Topic 1 Environmental Chemistry 2024.pptx

Unit C: Environmental Chemistry Topic 1: The environment is made up of chemicals Introduction Chemical substances are found everywhere We are made of chemicals and so is everything that makes up the world around us Chemicals can be naturally occurring and they undergo natural cycles and changes Chem...

Unit C: Environmental Chemistry Topic 1: The environment is made up of chemicals Introduction Chemical substances are found everywhere We are made of chemicals and so is everything that makes up the world around us Chemicals can be naturally occurring and they undergo natural cycles and changes Chemicals can also be introduced into the environment by human activity Big Questions: 1. What are these chemical substances? 2. How do changes in the concentration and distribution of these chemical substances affect living organisms? 3. How do we assess the impact of human introduced chemicals on the environment? How do we monitor this? Chemicals are found in nature! For hundreds of years, people relied on their knowledge of plants for food and medicine Eg. Indigenous people are important knowledge keepers of the health benefits of local plant life Eg. Knowledge of the health benefits of plants informs the development of medicines by pharmaceutical *However, it is important to recognize that the purpose companies of a pharmaceutical company is to… make money… they don’t actually want to make products that cure our health problems. Many manufactured medications have side effects that require us to take other medications… and many are on medications for life. Elements Found in Nature – combine to make chemicals Which elements do you What know the name of that chemicals are commonly are in the found in nature? environment? There are 118 elements on the periodic table – there are four that are essential for life. 1. Oxygen 2. Carbon 3. Hydrogen 4. Nitrogen Building Blocks (our proteins and DNA) – built with amino acids using elements H, C, N, O, P, S Enzymes control many functions in our bodies including respiration, digestion, metabolism, and the immune system Nerves require many metal elements to function as they allow for the conduction of electricity. Bones and Teeth are mainly composed of calcium and phosphate. Blood (composed of several types of cells) relies on the iron in the hemoglobin of the red blood cells to bring oxygen to cells and carry away carbon dioxide. Respiration and Energy – our cells use the oxygen we breath in combined with the food we eat to make ATP (adenosine triphosphate) – the energy currency of our cells. Chemicals support survival of living organisms Approximately 25 elements are necessary for normal growth C, O, H, N, P: the most abundant elements in living organisms are found in complex molecules such as sugars, lipids, proteins, and DNA Organic compounds = contain carbon (C) Inorganic compounds = do not contain carbon! Organic compounds far outnumber inorganic Therefore, carbon is the compounds! WHY?? backbone of many Carbon has the ability to make four bonds (remember that +/- 4 on the periodic table above carbon? molecules Macro vs Micro Nutrients Nutrients: elements and chemical compounds necessary for survival needed for living, growing, reproduction etc. Macronutrients: needed in relatively large amounts, eg. C, H, O Micronutrients: needed in relatively small (trace) amounts, eg. Se Optimum Amounts: The amount needed to provide the best health to an organism Overabundance or deficiencies can lead to poor health or death! Can you name macro and micronutrients Examples of Macronutrients Four Main Types of Organic Molecules Recall: Molecules are chemical compounds made only of non-metal elements! Organic molecules always contain carbon (C) Most chemical compounds in living organisms are organic molecules 4 important classes of organic molecules make up all living organisms: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids Carbohydrates What foods contain carbs?? Pasta, rice, potatoes, fruits, veggies, bread Made of C, H, and O Energy source for cellular respiration “simple carbohydrates” = simple molecules such as glucose and sucrose (sugar) “complex carbohydrates” = large, complex molecules such as starch, cellulose, and glycogen Question: what are “refined” or “processed” carbohydrates? They are starch-based foods that have had many of the natural ingredients and nutrients stripped away. Lipids What are sources of lipids? Fats, oils, waxes Animal = body oils, fat stores Plant = seeds, nuts, corn etc. Made of C, H, and O needed for energy storage for later use Can you think of sources of food that are high in fat? Why are fats good for us? Does it depend on the source? Avocados, fish, nuts are all sources of healthy fats. Fats are a great source of energy and our cells need fat to function. Proteins What are good sources of protein? Meat, fish, eggs, dairy products, legumes, nuts Made of C, H, O, N, S Proteins are the workhorses of living organisms Involved in growth, repair, chemical reactions (enzymes), etc. Made of chemical units called amino acids Each type of protein has its own unique number, sequence, and arrangement of amino acids that defines its 3D structure and function What are “essential amino acids”? They are amino acids that your body cannot make – you must get from your diet. Nucleic Acids You know what they are! – Adenine, Guanine, Thymine, Cytosine Made of C, H, O, N, P DNA = “deoxyribonucleic acid” – contains “deoxyribose sugar” Genetic code for the blueprint of life! Double stranded, found in nucleus Made of repeating units of deoxyribose, nitrogenous base (A, T, C, G), and phosphate (nucleotides) RNA = “ribonucleic acid” – contains “ribose sugar” Single stranded, found in cytoplasm Made of repeating units of ribose, nitrogenous base (A, U, C, G) and phosphate DNA is transcribed to RNA RNA is translated to proteins Importance of Good Nutrition 5 min Nutrition Labels Nutrition fact labels tell you the serving size, calories, and the % of daily value of nutrients Ingredients are listed from greatest amount to least amount These labels have been legally required on packaged foods since 2007 Related video on next slide** How to Read Nutrition Fact Labels 5:21 min How do organisms take in substances? Plants and animals rely on the environment for necessary chemical compounds Plants (producers) convert inorganic compounds to organic compounds Animals (consumers) consume plants and other animals to obtain organic compounds (can’t synthesize them themselves) Some compounds consumed from the environment are unnecessary but harmless, but some are not! Methods of Substance Uptake Nutrients must ultimately reach an organism’s cells where they are processed into the necessary organic molecules and used for cellular functions What are the different processes? 1. Diffusion 2. Osmosis 3. Active Transport 4. Ingestion -> hydrolysis -> absorption 5. Substrates Diffusion Definition: the passive movement of particles How does it work: Diffusion does not require energy Diffusion is the movement of particles from an area of high concentration to low concentration through a porous membrane Molecules naturally diffuse into the roots of plants Example: In the air: Spraying air freshener Osmosis Definition Osmosis is the passive movement of water molecules How does it work Water molecules move from an area of high concentration to an area of low concentration through a porous membrane Does not require energy Example: More water gets absorbed/moves into the roots Semi-permeable membranes https://www.youtube.com/watch/-g-VJymtAf4 (2 min) Active Transport Definition: Movement of molecules in which it takes energy to do so How does it work: Plants undergo active transport when they move molecules into their roots that are already at a high concentration within their roots It takes energy for the plants to move molecules the opposite of where they would go if they were diffusing There are specific proteins in the plants that move molecules such as sulphur, nitrogen, and potassium into the roots Example: Plant roots use energy to pull nutrients from the soil Ingestion and Absorption of Materials by Animals Definition: Humans and animals absorb nutrients by eating or ingesting plants or other animals How does it work: We chew our food so that there is higher surface area of the food to be digested and so that the nutrients can be absorbed Absorbed in the intestines We break down food physically (chewing) and chemically through enzymes and acids in our stomachs As the food moves through our stomachs and intestines the nutrients are absorbed into our bloodstream and flow until they are taken up by cells that need the nutrients Substrates Definition: the material on which an organism moves or lives How does it work: Some organisms are attached to their substrate (anemone) Some organisms obtain nutrients from their substrate Example: Mold Anemone Lichens Natural Processes Change Chemicals in the Environment Water, and elements such as C and O, in the form of different compounds, cycle through ecosystems Eg. Photosynthesis: Plants convert carbon dioxide and water to oxygen and glucose using energy from the sun Plant life change chemicals in the environment by absorbing carbon dioxide and releasing oxygen Eg. Cellular Respiration: Glucose (metabolic product of digestion) and oxygen are converted to water and carbon dioxide Living organisms change chemicals in the environment by digesting food, breathing in oxygen and breathing out carbon dioxide The Nitrogen Cycle Nitrogen also cycles through ecosystems Recall, nitrogen is an important element needed for protein and nucleic acid synthesis Air contains 78% free nitrogen (N2(g)), but this is not usable! N from N2(g) must be “fixed” into compounds with other elements (such as C and O) which can then be metabolized by living organisms = “Nitrogen Fixation” Bacteria in the root nodules of certain Nitrogen Cycle:clover, alfalfa) “fix” plants (eg. beans, nitrogen by breaking apart N2(g) to free N atoms which can then be combined with other atoms to form nitrogen containing compounds Lightning can also "fix" or break apart Nitrogen Cycle Nitrogen Cycle 3.5 min Nitrogen Cycle Bacteria fix nitrogen -> plants consume nitrogen containing compounds -> animals consume plants -> plants and animals produce waste -> nitrogen containing compounds are recycled back in the soil Re-consumed by plants and animals OR Metabolized by decomposers to simpler molecules -> other bacteria convert simpler nitrogen containing compounds to free N2(g) -> back in the air Cycle repeats! The concentration of nitrogen containing compounds can vary depending on the environment Lost as free N2(g) by overabundance of bacteria in soil Carried away by water runoff Plants are harvested How could farmers replenish agricultural soil of much needed nitrogen? Human Activities Change Chemicals in the Environment Chemicals from human activities can enter and impact the environment (air, water, and soil) – can often change the pH Some chemicals may be broken down Other chemicals cannot be broken down and negatively impact the environment long-term 1. Agricultural Activities 2. Solid Waste 3. Wastewater 4. Fuel Combustion Acids & Bases – Measured on the pH Scale pH – stands for the Power of Hydrogen Acid: a compound that dissolves in water to form a solution with a pH lower than 7 Base: a compound that dissolves in water to form a solution with a pH higher than 7 Neutral: a solution with a pH of 7 and is not an acid or a base These pH The pH number represents acidity values from 0-ratings are not official and will 14. appear slightly different on different references – it is most important to know which are acidic and basic Measuring pH You can use a pH meter or acid-base indicators to measure pH. Ex. Litmus paper, universal indicator, pH paper. The pH Scale 3 min Video Reflection What colour is red litmus paper in acid? RED What colour is red litmus paper in a base? BLUE What colour is blue litmus paper in acid? RED What colour is blue litmus paper in a base? BLUE What colour would blue and red litmus paper in neutral solution? PURPLE Neutralization An acid-base reaction that produces water and a salt Neutralizing the Effects of Acid Rain Ordinary rainwater is naturally slightly acidic. Precipitation dissolves carbon dioxide from the air to form very weak carbonic acid with a pH of about 5.6 In central Canada, acid rain can have a pH as low as 3. Many lakes in Ontario and Quebec became so acidic that organisms could no longer survive in them Acidic lakes are sometimes treated with lime (calcium hydroxide) to neutralize them Our beautiful Rocky Mountains are made of limestone so they can naturally neutralize acid rain! Water Pollution Next: Complete Water Pollution Article and Questions 7 min