Nature and Variety of living Things Grade 10 Combined Science Lesson 1 – What does it mean to be considered “alive”? Learning Objectives • To describe the characteristics of living things • To identify how living organisms are classified What does it mean to be alive? Characteristics of Living Things • The Future of Robots Are robots alive? As technology is progressing, the machines available today have the ability to make decisions. Take a look at the video and list all the characteristics the robots have that could be used as evidence to prove they are “alive”. Seven Life Processes Seven Processes of Living Things Can you remember the different processes? Match the process with the definition How do plants carry out these processes? • Plants are also classified as living organisms. Choose three characteristics from the list above and state how a plant carries out that function. Characteristic How? The 8th living characteristic Homeostasis – the control of an internal environment. What do we need to control? How are these things controlled? Are all living things the same? Can you group them? Using key features of these organisms, can you identify the 5 kingdoms of living things? Personal Study • Identify 3 features per classification that scientists use to group 5 kingdoms of living things. • Write your information next to each box on your worksheet. • Have the information ready for next class. Lesson 2 – How do living organisms differ? Learning Objectives • To describe the key characteristics of eukaryotic and prokaryotic organisms. • To make distinct comparisons between eukaryotic and prokaryotic organisms. Can you identify the kingdom? Complete the table with the matching letters Kingdom Fungi Animal Plant Prokaryote Protoctists Characteristics The Kingdoms The Kingdoms What does this timeline deduce? Eukaryotes versus Prokaryotes Venn Diagram Fungi – it’s found everywhere • Fungi is a saprotrophic organism. That means it secretes digestive enzymes onto dead organic matter to break it down and then absorbs the digested juices. Yeast is one example of fungi. Other examples - Mycelium Lesson 3 – Are all pathogens harmful? Learning Objectives • To understand the term pathogen. • To make distinct comparisons between different pathogens. What is a pathogen? • Any organism or virus that causes disease. Pathogens Viruses • Viruses are metabolically inert and incapable of reproducing independently of a host cell (hence are non-living) • They typically consist of an inner core of nucleic acid surrounded by a protein coat (capsid) • Simpler viruses may lack a capsid. Definition of Prokaryote A prokaryote is a singlecelled organism that lacks a nucleus and other membrane-bound organelles. Bacterium Cell Functions of key parts of the cell • Nucleoid – region of the cytoplasm where the circular DNA is located. • Plasmids – small circular DNA molecules that contain survival DNA and may be transferred between bacteria. • Capsule – a thick layer used for protection, especially in the stomach. • Flagella – Long, projections that enables movement of the cell (singular: flagellum) • Pili – Hair-like extensions that enables the cell to attach to surfaces or allow the passing of plasmids from one cell to Amoeba Sisters Video Different types of bacteria • Pneumococcus, a spherical bacterium that acts as the pathogen causing pneumonia • Lactobacillus bulgaricus, a rod-shaped bacterium used in the production of yoghurt from milk Spirochete is a group of spiralshaped bacteria, some of which are serious pathogens for humans, causing diseases such as Lyme disease, and relapsing fever. Question Time… Where on the body are you likely to find bacteria? Skin and digestive system What are the benefits of having good bacteria on your skin? Keep harmful bacteria and other pathogens from growing on your skin. Bad bacteria are also known as pathogens. These bacteria cause harm to your body. Name 2 illnesses that are caused by bacteria. Strep throat (tonsillitis), tooth decay, tetanus What do antibiotics do? They kill bacteria and prevent them from replicating. Question Time… Why are antibiotics harmful to your helpful bacteria? Antibiotics will attack all prokaryotic cells and cannot tell the difference between good and bad bacteria. Bacteria multiply through a process called Binary Fission. What happens to the bacterium during binary fission? A bacterium divides to produce an exact copy of itself. Binary fission is a form of Asexual Reproduction. What is special about the cells produced through asexual reproduction? They are genetically identical to the parent cell. Ideal conditions for bacteria to grow •Warm •Moist •Plenty of nutrients •Neutral pH How many bacteria?? Number of minutes Number of bacteria 80 16 100 32 120 64 140 128 160 256 180 512 200 1024 • In just 200 minutes, in ideal conditions, 1 bacterium cell will duplicate and result in a total number of 1024 bacteria cells! Life in a petri dish • Exponential phase – perfect temperature and enough nutrients for all cells. • Stationary phase – number of deaths = number of duplications. • Death phase - No more nutrients to sustain the life of the bacteria cells. Fill in the blanks Fill in the blanks Key viral diseases TMV AIDS • TMV, or tobacco mosaic virus, is a viral disease that affects plants, particularly tobacco plants. It causes mottled leaves, stunted growth, and reduced yields in affected crops. • AIDS stands for Acquired Immune Deficiency Syndrome. Months or years after infection by the HIV virus, it becomes active and starts to attack the patient's immune system . At this point HIV has become AIDS. Labelling viruses Let’s compare Lesson 4 – Do all eukaryotic cells have the same organelles? Learning Objectives • To describe the levels of organization within a living organism. • To identify the structure and describe the function of all cell organelles. • To make distinct comparisons between plant and animal cells. Levels of anatomical organization Where would you put organelles? Labelling Cells Using previous knowledge and using the key terms provided, label the parts of the plant and animal cell. Let’s take a closer look Matching the organelle with the function Functions Let’s compare Plant cell Animal cell Knowing the microscope Lab instructions To use the microscope… • Put the smallest objective lens so that it is over the hole in the stage. • Turn the coarse focusing wheel to make the gap between the stage and the objective lens as small as possible. • Place a slide on the stage and place the clips on the slide to hold it in place. • Adjust the light source. Either turn on the lamp or turn your mirror so that light is reflected up into the hole in the stage. • Look into the eyepiece lens. It is best to look down your microscope with both eyes open! • Turn the coarse focusing wheel so that the gap between the stage and the objective lens gets bigger. Keep turning until what you see is clear (in focus). • To see a bigger image, place the next largest objective lens over your specimen. • Look down the microscope again and turn the fine focusing wheel a small amount one way to get your image in focus again. If this doesn’t work, turn the fine focusing wheel a small amount the other way. What do you see? Lesson 5 – How do substances enter and leave cells? Learning Objectives • To describe the processes involved in the movement of substances in and out of a cell. What substances need to enter and leave a cell? Substances moving in Substances moving out The Cell Membrane Functions of the Membrane Proteins Peripheral protein Channel protein Carrier protein Glycoprotein Functions of the Membrane Proteins Peripheral protein Channel protein Carrier protein Glycoprotein Temporary attachments to the membrane – used for attachment of the cytoskeleton and anchorage to other cells. Used to allow large molecules through the membrane such as glucose through facilitated diffusion. Used to move substances against their concentration gradient through the process of active transport. Used for the recognition of substances and to recognize other cells. Osmosis • Osmosis is the net movement of water molecules across a semipermeable membrane from a region of low solute concentration to a region of high solute concentration (until equilibrium is reached) • Water is considered the universal solvent – it will associate with, and dissolve, polar or charged molecules (solutes) • Because solutes cannot cross a cell membrane unaided, water will move to equalise the two solutions • At a higher solute concentration there are less free water molecules in solution as water is associated with the solute • Osmosis is essentially the diffusion of free water molecules and hence occurs from regions of low solute concentration Simple Diffusion • Diffusion is the net movement of molecules from a region of high concentration to a region of low concentration • This directional movement along a gradient is passive and will continue until molecules become evenly dispersed (equilibrium) • Small and non-polar (lipophilic) molecules will be able to freely diffuse across cell membranes (e.g. O2, CO2, glycerol) • The rate of diffusion can be influenced by a number of factors, including: • Temperature (affects kinetic energy of particles in solution) • Molecular size (larger particles are subjected to greater resistance within a fluid medium) • Steepness of gradient (rate of diffusion will be greater with a higher concentration gradient) Facilitated Diffusion • Facilitated diffusion is the passive movement of molecules across the cell membrane via the aid of a membrane protein • Channel Proteins • Integral proteins that have a pore that allows larger molecules to cross from one side of the membrane to the other • Channel proteins are molecule selective and may be gated to regulate the passage of molecules in response to certain stimuli • Channel proteins only move molecules along a concentration gradient (i.e. are not used in active transport) • Channel proteins have a much faster rate of transport than carrier proteins Active Transport • Active transport uses energy to move molecules against a concentration gradient • This energy may either be generated by the direct breakdown of ATP. Active transport involves the use of carrier proteins (called protein pumps due to their use of energy) • A specific solute will bind to the protein pump on one side of the membrane • The breakdown of ATP causes a structural change in the protein pump • The solute molecule is moved across the membrane (against the gradient) and released. Lesson 6 - How do we determine the isotonic point of a cell? Learning Objectives •To understand movement of water molecules is based on the differences in solute concentrations in the surrounding environment. Starter Activity • Carefully read the directions on the worksheet and set up equipment as shown. Method • Method • Use a cork borer to take 5 cores from one potato. • Cut off any skin. • Then use a ruler and scalpel to trim them all to 4cm. • Blot the cylinders using paper towels to remove excess water. • Use a balance to record the mass of each cylinder and add it to the table below. • In each boiling tube add the following concentrations of sucrose solution: Boiling Tube Number 1 Concentration of sucrose solution (mol) 0.00 2 0.25 3 0.50 4 0.75 5 1.00 Method • Add each cylinder of potato to the following sucrose solutions and leave for 15 minutes. • Remove the cylinders using forceps. • Blot the excess water off them and record the final mass in the table. • Calculate the change in mass for each cylinder and add it to the table. Recording Data Cylin Sucrose Initial Mass Final Mass Change in der Concentration (g) (g) Mass (g) (mol) A 0.00 B 0.25 C 0.50 D 0.75 E 1.00 Data Processing • To make the results valid calculate the % change in mass for each cylinder using the following equation. % change in mass = change mass x 100 original mass Cylinder Sucrose % Change in Concentratio Mass n (mol) A 0.00 B 0.25 C 0.50 D 0.75 E 1.00 Graph the data Look at where % change is 0 and what concentration of salt that equates to. That indicates a net movement of water of zero, which is the isotonic point of the potato. Lesson 7 – What factors impact the rate of diffusion in a cell? Learning Objectives To understand how surface area, temperature and substrate concentration impact the rate of diffusion. Construct a conclusion from the data obtained Quick Recap – What is diffusion? • Diffusion is the net movement of molecules from a region of high concentration to a region of low concentration • This directional movement along a gradient is passive and will continue until molecules become evenly dispersed (equilibrium) Todays Investigation • Group 1 – Surface Area : Volume Ratio • Group 2 – Temperature • Group 3 – Substrate concentration Before we start the experiment.. Agar is a jelly that is used for growing cultures of bacteria. It has a consistency similar to the cytoplasm of cells. Like cytoplasm it has a high water content. Agar an be used to show how substances diffuse through a cell. This experiment uses the reaction between hydrochloric acid and phenolphthalein. Phenolphthalein indicator turns colourless in the presence of hydrochloric acid. You can also use beetroot and water Investigate how SA:VL ratio affects the rate of diffusion Remember!! Calculate the volume, surface are and volume to surface area of each cube! Experiment time! Read method and instructions carefully before you begin • WARNING – Phenolphthalein – Irritate • WARNING – Hydrochloric acid – Corrosive • WARNING - Be careful when using the scalpel to cut the pieces of agar Results Results Follow the instructions on the worksheet • Each group has a slightly different task to complete. • Once the practical has been completed, in your group you must add to the PowerPoint Presentation on Teams. • Next class you will present your findings to the rest of the class.
