Transcript Chapter 5 Notes - Industrial ISD

Photosynthesis
&
Cellular
Respiration
Energy and Living Things
Where does energy in
food come from?
 Directly or indirectly,
almost all energy
comes from the sun
Metabolism
 Metabolism involves either using
energy to build molecules or
break down molecules in which
energy is stored.
Photosynthesis
Photosynthesis- light
energy is changed
into chemical
energy (sun to
sugar).
Autotrophs
Autotrophs  organisms that can
use energy from the sun
through photosynthesis
Examples: plants, algae, some
protists and bacteria
Heterotrophs
Heterotrophs  organisms
that get energy from food
instead of directly from the
sun
Examples: humans, animals,
fungus, some protists and
bacteria
Flow of Energy
****Use different organisms!!!!
Cellular Respiration
Cellular RespirationMETABOLIC PROCESS
SIMILAR TO BURNING FUEL;
RELEASE OF ATP (TAKES
PLACE IN MITOCHONDRIA)
ATP- Adenosine
Triphosphate
 ATP is made up of:
1 adenine,
1 ribose, and
3 phosphates.
 When the outer
phosphate group
detaches from
ATP, energy is
released.
ATP- Adenosine Triphosphate
Flow of Energy
When you eat a hamburger, you get
energy from the sun (indirectly). The
beef comes from a cow that ate
grass. The bun, lettuce, and
tomatoes all come from plants
Stages of Photosynthesis
Stage 1 (Absorption of Light Energy):
Energy is captured from sunlight.
Stages of Photosynthesis
Stage 2 (Conversion of Light Energy):
LIGHT ENERGY IS
CONVERTED TO CHEMICAL
ENERGY WHICH IS STORED
IN ATP. THE ENERGY
CARRIER MOLECULE IS
NADPH.
Stages of Photosynthesis
Stage 3 (Storage of Energy):
Chemical energy stored in ATP and
NADPH powers the formation of
organic compounds using CO2.
***Stage 3 can happen in absence of
sunlight IF stage 1 & 2 have occured
Equation for Photosynthesis
6 CO2 + 6 H2O
Light
C6H12O6 + 6 O2
Glucose
(sugar)
Photosynthesis
Stage 1: Absorption of
Light
 Sunlight contains a mixture of all the
wavelengths (colors) of visible light.
 Pigments- contain light absorbing
substances. The color an object is
tells us what color is reflected by that
object and is not absorbed.
Stage 1: Absorption of
Light
 Chlorophyll is the main pigment
involved in photosynthesis. It
absorbs blue and red and reflects
green and yellow.
 The reflection of green light makes
many plants look green, especially
leaves. The leaves are where most
photosynthesis occurs.
Stage 1: Absorption of
Light
 2 types of chlorophyll:
chlorophyll a and chlorophyll b
 Yellow pigments are carotenoids
(Carotenoids are responsible for fall
colors in leaves and the color of fruits,
vegetables, and flowers.)
Stage 1: Absorption
of Light
Oxygen is produced in the 1st step of
photosynthesis. Where does this
happen?
Leaf
Chloroplast
Thylakoids
Draw a
chloroplast with
thylakoids
labeled.
Stage 1: Absorption of Light
When light is absorbed by the
thylakoids, energy is transferred to
electrons in chlorophyll . The electrons
get “excited” and jump from chlorophyll
to other nearby molecules in the
thylakoid membrane. The electrons are
used to power the 2nd step of
photosynthesis.
Stage 1: Absorption of Light
The excited electrons are replaced by
electrons from water molecules.
The water molecules are split by an
enzyme inside the thylakoid.
H+ electrons are taken by the chlorophyll,
leaving oxygen.
Stage 2: Conversion of
Light
 An excited electron is passed along the
membrane like a ball being passed down
a line of people.
 ETC (Electron Transport Chain)- a
series of molecules through which
excited electrons are passed along a
thylakoid membrane
Stage 1 & 2 Summary:
(Light Dependent)
Pigment molecules in the thylakoids of
chloroplasts absorb light energy.
Electrons in the pigments are
excited by light and move through
ETC’s in the thylakoid membranes.
Continued on next slide
Stage 1 & 2 Summary:
(Light Dependent)
These electrons are replaced by
electrons from H2O split by an
enzyme. Oxygen atoms from H2O
molecules combine to form oxygen
gas (O2). Hydrogen ions accumulate
inside setting up a concentration
gradient that provides the energy to
make ATP and NADPH.
Stage 3: Storage of Energy
 Carbon atoms from carbon
dioxide in the atmosphere are used
to make organic compounds in
which chemical energy is stored.
Stage 3: Storage of Energy
The transfer of carbon dioxide to
organic compounds is called carbon
dioxide fixation.
Stage 3: Storage of Energy
Calvin Cycle- a series of enzyme-
assisted chemical reactions that
produces a 3-carbon sugar.
Factors that affect
Photosynthesis include:
1). Amount of light
2). Amount of CO2
3). Temperature
(certain temps
can inactivate
certain enzymes)
Cellular Respiration
Equation
C6H12O6 + 6O2
enzymes
6CO2 + 6H2O + energy
(ATP)
Cellular Respiration
 Most Foods we eat contain
USEABLE ENERGY. But
before you can use that
energy it is transferred to
ATP
Cellular Respiration
Cellular Respiration- the process
cells use to make energy; uses
glucose and oxygen to make
ATPs which are necessary to run
our cells and body
Cellular Respiration
 OXYGEN in the air you
breathe make the production
of ATP more EFFECIENT,
although some is made
without oxygen.
Cellular Respiration
 Metabolic process that
REQUIRES OXYGEN is called
AEROBIC.
 A metabolic process that DOES NOT
REQUIRE OXYGEN is called
ANAEROBIC meaning “without air”.
Stage One- Breakdown of
Glucose
 Primary fuel for cellular
respiration is GLUCOSE
 GLUCOSE is broken down in the
CYTOPLASM during the process
called GLYCOLYSIS.
Stage Two: Production of
ATP
 When OXYGEN is present, PYRUVATE
produced during glycolysis enters a
MITOCHONDRION and is converted to
a two-carbon compound.
 This reaction produces 1 carbon dioxide,
1 NADH molecule, and 1 two-carbon
acetyl that is attached to a molecule
called a COENZYME A (CoA) forming a
compound called ACETYL CoA.
• Acetyl-CoA enters a series of enzyme assisted
reactions called the KREB’S CYCLE
Electron Transport Chain
Electron Transport Chain
 In AEROBIC RESPIRATION
electrons donated by NADH and
FADH2 pass through an
ELECTRON TRANSPORT
CHAIN located in the INNER
membranes of
MITOCHONDRIA.
STEPS FOR ELECTRON
TRANSPORT CHAIN
1.The electron transport
chain pumps
HYDROGEN ions out of
the inner compartment.
Label on picture.
STEPS FOR ELECTRON
TRANSPORT CHAIN
2. At the end of the chain
ELECTRONS and
HYDROGEN ions
combine with OXYGEN
forming WATER.
Label on picture.
STEPS FOR ELECTRON
TRANSPORT CHAIN
3. ATP is produced as
hydrogen ions diffuse into
the inner compartment
through a CHANNEL
protein.
Label on picture.
Fermentation in the
Absence of Oxygen
 What happens when there is not
enough oxygen for aerobic respiration?
 Under ANAEROBIC conditions,
electrons carried by NADH are
transferred to PYRUVATE produced
during GLYCOLYSIS. This recycles
NAD+ needed to continue making ATP.
Fermentation in the
Absence of Oxygen
 The recycling of NAD+ using an
ORGANIC HYDROGEN
ACCEPTOR is called
FERMENTAION.
Two Types of Fermentation
1). Lactic Acid Fermentation
 A three-carbon PYRUVATE is
converted to a three-carbon
LACTATE.
 Lactate is the ion of an
organic acid called LACTIC
ACID.
Examples of Lactic Acid
fermentation
 Used in the production of
YOGURT and CHEESE; also
during VIGOROUS exercise a
build up of lactate causes
muscle SORENESS.
Two Important Types of
Fermentation
2). Alcoholic Fermentation
 A three-carbon PYRUVATE is
broken down into ETHANOL
(ethyl alcohol).
 CARBON DIOXIDE is released in
the process.
Examples of alcoholic
fermentaion
 Used in the preparation of WINE,
BEER, rising of BREAD dough,
and CARBONATION of alcoholic
beverages.
Although both processes use electron carriers
and form ATP, they accomplish quite different
tasks as shown in the table.
Table 9.1 Comparison of Photosynthesis and Cellular Respiration
Photosynthesis
Cellular Respiration
Food synthesized
Energy from sun stored in glucose
Food broken down
Energy of glucose released
Carbon dioxide taken in
Carbon dioxide given off
Oxygen given off
Oxygen taken in
Produces sugars from PGAL
Produces CO2 and H2O
Requires light
Does not require light
Occurs only in presence of
chlorophyll
Occurs in all living cells