Science Notes PDF

Topic 4: Movement in cells Diffusion - Diffusion refers to the process by which molecules intermigle as a result of their kinetic energy of random motion Diffusion: The tendency of particles to move to a place of high concentration to a place low concentration Semi permeable Membrane...

Topic 4: Movement in cells Diffusion - Diffusion refers to the process by which molecules intermigle as a result of their kinetic energy of random motion Diffusion: The tendency of particles to move to a place of high concentration to a place low concentration Semi permeable Membrane - A semi permeable membrane is a membrane which will allow the passage of certain molecules through it (by the process of diffusion), and not other molecules - The rate of passage depends on thepressure, concentration, and temperature of the solvent on either side, as well as the permeability (how much it will let through) of the membrane to each type of molecule or solute Osmosis - Osmosis is the diffusion of water across a semi-permeable membrane - Water moves from and area of high concentration to and an area of low concentration - This means that water always moves toward the area that has more solutes The Cell Membrane - Liek customs/border between two nations, it controls what is allowed in and out of the cell and what is not - It is said to be Semi-Permeable meaning it lets some substance in and out and some not - Permeable- A membrane that lets everything cross - Impermeable- A membrane that lets nothing cross - Some substances can cross the membrane, between the phospholipids (eg. Oxygen, water, carbon dioxide) - Others are allowed through the proteins (called protein channels) (eg. sugar and charged particles like sodium ions) - Some substances are not allowed to move across at all Vascular Tissue - Vascular plants contain two main types of conduction tissue, the xylem and phloem - These two tissues extend from the leaves tot he roots and are vital conduits for water and nutrient transport - In a sense, they are to plants what veins and arteries are to animals - Vascular tissue consists of xylem and phloem. There are two types of vessels run side-by-side, extending from roots to leaves. They provide channels for the transport of water amd nutrients Xylem Tissue The Function of xylem tissue is to:  - Conduct water and dissolved minerals - Structural support Phloem Cells The function of the phloem cell is to: - Conduct food and other organic substances to different parts of the plant Transpiration- transfer of water from plants to the atmosphere - How it works: Plants dump the water up form the soil to deliver nutrients to their leaves. This pumping is driven by the evaporation of water through small pores called “stoma” (singular:Stomata), which are found on the undersides of leaves - Each stomata pore is bounded by two crescent shaped guard cells. Their opening and closing releases or retains water within Plant Traspiration - This evaporation produces what is known as the transpiration stream, a tension that draws water up from the roots through the xylem (water-carrying vessels in the stem) - This replaces the water that is lost, and allows minerals absorbed from the soil to be transported through the xylem to the leaves This important because many plant cells need the minerals as nutrients Topic 5: Cell Specialization and Organization - In a multicellular organism, different cells have different jobs - They are said to be Specialized for particular tasks - Muscle cells are shaped to move parts of your body - Skin Cells are built to protect your body from drying rays of the sun - Nerve cells have long, branched fibres running from the main part of the cell, shaped to carry nerve signals to different parts of the body - Red blood cells, which carry oxygen in the blood stream, have a thin, disklike shape. This gives them a large surface area to pick large amounts of oxygen Advantages of Being Multicellular 1. Multicellular organisms can grow very large as they can grow more cells 2. They can live in a wide variety of environments 3. They can obtain their energy from a wide variety of foods 4. Their cells function more efficiently as they are specialized to preform certain functions Example: - An Ameoba needs to have.. - Contractile vacuole (to store wastes, then transport to the outside of the cell - Food vacuole (where large pieces of food are broken down - Pseudopods (little feet that allow the amoeba to grab prey - To reproduce, the single cell must replicate all its genetic material and expand energy to divide We Have: - Systems to excrete waste (digestive, excretory) (plus our blood helping to move wastes) - A digestive system to break down our food. Tiny particles can be transported in the blood to individual cells - Reproductive system Tissues - Tissues are groups of similar cells - These are the main types of tissues found in animals: 1. Connective tissue 2. Epithelial tissue 3. Muscle tissue 4. Nervous tissue - Connective Tissue: connects ans supports different parts of the body (Examples- bone, blood, or loose sheets between organs) - Epithelial tissue: protects the outside of the body, or covers internal structures, like intestines - Muscle tissue: Moves parts of the body - Nerve tissue: carries signals between the brain and other body parts These are the main typesof tissues found in plants: - Epidermal - Xylem - Phloem Organs - Organs are distinct structures in the body that preform particular functions  - You use your eyes (to sense the apple) your brain ( to plan and co-ordinate your actions), and your mouth and stomach (to start digesting the apple) Examples of Organs in the Human Body - Heart - Kidney - Lungs Systems - Organs work together just as cells and tissues do - Organs form systems to preform activities that help plants and animals function as a whole Plants Have Fewer Systems Than Animals Have: Root System ( below ground) - Obtain water and materials from the soil - Anchor the plant in the ground Shoot System (above ground)-stems and leaves - Makes food for the plant Reproductive system (flowers,fruits, and seeds) -only sometimes - Reproductive Shoot and Root Systems Shoot System - produces sugars by photosynthesis - Carries out reproduction Root System - Anchors the plant - Penetrates the soil and absorbs water and materials - Stores food Topic 6: Body Systems in Humans The Digestive System Food enters the body through the mouth  Food is broken down in the mouth, stomach and intestines Unused food is expelled as waste Respiratory System We inhale and bring in oxygen We exhale and get rid of waste carbon dioxide The respiratory system is responsible for gas exchange Circulatory System The circulatory system transports food and oxygen through the body Made of the heart, blood and blood vessels Circulates blood around the body to deliver food particles, dissolved gas and other materials to cells Also takes away waste material from the cells Nervous System Coordinates and controls the actions of the organs and organ systems Detects, processes and responds to stimuli in the environment Excretory System Removes wastes from the system Digestive System 1. Mouth – Food broken down by chewing and chemical action of saliva.  2. Salivary Glands - Saliva contains enzymes that break down carbohydrates (like starch from potatoes, corn, rice, and bread) into smaller molecules. 3. Esophagus - The esophagus is a long tube that uses rhythmic, wave-like musclemovements (called peristalsis) to force food from the throat into the stomach. 4. Stomach - Food in the stomach is partly digested and mixed with stomach acids 5. Liver - Makes bile which breaks down fats and some blood proteins. Helps the smallintestine in digestion. 6. Gall Bladder - It stores and releases bile into the small intestine. 7. Pancreas - Enzymes from the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine. 8. Small Intestine – bile, pancreatic enzymes, and other digestive enzymes produced by the 9. inner wall of the small intestine help in the breakdown of food. Most food is absorbedhere. 10. Large Intestine - The large intestine is responsible for absorption of water and excretion of solid waste material. 11.Rectum – Feces are stored here. 12. Anus – Where feces exit the body. Respiratory System 1. Larynx – Place where moving air being breathed in and out creates sounds 2. Trachea – This is the windpipe, or the passage leading from the mouth and throat to the stomach 3. Lungs – The lungs perform respiration or gas exchange 4. Bronchi or Bronchus – The two main tubes of the lungs 5. Bronchioles – The smaller divisions of the bronchi 6. Alveoli – The very small air sacs where breathed in air goes 7. Diaphragm – Strong wall of muscle that separates the chest cavity from the abdominal cavity Circulatory System Heart – The body’s blood is circulated throughout the body by the heart Veins – Veins carry blood to the heart. Veins carry dark red blood that doesn’t have much oxygen Arteries – Arteries carry blood away from the heart. Arteries carry bright red blood that is high in oxygen Blood – Carries food and oxygen to cells as well as carrying wastes away from cells. Blood also carries disease fighting white blood cells through the body. It also helps maintain constant body temperature. The Heart Blood begins in the heart, is pumped through the arteries, then branches into arterioles and then capillaries. Gases and nutrients are exchanged in the capillaries by diffusion. Blood is carried back to the heart from the capillaries to the venules to the veins. Capillaries are extremely narrow to allow high surface area. This is where nutrient exchange occurs. Nervous System 1. Brain - It helps to control all of the body systems and organs, keeping them working like they should. The brain also allows us to think, feel, remember and imagine. 2. Spinal Cord - The brain communicates with the rest of the body through the spinal cord and the nerves. Information passed through the spine tells the body what to do and when to do it. 3. Nerve Cells - Neurons carry messages in the form of a electrical impulses. The messages move from one neuron to another to keep the body functioning. Excretory System Kidney – Cleans the blood of waste products. Waste is passed out your body in urine. - Wastes include: nitrogen waste from proteins, excess salts and water, and various other wastes that are products of chemical reactions in the body. Ureter – Takes urine from the kidney to the bladder. Bladder – Stores urine until it is passed out the body in urine. Urethra – Urine passes from the bladder to the urethra on the way out of the body. System Functions Digestive- Breaks down food, absorbs food particles, and eliminates wastes Respiratory- Exchanges oxygen and carbon dioxide Circulatory- Circulates blood. Transports food particles, dissolved gases, and other materials. Nervous- Controls and coordinates body activities. Senses internal and external changes. Excretory- Regulates blood composition and excretes waste fluids. Topic 7: Body Systems and Your Health Blood – Body’s Transportation System In multi-cellular organisms, substances must be brought to the cells and this is done by the blood. Blood also takes wastes away from the body’s cells. Blood is made of: Plasma - Liquid portion of blood that carry nutrients, waste products and blood cells Red Blood Cells – carry oxygen White Blood Cells – defend body against infections and cause clotting to stop bleeding Platelets – Help stop bleeding by forming clots A Healthy Circulatory System Living a health lifestyle keeps your circulatory system healthy Disorders of the Circulatory System Disorders of this system are the leading cause of death in North America High blood pressure and heart attacks are common disorders  Smoking, lack of exercise, poor diet and high cholesterol can lead to circulatory disorders A Healthy Digestive System Important Nutrients in food that lead to a healthy digestive system: Carbohydrates provide the body with main source of energy Fats are essential as they provide us with energy and cushion our organs Proteins are essential for muscle growth and repair of tissues Disorders of the Digestive System Cancers and ulcers are common disorders A Healthy Respiratory System Surrounding yourself with healthy air inside and outside the house keeps your respiratory system healthy Disorders of the Respiratory System Bronchitis, emphysema, lung cancer and asthma are common disorders of the respiratory system Smoking and other air pollutants are the major causes of respiratory disorders.