Cells and Systems: Fluid Movement in Plants PDF

Science 8 Cells and Systems Unit 2 Topic 4 Fluid Movement in Cells  The Cell Membrane and How It Functions Cell membranes only allow some substances to enter or leave the cell. Impermeable – Nothing crosses Permeable – All materials cross Selectively permeable...

Science 8 Cells and Systems Unit 2 Topic 4 Fluid Movement in Cells  The Cell Membrane and How It Functions Cell membranes only allow some substances to enter or leave the cell. Impermeable – Nothing crosses Permeable – All materials cross Selectively permeable – Certain materials cross  Diffusion Particle model states there is a constant movement of particles in all liquids. Diffusion is the movement of particles from an area of high to low concentration to eventually evenly spread out.  Cellular Diffusion Concentration determines the direction that a substance takes through the cell membrane Particles move from higher concentration areas to lower concentration areas. A higher concentration of particles on the inside of the cell will move to an area of lower concentration on the outside - movement will only occur from inside to outside until there is an equilibrium/balance. Equal concentration allows the movement of particles in and out equally.  Diffusion in Cells Diffusion plays a part in – Amoeba have a moving substances into and selectively permeable out of cells membrane that allows CO2 to move into and out of the cell so that the concentration on both sides is equal  Osmosis Water is important to living things because it dissolves many of the substances involved in cell processes. When water moves out of a cell, the dissolved substance inside the cell become more concentrated. When water moves into a cell, the dissolved substances inside the cell become more diluted. Water moves from a diluted solution to a more concentrated solution.  Osmosis Osmosis is the diffusion of water through a selectively permeable membrane. By definition: diffusion of a solvent (usually water) tends to move from high concentration to low concentration – Try it! Place limp celery in a glass of water overnight. Predict and explain what will happen.  Osmosis In a hypotonic solution, hypertonic, isotonic, hypoto water molecules enter a cell nic by osmosis. Animal cells swell until they burst! Plant cells swell beyond their normal size with the increase of pressure. flaccid vs plasmolyzed  Osmosis In an isotonic solution, Hypotonic, isotonic, water molecules move in hypertonic and out of cells at the same rate, and the cell maintains their normal shape.  Osmosis In a hypertonic solution, Hypotonic, isotonic, water molecules leave a cell hypertonic by osmosis, causing the cell to shrink. Animal cells shrivel up - crenation! Plant cells lose pressure and plasma membrane shrinks away from cell wall - plasmolysis.  Osmosis Water loss and compensation Water loss for the decrease in water in – Perspiration – sweating human body. – Respiration(breathing) Compensates – Osmosis: water replaced from other cells and structures in your body Finally … – Need to replace water by drinking Compare and Contrast Diffusion and Osmosis  Fluid Movement in Plants Vascular Tissue – in plants, tissues that connect the root system and the shoot system Phloem tissue transports Xylem tissue conducts water sugars manufactured in the and minerals absorbed by the leaves to the rest of the plant root cells to every cell in the plant video link  Fluid Movement in Plants The root system contains fine ‘ root hairs ‘ -extensions of epidermal cells (which protect the outside of the plant) When the concentration of water is greater on the outside of these ‘ root hairs ‘ - water passes through the membrane by osmosis - continues from cell to cell, until it reaches the xylem tissue - tube-shaped xylem cells move the water by a buildup of water pressure in the root hairs (high pressure to low pressure) forcing the water up the xylem tissue, into the stems and leaves.  Fluid Movement in Plants Transpiration Loss of water (in a plant) happens through evaporation in process called transpiration. Water loss not a problem unless the plant loses too much water that is not replaced by the roots. Movement of water throughout the plant happens because of the differences in pressure – high pressure in the root hairs to lower pressure in the leaves.  Fluid Movement in Plants: Pushing and Pulling According to the particle model, individual water particles are held together by bonds of attraction which make the plant’s water network behave as a single unit. Water drawn into the root hairs by osmosis - pushes slender water columns up the plant. Water lost from the leaves by transpiration pulls water up the xylem tissue all the way from the roots.  Fluid Movement in Plants Leaves - food-producing organs of plants (photosynthesis takes place here). Photosynthesis takes place in the layer of palisade cells that contain chloroplasts. Palisade cells are thin, allowing a large amount of light in (large surface area), and enabling the gases (in the air) to diffuse into the leaf cells. The tiny openings - stomata, allow air to enter the leaf, supplying oxygen for respiration and carbon dioxide for photosynthesis. The spaces between leaf cells allow the air to flow and the guard cells open and close the stomata.  Fluid Movement in Plants Plants require a large supply of water to make sugars in the process of photosynthesis. - Vascular tissues connect the roots to the leaves. - Phloem Tissue transports sugars manufactured in the leaves to the rest of the plant. - Xylem tissue conducts water and minerals, absorbed by the root cells, to every cell in the plant. * Xylem and Phloem tissue usually occur together, along the length of plant stems and roots  From Root To Leaf Illustrate and explain the events leading to the movement of water from root to leaf (p. 134-137) – phloem tissues – vascular tissues – xylem tissues – root hairs – high concentration – low concentration – osmosis – transpiration – stomata  Cells and Systems Topic 5 Cell Specialization and Organization  Cell Specialization and Organization In unicellular organisms Single cell performs all life functions. It functions independently. Multicellular organisms Have various levels of organization within the organism. Individual cells may perform specific functions and work together for the good of the entire organism. Cells become dependent on one another.  Plant Organization Animal Organization  Levels of Organization Cells with the same structure and function form tissue. Tissues - groups of similar cells that work together, having similar structure and function - form organs Organs - made up of several tissues all working together. They are distinct structures in the body that perform particular functions. Systems - organs work together to perform activities that help the organism function as a whole. e.g. A plant reproductive system (flowers, fruits and seeds) is often produced at certain times as well. Organ systems, perform all the life functions to keep the organism alive.  Specialized Cells Cells that meet the needs of the Although multicellular organism by performing a organisms grow from single certain task. cells that repeatedly divide, Different cells have different their cells are not all the appearances and perform same. different jobs specialized for Humans have about a particular tasks. hundred different types of cells, each with its own particular structure and function.  Specialized Cells e.g.nerve cell (neuron): - Nerve cells have long, branched fibres or axons that are - Cells found in the nervous system. surrounded by insulating cells. -Specialized cells designed to - Its structure is designed to stimulate other cells in the body in facilitate its function of carrying order to communicate. electrical signals long distances -Are excitable, through an electrical in the body to communicate message, known as an action information. potential. -Are able to initiate action in the cells they target.  Specialized Cells red blood cells e.g. red blood cells (erythrocytes) Have a thin, disk like shape. To give a large surface area to enable large amounts of oxygen diffusion. Aids its specialized function of carrying oxygen in the bloodstream.  Specialized Cells Onion skin cells e.g. Onion skin cells Are flat and brick shaped. Allows them to fit tightly together to form a continuous protective layer and barrier.  Being Unicellular Advantages Disadvantages All parts of the cell have Cannot grow very large access to food Because they take in all Simple process of excreting nutrients needed through waste cell membrane, most unicellular organisms can only live in wet, nutrient- rich surroundings If the cell of a unicellular organism dies, the organism dies!  Being Multicellular Advantages Disadvantages Can live in many Are more complex environments and grow Need to communicate large between cells Can obtain energy from a wide variety of foods If a cell of a multicellular organism dies, the organism will likely survive.  Levels of Organization LEVEL 1 - CELLS Are the basic unit of structure and function in living things. May serve a specific function within the organism. Examples: blood cells, nerve cells, bone cells, etc.  Levels of Organization LEVEL 2 - Tissues Made up of cells that are similar in structure and function. Work together to perform a specific activity so organism can function effectively. Classified according to the functions they perform. Examples: blood, nervous, bone, etc. Humans have 4 basic tissues: connective, epithelial, muscle, and nerve.  Connective (Bone) Tissue Bone cells or osteocytes secrete a mineral matrix in which they live to provide the body with a bony support. The matrix is what strengthens and supports the cell to provide the rigidity necessary for the strength of the bone.  Epithelial Tissue LI N K Epithelial cells or skin cells are thin, flat, and interlocking. This aids the function that skin has to serve as a barrier to keep water, bacteria, etc. out of the body. L I N K  Muscle Tissue Muscle cells are elongated and thin The function of a muscle cell is to shorten. The shape of the cell allows it to stretch and shorten without losing its elasticity.  Nerve Tissue Nerve tissue carries signals between the brain and all parts of the body  Tissues in Plants Plant tissues include xylem and phloem (conductive tissues) and epidermal tissue (protective tissue).  Levels of Organization LEVEL 3 - Organs Made up of tissues that work together to perform a specific activity Examples: heart, brain, skin, etc.  Animal Organ: Stomach Tissues: epithelial ⮚ lining, transport, secretion, absorption connective ⮚ support, strength, elasticity muscle ⮚ moves to mix contents nerve ⮚ information, synthesis, communication and control  Plant Organs Examples root : Roots, leaves, stems leaves stems  Levels of Organization LEVEL 4 - Organ Systems Groups of two or more organs that work together to perform a specific function for the organism. Examples: circulatory system, nervous system, skeletal system, etc. The human body has 10 organ systems - circulatory, digestive, endocrine, excretory (urinary), immune (lymphatic), integumentary, muscular, nervous, reproductive, respiratory, and skeletal. Human Organ Systems  Plant Systems Plants generally have three main systems, the shoot, root and reproductive systems. – Root system for absorbing molecules the plant needs. – Shoot system for producing stems and leaves (location of photosynthesis. – Reproductive system for producing flowers, fruits and seeds.  Levels of Organization LEVEL 5 - Organisms Entire living things that can carry out all basic life processes - require energy, eliminate wastes, grow and develop, respond to stimuli and environment, reproduce. Usually made up of organ systems, but an organism may be made up of only one cell such as bacteria or protist. Examples: bacteria, amoeba, mushroom, sunflower, human