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CHAPTER 6 CELLULAR RESPIRATION: OBTAINING ENERGY FROM FOODGeneral Biology
CM Lamberty
BIOLOGY AND SOCIETY
ENERGY FLOW AND CHEMICAL CYCLING
Animals depend on plants to covert solar energy to
Photosynthesis
PRODUCERS AND CONSUMERS
Plants and other autotrophs (self-feeders)
Heterotrophs (other-feeders)
Producers
Consumers
CHEMICAL CYCLYING: PHOTOSYNTHESIS AND CELLULAR RESPIRATION
Chemical ingredients for photosynthesis
Chloroplasts
Cellular respiration
CHEMICAL CYCLYING: PHOTOSYNTHESIS AND CELLULAR RESPIRATION
Waste products of cellular respiration
Animals
Plants
CELLULAR RESPIRATION : AEROBIC HARVEST OF FOOD ENERGY
Respiration
Cellular respiration
OVERALL EQUATION OF CELLULAR RESPIRATION Glucose
Many chemical steps
ROLE OF OXYGEN IN CELLULAR RESPIRATION
38 ATP for each glucose
REDOX REACTIONS
Chemical reactions involving transfer of electrons
Loss of electrons: Gain of electrons:
Cellular respiration is a fall of electrons Results in release of energy
NADH AND ELECTRON TRANSPORT CHAINS
Path of electrons from glucose to oxygen NAD+ (nicotinamide adenine dinucleotide)
NADH transfers electrons via electron transport chain
OVERVIEW OF CELLULAR RESPIRATION
Metabolic pathway
Three stages of cellular respiration Glycolysis
Citric acid cycle (Krebs cycle)
Electron transport
THREE STAGES OF CELLULAR RESPIRATION
Stage 1: Glycolysis (w/ most of E)
Energy investment phase
Carbon atomPhosphategroup
High-energyelectron
Key
Glucose
2 ATP2 ADP
INPUT OUTPUT
Figure 6.7-1
THREE STAGES OF CELLULAR RESPIRATION
Stage 2: Citric Acid Cycle
THREE STAGES OF CELLULAR RESPIRATION
Stage 3: Electron Transport
VERSATILITY OF CELLULAR RESPIRATION
Cellular respiration can also “burn”: Diverse types of carbohydrates Fats proteins
ADDING UP THE ATP FROM CELLULAR RESPIRATION
Remember up to 38 ATP/glucose Glycolysis and citric acid cycle each
contribute 2 ATP by direct synthesis Remaining from “fall” of electrons in
transport chain Each pair dropped down from NADH = 3 ATP Each pair dropped down from FADH2 = 2 ATP
FERMENTATION: ANAEROBIC HARVEST OF FOOD ENERGY
Cells can work for short periods w/o O2 Fermentation is anaerobic harvest of food
energy
FERMENTATION IN HUMAN MUSCLE CELLS
FERMENTATION IN MICROORGANISMS
Fermentation alone is able to sustain many microorganisms
The lactic acid produced by microbes is used to produce:
LIFE BEFORE AND AFTER OXYGEN
Glycolysis used by ancient bacteria to make ATP when little oxygen available and before organelles evovled
Today glycolysis Occurs in almost all organisms Is a metabolic heirloom of the first stage in the
breakdown of organic molecules
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