Energy represents the capacity to do work. Cells must acquire energy from their environment. In life, energy transformations consist primarily of movement of molecules and changes in chemical bonds. Metabolism is the set of chemical reactions that happen in living organisms to maintain life Catabolism Releasing energy by breaking down of larger molecules into smaller ones Digestion Anabolism Storing energy by creating larger molecules from smaller ones. Creating body fat 2 Types Ch.8 – Cellular Energy 8.1 – How organisms obtain energy

All living cells use adenosine triphosphate (ATP) for capture, transfer, and storage of energy. Ch.8 – Cellular Energy 8.1 – How organisms obtain energy Each cell needs millions of ATP molecules per second in order to drive its biochemical machinery

Ch.8 – Cellular Energy 8.1 – How organisms obtain energy

Autotrophs are able to create glucose from inorganic substances. That glucose is broken down to form ATP molecules Ch.8 – Cellular Energy 8.1 – How organisms obtain energy Heterotrophs obtain glucose from digesting other living things. That glucose is broken down to form ATP molecules Autotrophs Heterotrophs

Which of the following processes contributed the most to the increased mass of the “Light, Water” treatment? a) Absorption of mineral substances from the dish via the roots. b) Absorption of organic substances from the dish via the roots. c) Absorption of CO 2 gas from the atmosphere into molecules by green leaves. d) Absorption of H 2 0 gas from the dish into molecules by green leaves. e) Absorption of solar radiation into the leaf.

Ch.8 – Cellular Energy 8.2 – Photosynthesis Carbon Dioxide + Water Light Glucose + Oxygen 6 CO H 2 O Light C 6 H 12 O O 2 The story of how living things make ATP starts with…

Ch.8 – Cellular Energy 8.2 – Photosynthesis

Ch.8 – Cellular Energy 8.2 – Photosynthesis The light reactions (in the thylakoids) split water, release O 2, produce ATP, and form NADPH The Calvin cycle (in the stroma) forms sugar from CO 2, using ATP and NADPH The Calvin cycle begins with carbon fixation, incorporating CO 2 into organic molecules 3PGA Glucose

Ch.8 – Cellular Energy 8.2 – Photosynthesis Light Reaction Movie Red light is very important to plant reproduction. Phytochrome pigments absorb the red and far red portions of the light spectrum and regulate seed germination, root development, tuber and bulb formation, dormancy, flowering and fruit production. Therefore, red light is essential for stimulation of flowering and fruiting. Blue light stimulates Chlorophyll production more than any other colour, encouraging thick leaves, strong stems and compact vegetative growth. Chlorophyll absorbs blue and red light and transmits the energy to a pigment-based electron transport chain. The energy is ultimately used to produce high-energy chemical bonds that can be used for a range of biochemical transformations, including fixation of carbon-dioxide into sugars. Carotenoids, the yellow-orange pigment in plants, absorb blue light and control leaf fall and fruit ripening. Riboflavin (Vitamin B2) absorbs violet light and influences "phototropism", the movement of plant foliage in response to light.Chlorophyll

Ch.8 – Cellular Energy 8.2 – Photosynthesis Photosystem II Light energy is used to split an H 2 O molecule When H 2 O splits -O 2 is released -protons (H + ions) stay in the thylakoid space & -an activated electron enters the electron transport chain.

Ch.8 – Cellular Energy 8.2 – Photosynthesis Electron Transport Chain Electrons are moved through the thlakoid membrane and more protons are pumped into the thylakoid space

Ch.8 – Cellular Energy 8.2 – Photosynthesis Photosystem I Light reenergizes the electrons The reenergized electon is transferred to NADP + Reductase to form an NADPH from NADP +

Ch.8 – Cellular Energy 8.2 – Photosynthesis Chemiosmosis Protons build up in the thylakoid space and create a concentration gradient Protons then move across the thylakoid membrane through ATP synthase which causes ADP to convert to ATP Light Reactions Animation

Ch.8 – Cellular Energy 8.2 – Photosynthesis 1.What is the basic formula of photosynthesis? 2.How did plants acquire photosynthesis in evolution? Name three features of chloroplasts that are indicative of their origin. (It is referred to as endosymbiosis or the endosymbiotic theory) ClickClick 3.Photosynthesis can be divided in two different processes. What are these processes? What are their products and reactants? 4.Oxygen is released during photosynthetic light reactions. Where is this oxygen coming from? NameReactantsProducts Light Dependant Light & H 2 O (NADP+ & ADP) O 2 (NADPH & ATP) Light Independent or Calvin Cycle CO 2 (NADPH & ATP) Glucose (NADP+ & ADP) The splitting of H 2 O in Photosystem II

Ch.8 – Cellular Energy 8.2 – Photosynthesis 5.What is the driving force for ATP synthesis at the ATP synthase multi-protein complex? 6.Where do you find a higher pH value, inside or outside of the thylakoid? 7. Which process creates NADPH from NADP + ? The proton concentration gradient created by splitting water and the electron transport chain Outside There is a much higher concentration of H + ions in the thylakoid. This creates an acidic environment and thus a lower pH than in the stroma of the chloroplasts Photosystem I Energized e - are transferred to the enzyme NADP + Reductase

Ch.8 – Cellular Energy 8.2 – Photosynthesis

Ch.8 – Cellular Energy 8.2 – Photosynthesis 3PGA Glucose The Calvin Cycle (light independent reactions or the dark reactions)

Ch.8 – Cellular Energy 8.2 – Photosynthesis Carbon Fixation 3 CO 2 combine with 3 5-C compounds to form 6 3-C compounds called 3-PGA

Ch.8 – Cellular Energy 8.2 – Photosynthesis Reduction Energy from ATP and NADPH is used to form 6 G3P molecules (high energy molecules) From the 6 PGA molecules 1 G3P molecule leaves the cycle to form glucose, fructose starches, etc.

Ch.8 – Cellular Energy 8.2 – Photosynthesis Regeneration ATP and the enzyme rubisco convert the 5 G3P to 3 RuBP These molecules are then ready to bond with 3 more CO 2 Calvin Cycle Animation

Ch.8 – Cellular Energy Cellular respiration Aerobic Respiration requires O 2 to make ATP from the energy stored in glucose Cellular Respiration Glucose + Oxygen  Energy + Carbon Dioxide + Water C 6 H 12 O O 2  36/38 ATP + 6 CO H 2 O

Ch.8 – Cellular Energy Cellular respiration

Ch.8 – Cellular Energy Cellular respiration Electron Transport Chain Oxidative phosphorylation The 3 Processes of cellular respiration or Krebs Cycle CO 2 O2O2 H2OH2O Or 34 Respiration Overview - You Tube

Ch.8 – Cellular Energy Cellular respiration Glycolysis (“splitting of sugar”) breaks down glucose into two molecules of pyruvate Glycolysis occurs in the cytoplasm and has two major phases: -Energy investment phase -Energy payoff phase Net ATP = 2 Glycolysis - You Tube

Ch.8 – Cellular Energy Cellular respiration Citric Acid Cycle or Krebs Cycle Before the citric acid cycle can begin, pyruvate must be converted to Acetyl CoA It takes place in the matrix of the mitochondria Krebs Animation - YouTube (9min.)

Ch.8 – Cellular Energy Cellular respiration Citric Acid Cycle or Krebs Cycle The acetyl group of acetyl CoA joins the cycle by combining with the 4-C compound, oxaloacetate, forming citric acid (citrate)

Ch.8 – Cellular Energy Cellular respiration Citric Acid Cycle or Krebs Cycle The next seven steps decompose the citrate back to oxaloacetate The NADH and FADH 2 produced by the cycle send electrons to the electron transport chain

Ch.8 – Cellular Energy Cellular respiration e - from NADH & FADH 2 pass through protein complexes in the cristae (inner membrane) This causes H + to be pumped out of the matrix Electron Transport Chain Animation

To give you an idea of how much ATP we require to survive… We take in about 2 x molecules of O 2 per breath 200,000,000,000,000,000,000 Ch.8 – Cellular Energy Cellular respiration O 2 diffuses into the matrix and bonds with the e - passing through the transport chain. H + diffuses through ATP synthase back into the matrix (chemiosmosis) creating ATP ( phosphorilation )

Ch.8 – Cellular Energy Cellular respiration FOOD complex carbohydrates simple sugars pyruvate acetyl-CoA glycogenfatsproteins amino acids carbon backbones fatty acids glycerol NH 3 PGAL glucose-6-phosphate GLYCOLYSIS KREBS CYCLE urea

Ch.8 – Cellular Energy Cellular respiration Making energy when there is no oxygen Anaerobic Respiration or Fermentation It is essentially a cell just relying on glycolysis for its energy needs Only produces 2 ATP per glucose molecule (not the 36 or 38 that aerobic respiration can create) Other molecules are created through reactions that provide the NAD + needed for glycolysis to occur ATP can be created much faster than with aerobic respiration (just in smaller quantities)

CH 3 -C-C-OH =O -O-O CH 3 -CH -O CH 3 -CH 2 -OH CH 3 -CH-C-OH -OH =O CO 2 Lactic Acid Fermentation Alcoholic Fermentation 2 ATP 4 ATP

CH 3 -C-C-OH =O -O-O CH 3 -CH-C-OH -OH =O Lactic Acid Fermentation 2 ATP 4 ATP Used by some fungi and bacteria & is used to make cheese and yogurt Human muscle cells use lactic acid fermentation to generate ATP when O 2 is scarce

CH 3 -C-C-OH =O -O-O CH 3 -CH-C-OH -OH =O Lactic Acid Fermentation 2 ATP 4 ATP Used by some fungi and bacteria & is used to make cheese and yogurt Human muscle cells use lactic acid fermentation to generate ATP when O 2 is scarce

CH 3 -C-C-OH =O -O-O CH 3 -CH -O CH 3 -CH 2 -OH CO 2 Alcoholic Fermentation 2ATP 4ATP Used by yeast and some bacteria & is used in brewing, winemaking, and baking