topic 5: cellular energy after studying this topic you should be able to –describe the importance...
TRANSCRIPT
Topic 5: Cellular EnergyTopic 5: Cellular Energy• After studying this topic you should be able to
– Describe the importance of energy in the cell– Describe the First Law of Thermodynamics– Describe the Second Law of Thermodynamics– Explain how energy is stored in the bonds of ATP– Outline the uses of ATP in the cell
• Energy is the ability to do work• Where do organisms obtain
their energy?– FOOD!!!
Importance of Cellular EnergyImportance of Cellular Energy
Organisms Obtain Food in Two WaysOrganisms Obtain Food in Two Ways• Autotrophs
– Use sunlight directly to make their own food
– Examples: plants (trees, flowers, grass), photosynthetic algae
• Heterotrophs– Consume food, such as
plants and animals – Examples: animals (birds, reptiles,
fish, mammals, insects) In both autotrophs and heterotrophs,
energy transfers are occurring!
Energy Relationships: ThermodynamicsEnergy Relationships: Thermodynamics• The study of energy relationships is called thermodynamicsFirst Law of Thermodynamics
– Energy cannot be created or destroyed, but can be changed from one form into another
• Energy trapped by plants during photosynthesis is not destroyed when plants are eaten by a heterotroph...it just changes form
• Energy passes from organism to organism • At each passing of energy some energy is lost as heat
Energy Relationships: ThermodynamicsEnergy Relationships: Thermodynamics• Second Law of Thermodynamics
– All conversions of energy produce heat, which is waste energy and is not useful for life processes
• When a muscle cell uses chemical bond energy to contract, not all the energy is used for movement
• Some energy is given off as heat, which results in an increase in body temperature during exercise
• Heat is considered to be waste energy in the body, because it cannot perform any work in the cell
ATP: Adenosine TriphosphateATP: Adenosine Triphosphate• Burning glucose (sugar) with oxygen
outside a living system produces a large amount of energy!
• The amount of energy produced would destroy a cell if released all at once!
• Cells actually store most of the energy produced by the combustion of glucose in a molecule called ATP
(Adenosine TriPhosphate)
Gummy bear combustion
ATP ATP
Adenine
Ribose3 phosphate groups
Special High Energy Bond
From ADP to ATP? During cellular reactions (i.e. When we eat) a THIRD phosphate
group is added to ADP… creating ATP!
ATP then stores this energy until it is required by the cell for life processes (like muscle contractions)
ADPPhosphate
ATP
2. How is ATP broken down to release energy?
ATP ADP + P + energy
From ADP to ATP?
High energy bond is BROKEN to RELEASE energy!
From ADP to ATP?
3. What happens when energy is stored?
ADP + P ATP
High energy bond is FORMED to STORE energy!
Energy Release Cycle in the CellEnergy Release Cycle in the Cell
ATP
ADP
Energy and phosphate released
Energy and phosphate
stored
ATP – P ADP
ADP + P ATP
Photosynthesis: Introduction• Most organisms obtain their energy
indirectly or directly from the sun• Through photosynthesis, autotrophs
(plants) capture light energy from the sun
• The captured energy is stored in chemical bonds of many different molecules like sugars (glucose)
• Consumers eat autotrophs (or other animals that have eaten plants) to obtain energy from chemical bonds
Topic 6: Photosynthesis
photo synthesis
“light” “to make or build”
Purpose: to turn energy from the sun into energy that can be used by the plant (chemical)
Result: creation of glucose and O2 gas
Photosynthesis EquationPhotosynthesis Equation
6H2O C6H12O6 +water glucose oxygen
6CO2 +Carbon dioxide
6O2
sunlight
Chlorophyll (in
chloroplasts)
Reactants Products
PhotosynthesisPhotosynthesis
Oxygen
http://www.wonderville.ca/asset/photosynthesis Interactive video on
photosynthesis. Good for self practice
thylakoids =
“pancake” shaped structures inside a chloroplast. Site of light reactionsStroma = fluid surrounding thylakoids. location of chemical reactions that produce glucose. Site of light independent reactions
• In almost all producers, photosynthesis occurs inside cellular organelles called chloroplasts
Photosynthesis Song
Click here to listen to the Photosynthesis
Song!
• Pigments in the chloroplasts capture radiant energy from the sun. The most important pigment is the green pigment chlorophyll. Chlorophyll absorbs red and blue wavelengths and reflects green light.
Why are Plants Green?
Photosynthesis: Two Reactions• Light Reactions:
– radiant energy is trapped and converted to ATP and to another energy storage molecule known as NADPH
– Water (H2O) is split into hydrogen and oxygen– This is where the oxygen gas (which is a by-product of
photosynthesis) is produced
Light-DependentReactions
Light Energy
O2
ATP
NADPHWater
Thylakoid
• Light-Independent Reactions (Dark Reactions)– Given name not because they occur in the dark!!– Light is not necessary for them to occur– Energy stored in ATP and NADPH during light reactions
combine with carbon dioxide to produce glucose
Light-DependentReactions
O2
ATP
NADPH
Photosynthesis: Two Reactions
Light-IndependentReactions (dark)
Sugar(glucose)(C6H12O6)
Light Energy
Water
Thylakoid Stroma
Calvin-BensonCycle
– Water splits into oxygen and hydrogen.
– The oxygen is given off as a gas.
– Hydrogen enters the thylakoid and is added to NADP+ to form NADPH, a high energy molecule
Light Dependent Reactions
Light-DependentReactions
Light Energy
O2
WaterNADPH
H+
NADP+
=NADPH
Thylakoid
Chemiosmosis is the name for the process in which ATP is created when hydrogen atoms move out of the thylakoid membrane through an enzyme called ATP synthase
Light Dependent Reactions
Light-DependentReactions
Light Energy
O2
WaterNADPH
ATP
H+
ATP synthas
e
H+ADP +
Pi
ATP
Thylakoid
Chemiosmosis
In the Calvin-Benson cycle, the carbon atom in carbon dioxide is used to make glucose.
Light Independent Reactions in the Stroma
CO2 C6H12O6
PhotosynthesisEnergy Reactions Location
Light energy captured from the Sun
Water splits, forms oxygen
Large amounts of ATP produced
Chemiosmosis
Energy from the light-dependent reactions is used to make glucose
Calvin-Benson cycle
thylakoid membrane
thylakoid membrane and stroma
stroma
http://highered.mheducation.com/sites/0073532223/student_view0/chapter8/3d_animation_-
_photosynthesis.html
Photosynthesis video 7:24
Explain the results of the graphs.
Explain the results of the graphs.
Photosynthesis Lab (Bozeman) 6:44 https://www.youtube.com/watch?v=ZnY9_wMZZWI
Products
Reactants
1. Sunlight energy 2. Carbon
dioxide 3. Water
4. glucose
5. Oxygen
6. chloroplast
Photosynthesis Song (Let’s get into this rap)
Click here to listen to the photosynthesis rap!
http://www.youtube.com/watch?v=pE82qtKSSH4
Topic 7: Cellular RespirationTopic 7: Cellular RespirationNecessary for the life of EVERY cell (both plants and animals)Cellular respiration provides energy in the form of _____ for
processes in the cell such as:• Active transport – the movement of molecules across the cell
membrane against the concentration gradient• Phagocytosis – cell intake of large food particles• Muscle contraction – energy is required to move muscles
Aerobic RespirationAerobic Respiration
Reactants Products
CHEMICAL EQUATION:
C6H12O6 + 6O2 6CO2 + 6H2O + ATP
Aerobic•Uses oxygen•Produces 36 ATP
Anaerobic•Does not use oxygen•Produces only 2 ATP
CellularCellular RespirationRespiration
Two Types of Cellular Respiration
https://www.youtube.com/watch?v=00jbG_cfGuQ
Anaerobic
respiration in
cytoplasm
Crash course in cellular respiration 13:25
Aerobic Cell Respiration: Part 1• Two major steps in aerobic respiration
– #1. Glycolysis (occurs in cytoplasm)• Series of chemical reactions that break the glucose
molecule into two small pyruvic acid molecules• Only two molecule of ATP are produced in glycolysis
Glucose 2 pyruvates
Cell Respiration: Step 1 – Glycolysis (Occurs in the cytoplasm)
2 ATP
#2. Krebs Cycle (occurs in mitochondria)• Pyruvic Acid moves into the mitochondrion where it is
used to make to release a large amount of ATP, carbon dioxide, water and waste heat energy
ElectronTransport System
Kreb’s
Cycle
CO2
NADH
FADH2
2 ATP 32 ATP
H+ ions move through ATP synthase creating ATP through the process of chemiosmosis. (Just like photosynthesis)
H2O
O2
Products
Reactant
Reactants
36 ATP
A.Glycolysis 1. Glucose
2. Pyruvic acid3. oxygen
5. water
4. Carbon dioxide
6. Energy (ATP)
7. Mitochondrion
B. Krebs cycle
Alcohol Fermentation• occurs in yeast cells
Muscle Fermentation• Occurs in muscle cells
AnaerobicAnaerobic RespirationRespiration
Two types of anaerobic respiration (fermentation)
• Cell respiration WHEN OXYGEN IS NOT PRESENT! • Only two ATP produced due to the incomplete breakdown of
glucose• Occurs in the cytoplasm of yeast cells and muscle cells
• Have you ever eaten bread? Ever drank an alcoholic beverage? Enjoyed a warm mug of apple cider? Well, then you’ve experienced alcohol/ethanol fermentation!
Alcohol Fermentation(yeast cells):
Glucose 2 pyruvic acidsEthyl Alcohol
and CO2
2 ATP
Remember: This happens when there is
no oxygen
Have you ever worked out for a long period of time and were out of breath? How did your muscles feel after? If they were sore and cramped, then you’ve experienced the effects of lactic acid build up!
Muscle Fermentation (muscle cells):
Glucose 2 pyruvic acids Lactic Acid (aka Lactate)
2 ATP
Remember: This happens when there is
no oxygen
Anaerobic Cell Respiration AnswersAnaerobic Cell Respiration AnswersFill in the following chart:
Type of Respiration
Reactants Products Amount of ATP Produced
Aerobic
AnaerobicAlcohol Fermentation
Anaerobic Muscle Fermentation
Pyruvic acid
Carbon dioxide 34
Glucose Ethyl alcohol
2
Glucose Lactic Acid 2
CO2
Oxygen Water
Cellular Respiration Song (by the Black Eyed Peas? :)
Click here to listen to the cellular respiration
song (first half of the song)!
Comparison of Photosynthesis and Comparison of Photosynthesis and RespirationRespiration
Cellular RespirationPhotosynthesis
Reactants: Reactants: 6CO6CO2 2 + 6H+ 6H22OO
Products: Products: CC66HH1212OO66 + 6O + 6O22
- Energy is Energy is REQUIREDREQUIRED
Overall Chemical Reaction:Overall Chemical Reaction:6CO6CO2 2 + 6H+ 6H22O O C C66HH1212OO66 + 6O + 6O22
Reactants: Reactants: CC66HH1212OO66 + 6O + 6O22
Products: Products: 6CO6CO2 2 + 6H+ 6H22OO
- Energy is Energy is PRODUCEDPRODUCED
Overall Chemical Reaction:Overall Chemical Reaction:CC66HH1212OO66 + 6O + 6O2 2 6CO 6CO2 2 + 6H+ 6H22O O
Notice that photosynthesis and cellular respiration are opposite
reactions!
Comparing photosynthesis & cell respirationComparing photosynthesis & cell respirationStatement Photosynthesis Respiration
Occurs in green plants, algae and blue green algae
Occurs in both plants and animals
Uses carbon dioxide
Produces carbon dioxide
Uses glucose
Produces glucose
Uses water
Produces water Requires sunlight
Requires chlorophyll
Happens in the mitochondrion
Happens in the choloroplasts
Relationship between Photosynthesis Relationship between Photosynthesis and Respirationand Respiration
Photosynthesis (in chloroplasts)
Cellular Respiration (in mitochondria)
C6H12O6
O2
CO2
H2O
ATP