CELLULAR RESPIRATION

• CONVERTING FOOD TO ATP• IN EUKARYOTES OCCURS IN

CYTOPLASM & MITOCHONDRIA• IN PROKARYOTES OCCURS IN OUTER

MEMBRANES.

• Relate to evolution.

Usain Bolt, Jamaica• You use energy in the form of ATP to

allow your muscles to move.• Sprinters have a fast pace & use energy

quickly Long distance runners maintain a steady pace and a more stable supply of ATP? Why?

SPRINTERS

• Fast pace for a short distance use anaerobic respiration. Around 400 meters at this pace, lactic acid starts to build up, muscles get sore and pace slows.

• Endurance athletes use aerobic respiration.

Muscle fatigue lab

• In your non-writing hand: Squeeze a tennis ball as many times as you can in 10 seconds.

• A legal squeeze causes a dent from the heel of your hand in the ball

• Your partner should record the number of squeezes every ten seconds

• Keep going for 100 seconds• Average the class data for EACH TRIAL.

Muscle fatigue data table

TRIAL NUMBER OF SQUEEZES IN 10 SECONDS

1

2

3

4

5

6

7

8

9

10

• What are the independent & dependent variables in the muscle fatigue experiment?

• Graph class average (bar graph)• During what time frame(s) does

anaerobic respiration occur?• During what time frame(s) does

aerobic respiration occur?

Cellular Respiration• Organic

Compounds, in the presence of Oxygen, being converted to Carbon Dioxide, Water and ATP.

• Autotrophs – photosynthesis

• Autotrophs & heterotrophs – cellular respiration

Cellular Respiration :An Overview

• Cells break down glucose to produce Cells break down glucose to produce ATP.ATP.

• Some processes are Some processes are aerobic aerobic (uses (uses oxygen).oxygen).

• This process yields up to 38 molecules This process yields up to 38 molecules of ATP from every molecule of glucose.of ATP from every molecule of glucose.

Cellular Respiration• Cellular respiration occurs in three steps:steps:

Glycolysis

The Krebs cycle

Electron transport

• •

THREE STEPS - OVERVIEW

Cellular Respiration: Glycolysis

• Glycolysis takes place in the cytoplasm of cells.

• The glucose molecule is split into two molecules of pyruvic acid, releasing two molecules of ATP.

All organisms do some form of

glycolysis. Relate to evolution.

Glycolysisanaerobic

6 carbon sugar yields two 3-carbon pyruvate molecules2 NADH

Net gain of 2 ATP

STEPS 1 & 3 endo or

exothermic reactions?

Spontaneous or nonspontaneous

? ΔG positive or negative?

STEPS 5, 6 & 9: endo or

exothermic reactions?

Spontaneous or nonspontaneous

? ΔG positive or negative?

COUPLED REACTIONS: One reaction (break

down of ATP to ADP + Pi) is necessary

for another reaction(glucose to glucose

6-phosphate)Relate to entropy.

• The value of ΔG for ATP hydrolysis varies, primarily depending on Mg2+ concentration, and under normal physiologic conditions is about -50 kJ mol−1.

• In humans, approximately 60 percent of the energy released from the hydrolysis of one mole of ATP produces metabolic heat rather than fuel the actual reactions taking place. What is the ΔG for the synthesis of 1 mole of glucose 6-phosphate based on the above? 17

In the matrix areFree ribosomesMolecules of ATP SynthaseDNAAnd more

Similar in size and function to bacteria. Reproduce by binary fission, have DNA, ribosomes. . . Most likely existed at one time as a bacterium.May be a Symbiotic relationship.

Between Glycolysis & Krebs

3-carbon pyruvate reacts to form 2-carbon acetyl CoA and Carbon dioxide (aerobic)

• Where does glycolysis take place?

21

• What is the initial reactant in glycolysis?

22

• Is glycolysis aerobic or anaerobic? Explain.

23

• How many molecules of ATP are consumed during glycolysis? Is Gibbs free energy for this reaction negative or positive? Explain

24

• How many molecules of ATP are produced during glycolysis? What is the net gain/loss of ATP during glycolysis?

25

• If the hydrolysis of ATP has a about -50 kJ mol−1 value for Gibbs Free Energy and the synthesis of glucose 6-phosphate requires 30kJ/mole, explain, in detail, the most likely differences in Free Energy.

26

• Give an example of a coupled reaction in glycolysis.

27

• What other energy-storing molecule is produced during glycolysis?

28

• What is/are the final product(s) of glycolysis (name and number)

29

• Scientists are confident that glycolysis is an ancient process. Explain how they know this in evolutionary terms.

30

What evidence (at least 2) is there to support the theory of symbiosis in regards to the mitochondria?

31

• How does the cristae affect the surface area to volume ratio of the mitochondria? Why is this important?

32

• pyruvate will cross the mitochondrial membrane via a transport protein down the concentration gradient. What kind of transport is this, explain.

33

• The decomposition of pyruvate into carbon dioxide and acetyl gives off enough energy to be coupled with what other reaction? In which of these reactions is Gibbs Free Energy positive?

34

• The carbon dioxide produced by the decomposition of pyruvate exits the mitochondria by what process? Explain how you know.

35

• The decomposition of pyruvate into carbon dioxide and acetyl is an aerobic process, meaning what must be present for the reaction to proceed?

36

Cellular Respiration: Krebs Cycle• The Krebs cycle occurs in the cell’s

mitochondria.

• In the Krebs cycle, pyruvic acid is converted to acetic acid and bound to a molecule of coenzyme A. The result—acetyl-CoA—and CO2.

• Two molecules of ATP are harvested. Additional energy is stored in the molecules NADH and FADH2.

The Kreb’s Cycle is sometimes called the Citric acid cycle.

Kreb’s CycleProducts:2 Carbon dioxide from acetyl 2 ATPEnergy comes from NADH and FADH2 which release high energy electrons to the ETC

Cellular Respiration: Cellular Respiration: Electron TransportElectron Transport

Cellular Respiration: Electron Cellular Respiration: Electron TransportTransport

Electrons carried by NADH and FADH2 are sent down electron transport chains.

In the process, the electrons lose energy, which is used to pump hydrogen ions across a membrane inside the mitochondria.

At the end of the chain, the electrons combine with O2 to make water.

The concentration gradient generated by pumping hydrogen ions is used to make ATP.

ENERGY

• STORED IN CARBON-HYDROGEN BONDS IN GLUCOSE.

• TRANSFERRED TO BOND BETWEEN 2ND & 3RD PHOSPHATE GROUPS IN ATP

THREE STEPS - OVERVIEW

Copy. Convert to cellular respiration chart.

• Include reactants, products, amount of ATP consumed, produced, intermediate reactions.

44

Let’s look at the processes

Cellular RespirationElectron transport chainADP becomes ATP at the ATP synthase protein complex

anaerobic

• Gycolysis still occurs, • BUT• Pyruvate will not decompose into

acetyl molecule• SO• FERMENTATION

FermentationInvolves glycolysis but not the other two stages of aerobic respiration. Many bacteria and yeasts carry out fermentation. People use these organisms to make yogurt, bread, wine, and biofuels. Muscle cells also use fermentation. when muscle cells cannot get oxygen fast enough to meet their energy needs through aerobic respiration. There are two types of fermentation: lactic acid fermentation and alcoholic fermentation.

47

48

49

50