Download Cell Energetics

Cell Energetics
All Cells need energy. (Ability to perform work)
What do cells use energy for?
–Mitosis.
–Repair.
–Active transport.
–Movement.
What Is ATP?
• ATP – adenosine triphosphate is a chemical
molecule made up of an adenine + ribose
(adenosine), and 3 phosphate groups. It is like
a battery!
Adenine
Ribose
How Does ATP Work?
• Energy is stored in the bond between the
phosphate groups.
• When the end phosphates break off, energy is
released!
• (ATP-ADP-AMP)
Adenine
Ribose
ATP = Energy Currency
• Within the cell, formation of ATP from ADP and
phosphate (ADP +PATP) occurs over and over,
storing energy each time.
• As the cell uses energy, ATP breaks down repeatedly
to release energy and form ADP and phosphate.
• We refer to ATP as the battery or $ of the cell as it
can be used and recharged or re-earned again and
again!
Think about this…
• Write the chemical formula for when the
energy molecule of the cell is like a fully
charged battery.
• Besides batteries and $ what is something
else you can compare ATP to?
Complex Cells make energy in two
specialized organelles:
–Photosynthesis – takes place in the
chloroplasts
–Cellular Respiration – takes place in the
mitochondria
–What about simple cells?
Photosynthesis
Autotrophs make their
own food by trapping
light energy (solar) to
make chemical
energy (ATP) and
then using that to
build food energy
(carbohydrates).
Photosynthesis
Using light from the sun, plants make ATP that will in turn fuel the cells
ability to combine water and carbon dioxide to ultimately make sugar .
General Equation:
6CO2 + 6H2O + ------>
C6H12O6 + 6O2
Enzymes
Reactants
&
pigments
Products
Photosynthesis
Has 2 stages/phases
The light dependent reactions
The Calvin Cycle (also called
light independent reactions)
Light Dependent Reactions
Light energy (solar) is used to split hydrogen from water.
– Takes place in each thylakoid in the grana (plural for
granum) of the chloroplasts.
– Products are oxygen, NADPH, and ATP.
– H2O + NADP +ADP NADPH + O2 + ATP
– The process of splitting water is
called photolysis.
– A) What is NADP and NADPH?
– B) What are the correct catalysts?
Think About this….
• Based on what water is broken into, what do
you think the job of NADPH might be?
• What is it holding?
• Hint:
Chlorophyll is a green pigment
• Pigment = reflects some colors of light and
absorbs others
• A) What color of light is chlorophyll reflecting?
• B) What colors is it absorbing?
• C) What color of light would be least useful to a
plant?
• D) Why is your shirt color the color it is?
Overview!
NADP
vs.
NADPH
• A) What is the difference
between these two items?
•B )Specifically why does H need
a “taxi”?
•C) What would happen if we
had no “H” “taxi”?
Using Diagrams
• We use diagrams to explain complex
processes.
Calvin Cycle – Light Independent reactions
ATP and NADPH from the light reactions
are used along with CO2 to form a
monosaccharide. (like glucose)
– Takes place in the stroma of the
chloroplasts.
– Products are C6H12O6 (glucose), ADP,
and NADP
– General equation is:
NADPH + CO2+ ATP  C6H12O6 +
NADP+ADP
– ATP used to build, NADPH used as part
of the sugar (H12)
– Gas exchange-stomata
Sunlight
O2
NADP+
ADP
ATP
H2O
NADPH
CO2
CHLOROPLAST
Summarize
• 1) What is photosynthesis?
• 2) What are the 2 main stages/phases of photosynthesis?
• 3) Explain what the goal of each stage/process is.
• 4) Why do light reactions occur first?
• 5) Where do each of the stages/processes occur?
• 6) What is an autotroph? Give an example.
• 7) What is the chemical formula for the main product made in photosynthesis?
• 8) List all the catalysts of photosynthesis indicate which stage they are used.
• 9) Where do the Carbons, Hydrogens and Oxygen specifically come from to
make sugar?
• 10) Write the following equations; overall for photosynthesis, light dependent
and light independent.
STOP HERE!!!
• Please wait for instructions before proceeding!
Cellular Respiration
Two ways heterotrophs can make
energy:
1. Aerobic – requires oxygen,
produces lots of ATP and is
more efficient.
2. Anaerobic – requires an
absence of oxygen, not much
ATP, not efficient.
Aerobic Respiration has three separate reactions:
1) Glycolysis
2) Citric Acid Cycle
3) Electron Transport Chain
General equation is:
C6H12O6 + 6O2 --> 6CO2 + 6H2O
What is missing from this equation?
GOALS of each reaction
• Glycolysis- break sugar, recharge
some used ATP batteries
• Citric Acid Cycle- Collect
Hydrogen, get rid of waste
products
• ETC- use Hydrogen to make ATP
–
–
–
–
–
–
Glycolysis
break a 6 Carbon glucose into 2, 3 Carbon pyruvates.
Takes place in the cytoplasm of the cell.
Anaerobic
Glucose won’t break by itself, must spend some ATP to get it to break.
C6H12O6 + 2 ATP + NAD2 pyruvates + NADH + 4 ATP
Notice NAD…..
C3H4O3
C6H12O6
What’s missing????
C3H4O3
Think - Pair - Share
• Based on what happens in glycolysis, what
do you think the job of NADH might be?
• What is it holding?
Citric Acid Cycle / Kreb’s Cycle
each pyruvate is broken down further
Takes place right outside of the cristae (the folded
membrane in the mitochondrion).
– O2 + pyruvate + NAD  CO2 + NADH
– CO2 is released, and NAD captures
hydrogen ions (to be used later)
Electron Transport Chain
• hydrogen ions are moved using NAD to the cristae. (NADH)
• H’s leave the carrier NAD and move across the cristae and in so
doing, generate a ton of energy!
• That energy is harvested to build even more ATP!
• Oxygen picks up H after they move through ATP Synthase.
• The cristae is not permeable to the carrier. (NAD)
• Water is formed as the H’s and oxygen combines.
• ADP + O2 + NADH +  ATP + H20+ NAD
• We just used hydrogen power to anabolically build lots ATP!
(about 30 more)
• Once we are done with ETC the cell performs chemiosmosis to
move the water and the ATP out of the mitochondria for use.
Don’t talk about ATP synthase – next slide is t-p-s
Based only on the name what do you think
ATP synthase does?
• The enzyme in ETC responsible for
building the ATP is called ATP synthase.
Summarize
• Explain to your partner what happens in the
electron transport chain.
• Partner: repeat back what they said.
• Discuss if everything stated is accurate.
Heat
O2
H2O
CO2
Electron
Transport
System
NAD+
ATP
NADH
Glucose
Pyruvate
ATP
ATP
MITOCHONDRION
Turn to your partner
and explain the diagram
you just filled in.
Sunlight
Heat
Photosystem
II
NADP+
ADP
O2
PhotoSystem
I
ATP
Calvin
Cycle
H2O
NAD+
NADPH
ATP
NADH
CO2
Glycolysis
Glucose
CHLOROPLAST
Electron
Transport
System
Citric
Acid
Cycle
Pyruvate
ATP
MITOCHONDRION
ATP
Anaerobic Respiration
Certain cells in our body can produce energy
without oxygen, mainly our muscle cells.
Anaerobic respiration is the process that recycles
NAD the absence of oxygen. Through
fermentation, anaerobic organisms and cells can
exist w/o oxygen by using the small amount of
energy supplied by glycolysis.
Fermentation
Allows glycolysis
to continue in the
absence of
oxygen.
Recycles NAD+
Does not produce
any ATP
Two types of Fermentation:
•
Alcoholic fermentation (alcohol and CO2 are
waste products) – occurs in yeast and fungi
•
Lactic acid fermentation (lactic acid is a waste
product) – occurs in animals