Photosynthesis & Cellular Respiration

Characteristics of Life Review Living things need energy to survive Organisms get energy through a series of chemical reactions Chemical Reactions – the forming and breaking of chemical bonds Reactants Products Metabolism – all of the chemical reactions occurring in an organism

Chemical Reactions for Energy Photosynthesis – changes the sun’s energy to sugar Cellular Respiration – changes the energy in sugar into usable energy for organisms (ATP)

Ecology Review Primary source of energy is sunlight Autotrophs/Producers – organisms that use the energy in sunlight to make their own food Example: Plants (grass, flowers, trees), Moss, Algae

Ecology Review cont’d Heterotrophs/Consumers – Organisms that cannot make their own food and must eat to get energy Herbivores – eat plants Carnivores – eat animals Omnivores – eat plants and animals Decomposers – breakdown dead plants and animals

Chemical Energy and ATP Energy comes in many forms Light Heat Electricity Chemical Living things use chemical compounds to store and release energy ATP (Adenosine Triphosate) - one of the main chemical compounds that cells use to store and release energy ATP

Chemical Energy and ATP ATP consists of: Adenine Ribose 3 phosphate groups Adenine 3 Phosphate Groups Ribose

Chemical Energy and ATP STORING ENERGY Adenosine diphosphate (ADP) – has two phosphate groups instead of three When a cell has energy is available, it will store it in a chemical bond by adding third phosphate ADP + 1 phosphate ATP

ADP ---> ATP

Chemical Energy and ATP RELEASING ENERGY All of the energy that is stored in that chemical bond between the second and third phosphate is released when that bond is broken.

What is ATP? Let’s ask Bill Nye…

Photosynthesis – Let’s think… What things do plants need to grow? Water (H2O) Carbon dioxide (CO2) What do plants need to make? Sugar/Glucose (C6H12O6) What do plants give off as waste? Oxygen (O2)

Important Experiments Van Helmont – Mass does not come from soil Thought it all came from water Priestley – Plants give off oxygen Candle kept burning Ingenhousz – Light is necessary for plants to produce oxygen

Types of Energy Reactions - #1 Photosynthesis – process in which organisms use the energy of sunlight to convert carbon dioxide and water into sugar and oxygen Happens in plants Specifically in the chloroplast of plant cells

Photosynthesis Equation REMEMBER: What it needs = Reactants What it makes = Products 6CO2 + 6H2O C6H12O6 + 6O2 Carbon dioxide + Water Sugar/Glucose + Oxygen (Reactants) (Products) Light Light

How do Plants Capture Light? Sunlight comes down in the form of light in a mixture of different wavelengths. We see these different wavelengths as different colors.

How do Plants Capture Light? Plants use pigments – light absorbing molecules Chlorophyll – the main pigment that plants use to capture light Found in the the chloroplast of plants

Pigments and Light The color we see is the color wavelength that is reflected from (bounces off of) the object All other colors are absorbed by the object When chlorophyll absorbs light, the light’s energy gets absorb also and boosts the energy level of the chlorophyll’s electrons.   Reflected light

WHY ARE PLANTS GREEN? They reflect green light!! Reflected light Absorbed Transmitted Chloroplast What color is sunlight? White all colors What color of light do plants get energy from? Red, orange, yellow, blue, purple, violet Why? Because it absorbs those colors and therefore their energy What color of light do plants get the least energy from? Green Why? Because it does not absorb the light it reflects it. They reflect green light!! Remember: THE COLOR OF LIGHT SEEN IS THE COLOR REFLECTED, NOT ABSORBED

Light- dependent reactions Inside a Chloroplast H2O CO2 Light NADP+ ADP + P Light- dependent reactions Calvin Cycle Calvin cycle What would the plant need the sugar for? Store it for future use, make cellulose for their cell walls, energy (converted to ATP in cellular respiration), growth The process of photosynthesis includes the light-dependent reactions as well as the Calvin cycle. Factors affecting Photosynthesis amount of water temperature (too high or too low and the essential enzymes may be damaged) intensity of light Chloroplast O2 Sugars Copyright Pearson Prentice Hall

Four things are needed for photosynthesis: SUNLIGHT Gives the plant energy CHLOROPHYLL The green stuff where the chemical reactions happen WATER Travels up from the roots CARBON DIOXIDE Enters the leaf through small holes on the underneath

Let’s Think Some More… What things do we need to survive? Sugar/Glucose (C6H12O6) Oxygen (O2) What do we give off as waste? Water (H2O) Carbon dioxide (CO2)

Types of Energy Reactions = #2 Cellular Respiration – process in which organisms breakdown sugar to make ATP Happens in plants and animals Specifically in the mitochondria of cells

Cellular Respiration Equation REMEMBER: What it needs = Reactants What it makes = Products C6H12O6 + 6O2 6CO2 + 6H2O + Sugar/Glucose + Oxygen Carbon dioxide + Water + (Reactants) (Products) ATP ATP

Cellular Respiration – Step 1 Glycolysis – the breaking of glucose Anaerobic – does not require oxygen Occurs in cytoplasm Makes 2 ATP

Cellular Respiration – Step 2 Krebs Cycle Aerobic – does require oxygen Occurs in mitochondria Makes 2 ATP and lost of high energy electrons

Cellular Respiration – Step 3 ATP Electron Transport Chain Aerobic – does require oxygen Occurs in mitochondria Makes 32-34 ATP ATP ATP ATP

Types of Energy Reactions - #3 If there is no oxygen present, cells go through fermentation instead of cellular respiration to get the ATP they need. Allows the organism to continue to make ATP as long as the glucose supply lasts.

Types of Fermentation Lactic Acid Fermentation C6H12O6 6CO2 + 6H2O + Lactic Acid + ATP Used by animals when they need ATP but are not getting enough oxygen to go through cellular respiration. Used by some bacteria that live in environments without oxygen – make yogurt, milk, cheese

Types of Fermentation Alcoholic Fermentation C6H12O6 6CO2 + 6H2O + Ethyl Alcohol + Used by fruit – wine and liquors Used by yeast – bread and beer (holes in bread/bubbles in beer = CO2!) Some bacteria ATP