Pre IB Biology Cellular Respiration Presentation Transcript
INTRODUCTION TO CELLULAR RESPIRATION
Photosynthesis and cellular respiration provide energy for life
Photosynthesis uses solar energy to produce
glucose and O 2 from CO 2 and H 2 O
6CO 2 + 6H 2 0 + Energy C 6 H 12 O 6 + 6O 2
Occurs in Chloroplasts
Cellular respiration makes ATP and consumes O 2 during the oxidation of glucose to CO 2 and H 2 O
What is the relationship between photosynthesis and cellular respiration? Occurs in mitochondria
C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 0 + ATP
CO 2 H 2 O Glucose O 2 ATP ECOSYSTEM Sunlight energy Photosynthesis in chloroplasts Cellular respiration in mitochondria (for cellular work) Heat energy
( Breathing) provides for the exchange of O 2 and CO 2 between an organism and its environment
Cellular respiration breaks down glucose molecules and banks their energy in ATP
Happens in the mitochondrion of cells.
The Organelle of Cellular Respiration
Cellular respiration takes place in both plant and animal cells.
The organelle in which it takes place is the mitochondrion . – This is also known as the ‘power-house’ of the cell.
What is the relationship between respiration and cellular respiration ? CO 2 CO 2 O 2 O 2 Bloodstream Muscle cells carrying out Cellular Respiration Breathing Glucose O 2 CO 2 H 2 O ATP Lungs
The human body uses energy from ATP for all its activities
0 Energy Needs
Food serves as a source of raw materials for the cells in the body and as a source of energy.
Food energy is converted into a form the cell can use (ATP) during a process called cellular respiration .
Glucose is a main energy source used by all cells.
Cells don’t “burn” glucose. Instead, they gradually release the energy from glucose and other food compounds.
This process begins with a pathway called glycolysis .
Glycolysis releases a small amount of energy
If Oxygen is present glucose is completely
Grooming Pyruvic Acid
Electron Transport Chain (ETC)
I. First Phase – Glycolysis
Occurs in the cytoplasm
Breaks down of glucose into Pyruvic acid
Produces a net gain of 2 ATP and 2 NADH
Glycolysis NAD NADH H Glucose 2 Pyruvate ATP 2 P 2 ADP 2 2 2 2 + +
Glycolysis produces ATP by substrate-level phosphorylation
Enzyme Adenosine Organic molecule (substrate) ADP ATP P P P P P
In which a phosphate group is transferred from an organic molecule to ADP
Two Mechanisms Generate ATP
Substrate Level Phosphorylation : This mechanism generates less amount of ATP and is an enzyme-substrate based reaction.
Oxatative Phosphorylation : This mechanism use the mitochondrial membrane to generate ATP in much greater amounts.
II. Grooming Pyrvic Acid
The conversion of pyruvate into acetyl-CoA
Creating a Carbon Dioxide molecule
Making it possible for the two carbon molecule to enter the mitochondria.
III. Krebs Cycle (Citric Acid Cycle)
Occurs in the mitochondria. In the matrix (the open space) of
Acetyl (2C) joins with Oxaloacetic Acid (4C) molecule to produce Citric Acid (6C).
Citric Acid goes through a series of steps to produces energy by Substrate-level phosphorylation
NO OXYGEN USED YET!
For each turn of the cycle :
2 FADH 2
2 CO 2 (byproduct )
Two CO 2 molecules are released
The energy yield is 1 ATP, 1 FADH 2 and 3 NADH
CoA CoA CO 2 NAD NADH FAD FADH 2 ATP P CITRIC ACID CYCLE ADP 3 3 3 H Pyruvid Acid/Acetyl CoA 2
IV. Electron Transport Chain
Uses the energy stored in NADH and FADH2 to make ATP
Each NADH = 3 ATP
Each FADH 2 = 2 ATP
32-34 ATP – Oxidative phosphorylation
Produces H 2 O as a byproduct
Electrons from NADH and FADH 2
Travel down the electron transport chain to oxygen, which picks up H + to form H 2 O
Energy released by the reactions
is used to pump H + into the space between the mitochondrial membranes (against the concentration gradient)
In chemiosmosis , the H + diffuses back through the inner membrane through ATP synthase complexes
Driving the synthesis of ATP
Intermembrane space Inner mitochondrial membrane Mitochondrial matrix Protein complex Electron flow Electron carrier NADH NAD + FADH 2 FAD H 2 O ATP ADP ATP synthase H + H + H + H + H + H + H + H + H + H + H + H + H + H + P O 2 Electron Transport Chain Chemiosmosis . OXIDATIVE PHOSPHORYLATION + 2 1 2 Figure 6.10
Cellular Respiration NADH NADH NADH NADH FADH 2 Cytoplasm Electron shuttle across membrane Mitochondrion GLYCOLYSIS Glucose Pyruvate by substrate-level phosphorylation by substrate-level phosphorylation by oxidative phosphorylation OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) 2 Acetyl CoA CITRIC ACID CYCLE 2 ATP 2 ATP about 34 ATP Maximum per glucose: About 38 ATP 2 2 6 2 2 2 (or 2 FADH 2 )
2 ATP – Glycolysis ( Anaerobic)
2 ATP – Citric Acid/Kreb’s cycle
32-34 ATP – Oxidative phosphorylation
36-38 Total – Cellular Respiration
TOTALS (per 1 Glucose molecule )
If no oxygen is present or the cell does not contain mitochondria:
Fermentation is an anaerobic alternative to cellular respiration
Under anaerobic conditions, many kinds of cells
Can use glycolysis alone to produce small amounts of ATP
2 types – Lactic Acid Fermentation
I. lactic acid fermentation
The two ATP’s created in Glycolysis are the only energy yield in lactic acid fermentation
(muscles and bacteria) NADH is oxidized to NAD + as pyruvate is reduced to lactate (lactic acid)
The buildup of lactic acid causes a painful, burning sensation in your muscles
2 Lactate NAD NADH NADH NAD 2 2 2 2 2 ATP 2 ADP 2 2 Pyruvate GLYCOLYSIS P Glucose
II. alcohol fermentation
(yeast) NADH is oxidized to NAD + while converting pyruvate to CO 2 and ethanol
NAD NADH NADH NAD 2 2 2 2 GLYCOLYSIS 2 ADP 2 P ATP Glucose 2 Pyruvate released CO 2 2 Ethanol 2 2 Figure 6.13B
Cells use many kinds of organic molecules as fuel for cellular respiration
Carbohydrates, fats, and proteins can all fuel cellular respiration
When they are converted to molecules that enter glycolysis or the citric acid cycle
OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) Food, such as peanuts Carbohydrates Fats Proteins Sugars Glycerol Fatty acids Amino acids Amino groups Glucose G3P Pyruvate Acetyl CoA CITRIC ACID CYCLE ATP GLYCOLYSIS
The fuel for respiration ultimately comes from photosynthesis
Can harvest energy from organic molecules
Plants, but not animals
Can also make these molecules from inorganic sources by the process of photosynthesis