2 Kansas Science Standards The sun is the primary source of energy for life through the process of photosynthesis.-plants and other photosynthetic organisms use energy from the sun to make glucose.- photosynthesis is a series of chemical reactions that takes place in a chloroplast.
3 Energy for Life; all living things need energy! Without energy, things tend to get messy.ex: your room, deathEntropy: natural tendency toward disorder.
4 Two Laws of thermodynamics: 1. Energy cannot be created nor destroyed, just changed from one form to another, i.e. chemical (food) energy converted to mechanical (movement energy)2. Some energy is always lost (usually as thermal energy) during the change or “Entropy increases” i.e. trophic levels in the food chain.
5 Remember??Autotrophs:get energy from the sun (or chemicals) to make own food.Heterotrophs:obtain energy from food it eats.
6 Metabolism All of the chemical rxns in a cell Metabolic pathway = series of chem. rxn in which the product of one rxn is the substrate for the next. 2 types:Catabolic – (catabolism) break down molecules to release energyAnabolic – (anabolism) use energy to build larger molecules from smaller ones
7 Anabolic steroids?hormones that build up molecules of protein to make musclesBalance between catabolic and anabolic pathways affected by circadian rhythms, activity periods demand energy from glucose
9 Energy is stored in the bonds between atoms and molecules (food) = chemical energy
10 Photosynthesis sun 6CO2 + 6H2O -------- 6O2 + C6H12O6 Plants change light energy into chemical energy which is stored in the bonds of glucose molecules that make up organisms. (anabolic pathway)sun6CO2 + 6H2O 6O2 + C6H12O6Carbon water oxygen glucoseDioxide
11 Products of photosynthesis: Makes glucose to store energy.Also stores energy short term in the molecule ATP.
12 ATP: adenosine triphosphate Small molecule that stores small amounts of energy for a cell.Like pennies of energy compared to the $20 bill of glucose.Energy in ATP can be usedanywhere in the organism.
13 ATP Energy is stored in the bond of the last phosphate group. Like a rechargeable battery.Absolutely necessary for life processes!
14 Plants take in carbon dioxide Pore on bottom of leaf called stoma (stomata pl.).Let CO2 into leaf.Let water vapor out.
21 Chloroplasts gather sun energy Pigments: molecules that absorb certain wavelengths of light energy.Chlorophyll: several pigments that absorb mostly violet-blue and red wavelengths and reflect green.(chlorophyll a and chlorophyll b most common)Carotenoids (ex: β-carotene) absorb blue/green, reflect yellow, orange, red
22 Pigments:A pigment is a molecule that absorbs light in the visible portion of the electromagnetic spectrum. The leaves of most plants are rich in pigments. These pigments absorb light and convert it into chemical energy to fuel the production of sugars. The primary photosynthetic pigment is chlorophyll a. Other pigments such as chlorophyll b and carotenoids are referred to as accessory pigments. These absorb light and funnel the energy to chlorophyll a.Different pigments absorb different types (wavelengths) of light. Some pigments might absorb blue light better than other wavelengths of light, for example. Others may absorb all of the colors well, or none.
24 Glucose = C6H12O6The carbon in glucose comes from carbon dioxide (CO2)The hydrogen in glucose comes from water (H2O)The oxygen in glucose comes from CO2.The sun energy is stored in the bonds that hold the glucose molecule together.
25 Factors affecting Photosynthesis WaterTemperatureIntensity of lightConcentration of CO2
38 The Calvin Cycle Calvin Cycle Animation Photosynthesis Animated Overview
39 Alternate pathwaysC4 – plants in hot dry areas keep their stomata closed on hot days, fix carbon as a 4-carbon compound. (corn, sugar cane)CAM – crassulacean acid metabolismplants living where water is scarce keep stomata closed in day, store CO2 as an acid that they can use in daytime for Calvin cycle.(cacti, orchids, pineapple)
40 YouTube Resources: Photosynthesis song detailed overview Bozeman Photosynthesis