Post on 28-Dec-2015
Where Does Energy Come From?
The Sun = the ultimate energy source on Earth
Everyone needs me,
ha ha.
Ch. 8, PhotosynthesisPhotosynthesis is the most important
biological process on Earth Why? (list ONE reason)
– Transformed Earth’s environment so life could be sustained (gave us O2)
– Fulfils our requirements for food, fiber and building materials
– Learning and controlling photosynthesis rates can lead to greater crop yields of food, fiber, wood, fuel and a better use of our lands
– Can provide efficient energy for our use
Isn’t having more food, wood, fuel, and energy important to you?
Write 1 of the
reasons
Who Uses Sunlight for Energy?
Autotrophs = auto (self), self-sustaining, plants and some other types of organisms use sun’s light energy to produce food
Heterotrophs= hetero (other), animals and other organisms, can’t use the sun’s energy directly, they obtain energy from the foods they consume– Eat grasses (herbivores)– Eat other animals (carnivores)– Eat dead/decomposing things (decomposers)– Eat plants and animals (omnivores- you!)
What am I?
What Kinds of Energy Do You Use?
Coal – decaying fossils of plants and animals
Oil- decaying fossils of plants and animals
Natural Gas- decaying fossils of plants and animals
Wood/Peat/Moss- burning of plant materials
Solar- directly from the sun
All of these come from the Sun’sSun’s energy!There’s no escaping it, photosynthesis IS the most
important biological process for life.
Write 2-3 from this
list
Energy is stored in a chemical form called ATP
ATP = adenosine triphosphate, the main energy compound cells use to store and release energy
ADP= adenosine diphosphate is the base for making ATP, and a 3rd phosphate is added to ADP to make ATP, like charging a battery
By breaking the bonds (shared electrons) between the phosphate groups, energy is released
Chemical Energy- ATP
1 2 3
PhotosynthesisPhotosynthesis = the process
where plants use the sun’s energy to convert H2O and CO2 into high-energy carbohydrates (sugars and starches) and O2 (a waste product)
Photosynthesis Equation =
6CO2 + 6H2O C6H12O6 + O2
Light
carbon dioxide water sugars oxygen+ Light +
Write this equation, both lines!
Pigments = light absorbing molecules in plants
Chlorophyll = a plant’s main pigment2 main types: – Chlorophyll A– Chlorophyll B– They don’t absorb light in the
green spectrum, they reflect it, so plants are green
Other accessory pigments, such as red or orange, also absorb light in other regions of the spectrum
How Is Sunlight Captured?
Light absorbed by chlorophyll A and B is actually energy, and that energy is transferred to electrons in the chlorophyll molecule
Stroma = region outside the thylakoid membranes
What Structures Capture the Light Energy?
Photosynthesis happens in chloroplasts
Thylakoids = saclike photosynthetic membranes
In these stacks, Chlorophyll is organized into clusters
called Photosystems = Light collecting units
Grana (or singular Granum)
= thylakoids stacked on top of each other
Label the chloroplast Define the
terms
What Do Plants Do With the Light Energy?
Photosynthesis is divided into 2 parts:1. Light dependent reactions- happens in
the Thylakoid membranes
- Sunlight energy captured by chlorophyll
- Energy transferred to electrons
- O2 is a waste product of this reaction (whew! Thank goodness!)
2. Light independent reactions (Calvin cycle)- happens in the stroma
- CO2 used to create sugars (carbohydrates)
- ATP and NADPH, energy sources for this part of photosynthesis
NADPH = “carrier” molecule that holds electrons and passes them along (passes the energy)
Calvin Cycle in DetailCO2 comes in
Carbon is “fixed”
ATP usedturns into ADP
NADPH usedturns into NADP+
Product=
Sugars
Label the Calvin Cycle
What You Need To Know….
Shortened version, just for YOU:
Light reactions of Photosynthesis:
Captures Sunlight’s energy and uses H2O to passalong that energy through electrons to make ATP and NADPH, O2 is a waste product
Dark reactions of Photosynthesis:The Calvin Cycle “fixes” carbon from CO2 and, using
ATP and NADPH (from the light reactions) as energy
sources, makes Sugars (food for YOU)
What Can Affect the Rate of Photosynthesis?
What happens when something goes wrong?Too little H2O- can slow or stop photosynthesis
Desert plants have waxy coating on their leaves to reduce H2O loss
Too Hot or too Cold- photosynthesis depends on the temperature being between 0oC and 35oC, above or below this, and it will slow or stop
Too much or too little light- either one can slow or
stop photosynthesis
Ch. 9, Cellular RespirationWe need food.
When you’re hungry, you get weak, tired, cranky, irritable, and you could pass out! Eventually, you can die of hunger!
So, when you’re hungry, your body is actually saying….
“You idiot! I need energy! Feed me!”
How Much Energy Is In Food?
One calorie (cal)= amount of energy needed to raise the temperature of 1 g of H2O 1 degree Celsius
Food labels use a kilocalorie = 1000 cal(Calorie)
Your cells don’t “burn” glucose (sugar), instead they release the energy from glucose in a reaction called….
Glycolysis
Cellular RespirationIn the presence of O2……..
Gycolysis, the Krebs Cycle, and the electron transport chain make up a process called Cellular Respiration
Cellular Respiration = process that releases energy by breaking down glucose (sugar) and other food molecules (O2 present)6O2 + C6H12O6 6CO2 + 6H2O + Energy
oxygen + glucose Carbon dioxide + water + energy
Equation for cellular Respiration:
Write this equation, both lines!
Yes! O2 is present!!!
Overview of Cellular Respiration
Cytosol Mitochondrion
Glycolysis Krebs Cycle
Electron Transport
Chain
Electrons carried By NADH
Electrons carried byNADH and
FADH2
ATPATP ATPATP ATPATP
Glycolysis1st set of reactions in cellular
respiration
Glycolysis = the process where 1 molecule of glucose is broken in half, producing 2 molecules of pyruvic acid, a 3-carbon compound
At the beginning of the pathway, 2 ATP molecules are invested
At the end of the pathway, 4 ATP molecules are produced
Net Gain of 2 ATP molecules
This occurs in the Cytoplasm
2 Pyruvic acidmolecules
cc
c
c
c c
c
c
c
2ATPs
+ 4ATPs
I’m waiting!
Glycolysis cont….With or without O2, NADH production
occurs:
4 high-energy electrons are removed from glucose and passed on to an electron transport carrier called NAD+
NAD+ = waiting on electronsNADH = holding a pair of electrons (energy)
Ah, thank you.
FermentationWhen O2 isn’t present………
Fermentation = in the absence of O2, releases energy from food molecules by producing ATP
2 main types of fermentation:1. Alcoholic (bread, beer)
2. Lactic Acid (what makes your muscles sore after exercise)
Pyruvic acid + NADH Alcohol + CO2 + NAD+
Pyruvic acid + NADH Lactic Acid + NAD+
No O2 = anaerobic
The Next Step…After glycolysis, 90% of the chemical
energy in glucose is still in the form of pyruvic acid
O2 is a powerful electron acceptor, it loves electrons
The 2nd step in Cellular Respiration is the Krebs Cycle and
Krebs needs O2 to work= aerobic
Because Cellular Respiration needs O2 to be present, we call it “Respiration” like breathing, but for the cell
c
c
c
Pyruvic Acid
The Krebs CycleKrebs Cycle = pyruvic acid is broken
down into CO2 (carbon dioxide) in a series of energy-extracting reactions
A.K.A., the Citric Acid Cycle
The Krebs Cycle occurs in the matrix (inner portion) of the Mighty Mitochondria
c
c
c
Outer MembraneInnerMembraneMatrix
Cristae = folds in the inner membrane
Pyruvic Acid
Energy Produced by Krebs
Pyruvic Acid(from glycolysis)
CO2
CO2
3 NADH
3 NAD+
KrebsCycle
ADPATP
FAD
FADH2
Acetyl CoA
NAD+
NADH
Krebs occurs in the matrixof the Mitochondria
Fill in the boxesin your notes
And then….Krebs Cycle makes high energy electrons
that are passed on to NADH and FADH2
The electrons are passed from these carriers to the Electron Transport Chain or System
Electron Transport Chain (ETC) = uses the high energy electrons from Krebs Cycle to convert ADP to ATP
ETC occurs in the inner membrane of the mitochondria
Electron Transport Chain
Electron Transport Chain
Cytosol
Mitochondria Matrix
ADPATP
NADHNADP+
FADH2
FAD
ATPSynthase
InnerMitochondrialMembrane
OuterMitochondrialMembrane
e-e-e-
e-
e- e- e-
e-
e-
e-e-
e-
e-
e-
OH H
e-
electrons
H+
H+
H+
H+
H+
H+
CytoplasmThe gradient of H+ ions
“charges” ATP synthase, an enzyme, so it can
make ATPATP
How much chemical energy does cellular respiration yield from a single molecule of glucose?
Energy Totals
1 Glucose
2 ATP2 NADH 4 ATP
2 ATP
Glycolysis
2 Pyruvic Acid
KrebsCycle
2 NADH 6 ATP
2 ATP
18 ATP6 NADH
6 FADH2 4 ATP
Total 36 ATP !!!!!!
Krebs Cycle and ETC
Energy and ExerciseQuick Energy- when you need to run!
(sprinting)
Cells store enough ATP to last only the few seconds of a sprintOther ATP is formed through lactic acid fermentation (why you get sore!)
Long Term Energy- endurance runningCells use cellular respiration only to generate energy needed for longer periodsEnergy stored as Glycogen, and it’s used
first then your cells go for the fat storage
Photosynthesis vs. Cellular Respiration
Photosynthesis•Supplies energy plants get from sunlight
•Removes CO2 from the air
•Releases O2 into the air•Occurs only in plants, algae, and some bacteria
Cellular Respiration•Uses energy to break down food
•Puts CO2 back into the air
•Removes O2 from the air•Occurs in ALL eukaryotes and prokaryotes