BSF L3 pt. 1

The sum of all chemical reactions in a cell

Metabolism

Which pathway delivers chemical energy in the form of an ADH, NADPH, FADH2, GTP, and ATP?

Catabolic pathway

Which pathway converts, small, precursor molecules into cellular macromolecules?

Anabolic pathways

In a normal state, exercise/stress, extreme exercise/stress conditions what do red blood cells use as an energy source?

Glucose

Why do blood cells provide and only glucose?

They have no mitochondria

Why does the heart use FFA first in normal conditions?

Has to pump blood all the time; It has high energy demand; FFA has high energy (ATP) value

Why does the muscles FFA In exercise/stress and extreme exercise?

More energy is needed in those conditions and glucose and muscle is used up in 24 hours

Extreme exercise conditions what does the brain use as its energy source?

Ketones

for each molecule of glucose that passes through the preparatory phase of glycolysis, what is formed?

Two molecules of glyceraldehyde 3-phosphate

And step one of glycolysis what is the enzyme involved?

Hextall kindness

And one about glycolysis what is the reaction?

Glucose + ATP = G6P & ATP

Step two of lysis what is the enzyme involved?

Phosphohexose isomerase

Step two of glycolysis what is the reaction?

G6P = F6P

Step three of glycolysis what is the enzyme involved?

Phosphofructokinase-1

Instead of glycolysis, what is the reaction?

F6P = FBP

Step four of the lysis what is the enzyme involved?

Aldolase

Step four of glycolysis what is the reaction?

FBP = DHAP & G3P

In step five of glycolysis, what is the end and used?

Triose phosphate isomerase

What is the start of the payoff phase in glycolysis?

Step five

Step five of glycolysis what is the reaction?

DHAP = G3P

During the payoff phase of glycolysis ___ glyceraldehyde 3-phosphate molecules formed in the preparatory phase and the payoff phase producing what?

2; pyruvate

Each glucose yields a net gain of what?

2 ATP

In step six of glycolysis, what is the enzyme used?

Glyceraldehyde 3-phosphate dehydrogenase

Step six of glycolysis what is the reaction?

G3P = BPG

In step of six of glycolysis oxidation and phosphorylation happens producing what?

2NADH

In step seven of glycolysis what is the enzyme used?

Phosphoglycerate kinase

Step seven of glycolysis what is the reaction?

BPG = 3PG

What is the first ATP farming reaction In glycolysis?

Step 7

In step eight of glycolysis, what is the enzyme used?

Phosphoglycerate mutate

In step eight of glycolysis, what is the reaction?

3 PG = 2 PG

In step nine of glycolysis, what is the enzyme used?

Ebola’s

Step nine of glycolysis what is the reaction?

2PG = PEP

In step 10 of lysis what is the enzyme used?

Pyruvate kinase

In step 10 of glycolysis, what is the reaction?

PEP = pyruvate

What is the second ATP forming reaction in glycolysis?

Step 10

____ ATP are produced, but ___ are put back into the cycle in preparatory phase.

4; 2

how is NADH formed in glycolysis?

GPDH oxidizes the aldehyde group of G3P to a carboxyl group and transfers the electrons to NAD to form NADH

Glucose + 2 NAD+ + 2 Pi +2 ADP → 2 Pyruvate + 2 NADH + 2 H+ + 2 ATP + 2H2O

Glycolysis reaction

How is liquor made?

Pyruvate to ethanol fermentation

Why do muscles get sore after intense exercise?

Anaerobic pyruvate to lactate reduction

Under anaerobic conditions, what is pyruvate reduced to?

Lactate

When does anaerobic metabolism take place?

When there is a limited supply of oxygen, a few or no mitochondria, or greatly increased demands for ATP

What does lactic acid generated by skin act as?

Antibacterial agent

The quarry cycle is the cycling of lactate and glucose between what?

Peripheral tissues and liver

What are the sources of Acetyl-CoA

Acid, ketone body, sugar, pyruvate, amino acid, and ethanol

What does Acetyl-CoA undergo to become TCA?

Citrate synthase

Where does the pentose phosphate pathway occur?

In the cytosine

What regulates G6P partitioning?

NADPH

If NADPH is forming faster than it is being used, what happens?

It rises and inhibits the first enzyme

What does the pentose phosphate pathway achieve?

It yields reducing potential in the form of NADPH to be used in anabolic reactions requiring electrons

What does the PPP yield?

Ribose-5-phosphate

Ribose-5-phosphate is a nucleotide biosynthesis that leads to…

• DNA

• RNA

• Various cofactors

What is glutathione?

A tripeptide composed of glutamate, cystine, and Glycerine

Why is glutathione important?

Reduced glutathione (GSH) maintains the normal reduced state of the cell

How does reduced glutathione (GSH) protect the cell?

By destroying hydrogen peroxide and hydroxyl free radicals

What can be fatal in cases of high oxidative stress?

G6P dehydrogenase deficiency

What is required for the regeneration of GSH from its oxidized form (GSSG)?

NADPH

What does reduced glutathione Detoxify?

Reactive oxygen species (ROS)

Individuals with reduced GSH are subject to ___

Hemolysis

What is black urine an indicate of?

Reduced GSH; hemolysis

What do individuals with a G6PD deficiency not produce enough to cope with ROS

GSH

The cytosolic NADH generated via glycolysis transfers its equivalents to mitochondrial NAD+ via _____________

shuttle systems across the inner mitochondrial membrane

How does the pyruvate generated during glycolysis enter the mitochondria and be oxidized completely by CO2?

By pyruvate dehydrogenase and the TCA cycle

Why is glycolysis regulated?

To ensure that ATP homeostasis is maintained

Under anaerobic conditions, how is glycolysis continued?

Pyruvate is reduced to lactate by NADH, thereby regenerating the NAD required for glycolysis

On oxygen supply is not limited, what is oxidized to Acetyl-CoA?

Pyruvate

Acetyl-CoA + 3NAD+ + FAD + GDP + Pi + 2 H2O → 2CO2 + 3NADH + FADH2 + GTP + CoA + 3H+

The TCA cycle

What is generated in the TCA cycle?

3 NADH, 1 GTP/ATP, 1 FADH2, 2 CO2

Where does the TCA cycle occur?

Mitochondrial matrix and the cytosol for prokaryotes

What is step one in the TCA cycle?

Acetyl-CoA = citrate

What is step two in the TCA cycle?

Citrate = isocitrate

What is the net oxidation of the TCA cycle?

2 carbons = CO2

Citrate undergoes rearrangements that produce 2 CO2 and 2 NADH.

Where do the electrons transfer from the energy captured in the TCA cycle?

NADH and FADH2

What is step three in the TCA cycle?

Isocitrate = alpha-Ketoglutarate

What is step four in the TCA cycle?

alpha-Ketoglutarate = Succinyl-CoA

What is step five in the TCA cycle?

Succinyl- CoA = Succinate

What is step six in the TCA cycle?

Succinate = Fumarate

What is step seven in the TCA cycle?

Fumarate= Malate

What is step eight in the TCA cycle?

Malate = Oxaloacetate

Describe the TCA cycle

1. Acetyl-CoA joins oxaloacetate (four-carbon) to form citrate (six-carbon).

2. Citrate undergoes rearrangements that produce 2 CO2 and 2 NADH.

3. After the loss of two CO2, the resulting four-carbon molecule produces 1 GTP through substrate-level phosphorylation.

4. The molecule will now transfer electrons to 1 FAD, which is reduced into 1 FADH2.

5. Lastly, the molecule is converted back into oxaloacetate and also gives electrons to produce 1 NADH.

6. Two acetyl-CoA molecules produce 4 CO2 + 6 NADH + 2 FADH2 + 2 GTP

What steps in the TCA cycle is NADH/H+ produced?

3, 4, and 8

What step in the TCA cycle is GTP/ATP produced?

5

What step in the TCA cycle is CO2 produced?

3 and 4

What step in the TCA cycle is FADH2 produced?

6

In the liver, TCA cycle intermediates are continuously withdrawn into the pathways of…

fatty acid synthesis, amino acid synthesis, gluconeogenesis, and heme synthesis

In the brain, α-ketoglutarate is converted to _______ and _______ both of which are neurotransmitters.

glutamate and γ-aminobutyric acid (GABA)

Refers to the removal of intermediate from the metabolic cycle

Cataplerosis

Refers to the pathways which replenish the intermediate of the TCA cycle

Anaplerosis

What is a major annaplerotic enzyme?

Pyruvate carvoxylase

What also forms TCA cycle intermediate?

Amino acid degradation

Refers to cellular energy transformations

Bioenergetics

How is the electrochemical proton gradient created?

By active transport of protons across the membrane from complex one and complex five, chemically removing protons from the matrix and releasing protons into the intermembrane space

What does the electrochemical potential gradient create?

Proton motif force (PMF)

What is proton motif force (PMF)?

The energy that pushes the protons to re-enter the matrix to equilibrate on both sides of the membrane

Why can’t electron flow occur faster than protons are used for ATP synthesis or return to the matrix by uncoupling?

Because electron flow requires proton pumping

What happens as ADP levels increase?

• proton influx increases (through ATPase)

• Electrochemical gradient decreases

• Proton dumping electron transfer are increased to maintain electrochemical gradient

• Oxygen consumption increase

Why do we need ATP?

Mechanical work and transport work

how do we convert the chemical energy of ATP to mechanical work?

Muscle contraction

What requires ATP to transport molecules or ions against the concentration gradient?

Active transport

What has high energy phosphate bonds?

ATP