Transcript B 3 Energy in Living Systems

B 3.1 Photosynthesis
TSWBAT Summarize the overall process
by which photosynthesis converts solar
energy into chemical energy and interpret
the chemical equation for the process
Where does photosyhthesis
take place?
 Chloroplast:
 Thylakoid-contain
chlorophyll, a
chemical that captures
the sun’s energy and
gives plants their
green color
 Found in the cells in
plant leaves
Photosynthesis
 Photo = “light”
 Synthesis = “to put together”
 Using light energy to put molecules
together
 Convert inorganic molecules to organic
molecules
 6CO2 + 6H2O → C6H12O6 + 6O2
 2 phases
Phase 1: Light-Dependent
Reactions
 Step 1) Absorb light
 Where: Thylakoid
 Chlorophyll, found in the thylakoid
membrane, captures sunlight
 Step 2) Sunlight energy is used to
split water into oxygen & hydrogen
 The hydrogen atoms are forced inside
the thylakoid
sunlight
h+
NADPH
P+ ADP
h+
1
Thylakoid space
h+
2
h+
h20
thylakoid
granum
2h+ +
½O2
ATP
h+
h+
atp synthase
h+ h+
+
+
+
h+
h
h
+
h
+
h
+
h
+
+ h+
h
+
h
h
+
h h+
h h+
+
+ h+
h
+
+
+
h
+ h
h +h
h
h h+
h+ h+ h+
+
+
h
+
h
+
+
h
h
h
+
+
+
h
h + h+ h
h
Thylakoid
membrane
h+
 Step 3) Make ATP and NADPH
 Hydrogen atoms diffuse thru the thylakoid
membrane and make an ATP molecule
 Left over light energy makes NADPH
Phase 2: Dark Reactions
 Where: stroma inside chloroplast
 Jelly-like fluid
 Step 1) Carbon Fixation
 Calvin Cycle
 Carbon dioxide is added to different
organic molecules
Phase 2: Dark Reactions
cont’d
 Step 2) Energy transfer
 The ATP and NADPH made in the light
reactions give their energy away to the
Calvin Cycle
 Used to form G3P molecules
CO2
ATP
ADP
ATP
Calvin Cycle
ADP
NADPH
NADP+
g3p
To cytoplasm
glucose
Phase 2: Dark Reactions
cont’d
 Step 3) Make
Glucose
 G3P leaves the
chloroplast and is
used to make
glucose
G3P
Alternative Pathways
 C4 Plants: plants in hot climates
 Absorb CO2 differently
 Corn, sugar cane
 CAM Plants: plants in dry climates
 Absorb CO2 at night
 Pineapple, orchids, cactus
B 3.2 Cellular
Respiration
TSWBAT Summarize the basic aerobic
and anaerobic processes of cellular
respiration and interpret the chemical
equation for cellular respiration
Step 1: Glycolysis
 Where: Cytoplasm
 Plant & Animal cells
 A 6-carbon glucose molecule is broken
into two, 3-carbon pyruvate molecules
 2 ATP are USED
 2 NADH and 4 ATP are PRODUCED
 Net gain of 2 ATP and 2 NADH
Step 2: Pyruvate Conversion
 Where: Matrix of
the Mitochondria
 The two, pyruvate
molecules are
turned into two,
Acetyl CoA
molecules
 1 NADH is made
Step 3: Aerobic Respiration
 Where: Matrix of the
Mitochondria
 Both Acetyl CoA
molecules enter a
series of reactions
called the Krebs Cycle
 Producing:




2 ATP
6 NADH
2 FADH2
2 CO2
Acetyl CoA
co2
NAD+
NADH
NAD+
Krebs Cycle
NADH
NAD+
ATP
NADH
ADP+P
co2
fADH2
fAD
Step 4: Electron Transport
 Where: Cristae of
the Mitochondria
 Folded inner
membrane
 The NADH and
FADH2 from the
Krebs Cycle give
energy to proteins
found in the cristae.
Matrix
h+ +
h
h+
h+
 The energy is
h+
used to force
h+
+
h
hydrogen atoms
h+
out of the matrix
h+
and into the inner h+ + + h+
h h
membrane space
h+
Inner
Membrane
Space
Step 5: Chemiosmosis
 Hydrogen atoms diffuse thru the cristae
back into the matrix and form ATP
 1 NADH = 2 ATP
 1 FADH2 = 3 ATP
 Oxygen picks up left over hydrogen to
form water.
Inner membrane space
h+
h+
NADh +
FADH2
h+
h+
h+
h+
NAD+
FAD
+
h
+ h+
+
+
h
+
h
h
+
h
h + h+ +
+
h
+
h + h + h h+ + h+
h +h +
h h+
h
h
ATP
P+ ADP
+
matrix
h2o
2h+ +o
Anaeroebic Respiration
 If Oxygen is not available:
 Lactic Acid Fermentation:
 Glucose → Pyruvate → Lactic Acid
 Muscles after exercising
 Alcohol Fermentation:
 Glucose → Pyruvate → Ethanol + CO2
 yeast in bread production
 Produce less ATP