CH 7 CELLULAR RESPIRATION

What is the equation for photosynthesis? What do plants need? What do plants make?

If this is what plants do to make sugar… what do we do once we’ve eaten that sugar? What do YOU need? What do YOU make?

7-1: Glycolysis and fermentation Cellular respiration: complex process

by which cells make ATP by breaking down organic compounds

Heterotrophs must do this to obtain energy

Do autotrophs? Yup!

Overview

Overview The products of photosynthesis are the reactants for cellular respiration

The products of cellular respiration are the reactants for photosynthesis

Cellular respiration

Oxygen present:

Aerobic respiration

Oxygen not present:

Anaerobic respiration

•A process with options•Glycolysis always happens first•What happens next depends on Oxygen

Or…

Page 132 Copy figure 7-2 in your notebooks. Be

sure to include labels

Glycolysis 6-C Glucose broken into 2 3-C Pyruvic acid In the process we invest:

2 ATP In the process we create:

4 ATP 2 NADH

NADH? Familiar? Another high energy electron shuttle This is an ANAEROBIC process (?)

Does not require oxygen

What happens next depends on oxygen…

Aerobic respiration

If Oxygen present, Pyruvic acid

broken down to produce more NADH

NADH is used to make ATP

Anaerobic respiration (fermentation)

If oxygen is not present,

Pyruvic acid enters another cycle

Combination of glycolysis and anaerobic fermentation is called fermentation

Fermentation When oxygen is not present (anaerobic

conditions) Pyruvic acid converted to other compounds In cytoplasm Fermentation: Glycolysis + regeneration of NAD+

Does not produce ATP Fermentation reproduces NAD+ so ATP can be

gained through continual glycolysis If NAD+ not regenerated no glycolysis no ATP

Alcoholic fermentation Pyruvic acid converted to ethanol yeast bacteria Bread Wine, beer

Lactic acid fermentation Pyruvic acid converted to Lactic acid Cheeses Yogurt Cultivated dairy products Makes muscles sore after strenuous

workout

Review Glycolysis

Glucose 2x pyruvic acid, 2 NADH, & 2 ATP Fermentation (oxygen not present)

Alcoholic Pyruvic acid ethanol + NAD+, & CO2

Lactic acid Pyruvic acid lactic acid + NAD+

Aerobic respiration Pathway of cellular respiration that

requires oxygen Produces 20 times more ATP than

glycolysis alone Two major stages (both occur in the

mitochondria)1. Krebs cycle2. Electron transport chain

Mitochondria Pyruvic acid (from

glycolysis) diffuses into mitochondrial matrix

Krebs Mit. Matrix ETC Inner

membrane

Before krebs Pyruvic acid converted to acetyl CoA in

matrix Releases CO2 Creates NADH

Krebs cycle Acetyl CoA combines with oxaloacetate

to form citric acid Citric acid is broken down two times Each time we break off a piece from

citric acid, we make: CO2, NADH, and FADH2 (same function as

NADH)

So far we have made… A bunch of high energy electron carriers

NADH (glycolysis and krebs) FADH2 (Krebs)

A little ATP (glycolysis[2] and krebs[2]) CO2 (krebs) But the whole point of cellular respiration

is to make ATP So… now we turn to the……

Electron transport chain Series of proteins that transfer electrons Location: inner mitochondrial membrane H+ and e- removed from NADH and

FADH2 in the presence of O2 to make ATP

ETC1. H+ and e- removed from NADH and FADH2

2. e- moved through chain & lose energy3. Energy used to pump H+ from matrix into

inner membrane space 1. Creates concentration gradient of H+ across

inner mebrane4. Gradient used to make ATP as H+ move

through ATP synthase5. O2 is final e- acceptor at end of ETC

1. e- + H+ +O2 = H2O

Importance of Oxygen ATP can only be made as long as e-

move through ETC w/o oxygen, e- transport stops

Efficiency of aerobic respiration

Aerobic respiration

Fermentation (anaerobic respiration)

Number of ATP produced in Aerobic vs anaerobic respiration:

Efficiency of aerobic respiration

Aerobic respiration 38 (glycolysis + krebs + ETC)

Fermentation (anaerobic respiration)

2 (glycolysis only)

Number of ATP produced in Aerobic vs anaerobic respiration:

Summary of cellular respiration Draw figure 7-14 on page 143 Fill in table belowReaction Inputs Outputs Location

Gylcolysis

Pyruvic acid acetyl CoA

Krebs

ETC

Anaerobic pathway: Input Output Example organism

Lactic acid fermentation

Alcoholic fermentation