CELLULAR RESPIRATION
Living things get the ENERGY they need from the breakdown of glucose (sugar)
CELLULAR RESPIRATION
Living things get the ENERGY they need from the breakdown of glucose (sugar)
It all happens in what organelle?
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summary
All our cells need energy
ATP is the energy that the cells use for all life processes.
The cell makes ATP by breaking down a sugar called glucose.
Glucose is the energy of the body.
ATP is the energy of the cell
How does glucose get into the body?
Through the foods you eat.
You eat a piece of bread which is made of large carbohydrate molecules.
Your body breaks the large carbs into tiny sugars during digestion.
It starts with the saliva in the mouth, then in the stomach and finally the food passes through intestines.
When the carbs reach the large intestines, they are broken down so small that they get absorbed in the blood. The small sugars are monosaccharides
Glucose is one of these monosaccharides.
The red blood cells then carry the small sugars to the cells that need them.
When the sugars reach the cells, they cant pass through the cell membrane because of the lipid bilayer.
However, a protein channel recognizes then and lets them in.
The small 6-carbon sugar is now in the cell
Its brought to the mitochondria to be further broken down into ATP
CO2 is one waste product of these process.
AS you exhale now, you are releasing CO2 into the classroom from your mitochondria by the process of cellular respiration.
You need food, oxygen and water for this process.
All of your trillions of cells are doing this
Each cell can have hundreds of mitochondria, all making ATP.
Lets review this process a little better.
Cellular respiration
Key ideas behind cellular respiration
Organic sugar (glucose) is converted to inorganic gas Carbon dioxide.
ATP or cell energy is made in the process
Cell respiration occurs in the mitochondria of all cells.
It occurs 24/7.
The diagram at the bottom shows a six carbon glucose being broken down into six molecules of CO2 in a series of steps..
1 2 3 4
What is a calorie?
Calorie: amount of energy needed to raise the temperature of one gram on water by one degree Celsius.
It is how we measure the energy levels;
One gram of glucose releases 3811 calories of energy.
cellular respiration: process of breaking down food for energy.
From food to ATP (energy)
Steps in cellular respiration
Step one is always Glycolysis:
Step two: depends on whether oxygen is present or not.
if oxygen is not present, the pyruvic acid either enters fermentation.
In this process, alcohol or an acid is a waste product as small amounts of ATP are made from the sugar.
If oxygen is present, step two is the Krebs cycle. This is true for human muscle cells.
This will be explained better later.
Step One: Glycolysis
Step 1 in cellular respiration is always glycolysis.
Glyco means sugar; glucose
Lysis means to split.
Glycolysis mean to split glucose.
Glucose is a sugar made of six carbons.
glycolysis
Glycolysis is the process in which one molecule of glucose (6 Carbons) is broken “in half”, producing two molecules of pyruvic acid, a 3-carbon compound.
Occurs in CYTOPLASM of cell.
Glycolysis Summary (step one)
2 ATP needed to begin glycolysis.
4 ATP produced when its done.
NET gain 2 ATP. (4 – 2 = 2)
NADH is an electron carrier.
Glycolysis starts w/ ONE GLUCOSE
Ends with TWO PYRUVIC ACID
Glycolysis and cellular respiration
What next?
The next step after glycolysis depends on whether oxygen is present or not.
If oxygen is not present (anaerobic) Step two is Fermentation
Anaerobic means without oxygen. Fermentation is a type of anaerobic respiration.
If Oxygen is PRESENT (aerobic) step two is the Krebs Cycle & Electron Transport Chain
Aerobic means with oxygen as in aerobic respiration
Glucose
Glycolysis
Krebs cycle
Electron
transport
Fermentation (without oxygen)
Alcohol or lactic acid
Chemical Pathways
Go to Section:
Fermentation: occurs only when oxygen is not present.
Two types of fermentation
1. Alcoholic Fermentation
Used by Yeast and a few other microorganisms.
Produces alcohol and carbon dioxide from the three carbon pyruvic acid.
2. Lactic Acid Fermentation
Used by Bacteria and human muscle cells.
Produces lactic acid from the three carbon pyruvic acid. .
Glucose
Pyruvic acid
Lactic acid
Lactic Acid Fermentation
Go to Section:
In your own words, explain this diagram:______________________________
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Step 2: Krebs Cycle (oxygen)
When oxygen is present such as in muscles, step two in cellular respiration is the Krebs Cycle
Occurs in mitochondria (matrix).
Pyruvic acid is changed (modified) in a series of reactions.
these reactions produce high-energy electron carriers to be used in the electron transport chain
NAD+ and FAD+ are the high energy electron carriers
H+ is the electron that needs to be carried.
They turn into NADH and FADH2 when carrying electrons and provide the energy to drive the Electron Transport Chain.
2 molecules of ATP is generated per glucose.
CO2 is produced and released.
Step 3:Electron Transport Chain (oxygen)
Takes place in mitochondria (inner membrane).
Series of proteins accept high energy electron pairs from NADH and FADH2.
NADH and FADH2 (Energy taxi dropping off energy)
Oxygen bonds with 2 hydrogens (final electron acceptor) to form H20
32 molecules of ATP are produced per glucose molecule.
Summary
Step one is always glycolysis.
Step two depends on whether or not oxygen is present
If it is not, then step two is fermentation, (anaerobic respiration)
If it is, then step two is the Krebs Cycle and step 3 is the electron transport chain.
In the process, organic glucose is converted to inorganic CO2
If oxygen is present, its called Aerobic respiration, and 36 ATP are created.
During anaerobic respiration or fermentation, 2 ATP are created.
ATP is the universal energy molecule, meaning that all living organism use it as an energy source.
Notice that much more ATP is made when oxygen is present.
Flowchart
Section 9-2
Carbon
Dioxide
(CO2)
+
Water
(H2O)
Glucose
(C6H1206)
+
Oxygen
(02)
Glycolysis
Krebs
Cycle
Electron
Transport
Chain
Go to Section:
Aerobic Respiration
Summary of photosynthesis
Solar energy is converted to chemical energy.
The chemical energy is stored in the form of glucose (sugar).
Carbon dioxide, water, and sunlight are used to produce glucose, oxygen, and water.
Chemical equation for this process is:
6CO2 + 6H2O + light → C6H12O6 + 6O2 + 6H2O
6 molecules of carbon dioxide (6CO2) and
6 molecules of water (6H2O) are consumed in the process,
1 molecule of glucose (C6H12O6)
six molecules of oxygen (6O2)
and six molecules of water (6H2O) are produced.
Summary of cellular respiration
Organic sugar (glucose) is converted to inorganic gas Carbon dioxide.
Chemical equation for cellular respiration that occurs in the mitochondria
1)C6H12O6 + 6O2 6CO2 + 6H2O +38ATP
Looking at the equation, why are cellular respiration and photosynthesis sometimes considered to be opposites?
1)C6H12O6 + 6O2 6CO2 + 6 H2O ~38 ATP
2)6CO2 + 12H2O + light → C6H12O6 + 6O2 + 6H2O
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Cellular Respiration Summary