How do cells acquire and use energy?
Cellular Respiration and Photosynthesis
ATP is the nucleotide used as the cell’s energy currency
•
ATP is continually produced and consumed (10 million ATP per second each cell)
Anything that prevents ATP formation will most likely ____.
A)
B)
C)
D)
E)
Result in cell death
Force the cell to rely on lipids for energy
Force the cell to rely on ADP for energy
Have no effect on the cell
Cause denaturation
The overall reaction of Cellular Respiration
Series of chemical reactions that
transform chemical energy in food (organic molecules)
to a usable form of chemical energy (ATP)
What reactants need to be present for cell respiration to occur?
What is produced during cellular respiration?
Which organisms carryout cellular respiration? why?
What you need to know about CR
For each step:
Where does it happen?
What goes in?
What comes out?
Electrons stored?
ATP made?
Waste products produced?
TEST YOUR UNDERSTANDING
Why do we need O2?
A. O2 helps us synthesize proteins.
B. It counterbalances the CO2 in the atmosphere.
C. O2 plays a role in obtaining energy from food.
D. O2 is needed to deliver hemoglobin to our cells.
E. to make CO2.
Immediately after completion of the Krebs cycle, most of the energy
from the original glucose molecule is in the form of ___________.
A. ATP
B. CO2
C. CoA
D. acetic acid
E. NADH
Anaerobic respiration is an alternative
when oxygen gas is not present
• Aerobic respiration
with oxygen present
Glycolysis
Four steps
One glucose yields 36-38 ATPs
• Anaerobic respiration
without oxygen present
glycolisis + new step (fermentation
yields 2 ATPs only
Some organisms are facultative
anaerobes, like you
If O2 is present what type of
respiration will they do?
Two types of anaerobic respiration
Lactic acid fermentation
• in animals and bacteria
• Reaction:
Glucose  2 Lactic acid (lactate)+ 2ATP
• Steps:
Glycolysis (2 ATP)
+
fermentation
(Lactic acid as waste product)
Alcoholic fermentation
• in yeast
• Glucose  2 ethanol +2CO2 + Energy
• Steps:
Glycolysis (2ATP)
+
fermentation
(Ethanol + CO2 as waste products)
Is GLUCOSE the only source of our energy?
Cells use many organic molecules as fuel for cellular respiration
Digestive tract
Breaks down macromolecules
in to their monomers
Monomers can enter
cellular respiration
at different stages
Photosynthesis and Cellular Respiration
Glucose + O2
CO2 + H2O 
 CO2 + H2O
What is wrong with the following statement:
Animals do cellular respiration and plants do photosynthesis
Cellular Respiration lab
Procedure 5 and 6
Procedure 5: the effect of temperature
and food source on yeast fermentation
Reaction of Anaerobic Respiration in yeast:
What will the yeast consume from the solution?
What will the yeast produce into the solution?
How can we detect if yeast are respiring?
Fill out table and answer questions on page 42
Set up
• Work in groups of four (one person-one tube)
• Handle fermentation tubes carefully
• Label tubes
1: warm yeast only
2: warm yeast + sucrose
3: warm yeast + protein
4: warm yeast + sucrose (in cold)
• Remove air from tube before beginning time count
• Measure displacement of solution after after 30 min
Procedure 6: Aerobic respiration of Peas
Reaction of Aerobic Respiration:
Peas: embryo plants (alive) + nutrients
Embryo extracts energy from nutrients
via aerobic respiration
What will the peas consume from the surrounding solution?
What will the peas produce into the surrounding solution?
How can we detect if peas carrying out aerobic respiration?
Answer question on page 42