Transcript PHOTOSYNTHESIS & CELLULAR RESPIRATION

PHOTOSYNTHESIS &
CELLULAR RESPIRATION
•
ENERGY IN A
CELL!!
• Your body requires energy in order to
function…from your heart beating to
intense workouts.
• Energy is essential to LIFE!!
• Your body stores energy in a molecule
called ATP’s (adenosine triphosphate)
• This is a quick source of energy for any
organelle in the cell that needs it.
• The energy inside an ATP molecule is
released when it loses a phosphate and
becomes ADP (adenosine diphosphate)
• ADP is like a partially charged battery
while ATP is a fully charged battery.
“Chlorophyll, more like
borophyll!”
• Sorry, just had to
make an effort to take
away the chance for
the smart elacks that
will be lucky to make a
C in this class to use
this line and get a
laugh. Now they can
pay attention for the 5
minutes their little
pea-size brain will
allow them…
PHOTOSYNTHESIS
• Photosynthesis
is a process in
which solar
energy in the
form of light is
converted into
chemical
energy within
carbohydrate
molecules.
EQUATION FOR
PHOTOSYNTHESIS
•
6 CO2 + 6 H2O + light ---> C6H12O6 + 6 O2
PHOTOSYNTHESIS
• Photosynthesis
occurs in
organelles,
present in
green plants
and certain
algae, called
Chloroplasts.
Chloroplast
Chloroplast
CHLORPLAST
• A chloroplast is filled with stacks of
membrane sacs called thylakoids.
• Thylakoids are stacked in columns of
grana.
Chloroplast
• A chloroplast usually
has dozens of
granum.
• They are suspended
in a fluid matrix
called the stroma.
• Chlorophyll molecules
are embedded in the
thylakoid membranes.
This is a close up version of a
chloroplast in a leaf.
Chloroplast
• These
chloroplasts
contain the
green
pigment
called
chlorophyll.
CHLOROPHYLL
Chlorophyll- pigment found
in plants it will absorb red,
blue, and violet better than
other colors.
• Green light is primarily
reflected so most leaves
appear green to us.
• There are two types of
chlorophyll a and b
•
CHLOROPHYLL
• Notice how Chlorophyll a absorbs light mostly in the
blue-violet and red regions.
• Chlorphyll b absorbs light in the blue and red regions
more.
CHLOROPHYLL
• Because light is a form of energy, any
compound that absorbs light also absorbs
the energy in that light.
• When chlorophyll absorbs light much of the
energy is transferred directly to electrons in
the chlorophyll molecule, raising the energy
available in these electrons.
CHLOROPHYLL
• Electrons carriers are seen throughout the
Photosynthesis concept.
• They are compounds that can accept highenergy electrons and transfer them along
with most of their energy to another
molecule.
– NADP+
– ADP
NADPH
ATP
2 REACTIONS OF
PHOTOSYNTHESIS
• Photosynthesis involves 2
reactions:
1. Light Reaction.
2. Calvin Cycle.
(Also called Light Independent
Reaction and Dark Reaction.)
STOMATA
• The stomata are
important for the
exchange of gases
by diffusion
between the
outside air and
intercellular spaces
for respiration and
also for the
evaporation of
water by
transpiration.
• Notice how the equation for photosynthesis
relates to the reactions shown in the
diagram below.
6CO2 + 6H2O + Energy
•
C6H12O6 + 6O2
Melvin Calvin (1911 –1997)
• Again, this is also
known as the
Calvin Cycle
• Named after the
American scientist
Melvin Calvin, who
worked out the
details of this cycle
in 1948
• Won Nobel Prize in
chemistry in 1961
http://www.brainpop.com/science/plantsandanim
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CELLULAR
RESPIRATION
C6H12O6 + 6O2 ---> 6 CO2 + 6 H2O + Energy
CELLULAR RESPIRATION
• The process by which living
organisms obtain energy from
the bonds of food.
• There are two important ways
the cells can harvest energy
from food….cellular respiration
and fermentation
AEROBIC RESP.
• Aerobic respiration occurs
when oxygen is present.
• Aerobic respiration produces
a relatively large amount of
energy (ATP)
ANAEROBIC RESP.
• Anaerobic respiration occurs
when oxygen is not present.
• Produces few ATP’s
• Anaerobic respiration may
also be called fermentation.
WHAT IS ATP?
• (adenosine triphosphate)
compound that contains 3
high energy phosphate bonds
and is an important source of
energy for cells
ATP
CELLULAR RESPIRATION
• Cellular Respiration consists of 3
major stages:
• Glycolysis
• Krebs Cycle
• Electron Transport Chain..(ETC)
GLYCOLYSIS
• They (CR and Fermentation) both
start with the Glycolysis
• The 1st stage of cellular
respiration.
• Occurs in the cytoplasm of the
cell.
• Occurs in both aerobic and
anaerobic conditions.
• BUT Does NOT require oxygen
GLYCOLSIS
• This metabolic pathway breaks
down glucose (produced in
photosynthesis) to 2 molecules
of pyruvate
• There is a net gain of 2 ATP
molecules.
KREBS CYCLE
• Also known as citric acid
cycle
• 2nd phase of aerobic
respiration
• Occurs in the Mitochondria
Kreb Cycle
• The process of Kreb Cycle is
essentially removing carbon
dioxide, getting out energy in the
form of ATP, NADH and
FADH2, and lastly regenerating
the cycle.
Kreb Cycle
• The Kreb Cycle has a by-product of
CO2
• Energy is carried to the ETC by two
electron carriers….NADH and
FADH2
• A total of two ATP’s are produces
through the Kreb Cycle
Hans Krebs (1900 – 1981)
• Krebs cycle named after
Hans Krebs, biochemist
who demonstrated its
existence
• Born in Germany, son of
Jewish physician, forced to
leave Nazi Germany in
1933
• Spent rest of life in Great
Britain
• Discoveries were initially
rejected
• Won Nobel Prize in 1953 in
medicine & physiology
ELECTRON TRANSPORT
CHAIN (ETC)
• Last stage of cellular respiration
• Series of Reactions in which an
electron is passed from one
molecule to another to produce
energy for synthesis of ATP
ETC
• The electrons move down the
chain along the inner
membrane of the
mitochondria
• They are carried by NADH
and FADH2 (carrier
molecules)
ETC
• As hydrogen ions move across the
channels in the membrane to the
matrix, they release energy that is
used by an enzyme to make ATP
• Oxygen is the final electron acceptor.
• Water is formed in this process..it is
a by-product
ETC
• Results in ETC  the electron
transport chain produces 32
molecules of ATP
• With H2O being a by-product
• O2 enters the ETC
Cellular Respiration
• TOTAL ATP PRODUCTION IN
CELLULAR RESPIRATION 
o
Glycolysis, 2 ATPs
o
Krebs, 2 ATPs +
o
ETC, 32 ATPs
o
= 36 ATPs TOTAL
OVERVIEW
• Glycolysis is anaerobic
• When oxygen is present, then the
previously discussed pathway
(Krebs cycle, ETC) is taken
• When oxygen is NOT present, a
different pathway is taken,
fermentation
CELLULAR RESPIRATION
• A car and our
bodies are similar
in the fact that the
mitochondria is our
bodies engine that
burns sugar for
fuel. The exhaust
would be H2O and
CO2
FERMENTATION
• Fermentation releases energy
from food molecules in the
absence of oxygen.
The Process of Fermentation
• Glucose is broken down into
pyruvate during glycolysis
• Pyruvate is then broken down
into ethyl alcohol or lactic acid
• Only results in 2 ATP
molecules (vs. 36 from aerobic)
ALCOHOLIC
FERMENTATION
• Most common type of fermentation is
yeast cells converting pyruvate into
ethyl alcohol
• Fermentation by itself is able to
produce liquids that are about 15%
alcohol
• The same process enables yeast cells
to convert the sugar in dough to ethyl
alcohol & carbon dioxide
FERMENTATION
• Bakers use
alcoholic
fermentation of
yeast to make
breads
• As yeast ferments,
it causes dough to
rise & create the
bubbles that are
present in bread
FERMENTATION
• As the dough
bakes, yeast cells
die and the alcohol
they have made
evaporates
FERMENTATION
• Also used to
make wine,
beer, and
ethanol
added to
gasoline
LACTIC ACID
FERMENTATION
• Occurs in muscle
cells when they use
up all the available
oxygen
• Muscle cells feel
fatigued and sore b/c
lactic acid forms
when oxygen is NOT
present
LACTIC ACID
• Most lactic acid made in muscles
diffuses into bloodstream, then to
liver, where it is converted back to
pyruvate, which enters the aerobic
respiration process
• Yogurt, cheeses, rye bread, pickles,
sauerkraut, and olives are lactic acid
products
LACTIC ACID
• Yogurt, cheeses,
rye bread,
pickles,
sauerkraut, and
olives are lactic
acid products