Chapter9Respiration.ppt

Define:  _Glycolysis  _Respiration  _Chemiosmosis  _{Phosphorylation}  _Fermentation

 _{ATP (draw and label)}  _{Electrochemical}

gradient

 _{FAD  FADH2}  _NAD+_ NADH

1. What is the role of

phosphofructokinase? How does it “work”?

1. Remember: OILRIG

A. In the conversion of glucose and

oxygen to CO₂ and H₂O, which molecule is reduced?

B. Which is oxidized?

C. What happens to the energy that is

released in this redox reaction?

2. NAD+ is called a(n) ________________.

1. Why is glycolysis considered an ancient metabolic process?

2. Where in the cell does glycolysis occur?

3. What are the reactants and products of

glycolysis?

4. Which has more chemical energy?

A. NAD+ or NADH?

B. FAD+ or FADH 2?

1. Where does the Citric Acid Cycle

occur in the cell?

2. What are the main products of the

CAC?

3. Which process produces more ATP:

 _{Substrate-level phosphorylation} –or- _{Oxidative phosphorylation?}

4. What is 1 fact you remember from

1. How is the proton gradient generated?

2. What is its purpose?

1. What are 3 ways respiration can be

measured?

2. What is the purpose of using KOH

(potassium hydroxide) in this lab?

3. What are the Independent and

1. Where are the proteins of the ETC located?

2. Where does the ETC pump H+ ions

into?

3. In cellular respiration, how many ATP are generated through:

A. Substrate-level phosphorylation?

B. Oxidative phosphorylation?

4. In fermentation, how is NAD+

1. What is the function of the enzyme phosphofructokinase?

2. You eat a steak and salad. Which macromolecule cannot be broken down to make ATP?

E flows into ecosystem as Sunlight

Autotrophs transform it into chemical E

O₂ released as byproduct

Cells use some of chemical E in organic molecules to

make ATP

Complex organic molecules

Simpler waste products with

less E

Some E used to do work and dissipated as

heat

Respiration: exergonic (releases E)

C₆H₁₂O₆ + 6O₂  6H₂O + 6CO₂ + ATP

(+ heat)

Photosynthesis: endergonic (requires E)

Xe- + Y  X + Ye

- Oxidation = lose e - Reduction = gain e

-C₆H₁₂O₆ + 6O₂  6H₂O + 6CO₂ +

oxidation

reduction

oxidation (donor) lose e

-reduction (acceptor) gain e

-AT P

 Energy is released as electrons “fall”

from organic molecules to O₂

 Broken down into steps:

Food  NADH  ETC  O₂

 _{Coenzyme NAD}+ = electron acceptor

 _NAD+ picks up 2e- and 2H+ _ NADH (stores E)

 _{NADH carries electrons to the electron}

transport chain (ETC)

 ETC: transfers e- to O

2 to make H2O ; releases

 Phosphorylation:

enzyme transfers a phosphate to other compounds

 ADP + P_i  ATP

P compoun

1. Glycolysis

2. Citric Acid Cycle (Krebs Cycle)

3. Oxidative Phosphorylation (electron transport chain (ETC) &

NADH

NADH FADH₂

GLYCOLYSIS

Glucose Pyruvate CITRIC ACID CYCLE OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) Substrate-level phosphorylation Oxidative phosphorylation Mitochondrion and High-energy electrons

carried by NADH

ATP ATP

ATP CO2 CO2

Cytoplasm

 Believed to be ancient (bacteria,

eukaryotes – no O₂ necessary)

 Occurs in cytosol

 Partially oxidizes glucose (6C) to 2

pyruvates (3C)

 Net gain: 2 ATP + 2NADH  Also makes 2H₂O

Stage 1: Energy Investment Stage

 Cell uses ATP to phosphorylate

compounds of glucose

Stage 2: Energy Yielding Stage

 Two 3-C compounds oxidized  For each glucose molecule:

 _{2 Net ATP produced by substrate-level} phosphorylation

glucos e

2

pyruvate

P AD

P

2 ATP

2 NAD+

2 NADH +

2H+

(3-C) C₃H₆O₃

Citric Acid Cycle

(matrix)

Citric Acid Cycle

(matrix)

ETC (inner membrane)

ETC

 Occurs in mitochondrial matrix

 Pyruvate  Acetyl CoA  Citrate   Net gain: 2 ATP, 6 NADH, 2 FADH₂

(electron carrier)

 ATP produced by substrate-level

phosphorylation

CO

2

CO

ELECTRON TRANSPORT CHAIN

 Occurs in inner

membrane of mitochondria

 Produces 32-34 ATP

by oxidative

phosphorylation via chemiosmosis

CHEMIOSMOSIS

 H+ ions pumped

across inner mitochondrial membrane

 H+ diffuse through

ATP synthase (ADP 

 Collection of molecules

embedded in inner

membrane of mitochondria

 Tightly bound protein +

non-protein components

 Alternate between reduced/

oxidized states as accept/donate e

- Does not make ATP directly  Ease fall of e- from food to

O₂

 ATP synthase: enzyme

that makes ATP

 Use E from proton (H+)

gradient – flow of H+ back

across membrane

 Chemiosmosis = H+ ion

gradient across membrane drives cellular work

 proton-motive force: use

H+ gradient to perform

e- passed down E levels oxidative phosphorylation chemiosmosi s ATP ETC

O₂  H₂O

proton gradient proton motive force H+ redox reaction s ATP synthase uses uses E of in which

to final e- acceptor

generates which couples

called drives through to p rod uc_e

H+ pu mped

from matr

ix to

inter

memb rane

FERMENTATION

 Occurs in plants and

animals

 Occurs in cytosol

 Keep glycolysis going  No oxygen needed  Creates alcohol [+

CO₂] or lactic acid

RESPIRATION

 Release E from

breakdown of food with O₂

 Occurs in

mitochondria

 O₂ required (final

electron acceptor)

 Produces CO₂, H₂O and

up to 38 ATP (NADH,

FADH₂)

O₂ present

ALCOHOL FERMENTATION

 Pyruvate _ Ethanol +

CO₂

 Ex. bacteria, yeast  Used in brewing,

winemaking, baking

LACTIC ACID FERMENTATION

 Pyruvate _ Lactate  Ex. fungi, bacteria,

human muscle cells

 Used to make cheese,

yogurt, acetone, methanol

 Note: Lactate build-up

does NOT causes muscle fatigue and pain (old idea)

Note: NADH recycled for glycolysis ( NAD+_{) when pyruvate is}

 Carbohydrates,

fats and proteins can ALL be used as fuel for cellular respiration

 Monomers enter

glycolysis or citric acid cycle at

 Allosteric enzyme that

controls rate of

glycolysis and Krebs cycle

 Inhibited by ATP, citrate  Stimulated by AMP

Respiratio n (mitochondria) Respiratio n (mitochondria) Krebs cycle

(citric acid cycle)

Krebs cycle

(citric acid cycle)

ENERG Y glycolysis (cytosol) glycolysis (cytosol) fermentatio n fermentatio n ethanol + CO₂ (yeast, some bacteria) ethanol + CO₂ (yeast, some bacteria) anaerobic (without O₂) aerobic

(with O₂)