New Unit B Cells & Systems Gr 8 Science PDF

UNIt B CELLS & SYSTEMS 1.0 LIVING THINGS SHARE CERTAIN CHARACTERISTICS AND HAVE STRUCTURES TO PERFORM FUNCTIONS 1.1 Characteristics of living Things There are six characteristics that all living things must have. All living things with these characteristics are called organisms. 1. Made of cells 2....

UNIt B CELLS & SYSTEMS 1.0 LIVING THINGS SHARE CERTAIN CHARACTERISTICS AND HAVE STRUCTURES TO PERFORM FUNCTIONS 1.1 Characteristics of living Things There are six characteristics that all living things must have. All living things with these characteristics are called organisms. 1. Made of cells 2. Need Energy 3. Need to grow and develop 4. Be able to respond to their environment 5. Be able to reproduce 6. Be able to adapt to their environment 1. CELLS All living things have cells. The cell is the basic unit of living things. Cells are present in both abiotic and biotic things. Organisms can be unicellular or multicellular. UNICELLULAR Organisms made up of only one cell. MULTICELLULAR Organisms made up of two or more cells. 1. CELLS All living things have cells. The cell is the basic unit of living things. Cells are present in both abiotic and biotic things. Organisms can be unicellular or multicellular. UNICELLULAR Organisms made up of only one cell. MULTICELLULAR Organisms made up of two or more cells. Cells are found in non-living (abiotic) things if it was once living (biotic). Example: Cork is made from a tree that was once living, thus cork under a microscope reveals cells. Example: Scientists do not see viruses (unicellular organisms) as alive because they require a host (other living things to reproduce). 2. LIVING THINGS NEED ENERGY Energy is needed to make things move, to build structures, to stay warm. Organisms get energy from the environment: Plants (Producers) = Sun Animals (Consumers) = Surrounding environment Plants and animals get their energy from nutrients. Nutrients Substances that provide the energy and materials that organisms need to grow, develop, and reproduce. A variety of chemical processes occur inside cells, some produce energy (breakdown of nutrients), some use energy (eating, digesting, exercise). For an organism to survive, there must be a balance between the energy using and energy creating processes. The sum of all different processes that occur in an organism is called metabolism. 3. All Living Things Respond to Their Environment Stimulus - anything that causes a response in an organism. Response - an organism’s response to a stimulus. 4. Growth and Development Growth: Development: Every organism grows a specific amount. However, growth will continue when living things wear out or get damaged. As organisms grow they can change their shape drastically. Example: Your skin cells will grow new cells to repair cuts and scrapes. Example: A tree grows new leaves every year. Example: Frog: As each egg develops, it turns into a tadpole with a tail and gills. As the tadpole grows, it loses its gills and tail and develops lungs and limbs. Finally, it moves from the water onto the land. 5. Organisms Reproduce 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. 6. Organisms Adapt to Their Environment Adaptations: Physical or behavioural characteristic of a species that increases the species’ chances of survival in a particular environment. Can be a response to change in its environment. Physical Adaptations An adaptation can be structural, meaning it is a physical part of the organism. Examples: Cactus storing water Giraffe’s long neck Ducks webbed feet Behavioral Adaptations An adaptation can also be behavioral, affecting the way an organism responds to its environment. Examples: Bird and animal migration Living in groups Territorial behaviours Spontaneous Regeneration Obsolete theory by Aristotle that living organisms were generated from non- living matter when he observed mice exiting a bale of hay. However, in the 1600s, an Italian doctor called Francesco Redi performed an experiment to test the idea of spontaneous generation. By doing so spontaneous generation was disapproved. 1.2 Structure & Function All organisms have structures that provide specific functions to keep them living. Examples Human Heart - Divided into four chambers allowing blood to be received and sent throughout the body. Beaks - birds beaks vary depending upon their purpose, the pelican large pouch for collecting fish, other birds sharp beaks to dig insects out of trees. Darwin’s Finches On the Galapagos Islands, Darwin also saw several different types of finch, a different species on each island. He noticed that each finch species had a different type of beak, depending on the food available on its island. 1.3 Organ and Organ Systems cell - basic unit of life. tissue - a group of specialized cells with a similar structure that function together as a unit. organs - a group of tissue that perform a specific function. organ system a group of organs that work together to perform one or more specific functions. organism group of organ systems that create a biological living entity. The Body Systems Circulatory System Respiratory System Digestive System Nervous System Excretory System Skeletal System Muscular System Integumentary System SECTION 1 QUIZ 2.0 CELLS PLAY A VITAL ROLE IN LIVING THINGS MARCELLO MALPIGHI In 1660, Marcello Malpighi looked at an intricate network of thin, hair-like vessels connecting arteries and veins in the lung tissues of frogs. These blood vessels were later called capillaries, from the Latin word for “hair.” By the early 1600s, a technological device had been invented that would change our understanding of life and living things. This device was the microscope. 2.1 The Microscope Extends The Sense of Sight Types of Microscope There are generally two types of microscopes used in Science. 1. 2. Compound Light Microscope (up to 2000 X magnification) Electron Microscope (up to 2, 000, 000 X magnification) Compound Light Microscope A compound microscope is a high power (high magnification) microscope that uses a compound lens system. A compound microscope has multiple lenses: the objective lens (typically 4x, 10x, 40x or 100x) is compounded (multiplied) by the eyepiece lens (typically 10x) to obtain a high magnification of 40x, 100x, 400x and 1000x. Total Magnification Two lenses provide the total magnification. The ocular lens (usually 10x) multiplied by the magnification lens (4x, 10x, or 40x) results in the total magnification. FIELD OF VIEW : The entire area that can be seen when you look through a microscope. Higher the magnification, smaller the field of view. 4x 10x 40x Viewing Detail There are certain factors that can affect what you are able to see in the amount of detail when looking inside a microscope: 1. Type of microscope 2. Power of the lens 3. Quality of the prepared slides 4x 10x 40x Microscope Lab 2.2 The Cell is the Basic Unit of Life The Vital Role Cell Structures Play Within each cell there are a number of specialized structures called organelles that carry out specific functions. One way to think about cells’ organization is to think of them as living factories, making all the things necessary for them to live. Animal Cells Plant Cells 2.3 Cells can be Unicellular or Multicellular Unicellular Organisms They are made up of only a single cell. Most microscopic organisms, or micro-organisms, such as mycoplasma, are examples of unicellular (single-celled) organisms. Yeast **A single-celled organism can do most things that we need trillions of cells to do: eat, move, react to stimuli, get rid of waste products, and reproduce.** Virus Amoebas are common unicellular organisms that live in water. They move around using foot-like projections called pseudopods. They extend a pseudopod and the cytoplasm streams into it. Amoebas also use these pseudopods to capture food. Amoeba engulf food between two pseudopods. Paramecia (plural form of paramecium) move swiftly through the freshwater where they live. They are covered in hair-like structures called cilia, which move back and forth like oars to move them through the water. Cilia also help them gather food. On one side of the cell is a channel called an oral groove. It’s lined with cilia, which sweep food to the bottom of the groove. There, the food enters a food vacuole, which moves into the cytoplasm, and the food inside is digested. Multicellular Organisms This means that they are made up of two or more cells. Plants and animals are examples of multicellular (many-celled) organisms. 2.4 How Substances Move In and Out of Cells Diffusion Diffusion is the movement of particles from an area where there are more of them to an area where there are fewer of them in all cells. In other words, diffusion moves particles from a more concentrated area to a less concentrated area. It’s a “balancing out” or “evening out” process that continues until the concentration of particles is the same everywhere. The cell membrane acts like a filter with extremely tiny openings that allow some particles to pass through but not large enough to let the organelles out of the cell. The membrane allows only specific substances in and specific substances out. This membrane is called a selectively permeable membrane. Osmosis Water is a substance that has particles small enough to diffuse through the cell membrane. Osmosis is a special case of diffusion. The amount of water inside a cell must stay fairly constant. If the water concentration inside the cell gets too low, water from outside the cell diffuses in. If the concentration gets too high in the cell, water diffuses out of the cell. Diffusion vs. Osmosis The Effect of Osmosis on Cells Isotonic: In A the concentration of water in and out of the cell is the same. These cells are well balanced. Hypertonic: In B the blood cell was in salt water so the concentration of water inside the cell was higher than outside. This caused water to move out of the cell and shrink. These cells can die. Hypotonic: In photo C, the cell was placed in almost pure water. The inside of the cell contains far less water than the outside of the cell, so the water moves into the cell by osmosis, causing the cell to swell. These cells can explode. 2.5 Cells in Multicellular Organisms Combine to Form Tissues and Organs Unicellular Organisms Reproduce. When they reach the limits of their size, like the amoeba, unicellular organisms reproduce. Amoeba do this by dividing into two, which results in two smaller, identical copies of each organism. Your cells reproduce this way, too. That’s how, for example, your body replaces the 50 000 000 or so skin cells that it naturally loses each day! Your body cells also reproduce to repair tissues that get damaged. This process is called mitosis. Multicellular Organisms have Specialized Cells You and most other multicellular organisms are made up of specialized cells. This means that there are various kinds of cells, and each kind carries out a specific function or functions needed to support life. For example, the function of your red blood cells is to carry oxygen to all cells of your body. To do this, the red blood cells often must travel through extremely small blood vessels. Their thin, pliable disc shape enables them to do this. Red blood cells do not reproduce in the same way as skin cells. When red blood cells mature they lose their nucleus. Since the nucleus controls cell division (among other functions), red blood cells can’t reproduce by simply dividing to make more of themselves. The only way your body can make more red blood cells is by relying on specialized tissues in another body system. Most bones of the skeletal system contain a type of connective tissue called marrow, with specialized cells that make red blood cells. Plasma is the main component of blood and consists mostly of water, with proteins, ions, nutrients, and wastes mixed in. Red blood cells are responsible for carrying oxygen and carbon dioxide. Platelets are responsible for blood clotting. White blood cells are part of the immune system and function in immune response. bone marrow Types of Tissue Epithelial tissue covers the surface of your body and the outside of your organs. It also lines the inside of some of your organs such as the intestine. Makes up the brain, spinal cord, and nerves. Allows you to move. One type of muscle allows you to move your body. Cardiac muscle tissue pumps blood through your heart, and smooth muscle moves food along your intestine. Supports and connects different parts of the body. Blood is a connective tissue and so are fat, cartilage, bones, and tendons. Onion Skin Osmosis Lab Osmosis Egg Experiment SECTION 2 QUIZ 3.0 Body Systems 3.1 Digestive System Your digestive system is in charge of breaking down the food you eat into parts small enough to be used by your cells. Each of the different energy sources: carbohydrates, lipids, and proteins must be broken down into small usable particles as they travel through your digestive system. Types of Digestion 1. Mechanical Digestion involves the physical breakdown of food into very small pieces. 2. Chemical Digestion involves the breakdown of large particles into smaller particles by substances called enzymes. Path of your Digestive System 1 The food moves down toward your stomach by a wave-like movement known as peristalsis. Peristalsis is caused by contractions of muscle tissue that lines the esophagus. salivary glands makes saliva which chemically breaks down food using enzymes. tongue - mixes saliva with the food. teeth moved by the jaw to break down food. oesophagus wave-like muscle contractions called peristalsis, move the food down the oesophagus to the stomach. 2 The muscular wall of the stomach churns the food back and forth, while mixing it with secretions from the wall of the stomach, known as gastric juice. Gastric juice is composed of mucus, hydrochloric acid, water, and digestive enzymes. liver makes bile which helps neutralise stomach acid and digest some vitamins gall bladder bile is stored here until it is needed. stomach churns the food and is mixed with acid, gastric juices, until it turns into a goopy soup. stomach to small intestine wave-like muscle contractions called peristalsis, move the food down the oesophagus to the stomach. 3 stomach. duodenum - bile continues to break down food. large intestine absorbs water and electrolytes. pancreas makes enzymes that break down food. small intestine food is pushed through the small intestine by contractions absorbing nutrients. The area to absorb nutrients is increased by finger-like projections called villi. This process occurs over a distance, on average, of 22 feet. 4 REVIEW 3.2 Respiratory System Your respiratory system is responsible for supplying your blood with oxygen and removing the carbon dioxide from your blood and returning it to the air outside your body. Breathing Breathing is the process your respiratory system uses to move air in and out of your lungs. Breathing occurs because of your rib and diaphragm muscles. Gas Exchange Process bronchus large windpipe carrying oxygen from the trachea to the lungs. bronchiole smaller branches that the bronchus divides into. capillaries the smallest blood vessels. alveoli the tiny air sacs at the end of the bronchioles which exchanges oxygen for carbon dioxide. 3.3 Circulatory System One of the circulatory system’s jobs is to deliver the nutrients absorbed by your digestive system to each cell in your body. Besides nutrients, your circulatory system must also transport oxygen to your cells and remove waste products. The circulatory system, then, is your body’s transportation network. The Heart Superior Vena Cava - brings deoxygenated blood back from the body. Aorta - carries blood from the left ventricle to the body. Left Pulmonary Artery Carries oxygen poor blood to your lungs veins from lungs to heart veins from lungs to heart Left atrium - receives oxygen rich blood from the lungs and pumps it into the left ventricle. Right atrium - receives blood low in oxygen from the body and pumps it into the right ventricle. Left ventricle - when it contracts it pumps blood to the body. Right ventricle - when it contracts it pumps blood to the lungs. Inferior Vena Cava- large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. major vein from lower body to heart artery to the lungs vein from the body Blood vessels in the lungs Left atrium Blood vessels in the body Right atrium Left ventricle Right ventricle artery to the body vein from the lungs Arteries, Veins & Capillaries Arteries - Vessels that carry blood away from the heart to all parts of your body. Veins - return blood from the body to the heart. Capillaries - located between arteries and veins which diffuse nutrients and gases. They can diffuse nutrients and gases easily because they are only one cell thick The Blood Red Blood Cells - carry oxygen, have no nucleus in order to carry as much oxygen as possible White Blood Cells - fight infection. Platelets - helps stop the bleeding at cuts Plasma (Hemoglobin) - the liquid portion of your blood transports nutrients to your cells and carries away waste product such as carbon dioxide. 3.4 Excretory System The body produces a number of different types of wastes. These wastes are poisonous, and, if not removed from the body, can cause you serious harm. The job of waste removal, excretion, is done by the excretory system. The interesting thing about the excretory system is that it involves organs from other systems. Liver - It takes the highly toxic ammonia produced by the body’s cells out of the bloodstream and converts it into a less harmful substance called urea. This less harmful urea is released back into the bloodstream. Kidney - The kidney is the waste filtering and disposal system of the body. ⅓ of all blood passes through the kidneys prior to flowing to the rest of the body tissues. The kidney has millions of nephrons. These microscopic units remove wastes from the blood and produce urine. Bladder - The bladder is connected to the kidneys by a long tube called a ureters. The purpose of the bladder is to act as a storage location for urine before it is expelled through the urethra. Neurons The nervous system is mostly made up of one type of tissue called nervous tissue. Nervous tissue is made entirely of specialized cells called neurons. Your brain, spinal cord, and nerves are all made of them. A neuron’s job is to send and receive messages. soma - the core of the cell containing a nucleus dendrites - A dendrite (tree branch) is where a neuron receives input from other neurons connected by synapses. axon - The axon is a long extension of the cell that ends in small branches. It carries impulses away from the cell body & away from muscles and glands. Urine & Disease Doctors can determine if you have certain diseases by testing your urine. Kidney Failure - often those with failing kidneys have protein in their urine because their kidneys have lost the ability to filter blood properly. High blood pressure and diabetes are the two most common causes of kidney failure. They can also become damaged from physical injury, diseases, or other disorders. Diabetes - those with diabetes will often have glucose in their urine. Their cells cannot absorb glucose, and glucose builds up in the bloodstream. Sometimes, as a result of damage or disease, kidneys don’t work properly. It’s called a kidney dialysis machine, and it removes all the wastes from the blood that a kidney normally would. 3.5 The Nervous System Stimuli (the plural form of stimulus) can occur in many forms, such as changes in pressure, heat, cold, light, sound, or body chemistry. Stimuli may be external (outside your body), such as when you walk from the cold outdoors into a warm room, or they can be internal, such as the arrival of food in your stomach. It is the job of the nervous system to monitor and respond to these stimuli. How the Nervous System is Organized CNS - Central Nervous System Command center of the body containing the brain and spinal cord. The spinal cord connects the brain to the peripheral nervous system, and it acts as a highway for messages between the brain and the body. It contains a type of neuron called an interneuron. These neurons connect one neuron to another. The three broad functions of the CNS are to: - take in sensory information - process information, and - send out motor signals CNS - Spinal Cord The spinal cord is an elongated cylinder of neuron cell bodies, bundles of axons and other cells, protected by connective tissue and bone. It connects to the brain at the medulla oblongata and runs down the vertebral column, the hollow tunnel enclosed within the vertebrae of the spine. The spinal cord is part of the central nervous system and serves as a kind of superhighway. Sensory information and motor commands travel up and down, heading to and from the brain. These signals speed in and out of the spinal cord via spinal nerves—the “on-ramps and off-ramps” that branch out to supply the limbs, torso, and pelvis. Some incoming signals demand a simple, immediate response. The spinal cord can shoot out a reflex command without bothering the brain. CNS - Brain The brain controls what you think and feel, how you learn and remember, and the way you move and talk. But it also controls things you're less aware of — like the beating of your heart and the digestion of your food. Think of the brain as a central computer that controls all the body's functions. The rest of the nervous system is like a network that relays messages back and forth from the brain to different parts of the body. PNS - Peripheral Nervous System This system comprises of all the nerves that branch out from the brain and spinal cord. Your peripheral nervous system has two main subsystems: autonomic and somatic. 1. Autonomic: These are nervous system processes your brain runs automatically and without you thinking about them. (reflex response 2. Somatic: These are functions you manage by thinking about them. Types of Nerves The nervous system is comprised of bundles of nerves. There are three types of nerves found within the peripheral system.. 1. 2. 3. Sensory: These nerves carry information to your brain and spinal cord. They either connect directly to your brain through your cranial nerves or carry information to your spinal nerves, which then feed into your spinal cord. The sensory nerve connections to your spinal cord are on the back of your spinal cord. Motor: These nerves carry command signals from your brain to various parts of your body. They only carry information away from your brain. The motor nerve connections are on the front of your spinal cord; meaning, these nerves are for sending muscle movement commands only. Autonomic: These nerves control the automatic functions of the organs and systems in your body. Your autonomic nerves often involve mixed nerve fibers, some of which carry commands from your brain to their destination, and others that carry information about an organ’s function back to your brain. The Reflex Response Reflex action is a sudden and involuntary response to stimuli. It helps organisms to quickly adapt to an adverse circumstance that could have the potential to cause bodily harm or even death. If you put your hand on a hot stove, a reflex causes you to immediately remove your hand before a "Hey, this is hot!" message even gets to your brain. Other examples: When light acts as a stimulus, the pupil of the eye changes in size. Sudden jerky withdrawal of hand or leg when pricked by a pin. Coughing or sneezing, because of irritants in the nasal passages. Knees jerk in response to a blow or someone stamping the leg. HeART DISSECTION LAB SECTION 3 QUIZ UNIT FINAL