Krebs cycle diagram

Krebs cycle diagram DEFAULT

TCA Cycle

In order for ATP to be produced through oxidative phosphorylation, electrons are required for ATP to pass down the electron transport chain. These electrons come from electron carriers such as NADH and FADH₂, which are produced by the Tricarboxylic Acid Cycle (TCA cycle, also known as the Kreb's/Citric Acid cycle). In this article we will outline the steps and regulation of this essential part of cellular physiology.

Link Reaction

Prior to the TCA cycle, glycolysis has occurred, which generates molecules including pyruvate, ATP and NADH. Pyruvate is then decarboxylated to form acetyl-coA by the pyruvate decarboxylase complex. Acetyl-coA is the intermediate that enters the TCA cycle.

The TCA Cycle

The TCA cycle is a central pathway that provides a unifying point for many metabolites, which feed into it at various points. It takes place over eight different steps:

  • Step 1:  Acetyl CoA (two carbon molecule) joins with oxaloacetate (4 carbon molecule) to form citrate (6 carbon molecule).
  • Step 2: Citrate is converted to isocitrate (an isomer of citrate)
  • Step 3: Isocitrate is oxidised to alpha-ketoglutarate (a five carbon molecule) which results in the release of carbon dioxide. One NADH molecule is formed.

The enzyme responsible for catalysing this step is isocitrate dehydrogenase. This is a rate limiting step, as isocitrate dehydrogenase is an allosterically controlled enzyme.

  • Step 4: Alpha-ketoglutarate is oxidised to form a 4 carbon molecule. This binds to coenzyme A, forming succinyl CoA. A second molecule of NADH is produced, alongside a second molecule of carbon dioxide.
  • Step 5: Succinyl CoA is then converted to succinate (4 carbon molecule) and one GTP molecule is produced.
  • Step 6: Succinate is converted into fumarate (4 carbon molecule) and a molecule of FADH₂ is produced.
  • Step 7: Fumarate is converted to malate (another 4 carbon molecule).
  • Step 8: Malate is then converted into oxaloacetate. The third molecule of NADH is also produced.
[caption id="attachment_14547" align="aligncenter" width="754"]Fig 1 - Diagram showing the steps of the TCA cycle.[/caption]

While the primary role of the TCA cycle is production of NADH and FADH₂, it also produces molecules that supply various biosynthetic processes. These enter or exit the cycle at various points depending on demand. For example, alpha-ketoglutarate can leave the cycle to be converted into amino acids, and succinate can be converted to haem.

Net Output

Each cycle produces:

  • Two molecules of carbon dioxide.
  • Three molecules of NADH.
  • Three hydrogen ions (H+).
  • One molecule of FADH₂
  • One molecule of GTP.

Each molecule of glucose produces two molecules of pyruvate, which in turn produce two molecules of acetyl-coA. Therefore, each molecule of glucose produces double the net output of each cycle.

Regulation of the TCA Cycle

The TCA Cycle is regulated in a variety of ways:

  • Metabolites: Products of the cycle provide negative feedback on the enzymes that catalyse it. For example, NADH inhibits the majority of the enzymes found in the TCA cycle.
  • Citrate: Inhibits phosphofructokinase, a key enzyme in glycolysis. This reduces the rate of production of pyruvate and therefore of acetyl-coA.
  • Calcium: Accelerates the TCA cycle by stimulating the link reaction.

[start-clinical]

Clinical Relevance - Defects of the TCA Cycle

There are in fact no known defects of the TCA cycle that are compatible with life. This highlights the importance of this step in ATP production for sustaining life.

[end-clinical]

Sours: https://teachmephysiology.com/biochemistry/atp-production/tca-cycle-2/

Krebs Cycle (Citric Acid Cycle) — Steps & Diagram - Expii

Citric Acid Cycle

The second step in cellular respiration is called the citric acid cycle or the Krebs cycle.

The cycle requires oxygen, which means that it is an aerobic process. It takes place in the mitochondrial matrix. Recall that this is the liquid in the space between the folds of the inner membrane of the mitochondrion.

Mitochondrial membranes

Image source: By Charlie Jones CC0, via pixabay.com

Each pyruvate made in glycolysis goes through the cycle. Since there are two pyruvate molecules made from each molecule of glucose, this means that the whole cycle runs two times.

In the cycle, each pyruvate from glycolysis is harvested for its electrons. In the process, for every two pyruvate molecules, two ATP are produced.

The citric acid cycle produces one ATP per cycle.

One ATP is made for each turn of the cycle. The cycle goes around two times for each glucose we started with in glycolysis. So, there are a total of two ATP produced after these two turns. Image source: By Hannah Bonville

Let's talk for a second about this business of harvesting electrons. There are two electron carriers at work. They take electrons off molecules in the citric acid cycle and carry them to the next step of cellular respiration. Think of them as little electron suitcases.

The names of the carriers are NAD+ and FADH. We know if they've got an electron with them because their names change slightly to NADH and FADH2.

These guys will become important in the next step of cellular respiration.

Electron carriers

Notice how the names of the electron carriers (suitcases) change slightly when they are carrying an electron. Image source: Clker-Free-Vector-Images (modified by expii) CC0, via pixabay.com

For each turn of the cycle, three NAD+ are converted into three NADH, and one FADH is converted into one FADH2.

This means that for each glucose molecule we started with, we get a total of six NADH and two FADH2.

The cycle also produces (per turn) two molecules of carbon dioxide (CO2). You know the carbon dioxide you breathe out? This is where it comes from. Two acetyl groups each give up two carbon atoms, which are oxidized to create two molecules of CO2.

Let's add all of this onto our picture of the citric acid cycle. Keep in mind, all of the values need to be doubled since the cycle turns twice per glucose molecule (our starting molecule).

The citric acid cycle produces two CO2, three NADH, one ATP, and one FADH2.

Image source: By Hannah Bonville

Here's a summary for the entire cycle:

The citric acid cycle (Krebs cycle) occurs in the mitochondrial matrix, indirectly requires oxygen (is aerobic), turns twice for each glucose in glycolysis, and gains one ATP, three NADH, one FADH2, and two CO2 per turn.

Image source: By Hannah Bonville

Key Vocabulary

  1. Cellular respiration
  2. Citric acid cycle
  3. ATP
  4. Mitochondria
  5. Mitochondrial matrix
  6. Aerobic
Sours: https://www.expii.com/t/krebs-cycle-citric-acid-cycle-steps-diagram-10137
  1. Ram 2018 price
  2. Decried unscramble
  3. Custom g35 tail lights
  4. Sterling 48 shower kit
  5. Curt pocket camp

If you’re here because you’ve enjoyed my Krebs Cycle Song and want to learn more about the Krebs Cycle, I suggest that you go to my Krebs Cycle Tutorial (AP Biology Level)

Links

1. Krebs Cycle Interactive Lyrics

Ok: You’ve watched the video and heard the song. Now read through the lyrics, dragging in words as needed. Why? Research shows that adding this little bit of interactivity will increase your memory of what you read. Give it a try!

[qwiz]

[h]Interactive Lyrics: Krebs Cycle

[q labels = “top”]

In the _______ of the mitochondria of all our cells
Is the cycle of reactions that won Hans Krebs the Nobel Prize
This cycle takes the ______ in food
And makes it into other forms that your cells can use.

Krebs Cycle makes the electron carrier ______
Which later brings _________ to the electron transport chain.
And Krebs makes FADH2 its function is the same,
Krebs also makes some ATP another claim to fame.

[fx] No, that’s not correct. Please try again.

[f*] Great!

[fx] No, that’s not correct. Please try again.

[f*] Great!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No. Please try again.

[f*] Great!

[q labels = “top”]

CHORUS

(we’re talking) KREBS!
It’s the ______ Acid Cycle
KREBS!
Tricarboxylic Acid Cycle
Krebs– each cycle makes
_____ ATP, _____ NADH, one FADH2

[fx] No. Please try again.

[f*] Great!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No, that’s not correct. Please try again.

[f*] Excellent!

[q labels = “top”]

Right before the cycle’s a transitional part
Links Krebs to glycolysis, so Krebs can start
Enzymes break a CO2 off a ________
Yields an NADH and ___________

Acetyl-CoA carries _________ two
With all the energy that derives from food
It’s a highly ________ molecule with energized electrons
It fuels up the Krebs cycle as it cycles on.

[fx] No. Please try again.

[f*] Excellent!

[fx] No, that’s not correct. Please try again.

[f*] Good!

[fx] No. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Excellent!

[q labels = “top”]

Now at the start of Krebs this Acetyl-CoA
Has the two carbons it carries in ripped away
Enzymes put these on ____________ with carbons four,
Makes ___________ citric acid who could ask for more?

Notice ______ carboxyl groups on that citric acid
It’s why the cycle’s also named for ____________ Acid
Or TCA Cycle, if it’s acronyms that you prefer
Or Krebs in honor of its discoverer!

CHORUS

[fx] No, that’s not correct. Please try again.

[f*] Excellent!

[fx] No, that’s not correct. Please try again.

[f*] Good!

[fx] No. Please try again.

[f*] Excellent!

[fx] No. Please try again.

[f*] Great!

[q labels = “top”]

Enzymes work on Citric Acid and remove a _____
and other enzymes modify and oxidize it too,
The five carbon result is ________________.
Krebs cycle, it’s so great!

Every oxidation, can power the reduction,
of NAD plus which gains electron carrying function,
Becoming ________, that energy sensation
Which later on in respiration powers _____ creation

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No, that’s not correct. Please try again.

[f*] Excellent!

[fx] No. Please try again.

[f*] Correct!

[fx] No. Please try again.

[f*] Great!

[q labels = “top”]

Another __________ follows, another  CO2 removed
Leaving us with a _____ carbon molecule
Another ______ results from this oxidation
As Krebs does its energy transformations

 

This four carbon molecule (Succinyl CoA),
Still has lots of energy, enzymes can take away
A series of reactions yield one _____
The cell’s main energy currency.

[fx] No. Please try again.

[f*] Good!

[fx] No, that’s not correct. Please try again.

[f*] Great!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No. Please try again.

[f*] Great!

[q labels = “top”]

Leavin’ just enough energy for enzymes to reduce
An FAD to _______
And one last ______ will also get reduced
As the final ‘lectron carrier NADH gets produced.

 

We’ve harvested what energy came in at Krebs’s start,
Now we have ____________ at this final part
Oxaloacetate is the commencement and finale
Ready to meet _______ CoA, and here at the final tally

[fx] No. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Excellent!

[fx] No. Please try again.

[f*] Excellent!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[q labels = “top”]

BRIDGE

______ goes round and round, such an ancient cycle,
Spinning like the wheels of my bicycle.
Krebs is like the axle of ________ respiration,
I breathe out its CO2 with every exhalation!

 

We’ve walked through the cycle, so now lets review
Input is ___________ with carbons two
The carbons get removed, releasing _____
Exhaling sends this CO2 out of you.

[fx] No. Please try again.

[f*] Correct!

[fx] No. Please try again.

[f*] Great!

[fx] No, that’s not correct. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Good!

[q labels = “top”]

The cycle’s function’s energy transformation
Three ______, one _______ creation
And also synthesis of one _____
Which cells directly utilize for energy

For every glucose cells absorb the cycle runs _____ times
As long as cells get fuel, Krebs is running just fine,
It precedes electron transport chain, it follows __________
It’s spinning round and round in the mitochondrial matrix

[fx] No. Please try again.

[f*] Great!

[fx] No, that’s not correct. Please try again.

[f*] Good!

[fx] No, that’s not correct. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Excellent!

[fx] No. Please try again.

[f*] Correct!

[/qwiz]

2. Krebs Cycle Interactive Diagrams

2a. Key Molecules

Start by dragging all the names of the key molecules to their correct location.

[qwiz]

[h]Krebs: Interactive Diagram 1: Key Molecules

[q labels = “top”]

 

[fx] No. Please try again.

[f*] Excellent!

[fx] No, that’s not correct. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Correct!

[fx] No. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Correct!

[fx] No. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Good!

[/qwiz]

2b. Products

Now focus on the products of the Krebs Cycle.

[qwiz]

[h]Krebs Cycle interactive diagram 2: Products

[q labels = “top”]

 

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Good!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No, that’s not correct. Please try again.

[f*] Great!

[fx] No, that’s not correct. Please try again.

[f*] Good!

[fx] No. Please try again.

[f*] Great!

[/qwiz]

2c. The Link Reaction

This diagram will help you master the link reaction that precedes Krebs.

[qwiz]

[h]Interactive Diagram: The Link Reaction

[q labels = “top”]

 

[fx] No, that’s not correct. Please try again.

[f*] Good!

[fx] No, that’s not correct. Please try again.

[f*] Good!

[fx] No. Please try again.

[f*] Excellent!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[fx] No. Please try again.

[f*] Great!

[fx] No. Please try again.

[f*] Excellent!

[fx] No, that’s not correct. Please try again.

[f*] Good!

[fx] No, that’s not correct. Please try again.

[f*] Correct!

[/qwiz]

3. Krebs cycle Flashcards

3a. Krebs Deck 1

[qdeck]

[h]Krebs Cycle flashcards Set 1

[!!!]Card  1[/!!!!]

[q topic = “krebs cycle”] The Krebs cycle occurs in the _____ of the mitochondria

[textentry]

[a]The Krebs cycle occurs in the matrix of the mitochondria

[!!!]Card  4[/!!!!]

[q topic = “krebs cycle”]The Krebs cycle makes the electron carriers _____ and FADH2

[textentry]

[a]The Krebs cycle makes the electron carriers NADH and FADH2

[!!!]Card  7[/!!!!]

[q topic = “krebs cycle”]Krebs is also known as the _____ acid cycle

[textentry]

[a]Krebs is also known as the Citric acid cycle

[!!!]Card  10[/!!!!]

[q topic = “krebs cycle”]Each turn of the Krebs cycle produces one ATP, three NADH, _____ FADH2.

[textentry]

[a]Each turn of the Krebs cycle produces one ATP, three NADH, one FADH2.

[!!!]Card  13[/!!!!]

[q topic = “krebs cycle”]The link reaction converts _____ acid to Acetyl-CoA.  Carbon dioxide is released as a waste product, and one NADH is produced.

[textentry]

[a]The link reaction converts pyruvic acid to Acetyl-CoA.  Carbon dioxide is released as a waste product, and one NADH is produced.

[!!!]Card  16[/!!!!]

[q topic = “krebs cycle”]The link reaction converts pyruvic acid to Acetyl-CoA.  Carbon dioxide is released as a _____, and one NADH is produced.

[textentry]

[a]The link reaction converts pyruvic acid to Acetyl-CoA.  Carbon dioxide is released as a waste product, and one NADH is produced.

[!!!]Card  19[/!!!!]

[q topic = “krebs cycle”]Acetyl-CoA carries _____ carbon atoms into the Krebs cycle

[textentry]

[a]Acetyl-CoA carries two carbon atoms into the Krebs cycle

[!!!]Card  22[/!!!!]

[q topic = “krebs cycle”]The chemical energy brought into Krebs by acetyl Co-A is originally _____ energy

[textentry]

[a]The chemical energy brought into Krebs by acetyl Co-A is originally food energy

[!!!]Card  25[/!!!!]

[q topic = “krebs cycle”]At the start of Krebs _____ two carbons combine with oxaloacetate, a four carbon molecule

[textentry]

[a]At the start of Krebs Acetyl-CoA’s two carbons combine with oxaloacetate, a four carbon molecule

[!!!]Card  28[/!!!!]

[q topic = “krebs cycle”]At the start of Krebs Acetyl-CoA’s two carbons combine with oxaloacetate, a _____ carbon molecule

[textentry]

[a]At the start of Krebs Acetyl-CoA’s two carbons combine with oxaloacetate, a four carbon molecule

[!!!]Card  31[/!!!!]

[q topic = “krebs cycle”]Combining Acetyl-CoA with oxaloacetate creates _____-carbon citric acid.

[textentry]

[a]Combining Acetyl-CoA with oxaloacetate creates six-carbon citric acid.

[!!!]Card  34[/!!!!]

[q topic = “krebs cycle”]Citric acid has three _____ groups

[textentry]

[a]Citric acid has three carboxyl groups

[!!!]Card  37[/!!!!]

[q topic = “krebs cycle”]Removing a _____ from citric acid, along with other enzymatic modifications, creates five carbon ?-ketoglutarate.

[textentry]

[a]Removing a CO2 from citric acid, along with other enzymatic modifications, creates five carbon ?-ketoglutarate.

[!!!]Card  40[/!!!!]

[q topic = “krebs cycle”]Removing a CO2  from citric acid, along with other enzymatic modifications, creates five carbon _____.

[textentry]

[a]Removing a CO2  from citric acid, along with other enzymatic modifications, creates five carbon ?-ketoglutarate.

[!!!]Card  43[/!!!!]

[q topic = “krebs cycle”]During the Krebs cycle, every oxidation can power the reduction of _____, creating the electron carrier NADH.

[textentry]

[a]During the Krebs cycle, every oxidation can power the reduction of NAD+, creating the electron carrier NADH.

[!!!]Card  46[/!!!!]

[q topic = “krebs cycle”]During the _____, NADH powers ATP creation

[textentry]

[a]During the electron transport chain, NADH powers ATP creation

[!!!]Card  49[/!!!!]

[q topic = “krebs cycle”]Oxidation of _____, along with removal of a CO2,  produces one NADH. The resulting molecule is four carbon succinyl CoA.

[textentry]

[a]Oxidation of ?-ketoglutarate, along with removal of a CO2,  produces one NADH. The resulting molecule is four carbon succinyl CoA.

[!!!]Card  52[/!!!!]

[q topic = “krebs cycle”]Oxidation of ?-ketoglutarate, along with removal of a CO2,  produces one NADH. The resulting molecule is _____ carbon succinyl CoA.

[textentry]

[a]Oxidation of ?-ketoglutarate, along with removal of a CO2,  produces one NADH. The resulting molecule is four carbon succinyl CoA.

[!!!]Card  55[/!!!!]

[q topic = “krebs cycle”]As Succinyl CoA is transformed by enzymes to become _____, its energy is used to make one ATP.

[textentry]

[a]As Succinyl CoA is transformed by enzymes to become succinate, its energy is used to make one ATP.

[!!!]Card  58[/!!!!]

[q topic = “krebs cycle”]Oxidation of _____ is coupled with reduction of an FAD

[textentry]

[a]Oxidation of succinate is coupled with reduction of an FAD

[!!!]Card 61[/!!!!]

[q topic = “krebs cycle”]The final oxidation reaction in Krebs results in reduction of NAD+, and leaves us with _____ carbon oxaloacetate.

[textentry]

[a]The final oxidation reaction in Krebs results in reduction of NAD+, and leaves us with four carbon oxaloacetate.

[!!!]Card 64[/!!!!]

[q topic = “krebs cycle”]Overall, Krebs produces three NADH, _____ FADH2, and one ATP

[textentry]

[a]Overall, Krebs produces three NADH, one FADH2, and one ATP

[!!!]Card 67[/!!!!]

[q topic = “krebs cycle”]Overall, Krebs produces three NADH (an electron carrier), one _____ (an electron carrier), and one ATP (an immediate energy source)

[textentry]

[a]Overall, Krebs produces three NADH (an electron carrier), one FADH2 (an electron carrier), and one ATP (an immediate energy source)

[!!!]Card 70[/!!!!]

[q topic = “krebs cycle”]The four carbon molecule found at the start and end of Krebs is _____.

[textentry]

[a]The four carbon molecule found at the start and end of Krebs is oxaloacetate.

[!!!]Card 73[/!!!!]

[q topic = “krebs cycle”]For every _____ cells absorb the Krebs cycle runs two times.

[textentry]

[a]For every glucose cells absorb the Krebs cycle runs two times.

[x]

[restart]

[/qdeck]

3b. Krebs Deck 2

[qdeck]

[h]Krebs Cycle flashcards Set 2

[!!!]Card  2[/!!!!]

[q topic = “krebs cycle”]The Krebs cycle occurs in the matrix of the _____

[textentry]

[a]The Krebs cycle occurs in the matrix of the mitochondria

[!!!]Card  5[/!!!!]

[q topic = “krebs cycle”]The Krebs cycle makes the electron carriers NADH and _____

[textentry]

[a]The Krebs cycle makes the electron carriers NADH and FADH2

[!!!]Card  8[/!!!!]

[q topic = “krebs cycle”]Each turn of the Krebs cycle produces _____ ATP, three NADH, one FADH2.

[textentry]

[a]Each turn of the Krebs cycle produces one ATP, three NADH, one FADH2.

[!!!]Card  11[/!!!!]

[q topic = “krebs cycle”]The link reaction links _____ to the Krebs Cycle

[textentry]

[a]The link reaction links glycolysis to the Krebs Cycle

[!!!]Card  14[/!!!!]

[q topic = “krebs cycle”]The link reaction converts pyruvic acid to _____.  Carbon dioxide is released as a waste product, and one NADH is produced.

[textentry]

[a]The link reaction converts pyruvic acid to Acetyl-CoA.  Carbon dioxide is released as a waste product, and one NADH is produced.

[!!!]Card  17[/!!!!]

[q topic = “krebs cycle”]The link reaction converts pyruvic acid to Acetyl-CoA.  Carbon dioxide is released as a waste product, and one _____ is produced.

[textentry]

[a]The link reaction converts pyruvic acid to Acetyl-CoA.  Carbon dioxide is released as a waste product, and one NADH is produced.

[!!!]Card  20[/!!!!]

[q topic = “krebs cycle”]Acetyl-CoA carries two _____ atoms into the Krebs cycle

[textentry]

[a]Acetyl-CoA carries two carbon atoms into the Krebs cycle

[!!!]Card  23[/!!!!]

[q topic = “krebs cycle”]Acetyl-CoA is a highly _____ molecule with energized electrons

[textentry]

[a]Acetyl-CoA is a highly reduced molecule with energized electrons

[!!!]Card  26[/!!!!]

[q topic = “krebs cycle”]At the start of Krebs Acetyl-CoA’s two _____ combine with oxaloacetate, a four carbon molecule

[textentry]

[a]At the start of Krebs Acetyl-CoA’s two carbons combine with oxaloacetate, a four carbon molecule

[!!!]Card  29[/!!!!]

[q topic = “krebs cycle”]Combining _____ with oxaloacetate creates six-carbon citric acid.

[textentry]

[a]Combining Acetyl-CoA with oxaloacetate creates six-carbon citric acid.

[!!!]Card  32[/!!!!]

[q topic = “krebs cycle”]Combining Acetyl-CoA with oxaloacetate creates six-carbon _____ acid.

[textentry]

[a]Combining Acetyl-CoA with oxaloacetate creates six-carbon citric acid.

[!!!]Card  35[/!!!!]

[q topic = “krebs cycle”]Another name for _____ acid is tricarboxylic acid

[textentry]

[a]Another name for citric acid is tricarboxylic acid

[!!!]Card  38[/!!!!]

[q topic = “krebs cycle”]Removing a CO2  from _____ acid, along with other enzymatic modifications, creates five carbon ?-ketoglutarate.

[textentry]

[a]Removing a CO2  from citric acid, along with other enzymatic modifications, creates five carbon ?-ketoglutarate.

[!!!]Card  41[/!!!!]

[q topic = “krebs cycle”]During the Krebs cycle, every _____ can power the reduction of NAD+, creating the electron carrier NADH.

[textentry]

[a]During the Krebs cycle, every oxidation can power the reduction of NAD+, creating the electron carrier NADH.

[!!!]Card  44[/!!!!]

[q topic = “krebs cycle”]During the Krebs cycle, every oxidation can power the reduction of NAD+, creating the _____ carrier NADH.

[textentry]

[a]During the Krebs cycle, every oxidation can power the reduction of NAD+, creating the electron carrier NADH.

[!!!]Card  47[/!!!!]

[q topic = “krebs cycle”]During the electron transport chain, _____ powers ATP creation

[textentry]

[a]During the electron transport chain, NADH powers ATP creation

[!!!]Card  50[/!!!!]

[q topic = “krebs cycle”]Oxidation of ?-ketoglutarate, along with removal of a _____,  produces one NADH. The resulting molecule is four carbon succinyl CoA.

[textentry]

[a]Oxidation of ?-ketoglutarate, along with removal of a CO2,  produces one NADH. The resulting molecule is four carbon succinyl CoA.

[!!!]Card  53[/!!!!]

[q topic = “krebs cycle”]Oxidation of ?-ketoglutarate, along with removal of a CO2,  produces one NADH. The resulting molecule is four carbon _____.

[textentry]

[a]Oxidation of ?-ketoglutarate, along with removal of a CO2,  produces one NADH. The resulting molecule is four carbon succinyl CoA.

[!!!]Card  56[/!!!!]

[q topic = “krebs cycle”]As Succinyl CoA is transformed by enzymes to become succinate, its energy is used to make one _____.

[textentry]

[a]As Succinyl CoA is transformed by enzymes to become succinate, its energy is used to make one ATP.

[!!!]Card  59[/!!!!]

[q topic = “krebs cycle”]Oxidation of succinate is coupled with reduction of an _____

[textentry]

[a]Oxidation of succinate is coupled with reduction of an FAD

[!!!]Card 62[/!!!!]

[q topic = “krebs cycle”]The final oxidation reaction in Krebs results in reduction of NAD+, and leaves us with four carbon _____.

[textentry]

[a]The final oxidation reaction in Krebs results in reduction of NAD+, and leaves us with four carbon oxaloacetate.

[!!!]Card 65[/!!!!]

[q topic = “krebs cycle”]Overall, Krebs produces three NADH, one FADH2, and _____ ATP

[textentry]

[a]Overall, Krebs produces three NADH, one FADH2, and one ATP

[!!!]Card 68[/!!!!]

[q topic = “krebs cycle”]Overall, Krebs produces three NADH (an electron carrier), one FADH2 (an electron carrier), and one _____ (an immediate energy source)

[textentry]

[a]Overall, Krebs produces three NADH (an electron carrier), one FADH2 (an electron carrier), and one ATP (an immediate energy source)

[!!!]Card 71[/!!!!]

[q topic = “krebs cycle”]During Krebs _____ molecules of carbon dioxide are released as exhaust.

[textentry]

[a]During Krebs two molecules of carbon dioxide are released as exhaust.

[!!!]Card 74[/!!!!]

[q topic = “krebs cycle”]For every glucose cells absorb the Krebs cycle runs _____ times.

[textentry]

[a]For every glucose cells absorb the Krebs cycle runs two times.

[x]

[restart]

[/qdeck]

3c. Krebs Deck 3

[qdeck]

[h]Krebs Cycle flashcards Set 3

[!!!]Card  3[/!!!!]

[q topic = “krebs cycle”]The Krebs cycle makes the _____ carriers NADH and FADH2

[textentry]

[a]”krebs cycle”]The Krebs cycle makes the electron carriers NADH and FADH2

[!!!]Card  6[/!!!!]

[q topic = “krebs cycle”]Krebs is also known as the tri-_____ acid cycle.

[textentry]

[a]Krebs is also known as the tri-carboxylic acid cycle.

[!!!]Card  9[/!!!!]

[q topic = “krebs cycle”]Each turn of the Krebs cycle produces one ATP, _____ NADH, one FADH2.

[textentry]

[a]Each turn of the Krebs cycle produces one ATP, three NADH, one FADH2.

[!!!]Card  12[/!!!!]

[q topic = “krebs cycle”]The link reaction links glycolysis to the _____

[textentry]

[a]The link reaction links glycolysis to the Krebs Cycle

[!!!]Card  15[/!!!!]

[q topic = “krebs cycle”]The link reaction converts pyruvic acid to Acetyl-CoA.  _____ is released as a waste product, and one NADH is produced.

[textentry]

[a]The link reaction converts pyruvic acid to Acetyl-CoA.  Carbon dioxide is released as a waste product, and one NADH is produced.

[!!!]Card  18[/!!!!]

[q topic = “krebs cycle”]_____ carries two carbon atoms into the Krebs cycle

[textentry]

[a]Acetyl-CoA carries two carbon atoms into the Krebs cycle

[!!!]Card  21[/!!!!]

[q topic = “krebs cycle”]The chemical energy brought into Krebs by _____ is originally food energy

[textentry]

[a]The chemical energy brought into Krebs by acetyl Co-A is originally food energy

[!!!]Card  24[/!!!!]

[q topic = “krebs cycle”]Acetyl-CoA is a highly reduced molecule with energized _____

[textentry]

[a]Acetyl-CoA is a highly reduced molecule with energized electrons

[!!!]Card  27[/!!!!]

[q topic = “krebs cycle”]At the start of Krebs Acetyl-CoA’s two carbons combine with _____, a four carbon molecule

[textentry]

[a]At the start of Krebs Acetyl-CoA’s two carbons combine with oxaloacetate, a four carbon molecule

[!!!]Card  30[/!!!!]

[q topic = “krebs cycle”]Combining Acetyl-CoA with _____ creates six-carbon citric acid.

[textentry]

[a]Combining Acetyl-CoA with oxaloacetate creates six-carbon citric acid.

[!!!]Card  33[/!!!!]

[q topic = “krebs cycle”]_____ acid has three carboxyl groups

[textentry]

[a]Citric acid has three carboxyl groups

[!!!]Card  36[/!!!!]

[q topic = “krebs cycle”]Another name for citric acid is _____ acid

[textentry]

[a]Another name for citric acid is tricarboxylic acid

[!!!]Card  39[/!!!!]

[q topic = “krebs cycle”]Removing a CO2  from citric acid, along with other enzymatic modifications, creates _____ carbon ?-ketoglutarate.

[textentry]

[a]Removing a CO2  from citric acid, along with other enzymatic modifications, creates five carbon ?-ketoglutarate.

[!!!]Card  42[/!!!!]

[q topic = “krebs cycle”]During the Krebs cycle, every oxidation can power the _____ of NAD+, creating the electron carrier NADH.

[textentry]

[a]During the Krebs cycle, every oxidation can power the reduction of NAD+, creating the electron carrier NADH.

[!!!]Card  45[/!!!!]

[q topic = “krebs cycle”]During the Krebs cycle, every oxidation can power the reduction of NAD+, creating the electron carrier _____.

[textentry]

[a]During the Krebs cycle, every oxidation can power the reduction of NAD+, creating the electron carrier NADH.

[!!!]Card  48[/!!!!]

[q topic = “krebs cycle”]During the electron transport chain, NADH powers _____ creation

[textentry]

[a]During the electron transport chain, NADH powers ATP creation

[!!!]Card  51[/!!!!]

[q topic = “krebs cycle”]Oxidation of ?-ketoglutarate, along with removal of a CO2,  produces one _____. The resulting molecule is four carbon succinyl CoA.

[textentry]

[a]Oxidation of ?-ketoglutarate, along with removal of a CO2,  produces one NADH. The resulting molecule is four carbon succinyl CoA.

[!!!]Card  54[/!!!!]

[q topic = “krebs cycle”]As _____ is transformed by enzymes to become succinate, its energy is used to make one ATP.

[textentry]

[a]As Succinyl CoA  is transformed by enzymes to become succinate, its energy is used to make one ATP.

[!!!]Card  57[/!!!!]

[q topic = “krebs cycle”]_____ of succinate is coupled with reduction of an FAD

[textentry]

[a]Oxidation of succinate is coupled with reduction of an FAD

[!!!]Card 60[/!!!!]

[q topic = “krebs cycle”]The final oxidation reaction in Krebs results in reduction of _____, and leaves us with four carbon oxaloacetate.

[textentry]

[a]The final oxidation reaction in Krebs results in reduction of NAD+, and leaves us with four carbon oxaloacetate.

[!!!]Card 63[/!!!!]

[q topic = “krebs cycle”]Overall, Krebs produces _____ NADH, one FADH2, and one ATP

[textentry]

[a]Overall, Krebs produces three NADH, one FADH2, and one ATP

[!!!]Card 66[/!!!!]

[q topic = “krebs cycle”]Overall, Krebs produces three _____ (an electron carrier), one FADH2 (an electron carrier), and one ATP (an immediate energy source)

[textentry]

[a]Overall, Krebs produces three NADH (an electron carrier), one FADH2 (an electron carrier), and one ATP (an immediate energy source)

[!!!]Card 69[/!!!!]

[q topic = “krebs cycle”]The _____ carbon molecule found at the start and end of Krebs is oxaloacetate.

[textentry]

[a]The four carbon molecule found at the start and end of Krebs is oxaloacetate.

[!!!]Card 72[/!!!!]

[q topic = “krebs cycle”]During Krebs two molecules of _____ are released as exhaust.

[textentry]

[a]During Krebs two molecules of carbon dioxide are released as exhaust.

[x]

[restart]

[/qdeck]

Links

 

 

 

 

 

 

 

 

Sours: https://learn-biology.com/krebs-cycle-interactive-lyrics-diagrams-and-flashcards/
What is the point of the Krebs cycle?

2.28: Krebs Cycle

Cellular Respiration Stage II: The Krebs Cycle

Recall that glycolysis, stage I of cellular respiration, produces two molecules of pyruvate. These molecules enter the matrix of a mitochondrion, where they start the Krebs cycle. The reactions that occur next are shown in Figurebelow. You can watch an animated version at this link: http://www.youtube.com/watch?v=p-k0biO1DT8.

Steps of the Krebs Cycle

The Krebs cycle starts with pyruvic acid from glycolysis. Each small circle in the diagram represents one carbon atom. For example, citric acid is a six carbon molecule, and OAA (oxaloacetate) is a four carbon molecule. Follow what happens to the carbon atoms as the cycle proceeds. In one turn through the cycle, how many molecules are produced of ATP? How many molecules of NADH and FADH2 are produced?

Before the Krebs cycle begins, pyruvic acid, which has three carbon atoms, is split apart and combined with an enzyme known as CoA, which stands for coenzyme A. The product of this reaction is a two-carbon molecule called acetyl-CoA. The third carbon from pyruvic acid combines with oxygen to form carbon dioxide, which is released as a waste product. High-energy electrons are also released and captured in NADH.

Steps of the Krebs Cycle

The Krebs cycle itself actually begins when acetyl-CoA combines with a four-carbon molecule called OAA (oxaloacetate) (see Figureabove). This produces citric acid, which has six carbonatoms. This is why the Krebs cycle is also called the citric acid cycle.

After citric acid forms, it goes through a series of reactions that release energy. The energy is captured in molecules of NADH, ATP, and FADH2, another energy-carrying compound. Carbon dioxide is also released as a waste product of these reactions.

The final step of the Krebs cycle regenerates OAA, the molecule that began the Krebs cycle. This molecule is needed for the next turn through the cycle. Two turns are needed because glycolysis produces two pyruvic acid molecules when it splits glucose. Watch the OSU band present the Krebs cycle: http://www.youtube.com/watch?v=FgXnH087JIk.

Results of the Krebs Cycle

After the second turn through the Krebs cycle, the original glucose molecule has been broken down completely. All six of its carbon atoms have combined with oxygen to form carbon dioxide. The energy from its chemical bonds has been stored in a total of 16 energy-carrier molecules. These molecules are:

  • 4 ATP (including 2 from glycolysis)
  • 10 NADH (including 2 from glycolysis)
  • 2 FADH2

The Krebs cycle is reviewed at http://www.youtube.com/watch?v=juM2ROSLWfw.

Summary

  • The Krebs cycle is the second stage of cellular respiration.
  • During the Krebs cycle, energy stored in pyruvate is transferred to NADH and FADH2, and some ATP is produced.
  • See the Krebs Cycle at http://johnkyrk.com/krebs.html for a detailed summary.

Explore More

Use this resource to answer the questions that follow.

  • The Citric Acid Cycle at virtuallabs.stanford.edu/other/biochem/TCA.swf.
  1. Where does the Krebs cycle occur in the cell?
  2. What is the first product of this cycle?
  3. How many reactions does it take to complete the cycle?
  4. How many NADHs and FADH2s are produced during the Krebs cycle?

Review

  1. What is the Krebs cycle?
  2. What are the products of the Krebs cycle?
  3. Explain why two turns of the Krebs cycle are needed for each molecule of glucose.
Sours: https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_Introductory_Biology_(CK-12)/02%3A_Cell_Biology/2.28%3A_Krebs_Cycle

Cycle diagram krebs

.

Overview of Citric Acid Cycle

.

Now discussing:

.



2120 2121 2122 2123 2124