Download Cellular Respiration notes HONORS

• 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) called
PGAL. Enzymes rearrange the molecules
– Energized electrons from the molecules are transferred to
molecules of NAD+ to make NADH
– A series of reactions converts the PGAL molecules to pyruvate,
which will enter the mitochondria for cellular respiration
– 4ATP are made, but two were used to begin with, so only 2ATP
are gained
• Equation:
– Glucose+2ATP 2Pyruvate+NADH+4ATP
Oxidative Decarboxylation
• Pyruvic acid then comes into the
mitochondrial matrix
• It reacts with a molecule of coenzyme A to
form acetyl coenzyme A, abbreviated acetyl
CoA
• In the process, a carbon dioxide molecule is
released as waste, and a molecule of NAD+ is
reduced to NADH
Krebs Cycle (citric acid cycle)-aerobic
• Named after Sir Hans Adolf Krebs
• Each (2) acetyl CoA will enter the Kreb’s cycle
and be transformed into several products:
– 4NADH
– 3CO2
– FADH2
– 1ATP
• Equation:
• 2 Acetyl CoA 8NADH+6CO2+2FADH2+2ATP
Steps to Krebs Cycle
1. Acetyl CoA combines with oxaloacetic acid (4C) to
produce citric acid (6C) which in turn regenerates the
coenzyme A
2. Citric acid releases a CO2 molecule and a hydrogen
atom to form a 5C compound. The hydrogen in
transferred to NAD+ reducing it to NADH
3. The 5C molecule releases a CO2 molecule and a H
atom to form a 4C compound. Again, NAD+ is reduced
to NADH. Also, an ATP is synthesized from ADP
4. The 4C compound from step 3 releases a hydrogen to
form another 4C compound. This time FAD is reduced
to form FADH2
5. The 4C from step 4 releases an H atom to regenerate
oxaloacetic acid, which keeps the Krebs cycle
operating. The H atom reduces NAD+ to NADH
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.
• The NADH and FADH2 are converted into ATP
– 1 NADH=3 ATP and 1FADH2=2ATP
• Each reaction produces a small amount of
energy, which by the end of the cycle
produces 38 ATP molecules, but two are spent
in glycolysis so the net gain is 36 ATP
O2 + C6H12O6  CO2 + H2O + 36ATP
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
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