SNC2D Biology Readings PDF

Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.01 Topics: Materials: Review and Introduction Nelson: Science Perspectives 10 A) Intro: {Handout Textbooks} Course Over...

Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.01 Topics: Materials: Review and Introduction Nelson: Science Perspectives 10 A) Intro: {Handout Textbooks} Course Overview o Units: Living Systems (Biology), Optics (Physics), Chemistry, Climate Change o 70% Term, 30% Summative (Exam and Summative Exercise) o Evaluations: ▪ formal lab and 1* test per unit for major units (6) ▪ Assignment for climate change (1) ▪ Design Lab (1) ▪ TBA Assignment (1)** ▪ Summative (1) ▪ Exam (1) total evaluations (11) * In some units may be broken down into 2 smaller tests ** May be omitted o Marking based on curriculum expectations, levels ▪ Level 3 meets expectations (won’t be many level 4’s) Books o No assigned text books, but on-line version available > o Homework binder, signed out like a text, do not write in, has homework, and other assignments/activities. Always bring to class/study hall Expectations o Late – 1st period of day get a slip o Absence: ▪ You are responsible to get notes from a friend, read, try homework then get help ▪ If you know beforehand come see me beforehand. o Respect – There are no stupid questions but there are a lot of misconceptions. Be supportive, tolerant and most of listen, you might learn something. Studying o Homework – Do it. Not checked, it’s for you not me o Go over “How to Study and Get Good Grades” ▪ Vocabulary Sheets, Equation Sheets ▪ IB Command Terms o Extra help in mornings, email, study groups (mixed levels) and managebac Safety o HHPS, WHMIS symbols See Next Page Notes: Handout “How to Study…”, Vocabulary/Equation/Summary Sheets Homework: Homework Sheet – B01, Labelling Sheets: Microscope, Lab Equipment  Old Household Hazardous Products Symbols New Hazard symbols have three parts: 1. the picture 2. the frame 3. the caution (signal) words underneath the image 1. Hazard symbol pictures The picture tells you the type of danger: EXPLOSIVE The container can explode if heated or punctured. Flying pieces of metal or plastic from the container can cause serious injury, especially to your eyes. CORROSIVE The product can burn your skin or eyes. If swallowed, it can damage your throat and stomach. FLAMMABLE The product or its fumes will catch fire easily if it is near heat, flames, or sparks. Rags used with this product may begin to burn on their own. POISON If you swallow, lick, or in some cases, breathe in the chemical, you could become very sick or die. 2. Hazard symbol frames The shape of the frame around the hazard symbol tells you what part of the product is dangerous: If it's a triangle, it means the container is dangerous. If it's an octagon, it means the contents are dangerous. 3. Signal words The signal word(s) underneath the hazard symbol explain the degree of risk: Symbol - Signal word - DANGER EXPLOSIVE Signal words: CAUTION means temporary injury may result. Death may occur with extreme exposure. DANGER means may cause temporary or permanent injury, or death. EXTREME DANGER means exposure to very low amounts may cause death or serious injury. Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.02 Topics: Materials: Review and Introduction Nelson: Science Perspectives 10 A) Labs: {Handout Textbooks} Labs o Formal Labs, 3, one per major unit o Assigned partners (may change throughout the year) and stations – gathering equipment, clean-up, waste disposal o Lab tour – equipment & MSDS binders, safety equipment o Safety Contracts o Equipment, broken glass, accident reporting Microscope o About/parts, focusing o Calculations o Wet mounting Procedure 1. Place a drop of water on the center of a clean dry slide 2. Using the tweezers, place the specimen in the middle of the drop. 3. While holding the cover slip upright, carefully place one edge of the cover slip next to the water. 4. Slowly lower the upper edge of the cover slip onto the water. The objective is to minimize or eliminate air bubbles under the cover slip. You might find it helpful to use one toothpick to hold the lower edge in place, while using another to carefully lower the slip into place. 5. An absorbent towel can be placed at the edge of the cover slip to draw out some of the water, further flattening the wet mount slide. B) Biologicial Drawings: o Biological drawings (handout and template) C) Microscopes: Go over microscope, its handling and the parts, with students filling in labels on handout. Microscope calculations. ( o Total Magnification = objective occular )( ) o Field Diameter with the following objectives 4x – 4.5mm, 10x – 1.8mm, 40x – 0.45mm o Go over conversion between mm and µm o Measure actual field diameter on low power and convert to other diameters with: old power  old field of view new field of view = new power o Calculate size of observed object: field of view Actual size = estimate where the estimate is the estimated number needed to fill across the field of view o Calculate the drawing size, first measure along drawing as you estimated in the microscope view, Drawing size Drawing magnification = actual size Notes: Homework: Homework Sheet – B02 Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.03 Topics: Materials: Nelson: Science Perspectives 10 Living Systems and the Cell Section 2.1 Handouts 1.03h A) Intro: Collect E lab and review quiz if done. If not, start with quiz. B) Living Systems: Biology is based on Cell Theory’s 3 ideas: o All living things are made up of one or more cells and their products o The cell is the simplest unit that can carry out all life processes o All cells come from other cells; they do not come from non-living matter Insert flow chart (left) from page 29 here Prokaryotes are the simplest life forms, single celled life without nucleus e.g. bacteria and archaea. Eukaryotes have more complex internal organization (includes a nucleus) and may be either single celled like an amoeba or multi-cellular like animals and plants. All cells have to use energy, reproduce, store materials, take materials from the environment, move materials, and remove waste. Special structures within the cell affect these needs. The internal structures within a cell are called organelles and they carry out the specific functions necessary for life. o Cytoplasm – Composed of mostly water it fills the cell and supports organelles. All chemical reactions take place here and it also acts as a storage area for things the cell needs like enzymes, sugars, amino acids, water, vitamins, nucleotides etc. The consistence can change from jelly to water to allow organelles to be moved around. o Cell Membrane – Allows material into the cell and allows waste out. Double layered it is differentially permeable or semi-permeable allowing it to be selective on what comes in/out. o Nucleus – Roughly spherical, contains the genetic information that controls all cell activities. This information is stored in the chromosomes. o Mitochondria – The energy producer for the cell or power plant. Converts stored glucose (sugars) into a usable form using enzymes during respiration: gluco se + oxygen → carbon dioxide + water + usable energy The greater the energy the needs of cell (e.g. Muscle, liver) the greater the number of mitochondria in it than a less active cell that may only have one or two. o Endoplasmic Reticulum – Network throughout cell (3D) of branching fluid filled tubes and pockets from the nuclear membrane to the cell membrane that transports proteins and other materials through the cell. Most reactions occur across the membrane surface. o Golgi Bodies – Collect and process materials to be removed from the cell (garbage collectors☺). Produces and excretes mucus. The more mucus a cell excretes (e.g. stomach) the more Golgi bodies. o Vacuoles – Storage depot. What is stored varies greatly with the cell. Amoeba engulfs food into a vacuole. Maintains internal pressure. o Cell Wall – A rigid porous structure outside the cell membrane in plant cells only. Made of cellulose it provides support and protection for the cell. May persist for a long time after the cell dies (wood). o Chloroplasts – Contains chlorophyll and allows photosynthesis (plant cells only): carbon dioxide + water + energy → gluco se + oxygen Chlorophyll gives plants their green colour. The food produced is used by the Mitochondria. See next page Notes: Homework: Read 2.2 and 2.3, Sheet B03  o Lysosome – Produces enzymes which aid in disposal of waste. May cause cell destruction if ruptured. o Nucleoplasm – Contains material for creating DNA and RNA and allows interaction between nucleus and cytoplasm. o Nucleolus – Spherical structure within nucleus that contains the chromosomes. Not visible during mitosis. o Chromosomes – Made of DNA and proteins. o Centrioles – Used to form spindles for cell division. o Ribosomes – Synthesis of protein and attached to endoplasmic reticulum. o DNA – Deoxyribonucleic Acid. Contains genetic information for cell reproduction. Only found in nucleus. A double helix composed of a backbone made of sugar and phosphate with nucleotides attached as one of 4 bases – Adenine (A), Thymine (T), Guanine (G) and Cytosine (C). o RNA – Ribonucleic Acid. Contains genetic information for reproduction of ribosomes. Found within and without the nucleus. Single helix similar to DNA but has Uracil instead of Thymine. Hand out plant and animal cells to be labelled. Hand out organelle and functions sheet Discuss differences and similarities between plant and animal cells o Term cell came from first observed plant cells and reminded scientist of monk’s cells o Recall from cell theory the idea that live cannot come from inanimate material – expand on why – maggots and meat etc, maybe creation vrs evolution. Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.04 Topics: Materials: Nelson: Science Perspectives 10 Mitosis Sections 2.3 & 2.5 A) Intro: Take up organelle and cell labelling sheets. Collect plant & animal cell lab B) Cell cycle: Recall that all cells come from other cells. This is only possible if the organisms reproduce. We are familiar with how organisms (single and multicellular): o Asexual – Single parent. Child/offspring is identical (genetically) to parent organism. Go over pros and cons of this form of reproduction (only need one organism, any faults/weakness propagated) o Sexual – Two parents. Child/offspring shares genetic information from both parents. Pros & cons (harder to find mates, strongest traits become dominate and survive) Cells within a multicellular organism must also reproduce and do so through cell division to form two new, identical, daughter cells. Cell division is important (necessary) for organism growth and repair. Limit to cell size. Organisms typically have many cells rather than one giant cell because of chemistry. All cells need water and nutrients and also need to get rid of waste. Cells move these materials using diffusion and osmosis. Diffusion is from an area of high concentration to an area of low concentration and in osmosis water moves from areas of low solute concentration to high solute concentration. Both processes take time however and if the cell is too large, it may not get the things it needs in time or be able to expel waste quickly enough (i.e. it poisons itself). The cells in an adult are (on average) the same size as of those in a child but there are more of them. A cell goes through several stages in the cell cycle. We will concentrate on three: Interphase, Mitosis and Cytokinesis: o Interphase: This is the longest stage of a cell’s life (~90%), and during this stage the cell carries out all the processes (except for cell division) necessary for life: respiration, waste disposal, growth, transporting material etc. Towards the end of Interphase the DNA within the nucleus duplicates itself and more organelles are produced. Extension: The cell cycle is actually divided into 4 phases with the first three taking place during Interphase: o G1 Phase or First Growth Phase - takes place during interphase right after mitosis. During this phase the cell produces new proteins and organelles. If the cell is healthy it will move into the next phase. o S Phase or Synthesis Phase – the cell makes an entire copy of the cell’s DNA. Key proteins associated with chromosomes are also produced during this phase. o G2 Phase or Second Growth Phase – Now that the DNA has been copied the cell produces organelles and structures that will be needed for cell division. This is the shortest of the phases of interphase. o M Phase or Mitotic Phase – See Mitosis next See next page Notes: Homework: B04, Read 2.6 & 2.9  o Mitosis: Mitosis is the first stage of cell division in which the cell’s nucleus divides. This takes place in several phases: ▪ Prophase – During prophase the DNA condenses into visible bundles called chromosomes (each chromosome contains two identical sister chromatids) and are joined with a centromere. The nuclear membrane breaks down in this phase. The centrosomes move to opposite sides of the nucleus and spindle fibers form from the centrioles (in the centrosomes) to the centromeres on the chromosomes. ▪ Metaphase – Chromosomes line up in the middle of the cell. Spindle fibers are attached to each side of the centromeres. ▪ Anaphase – The centromere splits and sister chromatids are pulled apart ( daughter chromosomes). ▪ Telophase – Final stage of mitosis where the chromosomes stretch out and nuclear membranes form around each group of daughter chromosomes. The rest of the cell can now divide. o Cytokinesis: Cytokinesis is the second stage of cell division in which the cytoplasm and other organelles divide. In animal cells the membrane pinches closed in the middle and divides while in plant cells the cell plate develops into a cell wall. Memory Aids: I Prefer Mice And Talking Cats (Interphase Prophase Metaphase Anaphase Telophase Cytokinesis) Hands: Interlocked fingers (Prophase), Prayer (Metaphase), Pull hands apart (Anaphase), close fists (Telophase)  Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.05 Topics: Materials: Nelson: Science Perspectives 10 Specialty Cells Sections 2.9 A) Intro: Show video on cells “Cells the Basic Unit of Life” about 23min B) Special Cells: Cells contain organelles that allow the processes of life (for the cell) to continue. The number and type of organelles varies depending on the type of cell. In multicellular organism cells become specialized for certain functions with some good for movement (muscle), others for communication (nerve) and others for processing oxygen (blood), etc. Within an organism the specialization allows the organism to be more successful. For example the muscle cells allow the organism to move and find more food, or avoid danger. The muscles cells are specialized for this movement but can do this since other cells specialize to help them with respiration and waste processing etc. Collectively each cell helps the overall organism, much like a city with different buildings and roles within it. Special Cell Types in Animals (refer to page 59 in text): o Red Blood Cells – Prokaryotes, contain hemoglobin to carry oxygen, smooth for blood vessels o Muscle Cells – Bundles of fibres, able to contract, smooth (involuntary), skeletal (voluntary) and cardiac (heart) o Fat Cells – Large vacuole to store fat o Skin Cells – layers fitting together tightly, keeps water in, protection, household dust o White Blood Cells – Amoeba like and can move, fight bacteria and infection o Nerve Cells – Long, thin and branching, can conduct electrical impulses o Bone Cells – Collect calcium, build up bone around them o Sperm Cells – Able to move, carries DNA o Photophores – Able to emit light Special Cell Types in Plants (refer to page 60 in text): o Guard Cells – Control water loss in leave o Photosynthetic – Contain chloroplasts for photosynthesis o Epidermal – Can have tiny hairs on them o Storage – For storing materials o Xylem – For moving water and dissolved minerals throughout plant o Phloem – For moving dissolved sugars throughout plant Stem Cells (more later) o All cells come from pre-existing cells (cell theory☺), but humans, giant redwoods etc. all come from one cell initially. How is this possible? o Stem cells are cells that have the ability to change into different types of cells. o In animals there are two basic types: ▪ Embryonic Stem Cells– Able to turn into any type of cells (totipotent) ▪ Tissue Stem Cells (Adult Stem Cells) – Able to turn into a limited number of cells (pluripotent) o In plant cells there are: ▪ Meristematic Stem Cells- found in the growing tips of roots and stems and within the stem in a layer known as the cambium layer See next page Notes: Homework: B05  Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.06 Topics: Materials: Nelson: Science Perspectives 10 Aging Sections 2.9 A) Intro: We’ve looked at cells in general, their organelles, specialty cells, stem cells and mitosis. Two areas we have left to consider are what might happen when things go wrong; aging and cancer. Today we’ll look at Aging. B) Look Again at the Cell Cycle: The cell cycle of interphase, mitosis and cytokinesis explain how a cell replicates but not why. How long a cell remains in interphase depends on the type of cell and it’s role: o Years: Brain Cells: 30-50 years, Nerve Cells: 15 years o Months: Liver Cells: 200 days, Red Blood Cells: 120 days o Days: Stomach Lining Cells: 2 days, Intestine Lining Cells: 3 days, Skin Cells: 20 days Signals from surrounding cells can tell the cell not to divide Environmental factors such as pressure or chemicals can trigger or stall mitosis. Cell division is controlled by specialized proteins which monitor the cell activities and report to the nucleus which then instructs the cell whether or not to divide. There are three checkpoints where these proteins act to control the cycle: o After G1: ▪ Signals: Stop if lacking nutrients to support growth or the DNA is damaged, the cell must be destroyed. o After G2: ▪ Signals: Stop if the DNA has not replicated, the DNA is damaged, the cell needs to be repaired or destroyed o After Mitosis: Perhaps the most important checkpoint. ▪ Signals: Stop if some of the chromosomes haven’t attached to spindle fibers during metaphase, or some of the chromosomes haven’t moved to the poles in anaphase. The cell must be repaired or destroyed. If the DNA is damaged early enough in the cycle, the cell may be able to repair it, but if the damage is severe enough the cell is usually destroyed as a result If a cell is damaged it may die and this is known as cell necrosis. If the cell is damaged or no longer needed it may be killed off through apoptosis which is a regulated/controlled, natural part of functioning healthy multicellular organisms. Extension: Apoptosis or PCD (programed cell death) is often a result of targeting mitochondria in the cell and or releasing the enzymes from the lysosomes (hence the moniker suicide sacks). C) Aging: The only things certain in the world are death and taxes ☺ If we live a long life we grow old  but scientist have been studying the problem and have made some exciting discoveries on the topic. Three areas of investigation (there are more!) are: o Telomeres – about 50x replicated – free radicals increase need for replication ▪ Telomeres are the regions at the ends of chromosomes that protect the chromosome from damage during division. ▪ As we age these regions get smaller until they get too short and cell division stops. ▪ Researchers believe that cancer cells are creating an enzyme called telomerase, which prevents telomere shortening o Aging Genes ▪ Researchers have identified hundreds of genes that are linked to aging or “aging genes”\ ▪ Some make essential proteins etc, that may become damaged during replication. See next page Notes: Homework: B06  o Centromere location ▪ If the centromere does not align properly during metaphase (as happens in older organisms) the division of the chromosome may be flawed or the proteins guarding against such errors may stop the cell division until they line up. o Other Factors ▪ Researchers removed the pituitary gland of mice. This gland controls much of the endocrine system. The researchers then gave the mice all of the hormones that are currently known to substitute for the absence of the pituitary gland. The mice without a pituitary gland lived longer than a control group of normal mice. Researchers concluded that the pituitary must also excrete another, unknown, hormone that negatively impacts aging. The rate of living theory. This theory states that people (and other creatures) have a finite number of breaths, heartbeats or other measures. – little evidence to support Some organisms have found ways to live a long time: o Pando is a Populus tremuloides (Quaking Aspen) tree or clonal colony that has been estimated at 80,000 years old, although some claims place it as being as old as one million years. Unlike many other clonal "colonies" the above ground trunks remain connected to each other via a single massive underground root system. Whether it is to be considered a single tree is disputed, as it depends on one's definition of an individual tree. o A huge colony of the sea grass Posidonia oceanica in the Mediterranean Sea is estimated to be between 12,000 and 200,000 years old. The maximum age is theoretical, as the region it occupies was above water at some point between 10,000 and 80,000 years ago. o King's Lomatia in Tasmania: The sole surviving clonal colony of this species is estimated to be at least 43,600 years old. o A box huckleberry bush in Pennsylvania is thought to be as old as 13,000 years of age. o An individual of the fungus species Armillaria solidipes in the Malheur National Forest is thought to be between 2,000 and 8,500 years old. It is thought to be the world's largest organism by area, at 2,384 acres (965 hectares). o Specimens of the black coral genus Leiopathes are among the oldest continuously living organisms on the planet: around 4,265 years old. o The giant barrel sponge Xestospongia muta is one of the longest-lived animals, with the largest specimens in the Caribbean estimated to be in excess of 2,300 years. o The black coral Antipatharia in the Gulf of Mexico may live more than 2000 years. o The Antarctic sponge Cinachyra antarctica has an extremely slow growth rate in the low temperatures of the Southern Ocean. One specimen has been estimated to be 1,550 years old. o A specimen of the Icelandic Cyprine Arctica islandica (also known as an ocean quahog), a mollusk, was found to have lived 507 years. Another specimen had a recorded life span of 374 years. o Some koi fish have reportedly lived more than 200 years, the oldest being Hanako, who died at an age of 226 years on July 7, 1977. Videos: Aging Telomeres (3:08), Aging at the cellular level (2:04), Michio Kaku: How to Reverse Aging (4:38) Immortal Life of Henrietta Lacks Book  Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.07 Topics: Materials: Nelson: Science Perspectives 10 Cancer Sections 2.7 A) Intro: Last class we looked at one the problems that arise from a breakdown in the ability of cells to reproduce; aging. Today we will look at the other; cancer. B) Cancer: As we saw the cell can reproduce itself through Mitosis and Cytokinesis. Normally there are checkpoints or safety signals to prevent a cell from dividing at the wrong time: o Signals from the surrounding cells o DNA hasn’t been replicated o DNA is damaged o Not enough nutrients to provide for cell growth Once a cell has divided it gets a stop signal for the cell to begin interphase and live it’s normal life (cell life varies depending on its role from a few weeks up to 10 years) In cancer (a group of diseases) cells divide incorrectly. There are several things going on in cancer, research is discovering many mechanisms: o Cell’s replicate even if a checkpoint condition exists. o Cell’s don’t die off naturally because the produce the hormone telomerase and the telomere’s don’t shorten so the cells “live forever” o The receptor in the cell fails to get the “stop” signal Cancer isn’t infectious but it can be caused by both heredity and or environmental causes. Tumours – A tumour is a mass or lump of these out-of-control cells. There are two types: o Benign Tumour – The cells clump together but don’t affect the surrounding tissue. These are not considered “cancerous”. They may however eventually grow to a size that they start to crowd surrounding cells and affect normal function. o Malignant Tumour – In a malignant tumour the tumour negatively affects the tissue around it, interfering with its normal functions and may even destroy the other tissue. Malignant tumours are “cancerous”. If a piece of tumour breaks away, moves to another location in the body and then continues to grow it can form a second tumour. This process is call metastasis. C) Causes of Cancer: The replication of DNA during cell division is usually perfect, meaning an exact copy of the parent DNA is in both daughter cells. Errors however sometimes do occur during the process. These changes are called mutations. Cells with mutated DNA will often die but sometimes the cell can continue to live. If the mutation affects the DNA responsible for controlling cell division, the cell may act abnormally and become cancerous with uncontrolled mitosis and cytokinesis. This continues until all nutrients are used up. Causes: o Hereditary – One cause of cancer is through inherited genes. Breast and colon cancers are commonly inherited cancers. This is not to say a person inherits cancer itself, but rather the mechanism that allows cancers to form. o Environment – Another cause are carcinogens in the environment. Exposure to these chemicals can cause cancer in some people, but not all. Because it doesn’t cause cancer in everyone, it makes it difficult to predict who will get cancer with exposure and it is recommended that everyone should avoid carcinogens. ▪ Lung cancer is one of the most common forms of cancer and 9 out of 10 cases are caused by smoking. There are several carcinogens in tobacco smoke and smoking has attributed to not just lung cancer but mouth, larynx, pharynx, nasal cavity, liver, stomach, kidney, bladder and esophagus. D) Screening & Diagnosing Techniques: Screening is done before any symptoms of cancer are displayed. Regular screening can detect cancer at an early stage increasing the change of successful treatment. Women: Breast cancer can be detected at home by self-examination. Pap test can check for cervical cancer. Men: Testicular cancer can be detected at home by self-examination. A PSA blood test can check for prostate, and colon. Skin Cancer: Can be detected by careful observation for moles. See next page Notes: Homework: B07  Checking for moles using ABCD – Asymmetry, Border, Colour, Diameter Diagnosing cancer can be done when symptoms such as swelling, discomfort, very tired, or unexplained weight loss. Early detection is vital to increase the chance of successful treatment Techniques for Detection include: o Imaging Technologies: ▪ Endoscopy: Using an endoscope with fiber-optic cables to deliver lights and a tiny camera. The endoscope may have miniature forceps attached to take biopsy samples. ▪ X-Ray: Mammograms are routinely used for breast cancer detection. Not suitable for pregnant women. ▪ Ultrasound: Better for looking at soft tissue ▪ CT Scanning: Also called a CAT scan (Computerized Axial Tomography) is a specialized X-Ray technique using multiple images that are formed into a detailed image on a computer. ▪ MRI: Magnetic Resonance Imaging creates more detailed images than a CAT scan is capable of. o Examination of Cells: ▪ Cells can be directly examined with blood samples (blood cells) or when part of the tumour is removed (biopsy) and examined under a microscope. ▪ Leukemia is a cancer of the blood and can be detected by the abnormally high white blood cell count. ▪ Cancer cells are often irregularly shaped and can be detected by trained personnel. E) Treatment: Treatment is generally meant to slow down tumour growth and to destroy as many cancerous cells as possible. There are many treatments, some still being developed; the first three listed are the most commonly in use. Many treatments are often used in coordination with another type of treatment: o Surgery: The physical removal of the tumour. Often a preferred method it is not always possible. o Chemotherapy: The use of a cocktail of drugs designed to slow or stop the dividing of the cells and to kill the cancerous cells. Often it is used to shrink tumours prior to radiation treatment. One of the benefits of this method is that the drugs travel throughout the body and can reach almost all tumours. There are many side effects however including hair loss, nausea, and fatigue. o Radiation: Ionizing radiation targets cancer cells and kills them by damaging them to the point they can no longer divide. It can be done using a focused beam or implanting a radioactive source in the tumour. o Biophotonics: Beams of light to detect and treat. Potentially more accurate than radiation and with fewer side effects. Very sensitive allowing for early detection of cancer. o Biological Therapies: Work in different ways to kill, control or change the behaviour of cancer cells. These therapies use natural or manufactured substances that mimic or block natural cell responses. o Hormonal Therapy: Hormones may promote the growth of some types of cancer cells. Some breast and prostate cancer tumours are called hormone dependent or hormone sensitive. Hormonal therapy alters hormone levels in the body and may help to slow the growth and spread of these cancer cells. Drugs, surgery or radiation therapy to specific organs can be used to manipulate hormone levels. o Indiba Hyperthermia: Hyperthermia is a type of treatment in which body tissue is exposed to high temperatures (up to 113ºF), to damage and kill cancer cells, or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs. o Sono-Photo Dynamic Therapy: SPDT involves getting an agent into the whole body, (originally by injection, now orally), which adheres to cancer cells, so that when light and now, sound, of the correct frequency is applied, the agent "explodes" into free radical oxygen, instantly killing the cancer cells which cannot survive in oxygen.  Subject: SNC2D Unit: 1.0: Living Systems Lesson: 1.08 Topics: Materials: Introduction to Animal System Nelson: Science Perspectives 10 A) Recap: Quick review cells and classifications (prokaryotes, eukaryotes) B) Levels of Organization: All life forms are composed of one or more cells. Each is different, but multi-celled organisms have many different cells working together. To describe these relationships we organize the cells into levels. Cells are arranged in a hierarchy of complexity with the most complex at the top and the least complex at the bottom. o Tissues ▪ A collection of similar cells that perform a particular function ▪ Four major types Epithelial – a thin sheet of tightly packed cells that covers the body surfaces and lines internal organs and body cavities Connective – Tissue that provides support and protection for various parts of the body Muscle – Specialized cells that contain proteins that can contract Nerve – Specialized cells that can conduct electrical signals from one part of the body to another (see page 76) o Organs – A structure composed of different tissues working together to perform a complex body function. Usually organs belong to a single organ system, but some belong to more than one – pancreas (digestive/endocrine (controls hormones)) o Organ System – A system of one or more organs and structures that work together to perform a major vital body function such as digestion or reproduction. o Organism – The entire creature or plant. C) Cellular Differentiation: Cells can reproduce as we have seen in cell division. When a new organism is produced from sexual reproduction it involves an egg or zygote (single cell) growing into all the different types of cells the organism will need. As the cells reproduce they differentiate into those cells. Cellular differentiation is the process by which a cell becomes specialized to perform a specific function. Several factors influence cell specialization: o Cytoplasm Contents: ▪ Mitosis ensures the daughter cells receive identical DNA but the cytoplasm will divide with possibly different contents. What and how many of each organelle are present will help determine how it specializes (one containing more vacuoles (stored energy) may be able to use more energy as it grows. o Influence of Neighbouring Cells: ▪ Nearby cells in the organism may produce substances that may diffuse into the cell affecting how the DNA gets expressed during growth or reproduction. o Environmental Conditions: ▪ Conditions such as temperature or the nutrients available will influence how identical cells may develop. In Siamese cats only the cells that develop in cooler conditions produce dark colours and so Siamese cats have distinctively dark feet, tails, ears and faces. Environmental conditions can therefore also lead to abnormalities. When chemicals are in the environment that affect the DNA of an organism it may get mutated from the false or wrong signals. As cells mature more of their genes get turned off or on by the environmental conditions until as some point they become stabilized and continue their existence as a single type of specialized cell. See next page Notes: Homework: B08 D) Stem Cells: In animals, cells that can still differentiate into many other types of cell are called Stem Cells (recall 1.05) and in plants Meristematic stem cells. After cell division, the two identical daughter cells can specialize into different types of cells depending on which parts of their DNA are switched on or off. So a stem cell can divide and the daughters become different types of tissue layers such as epithelial, muscle, or nerve etc. There are two types of stem cells in animals: o Embryonic Stem Cells– Able to turn into any type of cells (totipotent) o Tissue Stem Cells (Adult Stem Cells) – Able to turn into a limited number of cells (pluripotent) In plant cells there are: o Meristematic Stem Cells- found in the growing tips of roots and stems and within the stem in a layer known as the cambium layer The potential uses of stem cells are very attractive for medical professionals since stem cells can be used to regenerate almost any type of cell. Embryonic or totipotent cells taken from embryos less than a week old can become anyone of over 300 different types of human tissues. These cells can keep dividing for over a year without ever differentiation. Adult/Tissue or pluripotent cells can change into a number of different cells but not as a totipotent stem cell. These can be harvested from umbilical cords. Umbilical cords can be banked or stored for future use in fighting diseases such as leukemia. Stem cells can be transplanted to help leukemia patients restore lost bone marrow etc. Regeneration of lost limbs is a distant goal of many medical researchers. Pluripotent stem cells can be induced from tissue cells using viruses but this may damage the DNA of the cells. o Ethical issues surround the use of stem cells particularly around the death of the embryo during harvesting of Embryonic Stem Cells (killing unborn child)