Science 8 Unit B: Cells & Systems Notes PDF

Unit B: Cells & Systems NOTES Science 8 1 CHAPTER Living things share certain characteristics and have structures to perform functions 1.1 Characteristics of Living Things Learning Goal: I can describe examples of the characteristics of living things. 8.SCI.B.1.1 Investigates and describes example scientiﬁc studies of the characteristics of living things 1.1 CHARACTERISTICS of LIVING THINGS What makes something living? For something to be considered living, it must have these: SIX CHARACTERISTICS: 1 Made of cells 4 Responds to the environment 2 Needs energy 5 Reproduces Has adaptations for their 3 Grows & develops 6 environment 1.1 1.1 All living organisms have these six characteristics! Non-living things may have some of them (but living need to have them all!) For example: A cloud might grow, but it doesn’t reproduce! Let’s take a closer look at these 6 Characteristics! 1 Made of cells The cell is the basic unit of life. A cell can perform all the processes that life depends on. All organisms are made up of at least ONE cell! Every cell comes from another cell. They are microscopic in size! 1.1 2 Needs energy Everything an organism does requires energy! ENERGY is the ability to makes things move or change. Plants get their energy from the sun through photosynthesis. Animals get their energy from their food. Energy is needed not only for movement, but for cells to function! The SUM of all the different processes that happen in an organisms is called organisms METABOLISM. 1.1 3 Grows & develops Growing isn’t just about getting bigger! Growth also involves a change in structure. Seeds grow roots and produce stems and leaves. Even when a plant reaches its max height, that doesn’t mean growth stops! Trees keep making new leaves every year! Cells die and are constantly being replaced with new cells 1.1 4 Responds to the environment You place your hand on a hot stove top... what do you do? You instantly move it out of the way! Ouch! The heat on your hand is the STIMULUS Anything that causes a response in an organism Moving it out of the way is a reaction, or a RESPONSE A reaction to a stimulus 1.1 5 Reproduces All living things come from other living things. This process is called REPRODUCTION Reproduction is not actually necessary for an organism to survive. BUT, since all individual organisms die, reproduction is necessary for the survival of each type of organism! 1.1 6 Adapted for their environment An adaptation is a characteristic that allows an organism to live in its environment. Plants and animals have many adaptations. A cactus has spines to stop animals from eating it for its water! Wood frogs freeze their bodies to live through the winter! Then they thaw out in the spring! Many animals have thick fur to help them withstand the cold. Snowshoe hares have white fur to blend into the snow to camoﬂauge 1.1 1.1 1.2 Structure & Functions Learning Goal: I can explain how different organisms have similar functions that are met in a variety of ways. 8.SCI.B.1.3 Illustrates and explains how different organisms have similar functions that are met in a variety of ways. 1.2 STRUCTURE & FUNCTION Structures and Functions As well as having certain characteristics, living things have to do certain things to keep themselves alive. Some of the things animals do are to exchange gases, move, and gather food. Plants don’t like to move like animals do, but they do exchange gases and gather nutrients. 1.2 Structures and Functions Organisms have developed many different ways of doing these tasks and have developed different body parts, or STRUCTURES to do them! Each STRUCTURE is used for a speciﬁc FUNCTION Structures are parts of Functions are a an organism that purpose or task perform a certain task 1.2 Different Structures... Same Function STRUCTURE: Legs STRUCTURE: Tail/Fins FUNCTION: Movement 1.2 Breathing Structures Some animals have unusual ways of breathing! Insects have small holes in the sides of their abdomens called spiracles. Insects adjust the amount of air that enters their bodies by adjusting the size of these spiracles. 1.2 Breathing Structures 1.2 Variations in Structures... Adaptations! The Galapagos Islands just off the west coast of South America were made famous by a scientist called Charles Darwin! Darwin was a biologist and he was amazed with the diversity on these islands. He is the scientist who came up with the Theory of Evolution and Natural Selection. 1.2 One common ancestor... but totally different STRUCTURES have been formed to help birds ADAPT to their environment! 1.2 Variations in Structures... Adaptations! Darwin is speciﬁcally known for his exploration of FINCHES! He noticed there were 13 closely related species of these ﬁnches, but they had differences in their structures to help them perform the function of food gathering. One bill was better for eating seeds, another was better for biting into fruit, another was good for picking around cacti thorns or breaking bark open. There were differences in the structure (but they have the same function!). 1.2 1.3 Organ & Organ Systems Learning Goal: I can show how the body is organized into systems and analyze their general function. 8.SCI.B.1.2 Applies the concept of systems to describe familiar organisms and analyzes their general structure and function. 1.3 ORGAN & ORGAN SYSTEMS ORGANS ORGANS make up organ systems that work together to perform a function. All organs are made of TISSUES, or groups of SIMILAR CELLS. Every CELL in the body needs a steady supply of food and oxygen to give it energy. They all have to work together to keep your body going! Groups of organs working together make a SYSTEM. 1.3 TISSUES There are 4 main types of tissues. Connective tissue supports the Epithelial tissue provides covering other tissues. and protection Ex) are bones, blood, lymph tissues Ex) skin, lining of your insides Muscle tissue includes striated Nervous tissue made up of nerve muscles which help move the cells called neurons. This tissue skeleton, and smooth muscles, like carries electrical “messages” the muscle that is around the around the body. stomach. 1.3 Examples: CELLS TISSUES ORGANS SYSTEMS 1.3 ORGANS SYSTEMS We are going to look at the: Digestive System Respiratory System Circulatory System Excretory System Nervous System Skeletal System Integumentary System 1.3 ORGANS SYSTEMS 1.3 Digestive System Structure Function of the System Salivary glands Break down food pieces into Mouth much smaller pieces (particles) so they can be Esophagus absorbed and transported Stomach throughout the body Liver Pancreas Gallbladder Small Intestine Large Intestine Science in Action 7 Text p. 93 - 96 1.3 Excretory System Structure Function of the System Kidneys Remove chemical and gaseous wastes Bladder from the blood Lungs Skin Liver Science in Action 7 Text p. 93 - 96 1.3 Nervous System Structure Function of the System Brain Coordinate and control the Spinal Cord actions of all organs and organ systems Nerves Detect, process, and Eyes, ears, and respond to changes in other sensing external and internal organs (hands, environments nose, etc) Science in Action 7 Text p. 93 - 96 1.3 Integumentary System Structure Function of the System Skin Protects the body’s internal environment from the external environment Senses pain, pressure, and temperature Science in Action 7 Text p. 93 - 96 1.3 Circulatory System Structure Function of the System Heart Transport oxygen, food, and other Arteries substances throughout the body Transport some wastes to other organs Veins for elimination Capillaries Defend the body against diseases Blood Connect all other organ systems Science in Action 7 Text p. 93 - 96 1.3 Respiratory System Structure Function of the System Nose Transport oxygen from the outside air to Mouth the blood Transport carbon dioxide from the Trachea blood to the outside air Diaphragm Bronchi Lungs Science in Action 7 Text p. 93 - 96 1.3 Skeletal System Structure Function of the System Bones Provide a movable support frame for Cartilage Tissue the body Protect soft-tissue organs such as the heart and lungs Science in Action 7 Text p. 93 - 96 1.3 Muscular System Structure Function of the System Muscles Move bones Tendons Move organs that contain muscle tissue (such as the heart and stomach) Science in Action 7 Text p. 93 - 96 1.3 2 CHAPTER Cells play a vital role in living things 2.1 Microscopes Extend Sight 2.1 MICROSCOPES EXTEND SIGHT Microscopes Can you see the dots in A B clearly? What about C & D? We have limits to our human sight... luckily, we have technology such as microscopes to help us see! Cells are too small to see with the naked eye, but with microscopes, we can see so MUCH! Microscopes come in many shapes and sizes! Some use ﬁbre optics and allow medical professionals to look inside and outside the body! Microscopes MAGNIFY objects so they look bigger and we can see them 2.1 Parts of a Microscope 2.1 Check out the insides of the cell through a very strong microscope! 2.1 2.2 The Cell is the Basic Unit of Life Learning Goal: I can describe the role of cells as the basic unit of life. 8.SCI.B.2.1 Describes the role of cells as a basic unit of life. 2.2 The CELL is the BASIC UNIT OF LIFE 2.2 Cells are the smallest know functioning units of life! Cells are the BASIC BUILDING BLOCK OF LIFE! All organisms are made of at least ONE cell. In most organisms, cells rarely work alone... cells with similar structure and function are organized into TISSUES TISSUES that work together for a common purpose form ORGANS, and ORGAN SYSTEMS. These organ systems work together for a common purpose to keep you alive. You can look at cells with a microscope - you can usually identify where one cell stops and another starts. 2.2 Cell Structures A cell is like a factory. Each machine in a factory has a special job. The machines work together to keep the factory running. The “machines” of a cell are its organelles. 2.2 Cell Structures Organelles are small structures that are suspended in the cytoplasm. Most organelles are so small that they can only be seen with something called an electron microscope. Each organelle has a special job to do! They work to produce energy, transport materials, and get rid of wastes. Organelles keep the cell working properly. The word organelle literally means “little organ”. 2.2 Cell Structures Cell Structure Feature that Help You to Identify It cell membrane Looks like a thin line that surrounds the whole cell A rigid, frame-like covering that surrounds the cell cell wall membrane A liquid inside the cell, which has a grainy-looking cytoplasm bits in it A fairly large, dark, spherical structure that’s usually nucleus near the centre of the cell Clear, liquid-ﬁlled spaces in various places within the vacuoles cytoplasm 2.2 Cell Structures If you look at a cell using a microscope, you might see structures on the outside of the cell. These appendages might look like long hairs or long tails - they often help the cell move! Flagella (singular: ﬂagellum) are long and tail like: They whip back and forth to move the cell Cilia (singular: cilium) are short, hair-like structures: They can move a cell or move molecules away from a cell The cilia in your windpipe move harmful particles away from your lungs! 2.2 Let’s look at some basic structures today - we will come back to Plant & Animal Cells! Plant Cell Animal Cell 2.2 Plant & Animal Cells Cytoplasm Cytoplasm Chloroplast Vacuole Nucleus Lysosome Cell Membrane Nucleus Cell Cell Wall Mitochondria Membrane 2.2 Plant & Animal Cells Lysosome Cell Membrane Cell Wall Cell Membrane Mitochondria Cytoplasm Vacuole Cytoplasm Mitochondria Nucleus Nucleus Lysosome Chloroplast Vacuole 2.2 Nucleus The NUCLEUS of the CELL contains DNA (genetic code). The nucleus controls the activities of the cell and is often called the “HEADQUARTERS” You can think of the nucleus like the “BRAIN” of the cell. The NUCLEUS is in BOTH Plant and Animal cells! 2.2 Cytoplasm CYTOPLASM is made of water, salts, and some proteins, and many small structures called organelles. It is a jelly-like substance that holds and suspends the organelles inside the cell. CYTO = preﬁx means “CELLS” The CYTOPLASM is in BOTH Plant and Animal cells! 2.2 Cell Membrane The CELL MEMBRANE is a protective barrier that surrounds the cell. It controls what goes IN and what goes OUT of the cell ⇒ SELECTIVELY PERMEABLE (it’s like a drawbridge) The cell membrane separates cells from its surroundings and gives it structure. The CELL MEMBRANE is in BOTH Plant and Animal cells! 2.2 Vacuole VACUOLES are clear, liquid ﬁlled spaces within the cytoplasm. Can contain//store food, oil, or waste products. Vacuoles store the different molecules a cell needs to survive. VACUOLES ARE in BOTH Plant and Animal cells! Plant Cells - usually have one large vacuole Animal Cells - usually have several small vacuoles 2.2 Mitochondria The MITOCHONDRIA is called the “POWERHOUSE” of the cell. Chemical reactions convert ENERGY into USABLE FORMS INCREASE (⇧) in FOLDS = INCREASE (⇧) in Surface Area = INCREASE (⇧) in ENERGY MITOCHONDRIA are in BOTH Plant and Animal cells! 2.2 Lysosomes LYSOSOMES are small sacs that destroy unwanted bacteria. They digest damaged or dead organelles. They are known as the “RECYCLING CENTRE” The LYSOSOMES is in BOTH Plant and Animal cells! 2.2 Let’s Learn about Plant Cells! 2.2 Cell Wall The cell wall is a rigid structure made of cellulose, which surrounds the cell membrane and gives the plant cell its shape. The CELL WALL is a rigid frame-like structure that surrounds the cell membrane. It protects a cell from viruses and other harmful organisms. It can help the cell keep its shape too! ! *ONLY PLANTS HAVE A CELL WALL* 2.2 CHLOROPLASTS CHLOROPLASTS occur in PLANTS ONLY ! These are known as the “SOLAR PANELS” of the cell. Chloroplasts carry out PHOTOSYNTHESIS. Recall... photosynthesis is where light energy is used to make food, a sugar called glucose, from water & carbon dioxide. They are the thing that makes plants green! 2.2 Plant Cell 2.2 Plant & Animal Cells Cytoplasm Cytoplasm Chloroplast Vacuole Nucleus Lysosome Cell Membrane Nucleus Cell Cell Wall Mitochondria Membrane 2.2 Plant & Animal Cells Lysosome Cell Membrane Cell Wall Cell Membrane Mitochondria Cytoplasm Vacuole Cytoplasm Mitochondria Nucleus Nucleus Lysosome Chloroplast Vacuole 2.2 2.2 Plant & Animal Cells 2.2 2.3 Organisms Can be Single-Celled or Multi-celled Learning Goal: I can compare and contrast between single and multi-celled organisms. 8.SCI.B.2.2 Analyzes similarities and differences between single-celled and multi-celled organisms. 8.SCI.B.2.3 Distinguishes between plant and animal cells. 2.3 Organisms Can be SINGLE-CELLED or MULTICELLED MULTICELLULAR ORGANISMS Multicellular organisms have MANY CELLS! Examples: YOU and ME! Or animals like bears, or plants! Anything with many cells! Multicellular Organisms: Live in a wide variety of environments Grow very large Obtain energy from a wide variety of foods Have complex bodies Specialize functions and work with other cells 2.3 MULTICELLULAR ORGANISMS A brick house is made up of many bricks. A brick is a basic unit of structure for a brick house. The basic unit of structure in living things is a CELL. BUT, cells are not just tiny bricks! For example, cells take in and break down food! They break down simple sugars like glucose to produce energy... recall... this process is called cellular respiration. Just like you, cells have the characteristics, or qualities of all living things! CELLS USE ENERGY, GROW, REPRODUCE, RESPOND TO THEIR ENVIRONMENT, and can ADAPT! 2.3 MULTICELLULAR ORGANISMS Instead of relying on a single cell to meet all of their needs, multicellular organisms rely on MANY very SPECIALIZED cells to perform functions such as feeding, moving, etc. Cells within multi celled organisms react to one another (or interact) For example, in a multi celled animal, such as a deer, there are cells specialized for the function of feeding. However, these cells are dependant on other specialized cells, such as muscle cells, to move the deer to new supplies of food! 2.3 SINGLE - CELLED ORGANISMS Single-celled or unicellular organisms can do most things that we need trillions of cells to do! They consist of a SINGLE CELL - and it can still do all these functions: Eat Move React to stimuli Get rid of waste products Reproduce Unicellular organisms, like AMOEBA often develop SPECIALIZED STRUCTURES to help them perform these functions! 2.3 SINGLE - CELLED ORGANISMS 2.3 SINGLE - CELLED ORGANISMS AMOEBA Amoeba are a common unicellular organism that live in water. Live in water Move around using pseudopods ○ Pseudopods ⇒ false feet, or foot-like projections Extend a pseudopod and the cytoplasm (the solution in cells) ﬁlls it Use pseudopods to capture and absorb nutrients ○ The end of the pseudopods fuse together and create a vacuole (space in the cytoplasm) around the food particle. ○ The food in the vacuole is digested and absorbed into the cytoplasm. 2.3 SINGLE - CELLED ORGANISMS AMOEBA eating a Paramecium! 2.3 SINGLE - CELLED ORGANISMS PARAMECIUM Unlike amoebas, paramecia (plural form of paramecium) move swiftly through the freshwater where they live. Paramecium are covered in hair-like structures called CILIA These cilia move back and forth like oars to move them through the water Cilia also gathers food by: ○ Bringing food to an oral groove ○ Sweeping the food into the cytoplasm ○ Forming a food vacuole 2.3 SINGLE - CELLED ORGANISMS 2.3 What are the differences? VS Bacteria Cell Poplar Tree 2.3 2.4 How Substances Move Into & Out of Cells Learning Goal: I can describe the movement of gases and liquids into and out of cells during diffusion and osmosis. I can describe diffusion and osmosis in terms of concentration differences. 8.SCI.B.2.4 Describes, in general, how the processes of diffusion and osmosis move ﬂuids into and out of cells. 2.4 How Substances Move Into & Out of Cells Every cell in your body is bringing in water, gases and food inside itself right now. HOW IS THIS HAPPENING? DIFFUSION!! Diffusion is the movement of particles of a substance from an area of HIGHER concentration to an area of LOWER concentration 2.4 Cell Membrane & DIFFUSION The CELL MEMBRANE allows substances to go into it and out of it through DIFFUSION. Diffusion moves particles from more concentrated areas to less concentrated areas to try and balance out the CONCENTRATION. 2.4 Selectively Permeable The cell membrane acts like a ﬁlter with very small holes that allow only certain particles to come into or out of the cell. Because of this, the cell membrane is SELECTIVELY PERMEABLE. (some particles are “allowed” to pass through, while others are not - kind of like a drawbridge!) These openings are small enough that the cell’s cytoplasm and organelles stay inside. 2.4 Selectively Permeable 2.4 Factors that Affect the Rate of Diffusion DISTANCE TEMPERATURE CHARACTERISTICS of INCREASING DIFFERENCE in the SUBSTANCE CONCENTRATION Particles at an For example, if The longer the increased The larger the difference particles are too distance the particles temperatures have in concentration the large, it might be need to travel, the more energy. These faster the particles will more difficult for them longer the process of particles move faster move to reach to diffuse across a diffusion will take. and therefore diffuse equilibrium. barrier. faster 2.4 Cell Membrane and OSMOSIS A cell needs to maintain a consistent level of water inside the cell. Water will move INTO or OUT of the cell to balance it out: If water is too LOW inside the cell, water will diffuse INTO the cell If water is too HIGH inside the cell, water will diffuse OUT the cell The DIFFUSION of WATER through a SELECTIVELY PERMEABLE MEMBRANE is called OSMOSIS. 2.4 2.4 2.4 The Effect of OSMOSIS on CELLS Think about when you leave your hand in water for too long and it goes all pruney → OSMOSIS! The same thing can happen to your BLOOD CELLS depending on the type of water solution it is in: 2.4 The Effect of OSMOSIS on CELLS HYPOTONIC SOLUTION → hypo means less than There is LESS water in the cell than there should be → water will diffuse INTO the cell HYPERTONIC SOLUTION → hyper means greater than There is way MORE water in the cell than there should be → water will move OUT of the cell to the region of higher solute concentration ISOTONIC SOLUTION → iso means same The extracellular ﬂuid has the SAME OSMOLARITY as the cell... so there will be NO NET MOVEMENT of water into or out of the cell. 2.4 The Effect of OSMOSIS on CELLS 2.4 2.5 Cells in Multicellular Organisms Combine to Form Tissues & Organs Learning Goal: I can identify contributing roles of cells, tissues, and organs in plant and animal structures. 8.SCI.B.2.5 Identiﬁes contributing roles of cells, tissues and organs in plant and animal structures. 2.5 Cells in Multicellular Organisms Combine to Form Tissues and Organs Cells Reproduce - Asexual Reproduction Unicellular organisms grow and develop and eventually reproduce. Your cells reproduce this way too. Your body replaces about 50,000,000 skin cells every day! 2.5 Multicellular - Specialized Cells Specialized cells - are specialized for a speciﬁc function(s) There are various kinds of cells, and each kind of cell carries out a speciﬁc function or functions needed to support life. These cells all work together to keep organisms alive! Each kind of cell has speciﬁc structures to help it carry out its function. 2.5 Specialized Cells - Red Blood Cells The function of red blood cells is to carry oxygen to all the cells of your body! Since they must travel through extremely small blood vessels, they are thin, pliable, and disc shaped. At maturity - they lose their nucleus! 2.5 Similar Cells Combine to Form TISSUES Cells are organized into tissues, these work together to support life! Tissues in ANIMALS: Connective Tissue Epithelial Tissue Nervous Tissue Muscle Tissue Tissues in PLANTS: Photosynthetic/Storage Tissues Protective Tissues Transport Tissues 2.5 2.5 Tissues in ANIMALS Connective Tissue Epithelial Tissue Nervous Tissue Muscle Tissue Covers surface of your Supports & connects body and the outside of Makes up the brain, Allow you to move! different parts of the your organs. Protects spinal cord, and nerves body. the body’s internal Examples: One type of muscles allows environment from the you to move your body. Examples: outside world. Cardiac muscle pumps blood Blood, fat, cartilage, through your heart, and bones, and tendons Examples: smooth muscle move your Skin; lining of your organs, food along your intestine. like the stomach - help with absorption. 2.5 Some muscle tissues... Tissues in PLANTS Photosynthetic / Protective Tissue Transport Tissues Storage Tissue Waterproof protective Transports food Uses sunlight to layer (PHLOEM) produce food, stores Transports water food (XYLEM) These tissues are organized into three organs that make up plants: Leaves Roots Stems Unlike animals, plant organs are not organized into organ systems. 2.5 2.5 Tissues and Cells of the LEAF 2.5 Plant Stem Plant Root 2.5 RECAP: Building up from the Smallest Unit of Life 2.5

Science 8 Unit B: Cells & Systems Notes PDF

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