Essential Questions for Unit 5 – Cellular Energy How can energy be transferred from one substance to another? How is matter/energy transferred/transformed in living systems? How are organisms dependent on each other? How is the structure of a mitochondria related to its function in aerobic respiration? What is the difference between aerobic and anaerobic respiration? Why are some organisms able to undergo aerobic respiration and others are not? How is the structure of a leaf/chloroplast related to the function of photosynthesis?

Where did the mass in a tree come from? In photosynthesis, all of the oxygen in water is released as oxygen gas into the atmosphere.

Where did the mass in a tree come from? Since carbon and oxygen are both much larger atoms than hydrogen, most of the mass in a tree came from the air (oxygen and carbon dioxide).

Where did the mass in a tree come from? Plants have a lot of carbohydrates (sugar and starch) and photosynthesis makes carbohydrates.

Where did the mass in an adult come from? Animals get all of their mass from the food they eat.

Bioenergetics - Mass Plants are called autotrophs since they make their own food using photosynthesis. Animals are called heterotrophs since they need to eat (consume) their food.

Think, Pair, Share What is the main way plants get molecules inside themselves?

Photosynthesis Plants break the water and carbon dioxide apart to make new molecules. 6H2O + 6CO2 get rearranged into C6H12O6 + O2

Photosynthesis Chemical Equation

Balanced Chemical Equation 6CO2 + 6H2O  6O2 + C6H12O6 Atoms are neither created nor destroyed, they are just transferred. This transferring of atoms is called the Law of Conservation of Matter.

Recall from past units… What type of organic molecule is ATP? Which organelle provides this source of energy for the cell?

Adenosine Triphosphate (ATP) Nucleic Acid Structure: Phosphate group 5 carbon sugar (ribose) Nitrogenous base (adenine) Function: Energy

Why ATP? An analogy to money… Glucose in our food is a great source of energy! ($100 bill) However, individual cell processes may only require a small amount of energy ($1 bill) Analogy: most vending machines do not accept $100 bills! We need a smaller form of “currency” for these processes. ATP (adenosine triphosphate) is this important cellular “currency” for life. ATP releases more appropriate amounts of energy for the individual cellular processes that require energy. (We will study this molecule in detail in our next activity!)

ATP and ADP Cycle ATP = Adenosine triphosphate = 3 phosphates ADP = Adenosine diphosphate = 2 phosphates The chemical energy in food is used to make ATP.

Energy Review Where does ATP come from and how is it made? ATP supplies most of the energy that drives metabolism in living things ATP releases energy when converted into ADP Where does ATP come from and how is it made?

How do cells get their energy? Cells perform cellular respiration to make ATP. Analogy: A fully charged battery

Cellular Respiration Cells have mitochondria that perform cellular respiration to make ATP.

Cellular Respiration Living things get most of the energy they need from glucose. Autrotrophs make glucose using photosynthesis Heterotrophs get glucose from food they eat Cellular Respiration The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

Cellular Respiration Reactants Inputs of cellular respiration are oxygen and glucose.

Cellular Respiration Products Outputs of cellular respiration are carbon dioxide, water, and ATP.

Cellular Respiration Overview Cellular Respiration Overall Equation 6O2 + C6H12O6  6CO2 + 6H2O + Energy The main form of energy produced = ATP

Do only animal cells perform cellular respiration? The BIG Question is… Do only animal cells perform cellular respiration? Or do plant cells too? Only plants perform photosynthesis Plants AND animals perform cellular respiration! Can you explain why??

Think, Pair, Share If plant cells need oxygen gas and glucose to make ATP, where do they get them?

If plant cells need oxygen gas and glucose to make ATP, where do they get them? Plants will perform photosynthesis to make the food (glucose) required to do cellular respiration. Plants also use glucose to make other molecules.

Recall from last unit… What was the organelle that plant cells have for energy that animal cells do not have?

Photosynthesis Plant cells have chloroplasts that perform photosynthesis to make glucose (sugar).

Photosynthesis Reactants Inputs of photosynthesis are carbon dioxide, water, and light energy.

Photosynthesis Products Outputs of photosynthesis are oxygen and glucose (sugar).

Photosynthesis Overview Photosynthesis Overall Equation Light Energy + 6CO2 + 6H2O  6O2 + C6H12O6

The Big Picture: Bioenergetics Cycle Plants take in water and carbon dioxide in order to perform photosynthesis to make glucose and oxygen gas. Animals take in oxygen gas and glucose to make water and carbon dioxide.

The Big Picture: Bioenergetics Cycle Plants perform photosynthesis. Animals and plants perform cellular respiration. Biology Theme: Interdependence

Can you answer the following questions… How can energy be transferred from one substance to another? How is matter/energy transferred/transformed in living systems? How are organisms dependent on each other?

Site of Cellular Respiration Plant and animal cells contain mitochondria: cell structures that transform chemical energy from glucose to ATP.

Glycolysis Glyco = Glucose lysis = Breakdown Occurs in the cytoplasm of the cell Molecules of GLUCOSE are broken down into 2 molecules of Pyruvic Acid. Cell must use (invest) 2 ATP Produces Energy Carrier Molecules 4 ATP 2 NADH

Mitochondria The mitochondria is the organelle where the final stages of cellular respiration occurs. Kreb’s Cycle Electron Transport Chain Cells that use a lot of energy have high numbers of mitochondria. Example: Muscle cells in the heart!!

Kreb’s Cycle Aerobic Process = Only if oxygen is present!! Occurs in the MATRIX of the mitochondria Pyruvic Acid from Glycolysis enters to form 1 ATP 3 NADH 1 FADH2 CO2 (which is released when we exhale!!) Also called the Citric Acid Cycle

Electron Transport Chain Energy carrier molecules produced during Glycolysis and the Kreb’s Cycle enter the ETC NADH FADH2 Occurs in the folds of the Inner Membrane of the Mitochondria The electrons are passed down a chain of proteins until they reach the final electron acceptor…..oxygen! So this step is aerobic (requires oxygen) The ETC produces 32 ATP and H2O

Significant ATP Production Aerobic cellular respiration releases energy SLOWLY, using oxygen to convert ONE molecule of glucose to 36 ATP!

Cellular Respiration Flowchart Section 9-2 Glucose (C6H1206) + Oxygen (02) Glycolysis Krebs Cycle Electron Transport Chain Carbon Dioxide (CO2) + Water (H2O) Process requires the presence of oxygen. This is called aerobic respiration.

Electron Transport Chain   Cellular Respiration: Overview Mitochondrion Electrons carried in NADH Electrons carried in NADH and FADH2 Pyruvic acid Glucose Electron Transport Chain Krebs Cycle Glycolysis Mitochondrion Cytoplasm

Aerobic Respiration – Equation C6H12O6 + 6 O2 6 H2O + 6 CO2 + 36 ATP food (glucose, a carbohydrate) oxygen water carbon dioxide Does this look familiar?

Aerobic Training Ex: long runs, biking, swimming Can increase the size and number of mitochondria in muscle cells Can increase the delivery of O2 to muscles by improving the heart and lungs

Think, Pair, Share What happens if no oxygen is available? The Kreb’s Cycle and Electron Transport Chain can’t function!

Anaerobic Respiration What happens when cells don’t have enough oxygen? Some organisms live in an oxygen-free environment. How do they get their energy?

Anaerobic Respiration Anaerobic respiration is also called fermentation, or the process by which energy is released from glucose when oxygen is NOT available. This process allows organisms to continue to produce energy until oxygen is available. However, this process only releases 2 ATP per molecule of glucose.

Fermentation The cell can use Fermentation instead!! Occurs in the Cytoplasm Just like glycolysis!! Fermentation A series of reactions that convert NADH (from glycolysis) back into NAD allowing glycolysis to keep producing a small amount of ATP

Two Types of Fermentation Alcoholic Fermentation Lactic Acid Fermentation

Alcoholic Fermentation Anaerobic way of converting energy for yeast and other microorganisms. Yeasts use this process to form ethyl alcohol and carbon dioxide as waste products. Glucose broken down to produce alcohol, CO2 and energy (ATP) This causes bread dough to rise This is how some alcoholic beverages are made C6H12O6  ethanol + CO2 + 2 ATP

Fermentation - Bread Source of sugar? DOUGH! (sugar and/or flour) Yeast use up the O2 and ferment sugar Produce CO2, which is trapped within tiny bubbles & results in the dough rising Produce ethanol, which evaporates in the baking process

Lactic Acid Fermentation Anaerobic way of converting energy in animal cells and some microorganisms. Glucose broken down to produce lactic acid, CO2 and energy (ATP). Occurs in bacteria (unicellular organisms) This is how cheese, yogurt, and pickles are made. Occurs in muscles during rapid exercise When your body runs out of oxygen your muscle cells must produce some ATP using fermentation and glycolysis Lactic Acid build-up causes muscle soreness or burning after intense activity. C6H12O6  lactic acid + CO2 + 2 ATP

Minimal ATP Production In the absence of oxygen, anaerobic respiration only releases 2 ATP for each molecule of glucose broken down.

Anaerobic Training Ex: sprints, strides, quick bursts of energy Increase the glycogen levels in the muscles Increase body’s tolerance to lactic acid

Comparing ATP Production First, your body breaks down glucose through aerobic respiration to produce 36 ATP per glucose molecule; however, this is a slow process. When muscle cells cannot get enough O2 they break down glucose through lactic acid fermentation to produce 2 ATP per glucose… Therefore, AEROBIC RESPIRATION is much more efficient in terms of ATP production – 36 ATP compared to 2 ATP!

Photosynthesis: A Closer Look Carbon dioxide + water glucose + oxygen sunlight absorbed by chlorophyll 6CO2 + 6H2O + energy  C6H12O6 + 6O2

What is the process that uses the sun’s energy to make simple sugars?

Plant leaves have many types of cells!

Plant Cells

The photograph below is an elodea leaf X 400 The photograph below is an elodea leaf X 400. Individual cells are clearly visible. The tiny green structures within the cells are chloroplasts this is where photosynthesis happens.           

Chloroplasts make the sugars!

Leaves are green because they contain Plants Leaves are green because they contain the pigment: chlorophyll Leaves have a large surface area to absorb as much light as possible "Thanks for the Glucose!"

Chloroplasts make the oxygen too!

Stoma This opening how plants exchange gases. Check it Stoma This opening how plants exchange gases! Check it! Can you name the two important gases that go in and out of the leaves? Why are the stomata located on the underside of leaves?

PHOTOSYNTHESIS Absorbing Light Energy to make chemical energy: glucose! Pigments: Absorb different colors of white light (ROY G BIV) Main pigment: Chlorophyll a Accessory pigments: Chlorophyll b and Carotenoids These pigments absorb all wavelengths (light) BUT green!

PHOTOSYNTHESIS Why do we see green? Green color from white light reflected NOT absorbed Chloroplast: organelle responsible for photosynthesis Chlorophyll: located within Chloroplast Green pigment

Visible light is only a small part of the electromagnetic spectrum (all forms of light).

LIGHT behaves as if it were composed of "units” of energy that travel in waves. These packets are photons. The wavelength of light determines its color.

Chlorophyll: A Light Absorbing Pigment The Solar Panel Chemical!

Photosynthesis Glucose provides the energy and carbon needed to make other plant materials like wax and proteins.

In plants and simple animals, waste products are removed by diffusion In plants and simple animals, waste products are removed by diffusion. Plants, for example, excrete O2, a product of photosynthesis.

EQUATION FOR PHOTOSYNTHESIS WATER OXYGEN 6CO2 + 6H2O + ENERGY C6H12O6 + 6O2 CARBON DIOXIDE GLUCOSE

PHOTOSYNTHESIS 2 Phases Light-dependent reaction Light-independent reaction Light-dependent: converts light energy into chemical energy; produces ATP molecules to be used to fuel light-independent reaction Light-independent: uses ATP produced to make simple sugars.

PHOTOSYNTHESIS Light-dependent reaction (LIGHT Reaction) Requires light Occurs in chloroplast (in thylakoids) Chlorophyll (thylakoid) traps energy from light Light excites electron (e-) Kicks e- out of chlorophyll to an electron transport chain Electron transport chain: series of proteins in thylakoid membrane Bucket brigade

PHOTOSYNTHESIS Light-dependent reaction (LIGHT Reaction) Energy lost along electron transport chain Lost energy used to recharge ATP from ADP NADPH produced from e- transport chain Stores energy until transfer to stroma Plays important role in light-independent reaction Total byproducts: ATP, NADP, O2

PHOTOSYNTHESIS How did we get O2 as a byproduct?! Photolysis: replaces lost electrons by splitting water

At each step along the transport chain, the electrons lose energy. Sun Light energy transfers to chlorophyll. At each step along the transport chain, the electrons lose energy. Chlorophyll passes energy down through the electron transport chain. Energized electrons provide energy that to ADP splits H2O bonds P forming ATP H+ NADP+ oxygen released NADPH for the use in light-independent reactions

PHOTOSYNTHESIS Light-independent reaction (Dark Reaction) Does not require light Calvin Cycle Occurs in stroma of chloroplast Requires CO2 Uses ATP and NADPH as fuel to run Makes glucose sugar from CO2 and Hydrogen

PHOTOSYNTHESIS What affects photosynthesis? Light intensity: as light increases, rate of photosynthesis increases

PHOTOSYNTHESIS What affects photosynthesis? Carbon Dioxide: As CO2 increases, rate of photosynthesis increases

PHOTOSYNTHESIS What affects photosynthesis? Temperature: Temperature Low = Rate of photosynthesis low Temperature Increases = Rate of photosynthesis increases If temperature too hot, rate drops