cell energy (photosynthesis and respiration) notes energy:
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Cell Energy (Photosynthesis and Respiration) Notes Energy: Energy for living things comes from food . Originally, the energy in food comes from the sun. Autotroph - Organisms that use an energy source (such as light from the sun) to produce sugar - PowerPoint PPT PresentationTRANSCRIPT
Cell Energy (Photosynthesis and Respiration) Notes
Energy:• Energy for living things comes from food. Originally,
the energy in food comes from the sun.
• Autotroph- Organisms that use an energy source (such as light from the sun) to produce sugar
• They can make their own food in their cells.• auto = self feedersEx: plants and some microorganisms (some bacteria and
protists)
• Heterotrophs- Organisms that must obtain food (sugar) from another organism.
• Hetero – “other feeder”Ex: animals and most microorganisms
Solar Energy
Process: PhotosynthesisLocation: ChloroplastEnzyme: Rubisco
Pigment: ChlorophyllOccurs in autotrophs
O₂
C6H12O6(glucose)Chemical energy
Process: RespirationLocation: MitochondriaOccurs in: Autotrophs and HeterotrophsPuts a phosphate on ADP to produce ATP (chemical energy)
Some energy lost as HEAT
These energy transformations provide energy for LIFE
CO2 and H2O
Adenine Ribose 3 Phosphate groups (triphosphate)
Cell Energy:• Cells usable source of energy is called ATP• ATP stands for adenosine triphosphate
• ATP is the only molecule the cell can actually use for cell energy. The energy released from breaking down glucose is used to put a phosphate on
Adenosine diphosphate- ADP (2 Phosphates). When ATP provides the energy for the cell it loses a phosphate.
• ADP stands for adenosine diphosphate
Adenine Ribose 2 Phosphate groups
ATP Cycle
ATPLoses a P- Provides energy for all cell work
ADP
Energy from food used to add a P
ATP is like a rechargeable battery
http://media.pearsoncmg.com/bc/bc_0media_bio/blast/index.htm?atp_adp_cycle
• All energy is stored in the bonds of compounds—breaking the bond releases the energy
• When the cell has energy available it can store this energy by adding a phosphate group to ADP, producing ATP
• General formula for photosynthesis:
carbon dioxide + water + light glucose + oxygen
6CO2 + 6H2O + light C6H12O6 + 6O2
Steps of Photosynthesis
1. Light reaction (depends on light)• Traps sunlight• Produces electrons and ATP required to power
the dark reaction• Oxygen given off here
2. Dark reaction, aka Calvin Cycle (does not directly depend on light)
• Uses ATP and electrons from light reaction and CO2 to make glucose
• Diagram Reactants
Products
LightH2O CO2
O2
C6H12O6
Glucose
Chloroplast
LightDependent
Reaction
Calvin Cycle
NADP+ADP + P
ATPNADPH
Summary:• Light Dependent
Reaction—H2O is broken down and light energy is stored temporarily in inorganic energy carriers, ATP and NADPH
• Calvin Cycle—energy is transferred from ATP and NADPH to the organic compound glucose
Cellular Respiration: (2 kinds—Aerobic and Anaerobic)• Cellular respiration is the process by which the energy
of glucose is released in the cell to be used for life processes (movement, breathing, blood circulation, etc…)
• Cells require a constant source of energy for life processes but keep only a small amount of ATP on hand. Cells can regenerate ATP as needed by using the energy stored in foods like glucose.
• The energy stored in glucose by photosynthesis is released by cellular respiration and repackaged into the energy of ATP.
• Respiration occurs in ALL cells and can take place either with or without oxygen present.
Aerobic Respiration: requires oxygen• Occurs in the mitochondria of the cell• Total of 36 ATP molecules produced• General formula for aerobic respiration:
C6H12O6 + 6O2 6 CO2 + 6H2O + 36 ATPglucose + oxygen carbon dioxide + water + energy
Human cells contain a specialized structure – the
mitochondrion – that generates energy.
Overall Reaction
C6H12O6 + 6O2 → 6CO2 + 6H2O + 38 ATP• Overall this is a three stage process1. Glycolysis:
• Occurs in the cytoplasm• Glucose is broken down
2. Krebs Cycle• Breaks down pyruvate into CO2• Occurs in mitochondrial matrix
3. Electron Transport Chain (ETC)• ATP is synthesized
Glycolysis
• Glyco = glucose Lysis = break down• Occurs in the cytoplasm • This stage occurs in BOTH aerobic and anaerobic
respiration• Glucose breaks down into 2 pyruvate (2 ATP are also
made) – Glucose is a 6-carbon sugar – Pyruvate is a 3-carbon molecule (there are two of
them)
Krebs Cycle (Citric Acid Cycle)
• Occurs in the matrix of mitochondria • Main purpose is to generate electrons for use
in ETC• 2 ATP is given off
Electron Transport Chain
• ETC: A series of reactions occur (this is not just one step), to generate ATP and H2O
• Diagram
Glucose GlycolysisElectron
Transport Chain
2
Krebs Cycle
Mitochondria
In Cytoplasm
2 32
Electrons carried in NADH
Electrons carried in NADH and
FADH2
Summary:3 steps: 1st glycolysis
2nd Krebs cycle3rd Electron Transport Chain (ETC)
Anaerobic Respiration: occurs when no oxygen is available to the cell (2 kinds: Alcoholic and Lactic Acid)• Also called fermentation• Much less ATP produced than in aerobic respiration
• fermentation—occurs in bacteria and yeast Process used in the baking and brewing
industry—yeast produces CO2 gas during fermentation to make dough rise and give bread its holes
glucose ethyl alcohol + carbon dioxide + 2 ATP
• Lactic acid fermentation—occurs in muscle cells
Lactic acid is produced in the muscles during rapid exercise when the body cannot supply enough oxygen to the tissues—causes burning sensation in muscles
glucose lactic acid + carbon dioxide + 2 ATP