Diffusion: Net movement of particles down the concentration gradient from a region of high concentration to a region of low concentration in attempt to reach a balance. Unicellular Organisms: Organisms composed of a single cell – bacteria, fungus, yeast Unicellular Organisms are composed of a single cell - They have a large surface area to volume ration With large SA:V, Unicellular Organisms have an efficient rate of diffusion This allows the cell to solely rely on diffusion to transport necessary substances in and out of cells Common Features of Exchange Surfaces: - - Thin cell walls o 1 cell thick to minimize distance of diffusion increasing the rate of diffusion Large Surface Area to Volume Ratio o Unicellular organisms are commonly long, thin, flat or folder to increase surface area to volume ration increasing rate of diffusion Moist o Unicellular organisms have moist membranes to allow substances to diffuse easily Multi-cellular organisms have a small surface area to volume ratio. - They have more than one cell Diffusion would be INEFFIECENT They rely on transport systems ventilation system and circulatory system Phloem: Tube system that transports organic compounds (sucrose and amino acids) from sources to sinks via translocation - Source: Where organic compounds are synthesized Sinks: Where organic compounds are delivered to for use or for storage Xylem: Tube system composed of dead cells (reinforced with lignin) which transports water through the plant via transpiration – evaporation of water from the surface of plant Red Blood Cell: - Transports oxygen in hemoglobin of cell from lungs to respiring cells for aerobic respiration White Blood Cell: - Composed of Two Types of Cells o Phagocytes Engulf and Digest pathogens o Lymphocytes Produce antibodies to deactivate antigens of Bacteria Platelets: - Cell fragments involved in blood clotting Plasma: - Medium of transport that carries of CO2, digested food, Urea, Hormones and Heat Liquid part of the blood Makes up 55% of blood Carbon Dioxide: - Plasma carries digested food to respiring cells for energy Digested Food: - Plasma carries digested to respiring cells for energy Urea: - Urea is a waste substance and is carried by plasma to the kidneys for excretion Hormones: - Hormones are secreted into plasms to carry to organs Heat Energy: - Plasma mainly consists of water Water is a good medium for heat transport Plasma maintains a balanced optimum body temperature (37C) Red Blood Cells Red Blood Cells: transport oxygen in hemoglobin of cell from Lungs to respiring cells for aerobic respiration Hemoglobin: - RBC contain Hemoglobin Hemoglobin combines with Oxygen to for Oxyhemoglobin to transport O2 to respiring cells No Nucleus: - RBC do NOT have a nucleus to allow more space for Hemoglobin to transport oxygen to respiring cells Small and Flexible: - RBC are small and flexible to squeeze through narrow capillaries and blood vessels for efficient transport Thin Cell Membrane: - RBC have thing cell membrane (1 cell thick) This minimizes distance of diffusion in oxygen molecules Biconcave: - RBC have flattened disc shape to increases surface area to volume ration for diffusion of O2 Allowing efficient diffusion and transport of O2 to respiring cells Phagocytes: WBC that engulfs and secretes digestive enzymes onto pathogens to remove them from the body - - - Sensitive Cell Surface Membrane: o Have sensitive cell surface membrane that detects and locates pathogens via chemical compound Digestive Enzymes in Cytoplasm o Phagocytes have digestive enzymes in cytoplasm to digestion and remove pathogen from body once engulfed Irregular Shaped Nucleus o Have irregularly shaped Nucleus to squeeze through narrow gaps in capillary walls allowing them to digest and remove pathogens quickly 1. Have sensitive cell surface membrane detects and located pathogens 2. When pathogen is encountered, it will engulf and release digestive enzymes to digest pathogens 3. Pathogen is removed from the body Lymphocytes: - WBC that produces antibodies to deactivate antigens on the surface of pathogens They produce memory cells that remain in the immune system for quick response to same antigens They have a Large Nucleus - The large nucleus contains multiple copies of DNA to produce antibodies in large amounts preventing spread of diseases and infections 1. When pathogen is detected Lymphocyte will split into 2 cells 2. One cell will produce antibodies to deactivate the antigens of pathogens 3. Other cell will be memory cell that remains in immune system The Heart: https://www.youtube.com/watch?v=zU90AkcTJEs Coronary Heart Disease: - Blockage of Coronary Artery by Fat globules This causes insufficient oxygen transport in blood leading to increased anaerobic respiration o Increasing anaerobic respiration causes buildup of lactic acid o This creates an acidic environment causing enzymes to denature o This causes Strokes Increasing Factor of Coronary Heart Disease: - - - Poor Diet o Diets that have high Saturated Fats, Salts, and Alcohol increase Cholesterol o This increases chance of CHD Stress o Stress stimulates the secretion of hormones that increases blood pressure o This increases the risk of build up fatty plaques which can cause CHD Smoking o Nicotine in cigarettes cause vasoconstriction o Increases the risk of the buildup of fatty plaques to cause CHD Heart Rate: Rate at which the heart beats (measured in beats per minute) Adrenaline: Hormone produced by Adrenal Gland which increases heart rate for ‘fight or flight’ response Process: - During exercise more energy is needed via respiration to allow muscle contraction to occur to facilitate movement Heart rate will increase to allow more oxygen transport in blood to respiring cells for movement to occur If energy demand exceeds oxygen intake, energy may be produced via anaerobic respiration producing lactic acid as a waste product After exercise, heart rate continues to increase as extra oxygen is needed to break down the lactic acid produced Effect of Adrenaline on Heart Rate: - During fear or stress, adrenaline is produced by adrenal glands Liver cells convert glycogen into glucose to increase blood glucose levels Breathing and Heart rate increases to increase blood flow Breathing and HR increases to allow more glucose and oxygen to be transported in the bloodstream to respiring cells for ‘flight or fight’ response to occur Arteries: - Transports Oxygenated blood away from the Heart Thick muscular walls Narrow lumen to maintain high pressure to pump blood around the body Veins: - Transported Deoxygenated blood towards the heart (excluding the pulmonary vein) Thin walls to allow skeletal muscle to exert pressure on Vein Wide lumen to transport large volume of blood Valves to prevent the backflow of blood under low pressure Capillaries: - Facilitates material exchange between cells Thing walls (1 cell thick) that are porous and permeable for efficient material exchange via diffusion Narrow lumen to fit between cells for extensive branching which increases surface area to volume ratio for efficient material exchange via diffusion. Circulator System: https://www.youtube.com/watch?v=bpYaKM2hVFY
