Download Cellular Respiration notes

• Test Date:
• Nov 28th(B-DAY)
• Nov 29th(A-DAY)
• Lab: Closed-toe shoes
• Thursday (BDAY)
• Friday (ADAY)
Essential Questions
• What is cellular Respiration?
• What is the equation for cellular respiration?
• What are the similarities/differences with
photosynthesis?
• Stages:
• Aerobic
Anaerobic
– glycolysis
– Krebs cycle
– Electron Transport
glycolysis
fermentation
Food
• A living organism such as an animal consumes
food, then converts some of that food into
useable ATP. The rest gets stored and converted
later
• Proteins, carbohydrates, lipids can all be used to
convert to ATP but at different rates
• Lipids give long term large amounts of energy
• carbs give short term quick energy
• Proteins give the least amount of useable energy,
so body usually stores it instead of converting it
The role of ATP
• Adenosine Triphosphate is the energy currency in living
organisms
• It cannot be stored-instead glucose is stored and
converted as the body needs it. This conversion is
called cellular respiration
• When ATP is made, it then can be released and used by
the cells in functions such as making proteins, active
transport, and maintaining homeostasis
• Glucose must be converted slowly in order to get the
maximum amount of ATP from it. It does this in stages
Cellular Respiration Overview
• Goal: to convert chemical energy (food) into
useable energy (ATP)
• Two types
– aerobic in the presence of oxygen
– anaerobic without oxygen
• Glycolysis is the first step regardless if there is
oxygen or not
– takes place in the cytoplasm of the cell
Equation
Glycolysis-pre step
• Goal: One molecule of glucose is broken in half, producing
two molecules of pyruvic acid
• Steps:
– Two ATP molecules are used to break down a glucose molecule
– It is split into two three carbon molecules (3Carbon; 3C).
Enzymes rearrange the molecules
– Energized electrons from the molecules are transferred to
molecules of NAD+ to make NADH
– A series of reactions converts the 2 3C molecules to pyruvate,
which will enter the mitochondria for cellular respiration
– 4ATP are made
• Equation:
– Glucose+2ATP 2Pyruvate+NADH+4ATP
Krebs Cycle (citric acid cycle)-aerobic
• Named after Sir Hans Adolf Krebs
• Each pyruvate will enter the Kreb’s cycle and
be transformed into several products:
– 4NADH
– 3CO2
– FADH2
– 1ATP
• Equation:
• 2pyruvate 8NADH+6CO2+2FADH2+2ATP
Steps to Krebs Cycle
1. Pyruvate broken down into two 2C moleculesNADH is formed, CO2 is released
2. Coenzyme A bonds to 2C molecule-this molecule
goes into Krebs cycle
3. The 2C part binds to a 4C molecule creating citric
acid (6C). Coenzyme A goes back to step 2
4. Citric acid is broken down into a 5C molecule.
CO2 is released. NADH is formed
5. 5C is broken down into a 4C molecule. CO2 is
released. NADH is released. ATP is released
6. 4C molecule is rearranged forming NADH and
FADH2 which get released out of the Krebs Cycle
Electron Transport Chain
• The electron transport chain is a series of
chemical reactions ending with hydrogen
combining with oxygen to form water. Carbon
dioxide is released as a waste product as it is
formed in several stages of the Krebs cycle.
• Each reaction produces a small amount of
energy, which by the end of the cycle
produces many (up to 36) ATP molecules.
• The ATP synthesized can be used by the cell
for cellular metabolism
ATP created
• All of the NADH and FADH2 from the Krebs
Cycle are converted into ATP which is usable
energy.
• Most scientists will agree that between 36-38
ATP are formed from the Krebs cycle and
Electron Transport. BUT… you spent 2 ATP in
glycolysis so truly you only NET 34-36 ATP.
Anaerobic respiration
• Glycolysis-same glycolysis as aerobic
respiration
– One glucose is split into two pyruvate producing
two ATP total
• Fermentation-Two types, both named after
products in which they produce. Aerobic
respiration produces water
– Lactic acid
– Alcoholic
Equation
Lactic Acid Fermentation
• Lactic acid fermentation occurs when oxygen is not available,
for example, in muscle tissues during rapid and vigorous
exercise when muscle cells may be depleted of oxygen.
• The pyruvic acid formed during glycolysis is broken down to
lactic acid, and in the process energy is released (which is
used to form ATP).
• Glucose Pyruvic acid Lactic acid + energy
• The process of lactic acid fermentation replaces the process of
aerobic respiration so that the cell can continue to have a
continual source of energy even in the absence of oxygen,
however this shift is only temporary and cells need oxygen for
sustained activity.
• Lactic acid that builds up in the tissue causes a burning,
painful sensation.
Alcoholic Fermentation
• Alcohol fermentation occurs in yeasts and
some bacteria.
• In this process, pyruvic acid formed during
glycolysis is broken down to produce alcohol
and carbon dioxide, and in the process energy
is released (which is used to form ATP).
• Glucose Pyruvic acid alcohol + carbon
dioxide + energy
Why learn about fermentation?
• Cheese
• Bread
• Alcohol
• Wine
Venn Diagram