase.
F6P is powered up again, how?
By ATP breaking down to ADP.
After F6P is powered up again, it forms what?
F 1,6 diphosphate.
Which enzyme speeds up the rate of reaction of F6P to F1,6diphosphate?
phosphofructrokinase
Why is PFK a rate limiting enzyme?
If you don’t have it maximally activated, then the process of glycolysis will stop there.
What will activate PFK?
ADP will activate it, so will phosphate, (so will ATP but its last resort).
F 1,6 diP breaks down to which 2 things?
Breaks down to 2 3-phosphoglyceraldehydes.
What happens to the 2 3-phosphoglyceraldehydes?
They both turn into pyruvate, then lactate.
What will get the excess hydrogens to use to take to pyruvate and then make lactic acid?
NAD+
As you move from pyruvate to lactate, the hydrogens from NADH + H+ will go to the lactate by which enzyme?
Lactate dehydrogenase
A low pH will ________ (increase/decrease) PFK activity.
Decrease
If you have decreased PFK activity, what does this cause?
Decrease glycolysis and decrease ATP production, which increases fatigue!
Explain how pyruvate becomes lactate by NAD+.
NAD+ breaks down to NADH + H, which allows pyruvate to add 2 hydrogens to it in order to become lactate.
What percentage of VO2 max in an untrained individual happens with increased lactate?
55%-60% VO2max.
Is NAD+ rate limiting?
YES
At 90% VO2 max, there is ______ (more/less) hydrogen in the cytosol. Cell pH will (decrease/increase).
More, decrease
At 90% VO2 max, what will be the NAD+ levels?
Will not change. Fixed amount, rate limiting.
Explain what happens at 90% VO2 max to lactate production.
- Since there’s more H available, you will max out NAD+ rapidly.
- This will cause a rapid increase in lactate production.
- Much more H+ in the cytosol still left over afterwards, causing the pH of the cell to drop (meaning cell function is inhibited).
What happens when PFK is in an area of low pH?
When it is in an acid environment, its activity starts to decline. All the glycogen and glucose will be broken down to a point in glycolysis and then it wont go through the point where the enzyme is needed. It will come to a halt. You’re not producing any additional ATP at this time. Elevated lactate levels, fatigue happens.
What happens if you are untrained and incapable of doing the 90%VO2 max… what is your body doing?
Do no bring in the necessary fats in to breakdown, instead they solely use them as carbs.
At 25% VO2 max, are you using very high or very low glucose?
Very low
At 25% VO2 max, hydrogen concentration is ______(small/large).
Hydrogen concentration is small.
At 25% VO2 max is lactate being formed? Explain.
No. Because the lactate theshold is 55-60%
Where does NADH + H go once formed from NAD+ at 25% VO2 max?
NADH + H ends up going down into the mitochondria, there it lets go of its hydrogens to generate the ETC to make ATP.
What is the threshold for lactate production for a TRAINED athlete?
75%
Are trained athletes more dependant on fats, carbs or proteins?
On fats.
How can you increase PFK?
With training
Explain the cori cycle.
In the skeletal muscle, glucose, turns into pyruvate which forms lactate that goes into the circulation and into liver. From the liver, it goes back to pyruvate, and back to glucose, to then be put back into the circulation and back into skeletal muscle.
What is the cori cycle good for?
Helps keep blood glucose levels constant while you’re exercising.
Where does gluconeogenesis happen?
In liver
Which are the 2 gluconeogenic precursors?
Alanine and glycerol
Alanine is a ____carbon structure. with a NH2 group.
3
Alanine can turn into what?
Pyruate
Where can you get new glucose from basically (3)?
Alanine, glycerol, and lactate.
Can you survive solely on those 3 in order to maintain exercise?
No, you need to have other carb sources for liver and muscle.
Which have a bigger diameter: fast twitch or slow twitch fibers?
Fast twitch
Which fatigue faster and why: fast twitch or slow twitch fibers?
Fast twitch because a lot of lactate is forming within fast twitch.
Which fibers are anaerobic and which are aerobic?
Ana = fast, aerobic = slow
Which fibers are good for endurance?
Slow
Which fibers are good for short bursts?
Fast
Explain the lactate shuttle.
Pyruvate turns into lactate in the fast twitch fiber and then goes next door to slow twitch fiber to for pyruvate, go to the kreb’c cycle and then ETC to form ATP.
At >55% VO2 max, you are using ________ of your fast twitch fibers for contraction.
75-90%
Will the adjacent fibers get lactate as well?
Yes
Why dont slow twitch fibers give their lactate to fast twitch?
Because fast twitch generally form a lot of lactate.
Can the heart take up lactate?
Yes
What else can the heart take up to use as ATP, other than lactate?
FFA and TG and the ketones and a.a.
When does the heart use lactate as energy as opposed to FFA and TG?1
When the heart is sick, like during a heart attack.
What can turn into acetyl coA?
Carbs, a.a. and FFA.
What do FAD and NAD+ do?
Serve to mop all of the hydrogens and bind them.
Whats the difference between GTP and ATP?
GTP = guanine instead of alanine.
What is pryuvate like for diabetics?
Less pyruvate so less glucose hence slower kreb’s cycle.
What do cytochromes do?
Take the pairs of electrons and pass them down to each other.
Where do the pairs of electrons come from?
NAD
How many ATP are formed for 1 NADH?
3
How many NADH are formed by the kreb’s cycle?
3
So how many ATPs are formed thanks to NADH in one cycle of KC?
9
How much ATP is being formed for one FADH2?
2
Just based on NADH and FADH2, how many ATPS are formed in one cycle of the KC?
11
How many ATPs does one GTP make?
1
What needs to be present in adequate amounts in order for ETC to work?
oxygen.
What needs to be present in adequate amounts in order for KC to work?
NAD+
If ETC fails, can KC still function?
No
The more oxygen you give to the mitochondria, the ______ (more/less) energy ATP you can make.
more
How does aerobic training affect ETC?
1) SIZE: increases the size of mitochondria, so a greater ETC capacity (more cytochromes) and greater amounts of substrate going through the Krebs’s cycle, more rate-limiting enzymes, more everything! 2) NUMBER: You will have new protein synthesis, because more mitochondrias as well. Greater blood flow to new skeletal fibers.
What is the only thing that wouldn’t change with improved aerobic training?
Oxygen content. BUT you will be able to accept it better.
Aerobic training improves your tissues…. not the way you…….
accept oxygen.
18C FFA gives you how many units of ATP?
147
Saturated is a ______ bond.
single
Unsaturated is _________ bond.
2 or more
What cleaves the x-number of Carbon FFA?
Beta-oxidation
What happens as soon as beta-oxidation cleaves a C-C bond?
coA thats flowing around in the mitochondria, binds to the C-C, making acetyl coA. Then used for the KC!
For every pairing of C-C, whats being let go…?
NADH and FADH2
What does the ETC form (equation)?
2H + 1/2 O2 = H20
How much ATP is formed from a 3C unit of glycerol?
19 ATPs
One C-C forms how many ATPs from NADH and from FADH2 and why?
3 ATPs from NADH. 2 ATPS from FADH2. Because of ETC.
How many ATPs per beta oxidation reaction?
5
Once you calculate your gorss value of ATPs for the KC and beta-oxidation, what do you have to substract?
1 ATP
What are the 2 causes of high rate of fat metabolism?
High fat diet and low carb diet.
High rate of fat metabolism causes extreme ______(increase/decrease) of acetyl CoA.
Increase
Explain the problem with high fat diet in relation to high rate of fat metabolism.
high FA causing excess acetyl coa, so pyruvate doesn’t want to convert into acetyl coA anymore because there’s already a lot, so pyruvate just stays there or goes somewhere else
Explain the problem with low carb diet in relation to high rate of fat metabolism.
pyruvate will be decreased, this causes less oxaloacetate to be formed, and will be an excess of acetylCoA now… cycle begins to shut down, 2 acetyl CoAs will bind together forming a ketone
Where are ketones primarily formed?
In liver
High ketone production means theres _______ pH levels and ________ H+. (increase/decrease)
Decreased, increased
Why are ketones bad?
Brain pH will drop, brain function will be low and chance of coma.
Ketone (acetoacetic acid) can be broken down into which 2 things?
Acetone AND/OR beta-hydroxybutyric.
Can CHO turn into both fats and a.a.?
Yes
Can a.a turn into both CHO and fats?
Yes
Can fats turn into both CHO and fats?
No, it cannot make CHO!!!!
How do fats make a.a.?
Add NH2.
ATP stands for what?
Adenoside triphosphate
ATP gets energy from what… .. awks Q
Energy from macronutrient oxidizatoin is harvested and funneled through the energy compound ATP
Adenosine is formed how?
Adenine and ribose
ADP stands for what
Adenosine diphosphate
ATP -> ADP done by which enzyme?
ATPase
Does ATP need oxygen to split?
no
Cells contain (small/large) amounts of ATP
small
Body stores how much ATP at any time (grams)?
80-100g
Major sources for maintaining ATP resynthesis
Fat and glycogen, or PCr
PCr(PHOSPHOCREATINE) and ADP form ATP by which enzyme?
creatine kinase
The energy from splitting PCr does what?
Rebonds ADP and Pi to form ATP.
Which is stored more in the body: PCr or ATP?
PCr
ADP phosphorylase
-
Adenylate kinase reaction does what?
2 ADPs —-> ATP + AMP.
Enzyme that helps another reaction for ATP regeneration.
Satisfying the following three conditions causes hydrogen and electrons to shuttle uninterrupted down the respiratory chain to oxygen during energy metabolism.
availability of NADH
Presence of oxygen
Sufficient concentration of enzymes and mitochondria.
2 end products of glycolysis.
Pyruvate and lactate.
Does glycolysis need oxygen?
no
Fast twitch contains large quantities of which enzyme?
Phosphofructokinase (PFK)
Term for glycogen breakdown
Glycogenolysis
Term for glycogen synthesis
glycogenesis
Three factors that regulate glycolysis.
1) oxygen
2) concentrations of key enzymes
3) Levels of the substrate fructose 1,6-diphosphate
ETC is the __________ of hydrogen atoms.
oxidation
triacylglycerol breakdown happens by adding what?
water
During intense exercise, when hydrogen oxidation fails to keep pace, what will pyruvate do?
Pyruvate will temporarily bind to hydrogen to form lactate.
What exerts the greatest effect on the rate-limiting enzymes that control energy metabolism?
Cellular ADP
