LS.2 Review

1.01 Defining Problems and InvestigationsImagine you observe a strawberry plant that has several white flowers. The next day, you notice all of the flowers are gone. What would you do to determine what happened to the plant? In this lesson, you will learn about the importance of asking questions and designing investigations to help better understand the natural world.Two flowers on the strawberry plant.This lesson is aligned to the VDOE Life Science Standard of Learning: LS.1The student will demonstrate an understanding of scientific and engineering practices.Key Idea:Asking questions and defining problems (LS.1a). Planning and carrying out investigations (LS.1b).Objectives:Ask questions and develop hypotheses.Identify parts of an experiment.Select appropriate tools and technologies.Evaluate the accuracy of data collection methods. Scientific MethodScience is a way of understanding the natural world based on experimentation and evidence. If observations, data, and evidence cannot be collected about something, then it is not a question that science can answer. For example, science can answer the question: What is causing the strawberry plant flowers to wilt? You could refine your question to ask, what it the effect of different amounts of water on the strawberry plant You could then do experiments to learn how the strawberry plant reacts to varying amounts of water.Ask Question Form HypothesisScientists study the world by asking questions about it and seeking answers. The first step in any scientific investigation is to make an observation using one or more of your five senses (sight, sound, taste, touch, hear and smell). From these observations, you will begin to ask questions: who, what, when, how or why. Make a prediction about what might answer the questions in the form of a hypothesis. The hypothesis may offer a simple solution to your observed problem. The hypothesis must be testable.Let’s return to our strawberry plant observation. You observe the flowers were gone. You may propose an animal has eaten them. Your hypothesis statement might be, “If the strawberry plant is not in a protective cage, then an animal will eat the white flowers.”Plan Conduct InvestigationExperiments are planned to test the hypothesis.Once you have a testable hypothesis, you can focus on the design of the experiment. The goal is to plan a controlled experiment in which only one variable is changed. All other conditions will need to be kept the same so that the dependent variable will be an accurate measurement of the variable you purposely changed. In addition, a control group should be included to use as a comparison to determine if there is an effect.Collect Evaluate DataWhat is Data?Data is a set of values that comes from gathering information. Data can be collected through observations made during experiments or through measurements. Data can be qualitative or quantitative.Data isqualitativeif it describes physical characteristics such as color, odor, or shape. If data can be observed through the five sense, it is usually qualitative.Data is quantitative if it describes numerical values (quantity) such as for temperature, pressure, volume. For example, you are determining how hot a liquid is or how fast a cheetah runs, you would be determining quantitative data. Scientific MethodScience is a way of understanding the natural world based on experimentation and evidence. If observations, data, and evidence cannot be collected about something, then it is not a question that science can answer. For example, science can answer the question: What is causing the strawberry plant flowers to wilt? You could refine your question to ask, what it the effect of different amounts of water on the strawberry plant You could then do experiments to learn how the strawberry plant reacts to varying amounts of water.Ask Question Form HypothesisScientists study the world by asking questions about it and seeking answers. The first step in any scientific investigation is to make an observation using one or more of your five senses (sight, sound, taste, touch, hear and smell). From these observations, you will begin to ask questions: who, what, when, how or why. Make a prediction about what might answer the questions in the form of a hypothesis. The hypothesis may offer a simple solution to your observed problem. The hypothesis must be testable.Let’s return to our strawberry plant observation. You observe the flowers were gone. You may propose an animal has eaten them. Your hypothesis statement might be, “If the strawberry plant is not in a protective cage, then an animal will eat the white flowers.”Plan Conduct InvestigationExperiments are planned to test the hypothesis. Once you have a testable hypothesis, you can focus on the design of the experiment. The goal is to plan a controlled experiment in which only one variable is changed. All other conditions will need to be kept the same so that the dependent variable will be an accurate measurement of the variable you purposely changed. These controlled conditions are called constants. In addition, a control group should be included to use as a comparison to determine if there is an effect.Collect Evaluate DataWhat is Data? Data is a set of values that comes from gathering information. Data can be collected through observations made during experiments or through measurements. Data can be qualitative or quantitative.Data is qualitative if it describes physical characteristics such as color, odor, or shape. If data can be observed through the five sense, it is usually qualitative.Data is quantitative if it describes numerical values (quantity) such as for temperature, pressure, volume. For example, you are determining how hot a liquid is or how fast a cheetah runs, you would be determining quantitative data. Complete the information below. The scientific method is a common phrase applied to a problem-solving system which involves steps and skills.Scientists study the world by asking questions about it and seeking answers.A hypothesis is a testable statement that may offer a solution to your observed problem.Once you have a developed a hypothesis, you design the experiment to test your hypothesis.A constant is a condition in the experiment that will remain unchanged during the experiment.Information gathered is called data.Data that describes a property is called qualitative data.Data that describes a quantity is called quantitative data. Cell Theory 1.02 Cell TheoryHow do scientists think "scientifically" about the natural world?In this lesson, you will learn how scientists used the nature of science to develop the cell theory.This lesson is aligned to the VDOE Life Science Standard of Learning:LS.2The student will investigate and understand that all living things are composed of one or more cells that support life processes, as described by the cell theory.Key Idea:The development of the cell theory demonstrates the nature of science (LS.2a).Objectives:Make connections among the components of the nature of science, their investigations, and the greater body of scientific knowledge and research.Differentiate among a scientific hypothesis, theory, and law.Identify the three components of the original cell theory.Provide examples to illustrate how the development of cell theory illustrates the nature of science.Explain how advances in microscope technology have improved our understanding of cells and their parts. TheoriesTheories and laws are two different types of knowledge used by scientists to describe natural phenomena. A phenomenon is an observable event or fact. As you recall,A theory explains complex natural processes not easily measured, such as evolution or cells functions.A law describes a natural phenomena or relationships, such as laws of gravity or motion.A hypothesis predicts what may occur, and is written as a testable statement.The Cell TheoryThe cell theory is a shared understanding that expresses our current understanding of the cell. The cell theory describes our current understanding of cells and is a shared theory throughout the scientific community. In the last lesson, we discussed the nature of science.The development of the cell theory illustrates the nature of science because:The development was dependent upon the improvements of the microscope (science is a blend of logic and innovation).The development was dependent upon notable scientists who studied cells (science is a complex social endeavor).The theory is based on evidence and has been modified (scientific ideas are durable yet subject to change as new data are collected).Original Cell TheoryThe original cell theory has three parts - which still hold true today!All living things are composed of cells.Cells are the smallest unit of living things that can perform the processes necessary for life.Living cells come only from other living cells. Advances to the Cell TheoryScience and technology are tightly linked. Science seeks to understand the natural world through observation and experimentation. With time, advances in science and technology have added to our understanding of the cell. These modern findings have come primarily from our ability to make observations on a microscopic level.The development of this theory illustrates the nature of science. Today, the modern cell theory includes both the original 3 parts as stated above, and these modern findings:- metabolism occurs within cells (photosynthesis cellular respiration)- hereditary information is passed from one cell to another (DNA)- all cells have a similar basic composition (organelles)A good example of the link between science and technology is how advances in microscopes have helped us investigate cells—the smallest part of living things—and how they work to sustain life processes.Electron microscopesare the most powerful type ofmicroscope, An electron microscope can show structures of very, very small objects (like the inside of cells!)Enduring UnderstandingsThe cell theory is a shared understanding that expresses our current understanding of the cell. The development of this theory illustrates the nature of science.Science and technology are tightly linked. Science seeks to understand the natural world through observation and experimentation.A good example of the link between science and technology is how advances in microscopes have helped us investigate cells—the smallest part of living things—and how they work to sustain life processes. 1.03 Cell Structure and FunctionCells are tiny structures that make up living organisms. How does each cell perform the necessary reactions to support life processes?In this lesson, you will learn about the structures and functions of cells, and how cells support life processes.This lesson is aligned to the VDOE Life Science Standard of Learning:LS.2The student will investigate and understand that all living things are composed of one or more cells that support life processes, as described by the cell theory.Key Idea:Cell structure and organelles support life processes (LS.2b). Similarities and differences between plant and animal cells determine how they support life processes (LS.2c).Objectives:Identify and relate cellular organelles with the life processes they perform within a living cell.Develop and use a model to demonstrate how organelles function as a system to carry out life processes within the cell.Compare plant and animals cells using images.Explore differences in the structure and function of animal and plant cells.Relate the parts of a cell to the life functions they perform within the cell.Explain how the parts of a cell work as a system to carry out life processes in the cell and the organism. CellsAs you learned when we discussed the cell theory, cells are the smallest unit of living things that can perform the processes necessary for life. And, all cells contain special structures with unique functions that keep living organisms alive. Cells are in control of many life processes such as: growth and repair, response, reproduction, gas exchange, and metabolism. We will discuss these life processes in more detail soon!Cell Structures and FunctionsIn order to complete life processes, we need energy. How do we get energy? Good question! We get energy from our cells. That's right, our cells. Cells have special structures that allow them to obtain (get) and transform (change) energy. This energy not only helps the cell, it helps us because we are made of cells. Cell structures and the functions of these structures are responsible for keeping us alive!Some cell structures, called organelles, have very special jobs inside cells. For Life Science, you need to identify and understand the functions of the following cell structures: cell membrane, cell wall, cytoplasm, nucleus, mitochondrion, endoplasmic reticulum, vacuole, and chloroplast.Enduring UnderstandingLiving cells are full of highly organized organelles that function as a system to carry out life processes within the cell. Life processes include growth and repair, reproduction, gas exchange, metabolism, and response. CellsCells are the smallest unit of living things that can perform the processes necessary for life. All cells contain special structures with unique functions that keep living organisms alive. Cells are in control of many life processes such as: growth and repair, response, reproduction, gas exchange, and metabolism. We will discuss these life processes in more detail soon!Cell Structures and FunctionsIn order to complete life processes, we need energy. We get energy from our cells. Cells have special structures that allow them to obtain (get) and transform (change) energy. This energy not only helps the cell, it helps us because we are made of cells. Cell structures and the functions of these structures are responsible for keeping us alive!Some cell structures, called organelles, have very special jobs inside cells.For Life Science, you need to identify and understand the functions of the following cell structures: cell membrane, cell wall, cytoplasm, nucleus, mitochondrion, endoplasmic reticulum, vacuole, and chloroplast.Enduring UnderstandingLiving cells are full of highly organized organelles that function as a system to carry out life processes within the cell. Life processes include growth and repair, reproduction, gas exchange, metabolism, and response. Define each organelle: cell membrane, cell wall, cytoplasm, nucleus, mitochondrion, endoplasmic reticulum, vacuole, and chloroplast. Plant Cells and Animal CellsLike objects, the structure of a living thing determine how the living things functions. Animal and plant cells are different in structure to include: size, organelles, and shape. Similarities and differences between plants and animals can be seen in their cells.Overall, plant cells and animal cells are similar, with a few key differences:plant cells are usually larger than animals cellsplant cells have chloroplasts (animal cells do not)plant cells have 1 large vacuole (animal cells have multiple, smaller vacuoles)plant cells have cell walls (animal cells do not)plant cells are cube shaped, due to their cell wall (animal cells are more round)CompareLet's look at the images below to compare some major differences between plant cells and animal cells. Note: Not all cell structures are present for the cells. This purpose of the images is to highlight the differences. Enduring UnderstandingsAnimal and plant cells may differ in shape, size, and the organelles they contain. Most often these differences in structure are related to the function of the cell.Similarities and differences between plants and animals can be seen at the cellular level. Plant cells differ from animal cells in that plant cells contain cell walls, chloroplasts, and large, central vacuoles Life ProcessesAs discussed at the beginning of this lesson, organisms undergo life processes such asgrowth and repair, response, reproduction, gas exchange, and metabolism.Growth and repair occurs through cell division producing cells identical to the parent cell. Organisms respond to their environment through adaptations to increase their ability to survive. Reproduction is a life process by which living things transfer genetic information, DNA, to their offspring. Let's look at some brief definitions of these terms. We will focus on metabolism for this lesson, you will learn more about the other terms later in this course.MetabolismMetabolism refers to the interactions between molecules within a cell. These interactions are sometimes called metabolic activities. Two important types of cell metabolic activities are photosynthesis and cellular respiration.PhotosynthesisPlants are autotrophs because they are able to make their own food. They are able to do so through the process of photosynthesis which takes place in the chloroplast inside the cells. The sun's energy, carbon dioxide and water are used to create a molecule called glucose. This molecule is a food source for the plant. Being able to undergo this process, establishes plants as producers of ecosystems.A chemical equation can show the summary of the events that take place during photosynthesis. Observe both the chemical and word equations below. Materials on the left side of the arrow are reactants or starting materials. The materials on the right side of the arrow are called products.chemical equation6CO2 + 6H2O + (light energy) ---> C6H12O6 + 6O2word equationcarbon dioxide + water + light energy ---> glucose + oxygenCellular RespirationOrganisms that cannot make their own food, heterotrophs, get glucose from food they eat. Both autotrophs and heterotrophs breakdown glucose into usable form of energy through the process of cellular respiration. The location of this process is the powerhouse of the cell, the mitochondrion. The energy made is called ATP and fuels the reactions and processes of other activities within the cell. The events of these reactions are summarized in the following equations.chemical equationC6H12O6 + 6O2 ---> 6CO2 + 6H2O + ATPword equationglucose + oxygen ----> carbon dioxide + water + energyThrough these two cell metabolic activities, energy is continually transferred between living organisms. As matter and energy flow through different organizational levels of living systems, chemical elements are recombined to form different products.You will learn more about the importance of photosynthesis and cellular respiration to living things, in the next module.The Big PictureAs we have discussed, living cells contain organelles that function to carry out life processes - for both the cell and us! (Thank you, cell.) Now, let's tie this all together.Think about this:From the sun's energy, a carrot makes its own food (photosynthesis)You eat the carrot, which brings nutrients into your body.The nutrients travel to your cells.The cell membrane allows the nutrients into the cell.The nutrients move through the cytoplasm to the mitochondria.The mitochondria converts the nutrients to cell energy (cellular respiration)This cell energy powers you!As you recall from this lesson, plant cells are different from animal cells in that plant cells contain cell walls, chloroplasts, and a single large vacuole. Plant cells are also usually larger than animal cells. Now, you can better understand that the plant's cell walls allow gas exchange; the chloroplasts convert solar energy into food (sugars); and the vacuole stores water and nutrients, essential to the plant.Enduring UnderstandingsLiving cells are full of highly organized organelles that function as a system to carry out life processes within the cell, to include metabolism.Metabolism refers to all interactions among molecules within the well-ordered environment of the cell. Photosynthesis and cellular respiration are two important metabolic activities within living cells.Plant cells differ from animal cells in that plant cells contain cell walls, chloroplasts, and large, central vacuoles to aid in photosynthesis that help them convert matter and energy to usable forms. Life ProcessesOrganisms undergo life processes such as growth and repair, response, reproduction, gas exchange, and metabolism.Growth and repair occurs through cell division producing cells identical to the parent cell.Organisms respond to their environment through adaptations to increase their ability to survive.Reproduction is a life process by which living things transfer genetic information, DNA, to their offspring.MetabolismMetabolism refers to the interactions between molecules within a cell. These interactions are sometimes called metabolic activities. Two important types of cell metabolic activities are photosynthesis and cellular respiration.PhotosynthesisPlants are autotrophs because they are able to make their own food. They are able to do so through the process of photosynthesis which takes place in the chloroplast inside the cells. The sun's energy, carbon dioxideand water are used to create a molecule called glucose. This molecule is a food source for the plant. Being able to undergo this process, establishes plants as producers of ecosystems.A chemical equation can show the summary of the events that take place during photosynthesis. Observe both the chemical and word equations below. Materials on the left side of the arrow are reactants or starting materials. The materials on the right side of the arrow are called products.chemical equation6CO2 + 6H2O + (light energy) ---> C6H12O6 + 6O2word equationcarbon dioxide + water + light energy ---> glucose + oxygenCellular RespirationOrganisms that cannot make their own food, heterotrophs, get glucose from food they eat. Both autotrophs and heterotrophs breakdown glucose into usable form of energy through the process of cellular respiration. The location of this process is the powerhouse of the cell, the mitochondrion. The energy made is called ATP and fuels the reactions and processes of other activities within the cell. The events of these reactions are summarized in the following equations.chemical equationC6H12O6 + 6O2 ---> 6CO2 + 6H2O + ATPword equationglucose + oxygen ----> carbon dioxide + water + energyThrough these two cell metabolic activities, energy is continually transferred between living organisms. As matter and energy flow through different organizational levels of living systems, chemical elements are recombined to form different products.You will learn more about the importance of photosynthesis and cellular respiration to living things, in the next module.The Big PictureAs we have discussed, living cells contain organelles that function to carry out life processes - for both the cell and us!From the sun's energy, a carrot makes its own food (photosynthesis)You eat the carrot, which brings nutrients into your body.The nutrients travel to your cells.The cell membrane allows the nutrients into the cell.The nutrients move through the cytoplasm to the mitochondria.The mitochondria converts the nutrients to cell energy (cellular respiration)This cell energy powers you!As you recall from this lesson, plant cells are different from animal cells in that plant cells contain cell walls, chloroplasts, and a single large vacuole. Plant cells are also usually larger than animal cells. Now, you can better understand that the plant's cell walls allow gas exchange; the chloroplasts convert solar energy into food (sugars); and the vacuole stores water and nutrients, essential to the plant.Enduring UnderstandingsLiving cells are full of highly organized organelles that function as a system to carry out life processes within the cell, to include metabolism. Metabolism refers to all interactions among molecules within the well-ordered environment of the cell. Photosynthesis and cellular respiration are two important metabolic activities within living cells.Plant cells differ from animal cells in that plant cells contain cell walls, chloroplasts, and large, central vacuoles to aid in photosynthesis that help them convert matter and energy to usable forms. 2.02 Organization of Living ThingsAll cells do not look alike. Some organisms are single-celled and others are multi-celled. What are some of the similarities among these cells? In this lesson, you will explore the cell's organization to answer this question.This lesson is aligned to the VDOE Life Science Standard of Learning: LS.3The student will investigate and understand that there are levels of structural organization in living things.Key Idea:Patterns of cellular organization support life processes (LS.3a). Unicellular and multicellular organisms have comparative structures (LS.3b).Objectives:Explain the relationship among cells, tissue, organs, and organ systems.Differentiate among common examples of unicellular and multicellular organisms.Compare how unicellular and multicellular organisms perform various life functions, including the application of knowledge about systems in organisms and division of labor.Explain how a cell's form fits its function with a multicellular organism. ReviewIn the last module, you learned that living cells are full of highly organized organelles that function as a system to carry out life processes within the cell to include: growth and repair, reproduction, gas exchange, metabolism, and response.To carry out these life processes, organisms are organized with special structures that carry out specific and special functions. Some organisms are very simple and some are very complex. But whether an organisms is simple or complex, it must carry out important functions to maintain life.Now, let's define "simple" and "complex", when it comes to living organisms.Unicellular OrganismsThe prefix uni- means one. Unicellular means a single celled organism. Unicellular organisms are considered "simple" organisms (in comparison to organisms made up of more than one cell).Examples of unicellular organisms include bacteria, amoeba and paramecium. One cell is responsible for all of the life processes including reproduction and digestion.Multicellular OrganismsThe prefix multi- means more than one. Multicellular organisms are made up of many cells. In comparison to unicellular organisms, multicellular organism are very complex.In multicellular organisms, large groups of cells work together to form systems of tissues and organs. These systems are are specialized to help the organism carry out life processes of growth, reproduction, gas exchange, metabolism, and response.You will learn more about the structures and functions of multicellular organisms when you take Biology. For now, let's look at an image that shows the general level of organization for multicellular organisms.Levels of OrganizationThe image below shows the organization for a multicellular organism (from atom to organism). For a unicellular organism, stop at "cell" (from atom to cell). That's a big difference between the two types of organisms!You do not need to memorize the order. Just become familiar for now. Transcript Download TranscriptForm and FunctionIn science you may hear: "structure determines function" or "form fits function". These says simply mean that the structure (shape) of the object determines function (use) of the object. Think about a fork and a spoon. They both have different structures and because of this, they both have different functions.In multicellular organisms, cells have special forms that allow them to perform special duties. Multicellular organisms have a level of organization that allows for a division of labor to help carry out life processes. You will learn more about specialized cells that carry out life processes later when you take Biology. But for now, let's take a quick peek just so you understand how special cells can be. Think: "Form fits function".Click the hotspots for a sneak-peek at red blood cells, nerve cells, and skin cells.Enduring UnderstandingsOrganisms range in composition from unicellular microorganisms to multicellular organisms.In multicellular organisms, large groups of cells work together to form systems of tissues and organs. These systems are are specialized to help the organism carry out life processes of growth, reproduction, gas exchange, metabolism, and response.Multicellular organisms have a level of organization that allows for a division of labor to help carry out life processes.A key concept in science is that form fits function. In multicellular organisms, cells have specialized shapes that enable them to perform specific roles within the organism. Living cells are full of highly organized organelles that function as a system to carry out life processes within the cell to include: growth and repair, reproduction, gas exchange, metabolism, and response.To carry out these life processes, organisms are organized with special structures that carry out specific and special functions. Some organisms are very simple and some are very complex. But whether an organisms is simple or complex, it must carry out important functions to maintain life.Now, let's define "simple" and "complex", when it comes to living organisms.Unicellular OrganismsThe prefix uni- means one. Unicellular means a single celled organism. Unicellular organisms are considered "simple" organisms (in comparison to organisms made up of more than one cell). Examples of unicellular organisms include bacteria, amoeba and paramecium. One cell is responsible for all of the life processes including reproduction and digestion.Multicellular OrganismsThe prefix multi- means more than one. Multicellular organisms are made up of many cells. In comparison to unicellular organisms, multicellular organism are very complex.In multicellular organisms, large groups of cells work together to form systems of tissues and organs. These systems are are specialized to help the organism carry out life processes of growth, reproduction, gas exchange, metabolism, and response.Form and FunctionIn science you may hear: "structure determines function" or "form fits function". These says simply mean that the structure (shape) of the object determines function (use) of the object. Think about a fork and a spoon. They both have different structures and because of this, they both have different functions.In multicellular organisms, cells have special forms that allow them to perform special duties. Multicellular organisms have a level of organization that allows for a division of labor to help carry out life processes.Enduring UnderstandingsOrganisms range in composition from unicellular microorganisms to multicellular organisms.In multicellular organisms, large groups of cells work together to form systems of tissues and organs. These systems are are specialized to help the organism carry out life processes of growth, reproduction, gas exchange, metabolism, and response.Multicellular organisms have a level of organization that allows for a division of labor to help carry out life processes.A key concept in science is that form fits function. In multicellular organisms, cells have specialized shapes that enable them to perform specific roles within the organism.