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BIOLOGY___NOTES_Chapters 8 and 9-Photosynthesis and Cellular Respiration
PHOTOSYNTHESIS-Chapter 8
I.
Energy = ability to do work
A. Autotrophs and Heterotrophs
– Originally most all energy comes from ________
• Plants and some other organisms use the sun’s energy to
produce____________.
• ________________make their own food.
• _________________obtain energy from food they consumer
• Some obtain energy as decomposers
B. Chemical Energy and ATP
• When electrons in bonds are shifted from higher to lower energy
levels,_______________is released as heat and light
• ___________________is one of the principal chemical compounds
used to store and release energy
The 3 Phosphate groups are the key to ATP’s ability to store and release energy
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•
1)_______________________is a compound that looks a lot like ATP,except it
has 2 phosphate groups and this difference is the key to storing
energy.When a cell has energy available it can store small amounts by
adding a phosphate to ADP,making ATP (think of ATP like a fully charged
battery)
• 2)Releasing Energy---Energy stored in ATP is released by breaking the bond
between the 2nd and 3rd phosphates,releasing energy as needed.This can
power such things as _______________across the membrane of the
cell,protein synthesis and muscle contraction
---ATP is exceptionally useful as the _____________________________.
C.Using Biochemical Energy– For active transport---________________________________________________
______________________that pumps Na+ out of cell
and K+ into the cell.ATP keeps the pump working and
keep ions balanced
– ATP powers synthesis of proteins,__________________ and responses to
_______________________________________
– . Cells only have a small amount of ATP,to last seconds…..not good for long
term storage(1 molecule glucose stores 90 x the chemical energy of
ATP).Cells can regenerate ATP from ADP as needed by the energy in foods
like glucose
II.PHOTOSYNTHESI-AN OVERVIEW
– Plants use the energy of sunlight to convert water and CO2 into
sugars and starches,as well as O2
a.Investigating PHOTOSYNTHESIS
– Centuries ago the simple question was did the increase
in tree’s mass come from soil,water or air?
– 1) Van Helmont’s Experiment2
–
1600’s-Belgian physician did an experiment to see if the soil caused plants to
grow,by trying to grow w/o soil….he concluded most of the gain in mass was
from water…..this accounts for ½ the products of photosynthesis.
2)Preistly’s Experiment
– Candle w/jar over it-concluded that air enabled it to burn
– He put a sprig of a plant under the jar and waited a few days,…The candle
could burn briefly under the jar…So he concluded the plant
________________________
3)Jan Ingenhoutz
• showed the plant produced oxygen only if exposed to light
» In conclusion to all 3 experiments,it is concluded
that plants exposed to CO2 and light and
water,produce O2 and carb’s
B. The Photosynthesis Equation
light
• 6 CO2 + 6 H2O--- C6H12O6 + O2

Plants use the sugars to produce complex carb’s such as _______
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C.Light and Pigments
•
•
Photosynthesis also requires light and Chlorophyll (found in Chloroplasts)
White light is a mixture of different wavelengths of light---seen as
____________________
• Plants gather the sun’s energy with light absorbing molecules
called_____________________.
• The principal plant pigment is__________________.-chlorophyll a and b
• Chlorophyll absorbs light well in the blue-violet and red regions,but not well
in the _______________region,which is reflected by leaves
• Contain red and orange pigments like _________________,that absorb light
in other regions
• When chlorophyll absorbs light,much of the energy is transferred directly to
electrons in
Chlorophyll ,raising _________________________-which make photosynthesis
work!!!
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Chapter 8 Photosynthesis Notes
III. The Reactions of Photosynthesis
A. Inside a Chloroplast
 Photosynthesis takes place in the ______________________________.
 The chloroplasts contain saclike membranes called
_______________________________ which are arranged in stacks
known as ________________
 Proteins in the Thylakoids membrane organize chlorophyll and other
pigments into clusters known as _____________________________These are the light –collecting units of the chloroplast
 Light dependent reaction happens in
__________________________________________________________.
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 Light-independent (Calvin-cycle) reaction happens in
_______________________________-region outside thylakoid
membranes
Figure 8-7 Photosynthesis: An
Overview
Section 8-3
Light
CO2
Chloroplast
Chloroplast
NADP+
ADP + P
LightDependent
Reactions
Calvin
Cycle
ATP
NADPH
O2
Sugars
Go to
Section:
B. Electron Carriers
When sunlight excites electrons in chlorophyll ,the electrons gain a great deal of
energy…..They require a carrier--_____________________________________________________________________
_____________________________________________________________________
________________by electron transport chain
 _________nicotinamide adenine dinucleotide phosphate-accepts 2 high
energy electrons along w/ a H+,converting it into _________.This is one
way some of the energy of sunlight is trapped in chemical form
 ____________________________________________________-then
becomes an electron carrier
C. Light –Dependent Reactions
 Require light
 Light is used to produce ATP and NADPH
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Figure 8-10 Light-Dependent
Reactions
Section 8-3
Photosystem II
Hydrogen
Ion Movement
Chloroplast
ATP synthase
Inner
Thylakoid
Space
Thylakoid
Membrane
Stroma
Electron
Transport Chain
Photosystem I
ATP Formation
Go to
Section:
1. Photosynthesis begins when pigments in photosystem II
absorb light.Energy is absorbed by high energy electrons
and passed on to electron transport chain.new electrons
come from the water,and O2 is released into air
2. High –energy electrons move from electron transport chain
from photosystem II to photosystem I.Energy from
electrons is used by molecules in electron transport chain to
transport H+ ions from stroma into the inner thylakoid
space.
3. Pigments in _______________________________ use
energy from light to regenerate electrons.NADP+ picks up
high energy electrons,along w/ H+ ions,at outer surface of
thylakoid membrane…+ H+ ion=NADPH
4. As electrons pass from chlorophyll to
NADP+,more________________are pumped along the
membrane….Eventually ,the inside of the membrane fills
w/ H+ ions……outside of membrane is
_______________________charged…The difference in
charges produces energy for ATP….This is why H+ ions
are so important.
5. H+ ions cannot cross membrane directly…..But, the
membrane contains a protein called
__________________________ that goes across the
membrane and allows H+ ions to pass through it.As H+
passes through, ATP synthase,the protein rotates,binding
w/ ADP and a phosphate group to
make_________________ So….. light-dependent part
makes high energy electrons and also ATP.
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D. The Calvin Cycle
o The ATP and NADPH from light-dependent part are not stable
enough to store energy for more than a few moments….these are used
in _____________________________to make high energy compounds
that can last a long time----it makes ________________.
o
o
o Does not require light so is called
_________________________________
Figure 8-11 Calvin Cycle
Section 8-3
CO2 Enters the Cycle
Energy Input
ChloropIast
5-Carbon
Molecules
Regenerated
6-Carbon Sugar
Produced
Sugars and other compounds
Go to
Section:
1) 6 CO2 molecules enter from the atmosphere .They combine w/ 6
___________________________________.The result is 12 3-C
molecules.
2) 12 3-C molecules convert to higher energy forms….The energy for
this comes from ATP and
________________________________________.
3) 2 3-C molecules removed from cycle…these are used to
produce__________________________________________________
___________________________needed for plant metabolism and
growth.
4) Remaining 10 3-C are converted back into 6 5-C molecules.They
combine w/ 6 new CO2 molecules to begin cycle again.
 2 sets of photosynthetic reactions work together-lightdependent traps energy of sunlight in ____________form and
light –independent reactions(Calvin Cycle) use that chemical
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energy to produce stable,high energy sugars from CO2 and
water….also O2 is produced.
E. Factors affecting Photosynthesis
 Water supply
 Temperature---affects enzymes
 Light intensity----it does reach a
maximum-or optimal level of
light,depending on plant type--eg.conifers only photosynthesize on
__________________________.
Chapter 9-Cellular Respiration/Notes
I.Chemical Pathways
➪ Food serves as a source of raw materials for molecular synthesis and
energy
A. Chemical Energy and Food
➪ 1 g glucose when burned in the presence of O2 releases 3811 calories of
heat energy.
➪ A _______________is the amount of energy needed to raise the
temperature of 1 g water 1 degree C.
➪ The calorie used on food labels is a kilocalorie,or 1000 calories
➪ Cells don’t “burn” glucose.Instead,they gradually release the energy from
glucose and other food compounds.
➪ Begins w/ __________________________-a pathway that releases a small
amount of energy.If O2 is present,it turns to 2 other pathways that release a
lot of energy and if O2 is not present,glycolysis is followed by another
pathway.
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Chemical Pathways
Section 9-1
Glucose
Glycolysis
Krebs
cycle
Fermentation
(without oxygen)
Electron
transport
Alcohol or
lactic acid
Go to
Section:
➪ Final steps of cellular respiration takes place in the _________________
B. Overview of Cellular Respiaration
➪ In the presence of O2,Glycolysis is followed by the Krebs cycle and the
electron transport chain
➪ Glycolysis,electron transport chain and Kreb’s cycle make
up_________________________________-the process that releases energy
by breaking down glucose and other food in the presence of O2
➪ Glycolysis
equation______________________________________________________
➪ Requires O2 ,food and gives off CO2 ,water and energy
➪ The cell has to find a way trap these little bits of energy to make ATP.
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Figure 9–2 Respiration: An
Overview
Section 9-1
Mitochondrion
Electrons carried in NADH
Pyruvic
acid
Glucose
Glycolysis
Krebs
Cycle
Electrons
carried in
NADH and
FADH2
Electron
Transport
Chain
Mitochondrion
Cytoplasm
Go to
Section:
C. Glycolysis= process in which one molecule of glucose is broken in ½ ,producing 2
molecules of __________________________,a 3-C compound
Figure 9–3 Glycolysis
Section 9-1
Glucose
2 Pyruvic acid
To the electron
transport chain
Go to
Section:
1.
ATP Production
➪ 2 molecules of _____ used @ beginning/4 molecules ATP are produced
@ end-net gain of 2 molecules
2.
NADH Production
➪ 4 high energy molecules are removed and passed onto electron carrier
_____________-nictotinamide adenine dinucleotide-these accept a pair of
high energy electrons making ________________ and it passes
electrons onto next molecule.Energy is passed from glucose to other pathways.
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➪ Process is fast so ATP is produced –a lot in a short amount of time.
➪ Does not require O2
➪ A problem:when a lot of ATP is made from glycolysis-NAD+ fills
w/electrons and w/o NAD+,glycolysis stops
D. Fermentation
➪ Follows glycolysis if O2 is not present
➪ _________________________releases energy from food molecules
by making ATP in the Absence of O2.
➪ Cells convert NADH to NAD+ by passing electrons to
_____________acid.This coverts NADH back to carrier
NAD+,allowing glycolysis to continue
➪ Called__________________because it does not require O2.
1) Alcoholic Fermentation
➪ Used by______________________________________
➪ Ethyl alcohol and CO2 are made as waste
Pyruvic acid + NADH-- alcohol + CO2 + NAD+
➪ Causes bread dough to rise due to _____
2) Lactic Acid Fermentation
➪ Fermentation that uses pyruvic acid produced to convert to
lactic acid
➪ Regenerates NAD+ so glycolysis can continue
➪ Pyruvic acid + NADH-- lactic acid + NAD+
➪ Produced in muscles during rapid exercise when the body
cannot supply enough ___ to the tissues.(for ATP production)
➪ Causes a painful burning sensation
➪ Unicellular organisms also produce lactic acid as a waste
during fermentation…..eg .prokaryotes in yogurt
production,buttermilk,sauerkraut…
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Figure 9–4 Lactic Acid
Fermentation
Section 9-1
Glucose
Pyruvic acid
Lactic acid
Go to
Section:
•
•
•
–
–
–
–
–
–
–
II. The Kreb’s Cycle and Electron Transport
At the end of Glycolysis,90 % of chemical energy available in glucose is still
unused,locked in high energy electrons of ____________________
O2 becomes a powerful electron acceptor
Called ______________because these pathways require O2
A. The Kreb’s Cycle
– During the Kreb’s Cycle,pyruvic acid is broken down into ______ in a
series of energy-extracting steps
Because ________________is the 1st compound formed,it is also called
___________________.
– 1) Begins when pyruvic acid produced by glycolysis enters the
_________________.
– 1 C-atom pyruvic acid becomes part of CO2 and gets
released into the air.
– 2) Citric acid is broken down into a 4-C molecule,more CO2 is
released,and _________________are transferred to energy
carriers
For each turn of the cycle,a molecule similar to ADP is converted into a
molecule similar to ATP.
Electron carrier NAD+ changes to ____________
Electron carrier FAD(flavine adenine dinucleotide) changes to
_________________
What happens to each of the Kreb’s Cycle Products?
CO2 released is the source of all CO2 you exhale
__________produced directly can be used for cellular activities
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–
•
•
•
•
•
•
In the presence of O2,high-energy electrons from electron carriers are used
to make large amounts of ATP
Kreb’s Cycle
B.Electron transport
• Kreb’s Cycle produces high-energy electrons passed to NADH
and FADH2
These electrons are passed from the electron carriers to
_______________________,which uses high energy electrons from Kreb’s
cycle to convert ADP into ATP
1)High energy electrons are passed from NADH and FADH2 are passed
along electron transport chain
In eukaryotes,the chain is composed of carrier proteins in the inner
membrane of the mitochondrion.
In prokaryotes,the same chain is in the ____________________
At the end of the chain,an enzyme combines these electrons w/H+ ions and
O2 to form __________
O2,then ,serves as the final electron acceptor of the electron transport
chain,getting rid of wastes(low energy electrons and H+ ions.)
2) Every time 2 high energy electrons transport down the transport
chain,their energy is used to transport H+ across the membrane…..H+ ions
build up in the intermembrane space making it positive…. and the other side
is negative.
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•
3) How does the cell use the charge difference?....The inner membranes of
mitochondria contain protein spheres called ATP synthase….As H+ ions
escape into the proteins,the enzyme rotates,adding phosphate to low energy
ADP to make _____.
On the average,each pair of high energy electrons moves down the
chain,providing enough energy to make 3 ATP from 3 ADP.
Section 9-2
Figure 9–7 Electron
Transport Chain
Electron Transport
Hydrogen Ion Movement
Channel
Mitochondrion
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production
Go to
Section:
C) THE TOTALS:
–
–
–
Glycolysis makes 2 ATP for each glucose molecule
w/o O2,that’s all the energy extracted
w/ O2,the Kreb’s Cycle and the transport chain make 34 more
ATP(36 molecules total,counting glycolsis)----18 x as much
– These 36 molecules of ATP are 38% the total energy in
glucose…actually efficient
– The other 62 % is released as _______________---one reason why you
feel warmer after exercise
D)ENERGY AND EXERCISE
• Glycolysis covers a few seconds of a runners run
• Next –lactic acid fermentation produces ATP w/o O2 present
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•
•
At end of race,runner breathes extra to use O2 to help rid body
of lactic acid
• For long term energy(eg. Cross-country running),cellular
respiration releases a continual supply of ATP
• Muscles store _____________ that help out w/ about 20 min. of
activity
After that,stored fats are broken down
E. Comparing Photosynthesis & Cellular Respiration
– __________________deposits energy by making glucose
– ____________________withdraws energy by breaking down glucose
– Photosynthesis removes CO2 from atmosphere and cellular
respiration puts it back.
– Photosynthesis releases ____ into atmosphere and Cellular
Respiration uses it to release energy from food.
– Cellular Respiration happens in eukaryotes and some prokaryotes
and________________________only happens in plants ,algae and
some bacteria.
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