Transcript File - mRS.eGG @ GHS

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Honors Biology
B_3 Energy
B-3.1-3
Standard: B-3 The student will
demonstrate an understanding of
the flow of energy within and
between living systems.
B-3.1-3
Chapter 8 and 9
Pigments
Pigments are molecules that absorb
specific wavelengths (energies) of light
and reflect others.
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Pigments are colored and what we
see is the color reflected.
Energy absorbed boosts electrons
to the next energy level… which is
then transferred
Chlorophyll A – absorbs red and
blue (reflects green)
Chlorophyll B – not as abundant but
increases range of light which can
be absorbed
Accessory Pigments:
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Carotenoids – appear read, yellow,
and orange; over 600 types; protect
chlorophyll from photodamage
Two main types – Xanthophylls and
Carotenes
sustainability.psa-peugeot-citroen.com
Stage 1 Light-Dependent
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LOCATION: Thylakoid
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Photosystem II:
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Electron Transport Chain:
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More light is absorbed by pigments.
High-energy electrons are picked up by NADP+ and form NADPH
ATP Synthase:
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High-energy electrons move from photosystem II to photosystem
I.
Photosystem I:
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Light is absorbed by chlorophyll in they thylakoid membrane.
Light energy is transferred to electrons.
Enzymes split water molecules into electrons, H+ ions, and oxygen
(waste product – released thru stomata)
Protein which allows H+ ions to pass thru the thylakoid membrane.
As ions pass thru the protein rotates and binds ADP and a phosphate
to produce ATP
Products:
 Oxygen (waste product) from photosystem II
 NADPH (transfers energy) from photosystem I
 ATP (transfers energy) from ATP synthase
NADP+  NADPH
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When pigments (like chlorophyll) absorb
sunlight electrons gain a ENERGY – these
electrons need a special carrier molecule.
NADP+ accepts and holds 2 high-energy
electrons and a hydrogen ion (H+)… creating
NADPH
NADPH is works very much like ATP,
transferring energy to be used in other
reactions
This is known as a “reduction” rxn = the gain of
elections (oxidation rxn = loss of electrons)
Stage 2 Light-Independent
 LOCATION:
 Calvin
 Uses
Stroma
Cycle:
ATP and NADPH to produce high-energy sugars
(this process does not require light)
 Six CO2 molecules enter and combine with six 5carbon molecules to produce twelve 3-carbon
molecules
 Energy from ATP and NADPH are used to convert
the 3-carbon molecules
 Two 3-carbon molecules are joined to make a 6carbon high-energy sugar
 Remaining carbon molecules are converted and
reused in the next cycle
 Products
 Glucose
(C6H12O6 ) – 6-carbon sugar
 ADP and NADP+ return to stage 1
Photosynthesis Adaptations
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C3 Plants (MOST plants)
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C4 Plants (sagebrush, corn, many summer plants)
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CO2 is incorporated into a 3-carbon compound
Photosynthesis takes place in the leaf and is more
efficient under cool, moist conditions; requires less
enzymes during normal light
CO2 is incorporated into a 4-carbon compound
Photosynthesis takes place in inner cells (requires
specialized structures) and is faster under intense light
and high temperatures; has less water loss from
transpiration
CAM Plants (cactuses, agaves, some orchids)
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CAM stands for Crassulacean Acid Metabolism because
CO2 is stored in the form of acid (stored)
Stomata open at night and closed during day
Better water efficiency under arid conditions
Can survived dry spells and recover quickly when water
is available
Structure and Function:
Mitochondria
 Matrix
– Contains highly concentrated mixture of
enzymes which participate in the Krebs cycle –
Contains ribosomes which synthesize proteins –
Contain mitochondrial DNA with info for synthesizing
proteins
 Cristae – Folds of the inner membrane; these folds
help increase ATP production
 Inner Membrane – Location of chemical rxns –
Contains electrons transport system (creates proton
gradient) and ATPase complex (uses gradient to
produce ATP from ADP)
 Outer membrane – Permeable to oxygen, pyruvate,
ATP
http://www.ivyrose.co.uk/Biology/Organelles/Structur
e-of-Mitochondria.php
http://hyperphysics.phyastr.gsu.edu/hbase/biology/celres.html
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1 molecule of glucose is broken in half  producing
2 molecules of pyruvic acid (3-carbon compound)
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Glycolysis uses 2ATP to start process and produces 4ATP
= net gain of 2ATP
4 high-energy electrons are passes to an electron
carrier, NAD+ which is then converted into NADH…
NADH carries the high-energy electrons to stage 3 (ETC)
Glycolysis is fast and does NOT require oxygen..
However soon all the available NAD+ become used
up and ATP production stops!
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Without oxygen FERMENTATION will follow… it can
convert NADH back to NAD+
Stage 1
Glycolysis
Stage 2
Krebs Cycle
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Pyruvic acid is broken down into CO2 in a series of energy
extracting rxns – high-energy electrons are transported by
NADH and FADH2 to stage 3.
Krebs cycle is also referred to as the Citric Acid Cycle
because citric acid is produced initially.
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Pyruvic acid enters the mitochondrion
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carbon is removed forming CO2
High-energy electrons are released and picked up by
transporters NAD+  NADH
Coenzyme A joins the 2-carbon molecule forming acetyl-CoA
Acetyl-CoA joins with a 4-carbon molecule producing Citric
Acid
As the cycle continues removing carbons
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CO2 is produced
High-energy electrons are released and picked up by
transporters NAD+  NADH
1 ATP molecule is created
High-energy electrons are released and pickup up by
transporters FAD  FADH2
Stage 3
Electron Transport Chain
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Uses high-energy electrons transported by NADH
and FADH2
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NADH and FADH2 are transported into and along
the electron chain by carrier proteins on the inner
membrane.
At the end of the chain is an enzyme, ATP synthase,
which combines H+ ions with oxygen to form Water
– oxygen serves as the final electron acceptor in this
chain.
As ATP synthase rotates it attaches a phosphate
with an ADP  producing ATP… LOTS OF ATP!
http://iws.collin.edu/biopage/faculty/
mcculloch/1406/outlines/chapter%209/
chap09.htm