U4-Lecture3IntroCellularRespiration.ppt

(1)

Warm-up (1/9/19)

1. What is the equation for photosynthesis?

2. What are the inputs and outputs of the light

reaction?

(2)

Welcome Back!

• _{Gum policy}

• _{Be respectful to each other, the teacher,}

and the classroom

(3)

Lecture 3

Introduction to Cellular

Respiration

(4)

LE 9-2

ECOSYSTEM

Light energy

Photosynthesis in chloroplasts

Cellular respiration in mitochondria

Organic molecules+ O2

CO₂ + H₂O

ATP

powers most cellular work

Heat energy

(5)

Cellular Respiration

• _{Where does it occur?}

• _Mitochondria

• _{Why is the structure of}

the mitochondria

(6)

• _{Nearly all the cells in our body}

break down sugars for ATP

production

• _{Most cells of most organisms}

harvest energy aerobically.

• _{Cellular respiration yields CO}

₂

_,

H

₂

O, and a large amount of ATP

(7)

• _{How are breathing and cellular respiration closely}

related?

Lungs

Figure 6.1

O₂ CO₂ _BREATHING

CO₂ Bloodstream O₂

(8)

Figure 6.2B

Burning glucose in an experiment

Energy released from glucose (as heat and light)

100%

Energy released from glucose banked in ATP

“Burning” glucose in cellular respiration

About 40%

Gasoline energy converted to

movement

Burning gasoline in an auto engine

(9)

• Involves the transfer of electrons

from organic fuels to oxygen

Glucose gives up energy as it is

oxidized

Energy

Figure 6.4

How do cells extract energy from

glucose?

Glucose

_{ Heat}

C

₆

H

₁₂

O

₆

6 O

₂

6 CO

₂

6 H

₂

O

ATP

Loss of hydrogen atoms

(becomes oxidized)

(10)

What shuttles electrons in redox

reaction?

• Hydrogen carriers such as a coenzyme, NAD

+

• (just like NADP+ in photosynthesis)

Figure 6.5

OXIDATION

Dehydrogenase

and NAD

+

(11)

1. Glycolysis

(in cytoplasm)

2. Krebs Cycle

(in mitochondria)

3. Electron transport chain

(in mitochondria)

STAGES OF CELLULAR RESPIRATION

(12)

You should now be able to

1. Compare the processes and locations of cellular

respiration and photosynthesis.

2. Explain how breathing and cellular respiration are

related.

3. Provide the overall chemical equation for cellular

respiration.

4. Compare the redox reactions in cellular respiration vs.

photosynthesis.

(13)

Cellular Respiration

Jigsaw

• _{You will be divided into 3 expert groups:}

1. Glycolysis

2. Krebs Cycle (Citric Acid Cycle)

3. Oxidative Phosphorylation (ETC)

• _{In your expert groups, research and create a}

powerpoint to teach the class about your stage.

(14)

Stages of Cellular

Respiration

(15)

LE 9-6_1

Mitochondrion Glycolysis

Pyruvate Glucose

Cytosol

ATP

(16)

LE 9-6_2

Mitochondrion Glycolysis

Pyruvate Glucose

Cytosol

ATP

Substrate-level phosphorylation

ATP

Substrate-level phosphorylation

(17)

LE 9-6_3 Mitochondrion Glycolysis Pyruvate Glucose Cytosol ATP Substrate-level phosphorylation ATP Substrate-level phosphorylation Citric acid cycle ATP Oxidative phosphorylation Oxidative phosphorylation: electron transport and chemiosmosis Electrons carried via NADH Electrons carried via NADH and

(18)

Stage 1: Glycolysis

• _{Glycolysis : breakdown of}

glucose into pyruvic acid

• _{Electrons transferred and stored in the form of:}

• _ATP

• _NADH

Figure 6.9A

Glucose

Pyruvic

(19)

Steps – A fuel molecule is energized, using ATP. 1 3 1 Glucose Energy Investement Step 2 3 4 Glucose-6-phosphate Fructose-6-phosphate Glyceraldehyde-3-phosphate (G3P)

Step A six-carbon intermediate splits into two three-carbon

intermediates.

4

Step A redox reaction generates NADH.

5

5 _{ENERGY PAYOFF}

PHASE

1,3-biphosphoglyceric acid (2 molecules)

6

Steps – ATP and pyruvic acid are produced.

6 9 3-Phosphoglyceric acid

(2 molecules) 7 2-Phosphoglyceric acid (2 molecules) 8 2-Phosphoenol pyruvate(2 molecules) 9 (2 molecules

per glucose molecule) Pyruvic acid

Fructose-1,6-diphosphate

There are two

phases:

(20)

Yield of Glycolysis

• The

energy-investing

reactions use 2 ATPs per

glucose molecule



2 G3P molecules.

• In the

energy-harvesting

reactions

• _{2 NADH molecules & 4 ATP molecules}

• Two pyruvate molecules are produced for each

glucose molecule.

• Net Gain?

• _{2 ATP!!}

(21)

So where does the Pyruvic

Acid go?

Depends on….

• _Oxygen

• _{to mitochondria}

• _{The Krebs Cycle (matrix)}

• _{Electron transport chain (cristae)}

• _{No oxygen}

• _{fermentation in cytoplasm}

(22)

CYTOSOL

Pyruvate

NAD+

MITOCHONDRION

Transport protein

NADH + H+

Coenzyme A CO₂

Acetyl Co A

(23)

Why make Pyruvic Acid?

• _{For the Krebs Cycle}

Why make Pyruvic Acid?

Figure 6.10 Figure 6.8

High-energy electrons carried by NADH

GLYCOLYSIS

Glucose Pyruvic acid

KREBS CYCLE

ELECTRON TRANSPORT CHAIN AND CHEMIOSMOSIS

Mitochondrion Cytoplasmic

(24)

Stage 2: The Krebs

Cycle

• _{For each Acetyl CoA, it}

generates:

• _{1 ATP}

• _{3 NADH}

• _{1 FADH}

₂

• _Byproduct:

• _{2 CO}

₂

Stage 2: The Krebs Cycle

Figure 6.11A

Acetyl CoA

KREBS CYCLE

(25)

Figure 6.11B

Oxaloacetic acid

Step

Acetyl CoA stokes the furnace

1

2 carbons enter cycle

Citric acid

Steps and

NADH, ATP, and CO₂ are generated during redox reactions.

2 3

CO₂ leaves cycle

Alpha-ketoglutaric acid CO₂ leaves cycle Succinic

acid

KREBS CYCLE

Steps and

Redox reactions generate FADH₂ and NADH. 4 5 Malic acid 1 2 3 4 5

(26)

E.T.C.

Figure 6.6

• _{Producing high energy electron}

carriers

o

NADH

o

_FADH

₂

• _{Electron Transport Chain}

o

Harnesses energy from carriers to

power ATP production

o

_{Final electron acceptor is O}

₂

_{, so this}

process is called

oxidative

phosphorylation

(27)

LE 9-15

Protein complex of electron carriers

H+

ATP ATP ATP

Glycolysis _{phosphorylation:}Oxidative electron transport and chemiosmosis Citric acid cycle H+ Q III I II FAD FADH2

+ H+

NADH NAD+ (carrying electrons from food) Inner mitochondrial membrane Inner mitochondrial membrane Mitochondrial matrix Intermembrane space H+ H+

Cyt c

IV

2H+₊1_/₂_O

2 H2O

ADP +

H+

ATP ATP synthase

Electron transport chain

Electron transport and pumping of protons (H+_), Which create an H+_{gradient across the membrane}

P_i

Chemiosmosis

(28)

Energy released and now available for making ATP

Final electron acceptor

(29)

LE 9-14

INTERMEMBRANE SPACE

H+ _H+

H+ H

+ H+ H+ H+ H+ ATP MITOCHONDRAL MATRIX ADP + P_i

A rotor within the membrane spins as shown

when H+_flows

past

it down the H+

gradient.

A stator

anchored in the membrane holds the knob stationary.

A rod (or “stalk

”) extending

into the knob also spins, activating catalytic sites in the knob.