IB Biology: Cell Respiration

Define cell respiration.

The controlled release of energy from organic compounds in cells to form ATP.

What is the equation for cellular respiration?

C6H12O6 + 6O2 ----->6CO2 + 6H2O

What is anaerobic cellular respiration?

It enables some cells to produce ATP without oxygen.

What is aerobic cellular respiration?

It is when pyruvate is broken down into carbon dioxide and water, with a large yield of ATP.

Does aerobic or anaerobic cellular respiration produce more ATP?

Aerobic respiration.

About how much ATP does aerobic cellular respiration make?

About 34-38 ATP.

About how much ATP does anaerobic cellular respiration make?

About 2 ATP.

Explain the process of lactic acid fermentation.

It's when NADH is oxidized to NAD, and pyruvate is reduced to lactate.

What organism uses lactic acid fermentation, and when?

Human muscle cells.

Explain the process of alcoholic fermentation.

It's when pyruvate is converted to ethanol in two steps:

-Pyruvate loses carbon dioxide and is converted to the 2 carbon compound, acetaldehyde.

-NAH is oxidized to NAD and acetaldehyde is reduced to ethanol.

What organism uses alcoholic fermentation, and when?

Bacteria and Yeast carry out alcoholic fermentation under anaerobic conditions.

Define phosphorylation.

Glucose recieves phosphate groups from ATP molecules. (ATP becomes ADP)

What is the effect of phosphorylating a molecule?

It destabilizes the molecule in preparation for another reaction.

What is glycolysis?

It is the breakdown of sugar by enzymes, releasing energy and pyruvic acid.

In oxidation reactions, electrons are __________.

lost

In oxidation reactions, oxygen is __________.

gained

In oxidation reactions, hydrogen is __________.

lost

In reduction reactions, electrons are __________.

gained

In reduction reactions, oxygen is __________.

lost

In reduction reactions, hydrogen is __________.

gained

Outline the process of glycolysis, including phosphorylation, lysis, oxidation, and ATP formation.

PHOSPHORYLATION- Glucose recieves phosphate groups from ATP molecules. (ATP-ADP)

LYSIS- The molecule splits into 2 molecules of glyceraldehyde-3-phosphate (G3P)

OXIDATION- 2 G3P undergo a dehydrogenation (oxidation) with NADH, and as the hydrogen and electron acceptor (NAD is reduced), orming 2 NADH.

ATP FORMATION- Another inorganic phosphate is added to each G3P. Removal of 4 ATP (substrate level phosphorylation) and 2 molecules of pyruvate.

Where does the link reaction occur?

In the mitochondrial matrix.

Explain the link reaction.

It's the decarboxylation of pyruvate. (x2) The remaining acetyl group is added to coenzyme A, forming acetyl CoA, and NADH is made.

KNOW HOW TO DRAW AND ANNOTATE THE KREBS CYCLE

KNOW HOW TO DRAW AND ANNOTATE THE KREBS CYCLE

Where is the electron transport chain?

In the inner mitochondrial membrane.

Explain the electron transport chain.

It's the transfer of electrons from FADH2 and NADH to oxygen. The electrons are transferred to a succession of electron carriers.

Define chemiosmosis.

The movement of ions across a selectively permeable membrane, down their electrochemical gradient.

Why is chemiosmosis referred to as oxidative phosphorylation?

It causes the phosphorylation of ADP to ATP.

KNOW HOW TO ANNOTATE THE DIAGRAM SHOWING THE ETC AND CHEMIOSMOSIS!

KNOW HOW TO ANNOTATE THE DIAGRAM SHOWING THE ETC AND CHEMIOSMOSIS!

KNOW HOW TO LABEL THE PARTS OF THE MITOCHONDRION!

KNOW HOW TO LABEL THE PARTS OF THE MITOCHONDRION!

Where does glycolysis occur?

In the cytoplasm.

Where does the Krebs cycle occur?

The mitochondrial matrix.

Where does Oxidative Phosphorylation occur?

The inner mitochondrial membrane.

What is the purpose of glycolysis?

It converts glucose to pyruvates.

What is the purpose of Link Reaction?

It converts pyruvate (3C) to acetyl CoA (2C).

What is the purpose of the Krebs cycle?

To make NADH and FADH2.

What is the purpose of the Electron Transport Chain?

It pumps H+ ions into the intermembrane space.

What is the purpose of oxidative phosphorylation?

It makes ATP by moving H+ ions through ATP synthase.

How many ATP does glycolysis yield?

2

How many ATP does Link Reaction yield?

0

How many ATP does the Krebs Cycle yield?

2

How many ATP does the Electron Transport Chain yield?

0

How many ATP does Oxidative Phosphorylation yield?

34-36

What is the function of the outer membrane of a mitochondrion?

It acts as a selectively permeable membrane. It doesn't let the hydrogen ions through.

What is the function of the inner membranne/cristae folds of the mitochondrion?

It contains the electron transport chain. The highly folded design allows for more membrane area and more copies of the ETC enzymes.

What is the function of the intermembrane space of the mitochondrion?

It is a small space where H+ gradient builds up for chemiosmosis.

What is the function of the matrix of the mitochondrion?

It contains enzymes of the link reaction and the Krebs cycle.

List the 4 stages of glycolysis in order.

Phosphorylation

Lysis

Oxidation

ATP Formation

How many carbon atoms does each pyruvate feed into the Krebs cycle?

2

Where are NAD and FAD oxidized?

In the Krebs Cycle.

In the ETC water if formed. Where does this hydrogen come from?

It is pumped from the NADH into the intermembrane space.

In the ETC, what is the last electron acceptor?

Oxygen

What happens during chemiosmosis?

Hydrogen ions have built up in the intermembrane space from the ETC.

When glucose is fermented to lactate, what's the net production of ATP?

2 net ATP

Considering only glycolysis and the link reaction, how many NADH molecules will be produced from one glucose molecule?

Glycolysis- 2

Link Reaction- 2 NADH/4

Which step(s) of respiration produces the most ATP?

ETC/Oxidative Phosphorylation

Which step(s) of respiration occurs in the cytosol?

Glycolysis

Which step(s) of respiration produces a net gain of ATP?

Krebs Cycle/ETC/Oxidative Phosphorylation/Glycolysis

Which step(s) of respiration releases CO2?

Krebs Cycle/Link Reaction

What are the 5 types of reactions involved in cellular respiration?

Dehydrogenation

Decarboxylation

Preparation reactions

Oxidations

Reductions

What is dehydrogenation?

When hydrogen atoms are removed from the substrate, and transferred to NAD or FAD.

What is decarboxylation?

When a part of a carboxyl group is removed from the substrate as CO2.

What are preparation reactions?

When molecules undergo rearrangements so they can undergo further reactions.

What are oxidations?

The loss of electrons from a molecule. It may be accompanied by the gain of oxygen and/or the loss of hydrogen.

What are reductions?

The gain of electrons from a molecule. It may be accompanied by a loss of oxygen and/or a gain of hydrogen.

What is OIL RIG?

Oxidation Is Lost

Reduction Is Gained

What happens during phosphorylation?

Glucose recieves phosphate groups from ATP molecules. (ADP becomes ATP). This destabilizes the molecule in preparation for another reaction.

What happens during lysis?

The molecule splits into 2 molecules of glyceraldehyde-3-phosphate (G3P)

What happens during oxidation?

2 G3P undergo a dehydrogenation (oxidation) with NAD+ as the hydrogen and electron acceptor (NAD is reduced), forming 2 NADH.

What happens during ATP Formation?

Another inorganic phosphate is added to each G3P.

What are the 3 products of glycolysis?

2 NADH

2 net ATP

2 Pyruvates

What are the 5 steps of the Krebs Cycle?

1) Attachment of a 2-carbon fragment from Acetyl CoA to a 4-carbon oxaloacetate molecule

2) Dehydrogenation and decarboxylation

3) Alphaketogluterate undergoes decarboxylation and dehydrogenation.

4) Substrate level phosphorylation

5) 2 hydrogens are transferred to FAD forming FADH2; Hydrogen is transferred to NAD+ to for NADH.

What are the 4 products of the Krebs Cycle per molecule of glucose?

4 CO2

6NADH

2FADH2

2 ATP

What are the 2 products of the ETC and chemiosmosis per molecule of glucose?

6H2O

Up to 36 ATP if functioning at full efficiency

What is fermentation?

The anaerobic catabolism of organic nutrients.