[BIOCHEM-LEC-FINALS] CITRIC ACID CYCLE (1/2)

Catabolic

Is CAC catabolic or anabolic?

Acetyl-CoA

CAC is a catabolic reaction involving particularly?

Citric Acid Cycle

This is the major catabolism involving Acetyl-CoA in the formation of ATP (energy).

Acetyl-CoA

What is the intermediate product of Proteins, Carbohydrates, and Lipids?

Citric Acid Cycle

This is a cyclic metabolic pathway that begins with the addition of Acetyl-CoA to a 4-carbon substrate.

ATP synthesis

The citric acid cycle produces high-energy compounds for ____ during ETC.

Cyclic

It means the continuous process/reaction/pathway.

Krebs Cycle

Citric Acid Cycle is also known as?

Hans Krebs

Who discovered the Citric Acid Cycle?

Tricarboxylic Acid Cycle

Aside from Krebs Cycle, CAC is also known as?

Electron Transport Chain

The citric acid cycle produces high-energy compounds for ATP synthesis during?

8

How many steps are there in CAC?

Acetyl-CoA

The 2-Carbon substrates that is being reacted to the 4-Carbon substrates in step one is the?

4-carbons

This carbon substrate is also the product in the last step.

6-carbons

Step 1:  Acetyl-CoA will react to a 4-Carbon substrate forming how many intermediate product?

Isomerization

Step 2: In the 6-carbon product in the first step, there is ____.

Isomerization

This is the process of converting one molecule into another molecule that has the same chemical formula but a different structure.

6-carbons

In isomerization (step 2), how many carbons are there?

Carbon

Steps 3-4: There is a removal of?

5-carbons

In step 3, how many carbons are left?

4-carbons

In step 4, how many carbons are left?

Carbon Dioxide

Since there is a removal of carbon atoms, there is a formation of?

Carbon Dioxide

The removed carbon atoms is in the form of?

2

Overall, how many molecules of carbon dioxide were formed?

Oxidizing agent

Steps 3 and 4 requires?

Oxidized

The reactant in the step 3 and 4 will be?

NAD

What is the oxidizing agent (coenzyme) needed in steps 3 and 4?

Oxidizing Agent

This the one that is being reduced in the reaction.

Reduced

The fate of the NAD (oxidizing agent) is to be?

Addition of hydrogen

Reduction

Removal of hydrogen

Oxidation

NADH

Because the fate of NAD is to be reduced, there will be an addition of hydrogen producing a product called?

NADH

What is the reducing equivalents of NAD?

Guanosine triphosphate (GTP)

Step 5: What is the side product in step 5?

ATP

Guanosine triphosphate (GTP) is equivalent to?

Yes

Is GTP an immediate energy like ATP?

FADH₂

Step 6: What is the side product in this step that implies that this step is another reaction that needs oxidizing agent.

FAD

What is the oxidizing agent needed for step 6? (FADH₂)

FADH₂

What is the reduced form of FAD?

• NADH

• NADPH

• FADH₂

What are the examples of reducing equivalents?

NAD

Step 8: What is the oxidizing agent in this step?

4 (3 NADH, 1 FADH₂)

In one cycle of CAC, how many reducing equivalents were formed?

Guanosine triphosphate (GTP)

What is the immediate energy formed in one CAC pathway?

1. Acetyl-CoA

2. Oxaloacetate

3. Citrate

Step 1: Reacts with the (1) 2-C with (2) 4-C to from (3) 6-C, and it is catalyzed by the enzyme, citrate synthase.

Acetyl-CoA

In step 1, what is the 2-carbons substrate?

Oxaloacetate

In step 1, what is the 4-carbons substrate?

Citrate

In step 1, what is the 6-carbons substrate?

Citrate synthase

In step 1, what is the enzyme that catalyzes the substrates?

8

The oxaloacetate (4-carbons) must be formed after step __, as it will be utilized again in step 1.

Alcohol

What is the functional group present in citrate?

Tertiary alcohol

What is the type of alcohol of citrate?

Isocitrate

Step 2: What is the isomer of citrate?

Secondary alcohol

What is the type of alcohol of isocitrate?

Aconitase

In step 2, what is the enzyme that catalyzes the substrates?

Oxidized

Since isocitrate was reacted with the oxidizing agent (NAD), what is the fate of isocitrate?

Decarboxylation

Step 3: Isocitrate loses CO₂ in the process called?

Isocitrate dehydrogenase

In step 3, what is the enzyme that catalyzes the reaction?

Oxidation

The enzyme, isocitrate will undergo?

Reduced

The oxidizing agent, NAD, will be?

Oxidized

VILEORA

The reducing agent will be?

Reduced

VDGEROA

The oxidizing agent will be?

a-ketoglutarate and NADH

The secondary alcohol of isocitrate is oxidized by the oxidizing agent NAD⁺ to form the ketone ___ and ___.

a-ketoglutarate

[Step 3] What is the oxidized form of isocitrate?

NADH

[Step 3] What is the side product of isocitrate?

Succinyl CoA and NADH

Step 4: Releases another CO₂ with the oxidation of a-ketoglutarate by NAD⁺ in the presence of coenzyme A to form ___ and ___.

a-ketoglutarate dehydrogenase

In step 4, what is the enzyme that catalyzes the reaction?

NAD

What is the oxidizing agent for steps 3 and 4?

2 NADH

In step 4, how many and what is the reducing equivalents were formed?

2

At the end of step 4, how many CO₂ were formed?

Succinate

Step 5: The thioester bond of succinyl CoA is hydrolyzed to form ___, releasing energy that converts GDP to GTP.

Succinate thiokinase

In step 5, what is the enzyme that catalyzes the succinate?

Phosphate group

What is the group that being transferred by the kinase

Guanosine triphosphate (GTP)

What is the intermediate product after step 5?

Oxidation

Step 6: Succinate will undergo what reaction?

Fumarate

Step 6: Succinate is converted (oxidized) to ___ with FAD and succinate dehydrogenase; FADH₂ is formed.

Fumarate

What is the oxidized form of succinate?

FAD

What is the oxidizing agent in step 6?

Succinate dehydrogenase

In step 6, what is the enzyme that catalyzes the reaction? (Succinate to Fumarate)

3 (1 FADH₂, 2 NADH)

After step 6, how many and what are the reducing equivalents were formed?

Malate

Step 7: Fumarate is being converted into ___ which has a secondary alcohol.

Fumarase

In step 6, fumarate is being converted into malate via the enzyme?

NAD

Step 8: Malate will be oxidized by what oxidizing agent?

Oxaloacetate and NADH

In step 8, the secondary alcohol of malate is oxidized by NAD⁺ to form the ketone portion of ___ and ___.

Malate dehydrogenase

In step 8, what is the enzyme that catalyzes the reaction.

Step 1

The product of step 8 is the starting material for?

Mitochondria

What part of the cell where the reactions to form/synthesize energy takes place?

Matrix

To be specific, this is where the Krebs Cycle take place.

Inner mitochondrial membrane

The ETC and Oxidative Phosphorylation will happen in what part of the mitochondria?