1. ……
Cellular Respiration

2. Most cells of most organisms obtain energy aerobically using oxygen
CELLULAR RESPIRATION
Introduction
Nearly all the cells in our body break down sugars to provide the energy to make ATP
Most cells of most organisms obtain energy aerobically using oxygen
The aerobic processing of energy from sugar is called cellular respiration
Cellular respiration yields CO2, H2O, and a large amount of ATP

3. Some cells only use anaerobic respiration
Differences in how cells break down glucose - aerobic vs. anaerobic respiration
Aerobic respiration requires O2 vs. Anaerobic respiration which doesn’t use O2
Some cells only use anaerobic respiration
Some cells use aerobic respiration
Some cells usually use aerobic but may resort to anaerobic respiration if necessary

4. Structure of the Mitochondrion
The process of cellular respiration takes place in the mitochondria of eukaryote cells
Structure of the Mitochondrion

5. Breathing and cellular respiration are closely related.
In Our Body:
Breathing and cellular respiration are closely related.
Breathing supplies oxygen to our cells for cellular respiration and removes carbon dioxide from our cells which is a waste product of cellular respiration
CO2 O2
BREATHING
Lungs
CO2 O2
Bloodstream
Muscle cells carrying out
CELLULAR RESPIRATION
Sugar + O2  ATP + CO2 + H2O
Figure 6.1

6. Cellular respiration breaks down glucose molecules and stores their energy in ATP (adenosine triphosphate: ADENOSINE –P—P--P)
The process uses O2 and releases CO2 and H2O
Chemical equation for cellular respiration
Glucose
Oxygen gas
Carbon dioxide
Water
Energy
Figure 6.2A

7. Respiration occurs in three main stages
STAGES OF CELLULAR RESPIRATION AND FERMENTATION
Respiration occurs in three main stages
Cellular respiration oxidizes sugar and produces ATP in three main stages
Glycolysis occurs in the cytoplasm
The Krebs cycle and
The electron transport chain occur in the mitochondria

8. Important Molecules Involved
NAD+
FAD++
Electron and hydrogen ion carrier molecules
NAD+ carries 2 electrons and one hydrogen ion/ molecule
FAD++ carries 4 electrons and two hydrogen ions/ molecule

9. Glycolysis – In cytoplasm
6 carbon sugar (1 molecule)
ATP needed to break molecule apart
NAD+ collects electrons and hydrogen and forms ATP
3 carbon molecule ( 2 molecules)

10. Kreb Cycle – matrix of mitochondrion
A multi-step process involving many enzymes that uses oxygen to break down the pyruvic acid molecules to CO2, captures energy as ATP, and collects energized electrons and hydrogen to send to cristae membranes of mitochondrion

11. ELT & Chemiosmosis – cristae of mitochondrion
Chemiosmosis involves the pumping of protons through special channels in the membranes of mitochondria from the inner to the outer compartment. The pumping establishes a proton gradient that flows through ATP synthase to make ATP

12. The 3 stages of aerobic cellular respiration
For each glucose molecule that enters cellular respiration, chemiosmosis produces ATP molecules
Cytoplasmic fluid
Mitochondrion
Electron shuttle across membranes
KREBS CYCLE
GLYCOLYSIS
2 Acetyl CoA
2 Pyruvic acid
KREBS CYCLE
ELECTRON TRANSPORT CHAIN AND CHEMIOSMOSIS
Glucose
by substrate-level phosphorylation
used for shuttling electrons from NADH made in glycolysis
by substrate-level phosphorylation
by chemiosmotic phosphorylation
Maximum per glucose:
Figure 6.14

13. Animal Cells use many kinds of organic molecules as fuel for cellular respiration
Polysaccharides can be broken down to monosaccharides and then converted to glucose for glycolysis
Proteins can be digested to amino acids, which are chemically altered and then used in the Krebs cycle
Fats are broken up and fed into glycolysis and the Krebs cycle

14. Fermentation is an anaerobic alternative to aerobic respiration
Under anaerobic conditions (no oxygen), many kinds of cells can use glycolysis alone to produce small amounts of ATP
But a cell must have a way of replenishing or regenerating NAD+ (NADH  NAD+)

15. Alcoholic Fermentation
In alcoholic fermentation, pyruvic acid (pyruvate) is converted to CO2 and ethanol
This recycles NAD+ to keep glycolysis working
released
GLYCOLYSIS
2 Pyruvic acid
2 Ethanol
Glucose
Figure 6.15A
Figure 6.15C XO

16. Lactic Acid Fermentation
In lactic acid fermentation, pyruvic acid (pyruvate) is converted to lactic acid (lactate)
As in alcoholic fermentation, NAD+ is recycled
Lactic acid fermentation is used to make cheese and yogurt
GLYCOLYSIS
2 Pyruvic acid
2 Lactic acid
Glucose
Figure 6.15B

17. Food molecules provide raw materials for biosynthesis
In addition to energy, cells need raw materials for growth and repair
Some are obtained directly from food
Others are made from intermediates in glycolysis and the Krebs cycle
Biosynthesis (making cell parts and organic compounds) uses ATP

18. The fuel for respiration ultimately comes from photosynthesis
All organisms have the ability to harvest energy from organic molecules
Plants, but not animals, can also make these molecules from inorganic sources by the process of photosynthesis
Figure 6.18