Download Photosynthesis & Respiration

Photosynthesis & Respiration
Cell Energy
(Photosynthesis and Respiration)
Energy:
•Energy for living things comes from food. Originally, the
energy in food comes from the sun.
• Organisms that use light energy from the sun to
produce food—autotrophs (auto = self)
Ex: plants and some microorganisms (some bacteria
and protists)
• Organisms that CANNOT use the sun’s energy to
make food—heterotrophs - must eat their food
Ex: animals and most microorganisms
Cell Energy:
•Cells usable source of energy is called ATP
•ATP stands for adenosine triphosphate
Adenine
Ribose
3 Phosphate groups
• ADP stands for adenosine diphosphate
Adenine
Ribose
2 Phosphate groups
• 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
• ATP is converted into ADP by breaking the bond
between the second and third phosphate groups
and releasing energy for cellular processes.
Importance of ATP!
1. ALL organisms release ATP from the break down of
glucose during cellular respiration
2. ATP powers the activities of the cell and allows living
things to do work
3. ATP/ADP is a cycle that releases/stores energy for cell
processes
4. ATP is used to actively transport material across the cell
membrane
Photosynthesis
•Photosynthesis is the process by which the energy of
sunlight is converted into the chemical energy of glucose
• Photosynthesis occurs in the chloroplasts of plants
• Light absorbing compound is a pigment
• pigments absorb some wavelengths of light and reflect
others
• the color our eyes see is the color that the pigment
reflects
• Chlorophyll is the pigment inside the chloroplast the
absorbs light for photosynthesis
As the chlorophyll in leaves decays
in the autumn, the green color fades
and is replaced by the oranges and
reds of carotenoids.
•General formula for photosynthesis
:
sunlight
carbon dioxide + water
—>
glucose + oxygen
sunlight
6CO2
+ 6H2O
—>
C6H12O6 + 6O2
Light Reaction
Takes place in the thylakoid
membrane
• (contains chlorophyll)
Reactants needed for the light reaction:
• Water, Light, ADP, NADP+
Products made from light reaction and USED in dark
reaction:
• ATP energy to make sugar
• NADPH supplies e- and H to make C6H12O6
Oxygen is released into the air
Dark Reaction
(Calvin Cycle)
Takes place in the stroma
Reactants needed for the dark reaction:
• CO2, ATP, NADPH
Products made from the dark reaction USED in light reaction
are:
• ADP returns to the light reaction to make more ATP
• NADP returns to the light reaction to pick up more
electrons and Hydrogens
Glucose is made in the dark reaction for use throughout the
organism.
Summary:
Light Reaction
• H2O is broken down and
light energy is stored
temporarily in ATP and
NADPH.
• Oxygen released.
Calvin Cycle (Dark Reaction)
• energy is transferred
from ATP and NADPH to
the organic compound
glucose
Location Reactants
Light
Reaction
Thylakoid
H2O
Light
ADP and
NADP from
dark reaction
Dark
Reaction –
Calvin
Cycle
CO2
Stroma
Products
Release
ATP – energy to
make sugar
NADPH –
electrons and
Hydrogen to
make glucose
O2 to the air
ADP and NADP
back to light
reaction
ATP and
NADPH from
light reaction GLUCOSE
Reactants
•Diagram
Light
H2O
CO2
NADP
ADP + P
Light
Dependent
Reaction
Chloroplast
O2
Calvin
Cycle
ATP
NADPH
Products
C6H12O6
Glucose
Cellular Respiration
•Process where energy of glucose is released in the cell to
be used for life processes (movement, breathing, blood
circulation, etc…)
• Respiration occurs in ALL cells
• Takes place in the mitochondria
• Can take place either with or without oxygen present.
Aerobic Respiration
• requires oxygen
• occurs in the mitochondria
• Net total of 36 ATP produced
• Formula
C6H12O6 + 6O2
glucose + oxygen
Human cells contain a
specialized structure – the
mitochondrion – that
generates energy.
6 CO2 + 6H2O + 36 ATP
carbon dioxide + water + energy
STEP 1: Glycolysis
-First pathway of respiration - ALL organisms perform
this (aerobic AND anaerobic)
-Takes place in the cytoplasm on enzymes
-Splits glucose in half to form 2 pyruvic acid (pyruvate)
-Gives off enough energy to make 2 ATP
STEP 2: Krebs Cycle
-Also called the Citric Acid Cycle
-pyruvic acid is broken down and CO2 is released
-Occurs in matrix of mitochondria
STEP 3: Electron Transport Chain
-electrons from Krebs Cycle converts ADP into ATP
-Occurs along inner membrane (cristae) of
mitochondria
• Diagram - Cellular Respiration
Electrons carried in NADH
Mitochondria
In Cytoplasm
Glucose
Krebs
Cycle
Glycolysis
2
2
electrons
carried in
NADH
Electron
Transport Chain
32
Summary:
3 steps: 1st glycolysis
2nd Krebs cycle
3rd Electron Transport Chain (ETC)
Anaerobic Respiration or Fermentation:
- pathway organisms use when no oxygen is available to
the cell
- Mostly unicellular organisms (low energy requirement)
- Much less ATP produced than in aerobic respiration
- Goes through glycolysis first, which makes 2 ATP
- 2 kinds: Lactic Acid and Alcoholic
Lactic acid
Glycolysis
Glucose
2 Pyruvate
+ 2 ATP
Ethyl alcohol + CO2
Lactic Acid Fermentation
pyruvic acid
-Performed by muscle cells (animals)
-Lactic acid is produced in the
muscles during rapid exercise,
when the body cannot supply
enough oxygen to the tissues
-causes a burning sensation in
muscles
-Also occurs in some bacteria
-Used to create food products like
yogurt and cheese
lactic acid
Alcohol fermentation
Pyruvic acid
ethyl alcohol + carbon dioxide
-occurs in bacteria and yeast
-Process used by baking and brewing industry
-yeast produces CO2 gas during fermentation to make
dough rise and gives bread its holes
Cellular Respiration Diagram
Anaerobic Respiration
Cytoplasm
C6H12O6
glucose
Alcoholic fermentation
Bacteria, Yeast 2 ATP
glycolysis
Lactic acid fermentation
Muscle cells
2 ATP
Aerobic Respiration
36 ATP
Krebs
Cycle
ETC
Mitochondria
Photosynthesis and Respiration
Products of one
reaction are the
Reactants of the other
(and vice versa)
• Cells require a constant source of energy for life processes, but
keep only a small amount of ATP on hand. Cells can make more
ATP 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.
Energy Flow: Producers
photosynthesize and provide glucose
for consumers
Carbon Cycle: Producers remove
CO2 from atmosphere while consumer
replaces CO2 during respiration
Water Cycle: Producers take water
out of ecosystem and consumers
produce water during respiration (also
O2 removed by producer and returned
by consumer)