Energy and Cycles of Matter Mr. I

Why do we need energy? All living things need energy to do work, Energy is the ability to do work. In terms of energy there are two types of organisms : 1)Autotrophs 2) Heterotrophs

Autotrophs Autotrophs make their own food through either photosynthesis or chemosynthesis. Examples of such organisms are plants, algae, and bacteria. They are the foundation of all ecosystems. Without autotrophs no ecosystem can flourish Also called producers

Heterotrophs Cannot make their own food, rely on autotrophs. Also known as consumers. Include all animals and fungi.

Energy Molecules Glucose – This is a sugar molecule made by plants through photosynthesis and it is broken down in cellular respiration in the mitochondria of all cells. ATP – This is a high energy molecule that is needed for all cell processes.

Chemosynthesis This is the formation of organic material by bacteria using energy derived from simple reactions. Micro-organisms in dark regions of the ocean can produce energy from single carbon molecules It was first discovered at hydrothermal vents, places where the temperatures are thought to be too hot for life to exists. Large populations of animals can be supported by chemosynthetic secondary production at hydrothermal vents, methane clathrates, cold seeps, whale falls, and isolated cave water

Photosynthesis This is the fundamental process that all life depends on. It is the conversion of light energy to glucose in the chloroplasts of plant cell. It is the conversion of radiant energy to chemical potential energy stored within the bonds of carbon sugars. (glucose) It uses carbon dioxide from the atmosphere, water, and sunlight and converts it to glucose and oxygen.

Respiration Takes place in the mitochondria of cells. the release of chemical energy from food molecules for use by the cell. Most organisms depend on respiration and/or photosynthesis to provide energy directly or indirectly.

Aerobic Respiration Takes place in the mitochondria of all eukaryotic cells, conversion of glucose to ATP (energy) for all life sustaining processes. It is the release of chemical potential energy from sugars. Uses oxygen and glucose and converts it to carbon dioxide, water, and 38 ATP molecules. (ATP= Adenosine Triphosphate) The products of photosynthesis are the reactants of respiration and vice versa.

Relationship Between Photosynthesis and Respiration 6H2O +6 CO2 → C6H12O6 + 6 O2 Carbohydrates and oxygen are products in photosynthesis, BUT reactants in respiration. Carbon dioxide and water are reactants of photosynthesis, BUT products of respiration. C6H12O6 + 6 O2 →6H2O +6 CO2+ ATP

Lets look at these processes in more detail Lets look at these processes in more detail! We will look at the biochemical pathway of each process Biochemical pathway – Complex series of reactions that involve the specific series of reactions, perform a specific function, and occur at different sites.

Photosynthesis Photosynthesis Divided into 3 sets of reactions : 1.Light absorption in chlorophyll 2.Light-dependent reactions. 3.Light-independent reactions.

Light absorption in chlorophyll 1.Light absorption by chlorophyll Chloroplasts found in the cells of green plants absorb chlorophyll from sunlight. Thylakoid- site of light absorption found in chloroplasts.

2. Light Dependent Reactions Main Stages : 1.Converts sunlight to electrical energy, which is the flow of electrons. Electron transport chain – Passage of electrons from a high energy level to a lower energy level. – Generates electrical energy 2. Electrical Energy is changed to chemical energy through a membrane, resulting in ATP formation that is used to drive the process of photsythesis Chemiosmosis – diffusion of chemicals through a membrane, forming ATP.

Light Independent Reactions 3. Light Independent Reactions – reactions that form organic compounds by using energy stored during light-dependent reactions. During these reactions carbon fixation produces organic compounds through carbon-carbon bonding. Here the ATP created in the light dependent reactions is stored within the bonds of the sugar (carbon-molecules)

Carbon Fixation Most plant species in moderate climates fix carbon through light- independent reactions called the CALVIN CYCLE. Other pathways that fix carbon: C4 and CAM pathways. C4Pathway is an adaptation for plants in environments having high temperatures, dry conditions and abundant light. Allows plants to grow quicker in hot dry climates ex... corn, sugar cane etc...

Carbon Fixation CAM pathways takes in CO2during the night then releases it during the day for use in photosynthesis. These plants lose less water due to collection CO2 at night, giving them a survival advantage over other plants in hot, dry environments. Ex. - cactus, pineapple, etc...

OGT Review Question What does the process of photosynthesis release to the atmosphere? a- carbon dioxide b- hydrogen c- nitrogen d- oxygen

OGT Review Question For many years scientists debated whether viruses should be considered living organisms. Which statement could a scientist use to support the position that viruses are not living? A-Viruses have genes encoded in DNA B- Viruses require a host cell in order to reproduce. C- Viruses infect both plant and animal cells. D-Viruses replicate to produce more viruses.

OGT Review Question What Structure is absent in the cells of fungi thereby preventing them from performing photosynthesis? a- Cilia b- Nuclei c- Chloroplast d- Mitochondria

OGT Review Question A scientist uses a microscope to examine two slides of living bacteria. Each slide has different bacteria. While the cells on the first slide are moving rapidly, the cells on the second slide are stationary. Based on these observations, the cells on the second slide most likely have no a- nucleus b- Flagella c- chloroplasts d- Mitochondria

Cellular Respiration Cellular Respiration- a set of chemical reaction that occurs inside every organism's cells and converts nutrients to ATP (Energy Molecule). C6H12O6+ 6 O2→ 6 H2O + 6CO2 + ENERGY (ATP) Glucose + Oxygen → Water + Carbon Dioxide +Energy

2 types of cellular respiration : 1.Anaerobic Respiration 2. Aerobic Respiration

Aerobic Respiration – Respiration that requires oxygen - Glycolysis is followed by Krebs Cycle then the Electron Transport Chain. - Krebs Cycle – a Biochemical pathway that releases CO2 AND H+(water) and results in the formation of ATP. Takes place in the mitochondria of a cell. - Electron transport chain – passage of electrons from high energy to lower energy level.

Types of Fermentation 1.Lactic acid Fermentation – converts Pyruvic acid to lactic acid. - Causes soreness in muscles. 2. Alcohol Fermentation – converts Pyruvic acid to ethyl alcohol. - Creates our beer, wine, and bread - Many calories in beer due to energy remaining in the ethyl alcohol and not being converted to ATP.

Anaerobic Respiration It is the incomplete breakdown of glucose in the ABSENCE of oxygen (NO OXYGEN) Consists of: 1- Glycolysis – glucose converted to Pyruvic acid without using oxygen. Produces a small amount of ATP. Takes place in the cytosol. 2- Fermentation – process of breaking down Pyruvic acid without the use of oxygen to form Lactic Acid (Muscle soreness)

Energy Yields Aerobic Respiration -Glycolysis = 2 ATP -Krebs Cycle = 2 ATP - Electron Transport = 34 ATP 38 ATP Total

Energy Yields Anaerobic Respiration -Glycolysis = 2 ATP 2 ATP total Aerobic Respiration is 19 times more effective that anaerobic respiration in providing a cell with energy for cellular activities.