Cellular Respiration

• Notes: 10/8/12

8.1.3 Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs

• Matrix: – Watery substance that contains ribosomes and

many enzymes. – These enzymes are vital for the link reaction and the

Krebs cycle. • Inner membrane:

– The electron transport chain and ATP synthase are found in this membrane.

– These are vital for oxidative phosphorylation.

8.1.3 Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs

• Space between inner and outer membranes: – Small volume into which protons are pumped into. – Small volume high concentration gradient can be

reached very quickly. – This is vital for chemiosmosis.

• Outer membrane: – Separates the contents of the mitochondrion from

the rest of the cell. – Creates a good environment for cell respiration.

8.1.3 Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs

• Cristae: – Tubular projections of the inner membrane – Increase the surface area for oxidative

phosphorylation. • Mitochondrial DNA

– Encode mitochondrial enzymes.• Ribosomes

– Translation of mitochondrial proteins.

8.1.6 Explain the relationship between the structure of the mitochondrion and its function

A. Matrixsite for Krebs' cycle link reaction ATP synthesis

B. Inner Membranesite of oxidative phosphorylation e– transport chain increase surface areaATP synthesis;

C. Inner Membrane SpaceH+ / proton build up;

C

A

B

C

8.1.3 Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs

A: Matrix

B: Inner membrane

C: Intermembrane spaceC

A

B

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

• Occurs in ________________• Is not ___________ dependent• Glucose is Phosphorylated (-__ ATP)• Lysis: phosphorylated 6-carbon sugar is

broken down into __ ____________– Glucose is ___________

• ___________ phosphorylation produces 2 ATP• NET synthesis of ___ ATP and ___ NADH

Glycolysis OverviewMajor phases

– Energy investment– Lysis– Energy harvesting

Summary of glycolysis:– Each molecule of glucose is broken down to two

molecules of pyruvate– A net of two ATP molecules and two NADH (high-

energy electron carriers) are formed

Energy Investment Phase– Glucose is phosphorylated twice– Requires the INVESTMENT of two ATP molecules

Lysis– The phosphorylated glucose is broken into two triose-

phosphate molecules (called G3P)

Energy harvesting phase– In a series of reactions, each molecule is converted

into a pyruvate, generating two ATPs per conversion, for a total of four ATPs

Energy harvesting phase

– each G3P has an inorganic phosphate group added (Pi).

– Simultaneously, NAD+ gains H and 2e- to become NADH

Pi

Pi Pi

NAD+

RemovesH+ and 2 e-

to become

NADH

G3P

Pi

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

Step 1 - Glucose is phosphorylated. Step 2 - Lysis of hexose (6C) biphosphate into two triose (3C) phosphatesStep 3 - Each triose (3C) phosphate molecule is oxidized. Step 4 – Two pyruvate molecules (3C) are formed by removing two phosphate groups from each molecule. Type of phosphorylation?

Glycolysis

• Glucose + 2 ATP + 2 NAD+ 2 Pyruvate (C3) + 2 NADH + 2 ADP + 4 ATP

• (6C) + 2 ATP + 2 NAD+ (6C)-P-P 2 Pyruvate (C3) + 2 NADH + 4 ATP

• NET: 2 Pyruvate + 2 NADH + 2 ATP

Fermentation enables some cells to produce ATP without the use of oxygen• Cellular respiration

– Relies on oxygen to produce ATP• In the absence of oxygen

– Cells can still produce ATP through fermentation

From glycolysisFermentation(anaerobic)

Does not produce more ATP, but is necessary to regenerate NAD+, which must be available for glycolysis to continue Human muscles cells

Bacteria

Yeast

• Fermentation consists of– Glycolysis plus reactions that regenerate NAD+,

which can be reused by glycolysis• In alcohol fermentation

– Pyruvate is converted to ethanol in two steps, one of which releases CO2

• During lactic acid fermentation– Pyruvate is reduced directly to NADH to form

lactate as a waste product

8.1.4 Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron transport chain and the role of oxygen

Glycolysis

Link Reaction

• Pyruvate (C3) + NAD+ + CoA Acetyl-CoA (2C) + NADH + CO2

• Per Glucose• NET: 2 NADH + 2 CO2 + 2 Acetyl-CoA

Krebs Cycle

• Acetyl-CoA (2C) + Oxaloacetate (4C) Citrate (6C) + CoA

• Citrate (6C) + 3 NAD+ + FAD+ + ADP Oxaloacetate (4C) + 2 CO2 + 3 NADH + FADH2 + 1 ATP

• Per Glucose• NET: 4 CO2 + 6 NADH + 2 FADH2 + 2 ATP

FAD+ accepts electrons from other molecules to form FADH2 which can then donate electrons to the ETC

1

2

3

4

Cellular Respiration (Pearson)

Electron Transport Chain (Pearson)

Summary of Cellular Respiration (Pearson)

Keeping Score

ATP NADH FADH2 CO2• Gly 2 2 0 0• Link 0 2 0 2• Krebs 2 6 2 4• Totals 4 10 2 6

Carbohydrates, proteins, and lipids can be used as energy sources; metabolites involved in energy

production can be used to synthesize carbohydrates, proteins, lipids, nucleic acids, and cellular structures.