cells use atp molecules for all of their functions that energy for ...€¦ · cellular respiration...
TRANSCRIPT
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Energy for Cells: Cellular Respiration
Cells Use ATP Molecules to Get Energy � Cells use ATP molecules for all of their functions that
need energy. � ATP – “adenosine triphosphate” � ATP undergoes a chemical reaction that releases energy.
ADP – ATP CYCLE During cellular respiration
A ~P~P + P + energy A ~P~P~P
ADP + P
ATP
energy
+
When body needs energy to live
ADP + P
energy
+
ATP
A ~P~P~P A ~P~P + P + energy
Cellular Respiration Makes ATP � The chemical energy in the macromolecules of the food
we eat is not in a form that cells can use. � Instead, many chemical reactions convert this energy
into ATP. 2 Types
1. Aerobic Cellular Respiration (in the presence of O2) 2. Fermentation (without O2, mostly in bacteria)
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Cellular Respiration
energy used for life functions • movement (heart & lungs) • nerve & brain activity • synthesis & repair of body parts
energy carbon dioxide + water glucose + oxygen +
• released into air • exhaled
6 CO2 C6H12O6 6 O2 + + 6 H2O 36 ATP +
Aerobic Cellular Respiration
Cellular respiration can occur in two stages: 1. Glycolysis – in the cytoplasm Glucose (6C) à 2 pyruvate (3C) -- produces 2 ATP
2. Oxidative Respiration – in the mitochondrion
Pyruvate + O2 à CO2 + H2O -- produces 34 ATP!!!
LACTIC ACID FERMENTATION (anaerobic)
glucose
Used in animal muscle cells: • During vigorous exercise muscles use lactic acid
fermentation as a quick source of ATP. • lactic acid build up in muscles causes muscle
fatigue
2 ATP • not very efficient
+ lactic acid
ALCOHOLIC FERMENTATION (anaerobic)
glucose 2 ATP + • not very efficient
carbon dioxide + alcohol
used by: yeast cells: under anaerobic conditions yeast break
down glucose to alcohol & CO2
commercial uses
1. beer & wine 2. bio-fuel
1. make bread rise
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Sources of Energy
� Cells will use… � Glucose first. � Then Lipids � Then Proteins
� They enter the C.R. pathway at different stages.
� W/o ATP the cell dies within seconds!
Cellular Respiration & Photosynthesis � Plants make their own food through photosynthesis. � Takes place in the chloroplast � The overall reaction is the reverse of cellular respiration.
The energy that fuels life cycles between P.S. and C. R. - The products of each reaction become the reactants of the other.
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Learning Check 1. What does ATP stand for, and what type of molecule is it? 2. How is ATP used in cell? 3. Describe the reaction in which ATP releases energy. 4. Write the overall reaction for aerobic cellular respiration. 5. Aerobic respiration has 2 parts. Which one produces more
ATP? 6. How is lactic acid fermentation different from aerobic
cellular respiration?