Transcript Supplemental PPT notes

Ch. 8 & 9
Photosynthesis
&
Cellular Respiration
Food and
Energy
Heterotrophs –
Eat food
Autotrophs Photosynthesis
Organisms & their Sources of Energy
-Autotrophs: organisms that make their
own food
Ex. Plants, algae, some bacteria
-Heterotrophs: feed on other organisms
Ex. Animals, fungi, some bacteria,
some protists
Chapter Overview: Food &
Energy
Plants
Food
Cell Respiration
(mitochondria)
Animals
ATP
ATP
Energy Molecule – ATP – adenosine triphosphate
• Cells store energy by adding a phosphate group to ADP
• Cells release energy from ATP by subtracting a phosphate
group
High energy bond
ATP= high energy molecule; ADP= low energy molecule
The Big Picture!
CO2
ATP!!
O2
We get our energy from
the food (glucose) plants
made during
photosynthesis when we
eat plants or eat animals
that ate the plants by
cellular respiration.
Green plants
trap energy
from sunlight in
their leaves and
make food
(glucose)
Photosynthesis and Cell Respiration Overview
Process
Photosynthesis
Who?
Autotrophs
Where?
Chloroplast
Cell Respiration
Auto &
Heterotrophs
Mitochondria
Source of energy Sun = light energy Glucose
(food/chem
energy)
Produces/makes? Glucose
ATP (energy)
(food/chem
energy)
Ch. 8-1 Energy and Life
Ch. 8-2: PHOTOSYNTHESIS
Photosynthesis Equation
6CO2 + 6H2O
C6H12O6 + 6O2
reactants
products
Photosynthesis occurs in the Chloroplast
Parts of the Chloroplast:
-thylakoid: flattened sacs that contain pigments
(chlorophyll)
-stroma: protein rich fluid surrounding thylakoid
-grana: stack of thylakoids
Photosynthesis
Pigments absorb light and convert it to
chemical energy (glucose)
Types of pigments:
Chlorophyll a (dark green);
chlorophyll b (light green);
carotenoids (yellow/orange/red)
Pigment - Chlorophyll
Responsible for absorbing and reflecting sunlight
Why do leaves change
color in the fall?
• Leaves contain many light absorbing/reflecting
pigments
• During autumn, when less light is available,
chlorophyll does not reflect as much, allowing
other pigments, which reflect different colors
to show through
Photosynthesis Overview
6CO2 + 6H2O
Carbon
Dioxide
LIGHT ENERGY
Water
C6H12O6 + 6O2
Glucose
Light Energy
CO2 + H2O
Chloroplast
Sugars + O2
Oxygen
Photosynthesis -“The Reaction”
6CO2 + 6H2O --> C6H12O6 + 6 O2
2 Stages of Photosynthesis
1. Light Dependent Rxn
2. Light Independent Rxn (Calvin cycle)
Light Dependent Reactions
1.light energy absorbed (by thylakoids)
2.H2O split, breaking into three pieces
H2O--> O2 + H+ + e3. O2 exits the leaves (becomes our breathing
O2)
4. H+ and e- carried onto step 2 by NADP+ and
ADP
Side Note: High Energy Electron
• Light energy produces high energy electrons in
chlorophyll, which are used in photosynthesis.
• Electron Carrier: accept high-energy electrons
and transfer them to another molecule.
-2 Types:
Name Without e- # of e- picked up Name With eNADP+
2e-
NADPH
FAD +
2e-
FADH
*FAD is used in cell respiration – we’ll talk about this
later!
Light Dependent Reactions
Sun (light
energy)
H2O
NADP+
ADP & P
LDR
thylakoid
eH+
ATP
NADPH
O2
Light Independent (Calvin Cycle)
- Takes place in the stroma
1. CO2 enters thru stomata
2. H+ (from light dependent rxn) is combined
with CO2 to produce
Glucose = C6H12O6
- ATP is a little burst of energy to make the
Calvin cycle start
*Can take place in light or dark
Stomata
CO2 enters leaf through Stomata
H2O and O2 leave through Stomata
CO2
NADP+
ADP & P
Calvin
Cycle
eH+
ATP
stroma
NADPH
Glucose!!
C6H12O6
Glucose C6H12O6
• Where does each atom come from?
–6 C comes from CO2
–12 H comes from H2O
–6 O comes from CO2
Follow the colored atoms!
Sun (light
energy)
CO2
H2O
NADP+
ADP & P
Calvin
Cycle
LDR
(granum)
eH+
O2
ATP
(stroma)
NADPH
C6H12O6
Glucose!!
Factors affecting Photosynthesis
1. Temperature
•
•
Optimal temps 0 – 35°C
Remember, enzymes work at specific temps!
2. Light
•
Too much light will not have an extra effect
on photosynthesis
3. Water
•
Waxy cuticle prevents water loss
Extreme Photosynthesis
• C4 Plants
–
–
–
–
Corn and sugar cane
Hot temps & intense light
Normal amounts of water
Efficient CO2 is obtained even when stomata
are closed
• CAM Plants
–
–
–
–
Hot temps & intense light
Dry (less water)
Cactus
Open stomata at night only!
Ch.9 Cell Respiration
Cellular Respiration
-Glucose is broken down to produce ATP (energy)
-Done by ALL living things (plants and animals)
Location: occurs in mitochondria
Equation:
C6H12O6 + 6 O2  6CO2 + 6H2O + ATP
(the reverse of photosynthesis)
2 Types of Cellular Respiration
1. Aerobic Respiration: O2 required
-produces net total of 38 ATP per
glucose
2. Anaerobic Respiration: occurs
when there is no O2
-produces 2 ATP per glucose
2 POSSIBLE
PATHWAYS
1. Glycolysis
Aerobic = O2
2. Citric Acid
Cycle (Krebs)
No O2
present
2. Alcoholic
Fermentation
OR
3. Electron
Transport Chain
2. Lactic Acid
Fermentation
Anaerobic = No O2
O2
present
3 Stages of Aerobic Cell Resp
1. Glycolysis
• Breaks glucose
• Releases 2 ATP
2. Citric Acid Cycle (Krebs Cycle)
• Releases 2 ATP
3. Electron Transport Chain
• Releases 34 ATP
1. Glycolysis
Electrons carried in NADH
Pyruvic acid
Glucose
Glycolysis
Cytoplasm
2
2. Citric Acid Cycle / Krebs Cycle
Electrons carried in NADH
Pyruvic acid
Glucose
Glycolysis
Krebs
Cycle
Electrons carried
in NADH and
FADH2
(matrix)
Mitochondrion
Cytoplasm
2
2
3. Electron Transport Chain
Electrons carried in NADH
Pyruvic acid
Glucose
Glycolysis
Krebs
Cycle
(Cytoplasm)
(matrix)
Electrons carried
in NADH and
FADH2
Electron
Transport Chain
(cristae)
Mitochondrion
2
2
34
Anaerobic Cell Respiration
•
•
If no oxygen is present…
Fermentation aka Anaerobic Cell Resp occurs
2 types:
–
–
•
Alcoholic Fermentation
Lactic Acid Fermentation
ONLY 2 ATP MADE TOTAL!
** Not efficient! **
Alcohol Fermentation
-done by bacteria and yeast, NOT
animals
1. Glycolysis
2. Product changed into
ethanol (alcohol) + CO2
Example: Yeast in bread; alcohol in wine/beer
Lactic Acid Fermentation
-done by animal cells (humans)
1. Glycolysis
2. Product changed into
lactic acid + CO2
Example: Muscle cramps/fatigue & bacteria in
cheese/yogurt
Summary of Cell Respiration
Relationship
between plants and
animals
Glucose + O2
•Without plants, animals
could not survive and vice
versa!
•Biochemical Pathway – a
set of reactions in which the
products of one reaction is
used as a reactant in the next
reaction.