Biology EOC Review Session Overview

Hi, and welcome to the Biology EOC review session day one. The Biology EOC is an assessment that is delivered via a computer-based test. The assessment is given in one 160-minute session with a 10-minute break after the first 80 minutes. Any student who has not completed the exam by the end of the 160 minutes may continue working, but the test must be completed within the same school day. There are multiple forms of the assessment, but each assessment includes a maximum of 66 multiple choice items on each test form. Students are provided with a four-page hard copy work folder to use as scratch paper, And the used folders are secured testing materials that must be returned to the testing proctor after testing is completed. The EOC will be averaged as 30% of your final course grade. The EOC is broken up into different areas based on standards that you have learned throughout your biology course. 35% of the EOC will cover standards that include molecular and cell biology standards. 25% of the EOC will include classification, heredity, and evolution. And 40% of the EOC will cover organisms, populations, and ecosystems. Today, we're going to cover these state standards, the nature of science, microscopes, special properties of water, basic molecular structure and function, enzymes, organization and development, which include the cell theory. We're going to talk about the different general structures of plant and animal cells and prokaryotic and eukaryotic cells, the structure and function, excuse me, the structure and function of plant and animal cells, photosynthesis, aerobic and anaerobic cellular the respiration, and then finally ATP. The first standard, nature of science, covers the purpose of science and how science is practiced. We know that the purpose of science is to provide logical explanations of the natural world around us and how things occur. All findings are supported with evidence that is collected from an experiment, and the experiment is a way to test out a problem to locate or find a solution. So what is it that makes an experiment reliable? Reliable experiments have been tested and observed numerous times by more than just one group of scientists, and those scientists will follow the scientific method. During the scientific method process, evidence will be gathered, and evidence in the form of facts are presented with no personal bias. The information that is... gathered from a reliable experiment must come from a third party that doesn't profit from the study, and those studies should be retested by other scientists with the same end results. Once the results are collected, those results should be reported and published into a scientific journal. The scientific method is a way for us to learn about the environment around us and to solve problems. And the scientific method isn't always a linear process. However, it does include all of these important aspects. We'll always start with making observations. And from the observations that we gather, we can then form a question. Our question must be testable. And from that question, you should be able to find research. from a reliable source, from that research that you gather, you can then construct a hypothesis. A hypothesis is a prediction of what you think will happen, and it is a testable statement. A hypothesis should be written in an if-then-because format. Once a hypothesis is created, you can then create an experiment to test your hypothesis. And all good experiments should have three variables present. Your independent variable is the variable that is changed purposely by the scientist. It is what the part of the experiment is that the scientist is purposely manipulating or testing. Our dependent variable is the one factor that will be measured or recorded as the result of the experiment. This is what we will observe occurring in the experiment. And your controlled variables are all the other factors that are kept constant in an experiment. So, for example, if you are testing the different types of fertilizer on plant growth, The thing that the scientist is testing is the different types of fertilizer. That would be your independent variable. If we are measuring how tall the plants get in response to different fertilizers, the height of the plant would then be our dependent variable. This is what we are measuring as our results. All the other factors in the environment should be controlled. So the things like how much water each plant is getting, how much sun each plant is getting, or even the place where the plants are growing, should all be controlled. Once you perform your experiment, you're going to collect some data, and the data collection is to help avoid bias so that you're only focusing on the facts. Once you collect that evidence, that data, you can use that data to draw some conclusions. And your conclusions are going to refer back to the data. And with that, you can then confirm or reject your initial hypothesis. So does the scientific method apply to laws and theories? In order to get to a theory or a law, the scientific method has been practiced many times. One common misconception is that a law can become a theory or vice versa. And this is simply not the case. The reason is because a theory and a law have two different purposes. A theory is a broad explanation of the natural world that is based on strong scientific support. It answers questions like why something occurs. A law is a description of what we expect to happen in the natural world based on many observations and data collected over time. So a law answers questions like, what happens? Because a theory and a law do two different things, they will never become one another. Theories can change and be strengthened based on further scientific study and more evidence to support it. And theories will never become a law, and a law will never become a theory. because again, they do two different purposes. They have two different purposes. Within an experiment, when you are gathering data, there are certain types of measurements that you likely will be collecting. In science, we have base quantities and base units of measure that are measured by specific instrumentation. For example, length is measured by a meter, and we use either a metric ruler or a meter stick. If we're looking for mass, the unit of measure will be the gram, and we can use a balance to measure mass. Volume is measured in liters, and a graduated cylinder is used to collect that data. Time is typically reported as seconds. and measured with either a stopwatch or a clock. And temperature is measured by either Kelvin or Celsius, and we use a thermometer to collect that type of data. Once data is collected, the easiest way to analyze the data is to graph your data. Depending on the type of data that you collect, that will determine the type of graph that you're going to create. For example, the bar graph will help you to show different types of data that may have some similarities, but you are comparing those data sets. For example, this bar graph is showing the number of different types of pets people own. So the different types of pets are along the x-axis, and the number of people are along the y. Here we're showing similar data, similar types of pets. The line graph shows change over time. So here we have along the x-axis the months of the year, and along the y-axis we're showing how much precipitation has fallen, although this y-axis is improperly labeled. So because we're looking at the change in monthly precipitation over time, this is going to be demonstrated by a line graph. A pie graph or a circle graph will show parts of a whole. Anytime you are asked to graph percentages, this is the best graph to use. So here's a sample question. Please read the question. and determine what you think the best answer to this is. You can pause the video at this point to read through the question. For this question, the correct answer would be B, research what others have already found. Oftentimes, we need to view things that are not visible to the naked eye. in which we would employ a microscope. There are different types of microscopes that can be used based on what it is that you are trying to view. First of all, the light microscopes. The light microscopes have capabilities that allow lower magnification. There are two main types of light microscopes. The dissecting microscope offers the lowest magnification. it can magnify images up to 40 times their normal size. These microscopes are terrific for looking at organs and tissues during a dissection and also the surfaces and details of things like leaves, stems, mold spores, or other small objects. The compound light microscope can magnify images a little bit more, ranging anywhere from 40 times up to 40 times. up to 400 times, or even some microscopes can magnify a thousand times the true size of a specimen. With the compound light microscope, we would look at things like tissue samples, blood cells, different types of microorganisms that may live in pond water, microscopic cells, and even some of the larger details within the cell, like the nucleus or the cell membrane. The electron microscopes are another category of microscope that have a much higher ability to magnify things. Electron microscopes use electron beams to pass through certain materials. The transmission electron microscope, or the TEM, passes a beam of electrons through a very thin specimen. And with these types of microscopes, you can view... internal structures of cells that cannot be viewed under light microscopes. Things like the mitochondria or the chloroplast can be viewed looking at using a transmission electron microscope. The scanning electron microscope is similar, but instead of going through, transmitting through a specimen, here we're just scanning the surface. So the SEM, or the scanning electron microscope, is useful for studying the details of the specimen's surface. And the electron beam scans the specimen's surface, which typically is coated with a thin layer of gold metal. And the image projected from the scanning electron microscope is typically a three-dimensional image in black and white. So our next question. Feel free to pause the video. Read through the question and see if you can get the correct answer. The correct answer is D, viewing a cell's mitochondria in detail. And the next standard we're going to talk about is the properties of water. Water has some very unique properties based on its molecular structure. Water is considered polar, which means that there is a slightly positive charge at one end of the molecule and slightly negative on the other side of the molecule. Because of this, this is what makes water polar. Hydrogen bonding is something that occurs as a result of this polarity. The attraction of the slightly positive hydrogens of one water molecule attract the negative oxygen side of a neighboring. water molecule. And that is what allows water molecules to stick together. So looking at this image, this spider is able to stand on water because it exhibits surface tension. Surface tension is the tendency of water molecules to stick together and create a strong surface. Remember that we said those water molecules stick together. because of the positive hydrogen side of one water molecule attracting the partial negative oxygen side of a neighboring molecule. So this idea of surface tension is possible because of those hydrogen bond attractions. Water is also often known as the universal solvent due to its ability to dissolve a lot of different substances. Ionic compounds like salt and polar molecules like sugar have an easy time dissolving in water because they have both positive and negative charges, which can interact with the positive and negative charges of the water molecules. Because of these differences in charges within a water molecule, water can exhibit the property of cohesion. Cohesion is when two like substances are attracted to each other. So again, when the water is attracted to itself, the positive end of one water molecule will attract the negative end of an adjacent water molecule. So here we are showing cohesion, the prefix co- meaning together. So the water molecules are stuck together. Adhesion is where the... positive or negative side of a water molecule is attracted to a different substance, not water. So this is where water molecules are attracted to a different substance. Cohesion, the water is attracted to itself. Adhesion, the water is attracted to a different substance. Please read this question and see if you can't find the correct answer. Feel free to pause the video at this point. The answer to this question is C. Water has a slightly positive charge at one end and a slightly negative charge at the other end. Because of water's polarity and its ability to show these very special properties, water is essential to all life on Earth. There are some things that water does when the temperature changes. For example, water expands when it freezes. It gets bigger. As a result, frozen water is also less dense, so it has the ability to float in liquid water. This is because frozen water has a much more rigid structure, which takes up more room and has smaller spaces between. This is an important feature of water because if you think what would happen to lakes and ponds in winter if ice were more dense, that ice would float to the bottom, sink to the bottom, excuse me, and never melt. And that would definitely disrupt aquatic ecosystems. Water also has a very high specific heat. It has an ability. to absorb a lot of energy before it experiences a change in temperature. It also has a very high heat of vaporization. So it also, as a result, takes a lot of energy to evaporate. And this is important because, as a result, water has the ability to moderate temperatures on Earth. This helps to prevent big temperature changes. Please read this question, decide what you think the best answer is, and pause the video if you need some more time. The answer to this question is letter C. Water exhibits cohesive behavior. Water is an essential substance for all living things, but all living things are also built on other types of molecules. The four major types of biological macromolecules are carbohydrates, proteins, lipids, and nucleic acids. Each of these macromolecules is made up of something very specific and has very specific functions that help to support life. For example, carbohydrates are made up of monosaccharides. These are their building blocks or monomers. And all monosaccharides are made up of the elements carbon, hydrogen, and oxygen. Carbohydrates are a terrific source of energy. They also can provide structure in things like cellulose and chitin. Some common examples of carbohydrates are things like glucose, sucrose, maltose, starch, and cellulose. Sucrose and maltose are examples of disaccharides, whereas glucose is a monosaccharide. Starches and cellulose are very large carbohydrates. So these are considered polysaccharides. And this is what a basic structure of this particular carbohydrate looks like. This is disaccharide, which is sucrose, which is table sugar. The next biological macromolecule is proteins. All proteins are made up of amino acids. And proteins are a very diverse group of macromolecules. They can function in structure of certain organisms, movement. They can offer defense in the form of antibodies. They can help to signal other cells. They can offer help in transport. So proteins have a lot of different functions. Some examples are things like hormones. like insulin or enzymes, which help to lower the amount of activation energy needed to start a chemical reaction. And proteins have a very intricate structure. The third group is the lipids. All lipids are made up of three different types of atoms, carbon, hydrogen, and oxygen. The main functions of lipids are for energy storage and insulation, if the lipid is a fat, or if it's a phospholipid, can help to make up the majority of a cell membrane. Some examples of lipids are fats, phospholipids, and steroids like hormones or cholesterol. This is an example of what the lipid bilayer of a cell membrane looks like. The last group. macromolecules are the nucleic acids. All nucleic acids are made up of nucleotides. And the main function of a nucleic acid is to provide genetic information. The genetic information contained in a nucleic acid is essentially the code to make every protein in a cell. Some examples of nucleic acids that are very common are DNA and RNA. The NA stands for nucleic acids. And here you see the structure of DNA. So here's a question. Please read it. And if you need to pause the video, please do so. The answer to this question is B. Both consist of carbon, hydrogen, and oxygen, but carbohydrates have repeating structural units. and lipids do not. One very special type of protein is an enzyme. Enzymes are considered biological catalysts, meaning that they can speed up the rate of a biochemical reaction by lowering how much activation energy is needed. Enzymes are very efficient because they are not used up during a reaction. they can actually be reused over and over again. The only time that they cannot be reused is if an environmental factor alters the structure of the enzyme. So enzymes can be affected by things like a change in pH, a change in the temperature, or the concentration of either the enzyme or the molecules that they work with. Question six. Please read the question and decide what the best answer is. And if you need to pause the video, you may do that now. The correct answer is B. Nucleic acids contain the genetic code for protein synthesis, while enzymes catalyze chemical reactions. Our next standard that we'll cover is the organization and development of the cell, which we'll start off with the cell theory. The modern cell theory has some basic parts to it. It says first that all living things are made up of cells, and the cell is the basic unit of structure and function in all living things. Finally, new cells can only be produced from pre-existing cells. Please read this following question, and if you need to pause the video, you can do that now. The correct answer is B. They are both made of one or more cells. All cells have very specific parts to them. There are two main types of cells that we're going to talk about, prokaryotic cells and eukaryotic cells. Prokaryotic cell structures have things like a cell wall, cell membrane, cytoplasm. a nucleoid region, ribosomes, and a flagella. Some similarities between prokaryotic cells and eukaryotic cells are that both of these cells are enclosed by a plasma or cell membrane. They both have cytoplasm inside, and they both contain small structures called ribosomes, which are important in protein production. Please read the following question and decide what you think the best answer is and pause the video if you need to take some more time. The correct answer here is D, the ribosome. The cell membrane, which is found in both prokaryotic and eukaryotic cells, is very important because it serves as a boundary for the cell. It controls what moves in and out of the cell, and it's made up of carbohydrates, phospholipids, and proteins. Remember those macromolecules we just talked about. We can describe the cell membrane as having a phospholipid bilayer, and it is selectively permeable, only allowing certain things to enter and exit the cell. There are different ways that molecules can enter and exit the cell. One is endocytosis, where the cell will extend its plasma membrane and engulf an exterior molecule and pull it in. Exocytosis, which is sort of the opposite. If there's a molecule in the cell, the cell membrane will push that molecule out. Passive transport, where no energy is required and it moves molecules with the concentration gradient from areas of high to low concentration. These are things like simple diffusion or facilitated diffusion. And then active transport, which is going to use energy in the form of ATP to help move molecules against the concentration gradient, going from low concentrations to high concentrations. Please read this question, and if you need more time, you may pause the video. The correct answer is D. The water in the gums has moved out due to the high concentration of salt in the solution. Moving to structure and function of plant and animal cells. Both plant and animal cells are considered eukaryotic, meaning that they have a true nucleus and membrane-bound organelles. All eukaryotic cells, like prokaryotic cells, have a cell membrane, which is a selectively permeable barrier. However, the eukaryotic cell has a well-defined nucleus. This is where you'll find the cell's genetic information in the form of DNA. Eukaryotic cells also have the mitochondria, sometimes known as the powerhouse of the cell. This is the site of cellular respiration, where energy for the cell is produced. The cytoplasm is a very thick fluid that fills up the cell, and this is where cell reactions will take place. The cytoskeleton is a network of fibers that are distributed throughout the cell within the cytoplasm. And it helps to anchor organelles in place and directs movement of organelles, providing the cell also with some support. There are two types of endoplasmic reticulum. The endoplasmic reticulum is a maze of membranes that each part of the endoplasmic reticulum has a specialized function. You have rough ER. and smooth ER. Rough ER or rough endoplasmic reticulum is called rough because it has ribosomes that stud the surface of the membrane. This is where proteins are made and stored. It also helps to make its own proteins and phospholipids that are added to the cell membrane and has the ability to form vesicles to carry proteins to the Golgi. apparatus. The smoothie jar does not have ribosomes, which is why it's known as smooth. And the function of the smoothie jar is dependent on the cell that it's found in. Plant and animal cells also have lysosomes. Lysosomes are membrane sacs that contain digestive enzymes that help to break down molecules. Usually the pH is very low in a lysosome. And as a result, the environment in the lysosome is very acidic. A vacuole is found in both plant and animal cells. And this is where things are stored. Different vacuoles are used for food and water. And in plants specifically, they have a very large central vacuole. It's... usually one of the largest structures within the plant cell. Here's where a lot of water is stored in a plant cell. Things that are found only in plant cells and not in animals are the cell wall and the chloroplast. The cell wall provides an additional layer of protection for the cell and also helps to provide support. And the chloroplast is the area where photosynthesis occurs. This is where energy is converted from sunlight into chemical energy. These are very small structures that allow the plant to expose more chlorophyll to sunlight. The chlorophyll is the photosynthetic pigment that can absorb sunlight. Please read this question and decide what you think the best answer is. And feel free to pause the video. The answer to this question is D, a plant cell. Here's another question. Please read through the question, decide what the best answer is, and pause the video if you need to take some more time. The answer to this question is B, the organism's internal structures. Looking at the plant cell, we just talked about the chloroplast, and this is the place in a plant cell where photosynthesis occurs. What you're seeing here is the structure of the chloroplast. Photosynthesis happens in two main stages. The light-dependent reactions followed by the light-independent reactions. The light-dependent reactions requires light energy. It's dependent on the sun. So during the light dependent reactions, light will enter into the chloroplast and splits a water molecule. When that water molecule is split, it will release high energy electrons and the electrons are going to move through carrier protein chains. This helps the protein chains to carry those excited hydrogens to enter into the phyllochoid space. The phyllochoid space starts to fill with hydrogen ions. And as a result, it pushes those hydrogen ions through an enzyme called ATP synthase. And those hydrogen ions then are now transported to the free space of the stroma of the chloroplast. As a result of the passage of these hydrogen ions through ATP synthase, this helps to create ATP by attaching a phosphate group to ADP. ATP is used in the next stage of photosynthesis. Something else that's made during the light-dependent reactions is a molecule called NADPH2. NADPH is going to be carried also to the next stage of photosynthesis, but it's formed by NADP+, picking up hydrogen ions. So ATP and NADPH are the final products. of the light-dependent reactions, which will then move to the light-independent reactions. The light-independent reactions are where we are going to rearrange carbon dioxide to create glucose. And if you notice the formula for glucose, C6H12O6, this is going to require six carbon dioxide molecules to enter. And this is going to then form 12 three-carbon molecules. 10 of those three-carbon molecules move on, and we're going to keep two of them. With the presence of a little bit of ATP and NADPH that was generated from the previous light-dependent reaction, We're also going to use a little bit of oxygen and hydrogen. And collectively, at the end of the light-independent reactions, we're going to create glucose. So the light-dependent reactions depend on the energy from the sun. The light-independent reactions relies on the energy from ATP and NADPH to create glucose. Please read the following question, choose the best answer, and pause the video at this point if you need some additional time. The correct answer is C. Photosynthesis occurs at the highest rate under the most intense light. Another process that is a... going to create energy and is very closely related to photosynthesis is cellular respiration. Cellular respiration happens in three main parts, glycolysis, the Krebs cycle, and the electron transport chain. Glycolysis is an anaerobic portion of the process. It does not require oxygen. The prefix and means without. So here we are creating energy in the absence of oxygen. Glycolysis occurs in the cytoplasm or the cytosol of the cell. The Krebs cycle and the electron transport chain are both aerobic processes, meaning they do need oxygen. And as a result, are going to both occur within the mitochondria. Glycolysis and the Krebs cycle are where glucose is going to be broken down to make ATP, and the electron transport chain is going to make more ATP. A little bit of accounting for ATP production. For every one glucose molecule, glycolysis, the anaerobic process, will only make two ATP molecules. The Krebs cycle also makes 2 ATP. But if you notice, the electron transport chain can make 26 or more ATP. for a grand total of more than 30 ATP for one molecule of glucose that you eat. So the electron transport chain is where you're going to get the majority of your ATP from. Looking at a little bit closer at these processes, glycolysis is, again, happening in the cytoplasm of the cell. So if this is the cell, This is the cytoplasm. This is the mitochondria. So glycolysis is occurring outside of the mitochondria. We're taking one glucose molecule and we're going to split it into two, three carbon pyruvate molecules. Remember glucose? Its formula is C6H12O6. So glucose itself has six carbons broken in half. We now have two, three carbon molecules that we named. pyruvate. During glycolysis, four ATP are made, but two are used in the process. So after glycolysis is completed, this gives us a net gain of two ATP molecules. And no oxygen is required for glycolysis. This is an anaerobic process. The Krebs cycle occurs in the mitochondria. This is an aerobic process, meaning it does need oxygen. It can only occur when oxygen is present. The pyruvate that was created during glycolysis will enter into the Krebs cycle. And as a result, it will release one carbon dioxide molecule. It forms two more carbon dioxides for each turn of the Krebs cycle. And it produces two ATP molecules for each turn of the Krebs cycle. It also sends energy-rich NADH and FADH2 molecules to the electron transport chain. NADH and FADH2 are electron carriers. So no carbon compounds are sent on to the next stage, but the energy-rich molecules are. And again, this is an aerobic process. because it can only occur in the presence of oxygen. The electron transport chain is the last stage of cellular respiration, and it produces significantly more ATP than any of the other stages of cellular respiration. It uses high energy electrons that are stored in NADH and FADH2 that were made during the Krebs cycle, and it occurs in the inner membrane of the mitochondria. Because it's an aerobic process, it will require oxygen. And the oxygen that's used in the electron transport chain is used to make water molecules. It reforms NAD plus and FAD, which then are sent back to the Krebs cycle to participate in that stage. So if there's no oxygen, ATP still can be made, but it's made in a different process. It's made in the process of fermentation. So if you notice, aerobic respiration that requires oxygen is a much more efficient process because here we get approximately 30 or more ATP per every one glucose molecule that's consumed. In fermentation though, and there are two types, alcoholic or lactic acid that can occur without oxygen, only two ATP are synthesized or made here. So anaerobic fermentation is not nearly as an efficient process as there is very little ATP made here. One thing to keep in mind is that photosynthesis and cellular respiration. are very closely related to one another. The reactants of photosynthesis, carbon dioxide and water in the presence of sunlight are the same reactants that are the products of cellular respiration. So the reactants, carbon dioxide, water, and energy are the products in cellular respiration, carbon dioxide, water, and energy. And the products of photosynthesis, glucose and oxygen, end up becoming the reactants of cellular respiration, glucose and oxygen. The big difference here is where these processes occur. Photosynthesis happens in the chloroplast of a plant cell. Cellular respiration happens in the mitochondria of both a plant and animal cell. Please read the following question and the answer choices. Decide which answer choice you think is best. And now is a good time to pause the video if you need more time. The answer to this question is B. Glycolysis takes place in the cytosol while the Krebs cycle and electron transport chain take place in the mitochondria. Here's another question for you. Please read through the question and the answer choices and pause the video if you need some more time. The correct answer to this question is B. Fermentation is taking place as a result of a lack of oxygen. Question 15. Please read the question and pause the video if you need some time. The answer to this question is A. The energy captured in photosynthesis is used to power cellular respiration. ATP is an energy molecule that is created both during photosynthesis and in cellular respiration. ATP is what all activities and functions within a cell depend on. It is the major fuel source for all cells. And ATP is built by adding a phosphate group to an ADP molecule, which requires energy. A T. ADP stands for adenosine triphosphate, that prefix tri meaning three phosphates, and ADP stands for adenosine diphosphate, that di means two, which has, this one has two phosphates. This energy that is stored in ATP is temporary energy storage until it's used to power the movement and functions of the cell. Question 16. Please read the question and the answer choices and feel free to pause the video if you need some more time. The answer to this question is B, use to capture and transfer energy. Thank you for participating in this review. If you still have any questions, please know. that your guidance counselor is a terrific source of information, specifically with regards to specific testing information dates and guidelines. And if you're not sure of your testing location, you can contact your home district office to find out what testing location you should be reporting to on test day. There are also some resources on the FLVS EOC site, as well as the Florida Department of Education site. And remember, guys, the brain is like a muscle. The more you practice, the more nerve connections you make, and the stronger those nerve connections become. Grow your mind, kiddos, and best of luck on the EOC.

There are multiple forms of the assessment, but each assessment includes a maximum of 66 multiple choice items on each test form. Students are provided with a four-page hard copy work folder to use as scratch paper, And the used folders are secured testing materials that must be returned to the testing proctor after testing is completed. The EOC will be averaged as 30% of your final course grade.

The EOC is broken up into different areas based on standards that you have learned throughout your biology course. 35% of the EOC will cover standards that include molecular and cell biology standards. 25% of the EOC will include classification, heredity, and evolution.

And 40% of the EOC will cover organisms, populations, and ecosystems. Today, we're going to cover these state standards, the nature of science, microscopes, special properties of water, basic molecular structure and function, enzymes, organization and development, which include the cell theory. We're going to talk about the different general structures of plant and animal cells and prokaryotic and eukaryotic cells, the structure and function, excuse me, the structure and function of plant and animal cells, photosynthesis, aerobic and anaerobic cellular the respiration, and then finally ATP. The first standard, nature of science, covers the purpose of science and how science is practiced. We know that the purpose of science is to provide logical explanations of the natural world around us and how things occur.

All findings are supported with evidence that is collected from an experiment, and the experiment is a way to test out a problem to locate or find a solution. So what is it that makes an experiment reliable? Reliable experiments have been tested and observed numerous times by more than just one group of scientists, and those scientists will follow the scientific method.

During the scientific method process, evidence will be gathered, and evidence in the form of facts are presented with no personal bias. The information that is... gathered from a reliable experiment must come from a third party that doesn't profit from the study, and those studies should be retested by other scientists with the same end results.

Once the results are collected, those results should be reported and published into a scientific journal. The scientific method is a way for us to learn about the environment around us and to solve problems. And the scientific method isn't always a linear process.

However, it does include all of these important aspects. We'll always start with making observations. And from the observations that we gather, we can then form a question.

Our question must be testable. And from that question, you should be able to find research. from a reliable source, from that research that you gather, you can then construct a hypothesis. A hypothesis is a prediction of what you think will happen, and it is a testable statement. A hypothesis should be written in an if-then-because format.

Once a hypothesis is created, you can then create an experiment to test your hypothesis. And all good experiments should have three variables present. Your independent variable is the variable that is changed purposely by the scientist. It is what the part of the experiment is that the scientist is purposely manipulating or testing.

Our dependent variable is the one factor that will be measured or recorded as the result of the experiment. This is what we will observe occurring in the experiment. And your controlled variables are all the other factors that are kept constant in an experiment. So, for example, if you are testing the different types of fertilizer on plant growth, The thing that the scientist is testing is the different types of fertilizer.

That would be your independent variable. If we are measuring how tall the plants get in response to different fertilizers, the height of the plant would then be our dependent variable. This is what we are measuring as our results.

All the other factors in the environment should be controlled. So the things like how much water each plant is getting, how much sun each plant is getting, or even the place where the plants are growing, should all be controlled. Once you perform your experiment, you're going to collect some data, and the data collection is to help avoid bias so that you're only focusing on the facts.

Once you collect that evidence, that data, you can use that data to draw some conclusions. And your conclusions are going to refer back to the data. And with that, you can then confirm or reject your initial hypothesis.

So does the scientific method apply to laws and theories? In order to get to a theory or a law, the scientific method has been practiced many times. One common misconception is that a law can become a theory or vice versa. And this is simply not the case. The reason is because a theory and a law have two different purposes.

A theory is a broad explanation of the natural world that is based on strong scientific support. It answers questions like why something occurs. A law is a description of what we expect to happen in the natural world based on many observations and data collected over time. So a law answers questions like, what happens? Because a theory and a law do two different things, they will never become one another.

Theories can change and be strengthened based on further scientific study and more evidence to support it. And theories will never become a law, and a law will never become a theory. because again, they do two different purposes.

They have two different purposes. Within an experiment, when you are gathering data, there are certain types of measurements that you likely will be collecting. In science, we have base quantities and base units of measure that are measured by specific instrumentation.

For example, length is measured by a meter, and we use either a metric ruler or a meter stick. If we're looking for mass, the unit of measure will be the gram, and we can use a balance to measure mass. Volume is measured in liters, and a graduated cylinder is used to collect that data. Time is typically reported as seconds.

and measured with either a stopwatch or a clock. And temperature is measured by either Kelvin or Celsius, and we use a thermometer to collect that type of data. Once data is collected, the easiest way to analyze the data is to graph your data.

Depending on the type of data that you collect, that will determine the type of graph that you're going to create. For example, the bar graph will help you to show different types of data that may have some similarities, but you are comparing those data sets. For example, this bar graph is showing the number of different types of pets people own.

So the different types of pets are along the x-axis, and the number of people are along the y. Here we're showing similar data, similar types of pets. The line graph shows change over time. So here we have along the x-axis the months of the year, and along the y-axis we're showing how much precipitation has fallen, although this y-axis is improperly labeled.

So because we're looking at the change in monthly precipitation over time, this is going to be demonstrated by a line graph. A pie graph or a circle graph will show parts of a whole. Anytime you are asked to graph percentages, this is the best graph to use. So here's a sample question.

Please read the question. and determine what you think the best answer to this is. You can pause the video at this point to read through the question.

For this question, the correct answer would be B, research what others have already found. Oftentimes, we need to view things that are not visible to the naked eye. in which we would employ a microscope. There are different types of microscopes that can be used based on what it is that you are trying to view. First of all, the light microscopes.

The light microscopes have capabilities that allow lower magnification. There are two main types of light microscopes. The dissecting microscope offers the lowest magnification. it can magnify images up to 40 times their normal size. These microscopes are terrific for looking at organs and tissues during a dissection and also the surfaces and details of things like leaves, stems, mold spores, or other small objects.

The compound light microscope can magnify images a little bit more, ranging anywhere from 40 times up to 40 times. up to 400 times, or even some microscopes can magnify a thousand times the true size of a specimen. With the compound light microscope, we would look at things like tissue samples, blood cells, different types of microorganisms that may live in pond water, microscopic cells, and even some of the larger details within the cell, like the nucleus or the cell membrane. The electron microscopes are another category of microscope that have a much higher ability to magnify things. Electron microscopes use electron beams to pass through certain materials.

The transmission electron microscope, or the TEM, passes a beam of electrons through a very thin specimen. And with these types of microscopes, you can view... internal structures of cells that cannot be viewed under light microscopes. Things like the mitochondria or the chloroplast can be viewed looking at using a transmission electron microscope. The scanning electron microscope is similar, but instead of going through, transmitting through a specimen, here we're just scanning the surface.

So the SEM, or the scanning electron microscope, is useful for studying the details of the specimen's surface. And the electron beam scans the specimen's surface, which typically is coated with a thin layer of gold metal. And the image projected from the scanning electron microscope is typically a three-dimensional image in black and white.

So our next question. Feel free to pause the video. Read through the question and see if you can get the correct answer.

The correct answer is D, viewing a cell's mitochondria in detail. And the next standard we're going to talk about is the properties of water. Water has some very unique properties based on its molecular structure.

Water is considered polar, which means that there is a slightly positive charge at one end of the molecule and slightly negative on the other side of the molecule. Because of this, this is what makes water polar. Hydrogen bonding is something that occurs as a result of this polarity. The attraction of the slightly positive hydrogens of one water molecule attract the negative oxygen side of a neighboring.

water molecule. And that is what allows water molecules to stick together. So looking at this image, this spider is able to stand on water because it exhibits surface tension. Surface tension is the tendency of water molecules to stick together and create a strong surface.

Remember that we said those water molecules stick together. because of the positive hydrogen side of one water molecule attracting the partial negative oxygen side of a neighboring molecule. So this idea of surface tension is possible because of those hydrogen bond attractions.

Water is also often known as the universal solvent due to its ability to dissolve a lot of different substances. Ionic compounds like salt and polar molecules like sugar have an easy time dissolving in water because they have both positive and negative charges, which can interact with the positive and negative charges of the water molecules. Because of these differences in charges within a water molecule, water can exhibit the property of cohesion.

Cohesion is when two like substances are attracted to each other. So again, when the water is attracted to itself, the positive end of one water molecule will attract the negative end of an adjacent water molecule. So here we are showing cohesion, the prefix co- meaning together.

So the water molecules are stuck together. Adhesion is where the... positive or negative side of a water molecule is attracted to a different substance, not water.

So this is where water molecules are attracted to a different substance. Cohesion, the water is attracted to itself. Adhesion, the water is attracted to a different substance. Please read this question and see if you can't find the correct answer. Feel free to pause the video at this point.

The answer to this question is C. Water has a slightly positive charge at one end and a slightly negative charge at the other end. Because of water's polarity and its ability to show these very special properties, water is essential to all life on Earth.

There are some things that water does when the temperature changes. For example, water expands when it freezes. It gets bigger. As a result, frozen water is also less dense, so it has the ability to float in liquid water.

This is because frozen water has a much more rigid structure, which takes up more room and has smaller spaces between. This is an important feature of water because if you think what would happen to lakes and ponds in winter if ice were more dense, that ice would float to the bottom, sink to the bottom, excuse me, and never melt. And that would definitely disrupt aquatic ecosystems.

Water also has a very high specific heat. It has an ability. to absorb a lot of energy before it experiences a change in temperature.

It also has a very high heat of vaporization. So it also, as a result, takes a lot of energy to evaporate. And this is important because, as a result, water has the ability to moderate temperatures on Earth. This helps to prevent big temperature changes. Please read this question, decide what you think the best answer is, and pause the video if you need some more time.

The answer to this question is letter C. Water exhibits cohesive behavior. Water is an essential substance for all living things, but all living things are also built on other types of molecules.

The four major types of biological macromolecules are carbohydrates, proteins, lipids, and nucleic acids. Each of these macromolecules is made up of something very specific and has very specific functions that help to support life. For example, carbohydrates are made up of monosaccharides. These are their building blocks or monomers. And all monosaccharides are made up of the elements carbon, hydrogen, and oxygen.

Carbohydrates are a terrific source of energy. They also can provide structure in things like cellulose and chitin. Some common examples of carbohydrates are things like glucose, sucrose, maltose, starch, and cellulose. Sucrose and maltose are examples of disaccharides, whereas glucose is a monosaccharide. Starches and cellulose are very large carbohydrates.

So these are considered polysaccharides. And this is what a basic structure of this particular carbohydrate looks like. This is disaccharide, which is sucrose, which is table sugar.

The next biological macromolecule is proteins. All proteins are made up of amino acids. And proteins are a very diverse group of macromolecules.

They can function in structure of certain organisms, movement. They can offer defense in the form of antibodies. They can help to signal other cells. They can offer help in transport.

So proteins have a lot of different functions. Some examples are things like hormones. like insulin or enzymes, which help to lower the amount of activation energy needed to start a chemical reaction. And proteins have a very intricate structure. The third group is the lipids.

All lipids are made up of three different types of atoms, carbon, hydrogen, and oxygen. The main functions of lipids are for energy storage and insulation, if the lipid is a fat, or if it's a phospholipid, can help to make up the majority of a cell membrane. Some examples of lipids are fats, phospholipids, and steroids like hormones or cholesterol.

This is an example of what the lipid bilayer of a cell membrane looks like. The last group. macromolecules are the nucleic acids.

All nucleic acids are made up of nucleotides. And the main function of a nucleic acid is to provide genetic information. The genetic information contained in a nucleic acid is essentially the code to make every protein in a cell. Some examples of nucleic acids that are very common are DNA and RNA.

The NA stands for nucleic acids. And here you see the structure of DNA. So here's a question. Please read it. And if you need to pause the video, please do so.

The answer to this question is B. Both consist of carbon, hydrogen, and oxygen, but carbohydrates have repeating structural units. and lipids do not.

One very special type of protein is an enzyme. Enzymes are considered biological catalysts, meaning that they can speed up the rate of a biochemical reaction by lowering how much activation energy is needed. Enzymes are very efficient because they are not used up during a reaction. they can actually be reused over and over again. The only time that they cannot be reused is if an environmental factor alters the structure of the enzyme.

So enzymes can be affected by things like a change in pH, a change in the temperature, or the concentration of either the enzyme or the molecules that they work with. Question six. Please read the question and decide what the best answer is.

And if you need to pause the video, you may do that now. The correct answer is B. Nucleic acids contain the genetic code for protein synthesis, while enzymes catalyze chemical reactions.

Our next standard that we'll cover is the organization and development of the cell, which we'll start off with the cell theory. The modern cell theory has some basic parts to it. It says first that all living things are made up of cells, and the cell is the basic unit of structure and function in all living things. Finally, new cells can only be produced from pre-existing cells.

Please read this following question, and if you need to pause the video, you can do that now. The correct answer is B. They are both made of one or more cells. All cells have very specific parts to them.

There are two main types of cells that we're going to talk about, prokaryotic cells and eukaryotic cells. Prokaryotic cell structures have things like a cell wall, cell membrane, cytoplasm. a nucleoid region, ribosomes, and a flagella. Some similarities between prokaryotic cells and eukaryotic cells are that both of these cells are enclosed by a plasma or cell membrane.

They both have cytoplasm inside, and they both contain small structures called ribosomes, which are important in protein production. Please read the following question and decide what you think the best answer is and pause the video if you need to take some more time. The correct answer here is D, the ribosome.

The cell membrane, which is found in both prokaryotic and eukaryotic cells, is very important because it serves as a boundary for the cell. It controls what moves in and out of the cell, and it's made up of carbohydrates, phospholipids, and proteins. Remember those macromolecules we just talked about.

We can describe the cell membrane as having a phospholipid bilayer, and it is selectively permeable, only allowing certain things to enter and exit the cell. There are different ways that molecules can enter and exit the cell. One is endocytosis, where the cell will extend its plasma membrane and engulf an exterior molecule and pull it in.

Exocytosis, which is sort of the opposite. If there's a molecule in the cell, the cell membrane will push that molecule out. Passive transport, where no energy is required and it moves molecules with the concentration gradient from areas of high to low concentration. These are things like simple diffusion or facilitated diffusion.

And then active transport, which is going to use energy in the form of ATP to help move molecules against the concentration gradient, going from low concentrations to high concentrations. Please read this question, and if you need more time, you may pause the video. The correct answer is D.

The water in the gums has moved out due to the high concentration of salt in the solution. Moving to structure and function of plant and animal cells. Both plant and animal cells are considered eukaryotic, meaning that they have a true nucleus and membrane-bound organelles.

All eukaryotic cells, like prokaryotic cells, have a cell membrane, which is a selectively permeable barrier. However, the eukaryotic cell has a well-defined nucleus. This is where you'll find the cell's genetic information in the form of DNA.

Eukaryotic cells also have the mitochondria, sometimes known as the powerhouse of the cell. This is the site of cellular respiration, where energy for the cell is produced. The cytoplasm is a very thick fluid that fills up the cell, and this is where cell reactions will take place.

The cytoskeleton is a network of fibers that are distributed throughout the cell within the cytoplasm. And it helps to anchor organelles in place and directs movement of organelles, providing the cell also with some support. There are two types of endoplasmic reticulum. The endoplasmic reticulum is a maze of membranes that each part of the endoplasmic reticulum has a specialized function. You have rough ER.

and smooth ER. Rough ER or rough endoplasmic reticulum is called rough because it has ribosomes that stud the surface of the membrane. This is where proteins are made and stored.

It also helps to make its own proteins and phospholipids that are added to the cell membrane and has the ability to form vesicles to carry proteins to the Golgi. apparatus. The smoothie jar does not have ribosomes, which is why it's known as smooth.

And the function of the smoothie jar is dependent on the cell that it's found in. Plant and animal cells also have lysosomes. Lysosomes are membrane sacs that contain digestive enzymes that help to break down molecules.

Usually the pH is very low in a lysosome. And as a result, the environment in the lysosome is very acidic. A vacuole is found in both plant and animal cells.

And this is where things are stored. Different vacuoles are used for food and water. And in plants specifically, they have a very large central vacuole.

It's... usually one of the largest structures within the plant cell. Here's where a lot of water is stored in a plant cell. Things that are found only in plant cells and not in animals are the cell wall and the chloroplast.

The cell wall provides an additional layer of protection for the cell and also helps to provide support. And the chloroplast is the area where photosynthesis occurs. This is where energy is converted from sunlight into chemical energy. These are very small structures that allow the plant to expose more chlorophyll to sunlight. The chlorophyll is the photosynthetic pigment that can absorb sunlight.

Please read this question and decide what you think the best answer is. And feel free to pause the video. The answer to this question is D, a plant cell.

Here's another question. Please read through the question, decide what the best answer is, and pause the video if you need to take some more time. The answer to this question is B, the organism's internal structures. Looking at the plant cell, we just talked about the chloroplast, and this is the place in a plant cell where photosynthesis occurs. What you're seeing here is the structure of the chloroplast.

Photosynthesis happens in two main stages. The light-dependent reactions followed by the light-independent reactions. The light-dependent reactions requires light energy. It's dependent on the sun.

So during the light dependent reactions, light will enter into the chloroplast and splits a water molecule. When that water molecule is split, it will release high energy electrons and the electrons are going to move through carrier protein chains. This helps the protein chains to carry those excited hydrogens to enter into the phyllochoid space.

The phyllochoid space starts to fill with hydrogen ions. And as a result, it pushes those hydrogen ions through an enzyme called ATP synthase. And those hydrogen ions then are now transported to the free space of the stroma of the chloroplast. As a result of the passage of these hydrogen ions through ATP synthase, this helps to create ATP by attaching a phosphate group to ADP.

ATP is used in the next stage of photosynthesis. Something else that's made during the light-dependent reactions is a molecule called NADPH2. NADPH is going to be carried also to the next stage of photosynthesis, but it's formed by NADP+, picking up hydrogen ions.

So ATP and NADPH are the final products. of the light-dependent reactions, which will then move to the light-independent reactions. The light-independent reactions are where we are going to rearrange carbon dioxide to create glucose.

And if you notice the formula for glucose, C6H12O6, this is going to require six carbon dioxide molecules to enter. And this is going to then form 12 three-carbon molecules. 10 of those three-carbon molecules move on, and we're going to keep two of them.

With the presence of a little bit of ATP and NADPH that was generated from the previous light-dependent reaction, We're also going to use a little bit of oxygen and hydrogen. And collectively, at the end of the light-independent reactions, we're going to create glucose. So the light-dependent reactions depend on the energy from the sun. The light-independent reactions relies on the energy from ATP and NADPH to create glucose. Please read the following question, choose the best answer, and pause the video at this point if you need some additional time.

The correct answer is C. Photosynthesis occurs at the highest rate under the most intense light. Another process that is a... going to create energy and is very closely related to photosynthesis is cellular respiration. Cellular respiration happens in three main parts, glycolysis, the Krebs cycle, and the electron transport chain.

Glycolysis is an anaerobic portion of the process. It does not require oxygen. The prefix and means without.

So here we are creating energy in the absence of oxygen. Glycolysis occurs in the cytoplasm or the cytosol of the cell. The Krebs cycle and the electron transport chain are both aerobic processes, meaning they do need oxygen.

And as a result, are going to both occur within the mitochondria. Glycolysis and the Krebs cycle are where glucose is going to be broken down to make ATP, and the electron transport chain is going to make more ATP. A little bit of accounting for ATP production.

For every one glucose molecule, glycolysis, the anaerobic process, will only make two ATP molecules. The Krebs cycle also makes 2 ATP. But if you notice, the electron transport chain can make 26 or more ATP. for a grand total of more than 30 ATP for one molecule of glucose that you eat. So the electron transport chain is where you're going to get the majority of your ATP from.

Looking at a little bit closer at these processes, glycolysis is, again, happening in the cytoplasm of the cell. So if this is the cell, This is the cytoplasm. This is the mitochondria.

So glycolysis is occurring outside of the mitochondria. We're taking one glucose molecule and we're going to split it into two, three carbon pyruvate molecules. Remember glucose? Its formula is C6H12O6.

So glucose itself has six carbons broken in half. We now have two, three carbon molecules that we named. pyruvate. During glycolysis, four ATP are made, but two are used in the process.

So after glycolysis is completed, this gives us a net gain of two ATP molecules. And no oxygen is required for glycolysis. This is an anaerobic process. The Krebs cycle occurs in the mitochondria.

This is an aerobic process, meaning it does need oxygen. It can only occur when oxygen is present. The pyruvate that was created during glycolysis will enter into the Krebs cycle. And as a result, it will release one carbon dioxide molecule. It forms two more carbon dioxides for each turn of the Krebs cycle.

And it produces two ATP molecules for each turn of the Krebs cycle. It also sends energy-rich NADH and FADH2 molecules to the electron transport chain. NADH and FADH2 are electron carriers. So no carbon compounds are sent on to the next stage, but the energy-rich molecules are.

And again, this is an aerobic process. because it can only occur in the presence of oxygen. The electron transport chain is the last stage of cellular respiration, and it produces significantly more ATP than any of the other stages of cellular respiration. It uses high energy electrons that are stored in NADH and FADH2 that were made during the Krebs cycle, and it occurs in the inner membrane of the mitochondria. Because it's an aerobic process, it will require oxygen.

And the oxygen that's used in the electron transport chain is used to make water molecules. It reforms NAD plus and FAD, which then are sent back to the Krebs cycle to participate in that stage. So if there's no oxygen, ATP still can be made, but it's made in a different process. It's made in the process of fermentation. So if you notice, aerobic respiration that requires oxygen is a much more efficient process because here we get approximately 30 or more ATP per every one glucose molecule that's consumed.

In fermentation though, and there are two types, alcoholic or lactic acid that can occur without oxygen, only two ATP are synthesized or made here. So anaerobic fermentation is not nearly as an efficient process as there is very little ATP made here. One thing to keep in mind is that photosynthesis and cellular respiration.

are very closely related to one another. The reactants of photosynthesis, carbon dioxide and water in the presence of sunlight are the same reactants that are the products of cellular respiration. So the reactants, carbon dioxide, water, and energy are the products in cellular respiration, carbon dioxide, water, and energy. And the products of photosynthesis, glucose and oxygen, end up becoming the reactants of cellular respiration, glucose and oxygen. The big difference here is where these processes occur.

Photosynthesis happens in the chloroplast of a plant cell. Cellular respiration happens in the mitochondria of both a plant and animal cell. Please read the following question and the answer choices.

Decide which answer choice you think is best. And now is a good time to pause the video if you need more time. The answer to this question is B.

Glycolysis takes place in the cytosol while the Krebs cycle and electron transport chain take place in the mitochondria. Here's another question for you. Please read through the question and the answer choices and pause the video if you need some more time.

The correct answer to this question is B. Fermentation is taking place as a result of a lack of oxygen. Question 15. Please read the question and pause the video if you need some time. The answer to this question is A. The energy captured in photosynthesis is used to power cellular respiration.

ATP is an energy molecule that is created both during photosynthesis and in cellular respiration. ATP is what all activities and functions within a cell depend on. It is the major fuel source for all cells.

And ATP is built by adding a phosphate group to an ADP molecule, which requires energy. A T. ADP stands for adenosine triphosphate, that prefix tri meaning three phosphates, and ADP stands for adenosine diphosphate, that di means two, which has, this one has two phosphates. This energy that is stored in ATP is temporary energy storage until it's used to power the movement and functions of the cell. Question 16. Please read the question and the answer choices and feel free to pause the video if you need some more time. The answer to this question is B, use to capture and transfer energy.

Thank you for participating in this review. If you still have any questions, please know. that your guidance counselor is a terrific source of information, specifically with regards to specific testing information dates and guidelines. And if you're not sure of your testing location, you can contact your home district office to find out what testing location you should be reporting to on test day.

There are also some resources on the FLVS EOC site, as well as the Florida Department of Education site. And remember, guys, the brain is like a muscle. The more you practice, the more nerve connections you make, and the stronger those nerve connections become. Grow your mind, kiddos, and best of luck on the EOC.

Transcript for:Biology EOC Review Session Overview

Transcript for:
Biology EOC Review Session Overview