ATI TEAS 7 I BIOLOGY REVIEW PART 1 l

hello everyone welcome to this biology quick review for your atit's exam this is part one of three quick reviews that are gonna be biology focused go ahead and grab all your snacks grab your coffee because we're going to go ahead and jump right in and we're going to begin with the scientific method the scientific method is systematic way to find the answers to questions or problems of the natural world it's used to explain all of the wonders of the world and also used to question the wonders of the world you may recall that the scientific method is performed in steps the first step is always observation we observe something of the natural world and we form question or hypothesis about it our second step is the hypothesis the hypothesis is an informed logical plausible explanation for what we observed one important thing about the hypothesis is it must be testable so you must be able to construct an experiment to prove that the hypothesis is correct or not our third step is experiment this is where we test our hypothesis in our experiment we collect measurable data that we use to analyze the results and come to conclusion the one most important thing that you have to remember about this step the experiment is that you're going to have an independent variable and dependent variable so let me just give you really quick example of an experiment so you can identify the independent variable dependent variable and also the constant variable okay so let's just say for example here we are conducting an experiment on few plants we have three plants here and let's just say we want to know if feeding them different type of liquid will change the results of the way they grow the independent variable is the one thing that you can change in an experiment it's the one thing that we will manipulate and in this case it's the type of liquid we're using on each plant this independent variable is going to be manipulated or changed in each in each plant now the dependent variable is the result of the independent variable so in this case it's what results will the plant have as an effect from the liquid that we gave them so if we gave the first plant coca-cola and the plant withered up and died then withering would be the dependent variable that is result of the independent variable if the next plant we gave orange juice and let's just say it its leaves got more green and bright then our dependent variable would be the leaves becoming bright green this is result of the orange juice and let's just say that the third plant we gave water to and this plant in particular grew very very tall now the independent variable is the water and the dependent variable is the growth the height of the plant the plant grew very high now everything else in the experiment must be what we call controlled everything must remain constant and unchanged therefore we know that what is causing the dependent variable or the outcome or the data the results is in fact the the independent variable the the change in the type of liquid that we're feeding each plant some examples of constant variable in this particular example could be the amount of liquid that we give each plant so you see that's different than the type of liquid we're giving each plant right so the amount of liquid has to be constant on the amount of sunlight we give each plant can be constant the type of soil we're giving each plant can be constant and let's say how big each pot that we put each plant in can be constant so everything else all other variables must be constant except for the independent variable which is being manipulated alrighty so as far as as far as the experiment portion of the scientific method goes personally feel it's the most important you must must know the difference between independent variable and dependent variable and if somebody gives you question you must be able to sorry if someone gives you an experiment you must be able to point out the independent dependent variables in the experiment the final step of the scientific method is the conclusion in the conclusion there are three important things that you must include the first is the summary of the overall experiment the second is the results of the experiment and the third is whether you accept or reject the hypothesis next we're going to jump into the biological hierarchy this is just systematic way of putting every living thing into levels of complexity so we begin first with the atom the atom is what makes up all matter it also makes up molecules molecules are any two or more atoms put together by chemical bond molecules are what make up cells cells are the basic building blocks of all living things cells are what make up our tissues and our tissue is group of cells that have similar structure and that function together as unit tissues are what make up our organs and an organ is collection of different types of tissue that structurally form functional unit specialized to perform specific function our organs create our organ systems one example of an organ system is the cardiovascular system and its main organ is the heart which helps pump blood but it also includes the accessories to the heart that help the heart pump blood and take it to where it needs to go so it includes all of the blood vessels that is very crucial that work hand in hand with the heart to to spread blood throughout the body now our organ systems work together to create an organism an organism is an individual animal plant or single cell life form so any living thing any singular living thing is organism and any organism is going to have all of the things we just discussed included in it so it's going to have organ systems organs tissue cells molecules atoms etc after organism we have population when you have group of organisms of the same species grouped together we call this population so for example we have group of the hume of humans the human species and they're grouped together so this is one population in this other photo have group of bats hanging out together and they are they are of the same species and they are multiple organisms hanging out together so we call this population now populations build communities and community is collection of different types of populations of species living together so lot of people get population and community mixed up so the major difference is that population is referring to one particular species living together and community is referring to different populations of different species living together so there is population of these bats and they actually live in this community in this cave in new zealand the reason why this cave is community is because there are different types of species living in it there is the population of bats but there's also this population of cave fish that you see this guy holding there's also this population of this really gnarly fungus that is glow in the dark that you can see here we have these three different types of population these three population of three different species living together that makes this community so after we have community we have an ecosystem an ecosystem is all of the communities in particular area but it also includes the physical environment in which they live in ecosystem basically includes the community and population and all the organisms but added to it is the physical environment like the trees the ocean the grasslands the mountains everything in which they live in that is part of earth that is an ecosystem next we have biome biome is really really large area environmental area that has very unique characteristics to that area it shares very similar types of temperature soil type maybe water type amount of light similar type of black bacteria fluoride fungi fauna things like this very similar types of species like animals that occupy this area so our biomes are collection of all the different ecosystems but they share very similar climate conditions or environmental conditions in general so here have picture of some of our most common biomes we have grassland savannah desert marine fresh water tundra all of these have very distinct let's just say temperature ranges soil type species and the picture kind of makes it very easy to see the drastic differences so moving on lastly we have our biosphere the biosphere includes all of the biomes within it and it includes all the places on earth where life exists and this my friend completes the biological hierarchy alrighty guys moving on to the ph scale although ph scale is super super simple and there's not much you need to memorize about it it's still very important in biology and it's one of those high yield questions that you might get on your teas exam so if you know the basics of the ph scale you can go ahead and skip ahead but if you need refresher stick around this will only take minute first thing first the ph scale is the measurement of hydrogen ion concentration in water-based substance so your acids are going to have high concentration of hydrogen ions but your bases are going to have low concentrations of hydrogen ions so you have your acidic on one side and your alkaline or base on the other side and you have your neutral smack in the middle your neutral is number seven and only number seven every other number belongs to either an alkaline or an acidic so our acidic solutions are going to be numbered one to six and our alkaline solutions are going to be numbered eight to fourteen so here are some very common solutions that you will find on our ph scale remember that number seven is your neutral the further you go to your right closer to 14 the more alkaline or basic substance gets and the further downwards you go to number to zero the more acidic solution gets alrighty everyone so we're going to move on to macromolecules or what's also called the organic molecules now there are four macromolecules proteins carbohydrates lipids and nucleic acids as far as the atit's exam goes there's really only three things you must know about each of these one is what they're composed of or made of two is the structure of the molecule and three is their functions in our body the four macronutrients that we're going to be studying are the carbohydrates lipids proteins and nucleic acids macronutrients are nutrients required in large amounts that provide energy needed to maintain bodily functions and carry out the activities of daily life macromolecules are associated with this process called hydrolysis hydrolysis means that when the molecules enter water when they're immersed in water they can be easily broken down into smaller molecules so essentially we have these macromolecules like fats carbohydrates and proteins and when they enter our digestive system the water breaks them down also with the help of enzymes breaks them down so that those nutrients or macromolecules are easily absorbed into the bloodstream so just remember that word hydrolysis the true definition of it is the chemical breakdown of compound due to reaction with water so just remember that in hydrolysis process compounds are immersed in water and enzymes help break down these compounds into smaller substances so let's first start with what these macromolecules are made out of they're made out of something called monomers and monomers are just building blocks of smaller molecules that build macro big molecules carbohydrates are made out of monomer called monosaccharides lipids are made out of fatty acids and glycerol proteins are made out of amino acids and nucleic acids are made out of nucleotides all of these are monomers that help build our macromolecules so how are these four macromolecules used in our body starting with the carbohydrates carbohydrates are used as fuel for our body your body breaks down carbohydrates into glucose and glucose is the main source of energy for your body's cells tissue and organs there are three types of carbohydrates there's your monosaccharides disatrodes and polysaccharides remember that mono is referring to one or singular so monosaccharides are your singular simple sugar dye means two so disatrods are two monosatuides that are bonded together poly means many so polysaturade is referring to long chain of multiple or many monosaccharides common monosaccharides are glucose and fructose common disatrods are sucrose and lactose and common polysaturates are starch cellulose and glycogen so next we have our lipids and remember that the monomer of the lipids is fatty acids and glycerol these are the building blocks of lipids it's what make up the lipids so we're gonna go into lot more detail with the lipids because there's lot to know here so hang in there guys if you're not already bored you might just get bored here so just hang in there so first and foremost when we talk about lipids we're talking about fats and there are three types of lipids there are your triglycerides your phospholipids and your steroids triglycerides include your animal fats and your oils there are significant differences between these two animal fats are normally solid at room temperature and oils like vegetable oil avocado oil olive oil these are liquid at room temperature and the reason why animal fats become solid and oils are kept as liquid has to do with their molecular structure so your animal fats are what we call saturated fats and your oils are what we call unsaturated fats on molecular level this is what it's going to look like saturated fats is going to have generally carbon carbon hydrogen atom chain and all of your carbon atoms are going to be connected or bonded by single bond so single bond is represented by this single line so that's the takeaway here is that your saturated fats your carbons are going to be bonded by single bond there's going to be single lines between them now your unsaturated fats they look little bit different because they have at least one double bond between their carbons so it might look little bit like this you have carbons with single lines but maybe you have one or two double bonded carbons linked to each other this is going to make it unsaturated fat and in fact these double bonds is what changes the melting point of the substance so this is what makes these oils liquid at room temperature basically so this is generally what you need to know triglycerides again you have your animal fats and your oils your animal fats are saturated fats meaning molecularly the carbon to carbon bonding is going to be singular and then your oils are unsaturated fats meaning on molecular level your carbon to carbon you're going to have at least one double bond and also remember that saturated fats are solid at room temperature like your animal meats and your unsaturated fats are linked liquid at room temperature let's go ahead and move on to our second type of lipid the phospholipid so the major thing about phospholipid is that it has two sides to it it has this head that is made out of glycerol and remember that glycerol is one of the monomers that help build and construct the lipid and attached to this glycerol is phosphate group now this phosphate group molecularly it would look something like this but what's really important about this phosphate fate group is that it makes this this part of the phospholipid it makes it hydrophilic meaning hydro meaning water philic meaning loving so this part of the phospholipid lipid is water loving and the other side of the phospholipid are these two little legs that come out here and these are made out of fast fatty acids now these fatty acids are i'm sorry these are called the tails my bad not the legs the tails so these these tails are made out of fatty acids and they are actually hydrophobic meaning they hate the water so to sum that up phospholipids have hydrophobic side and hydrophilic side your phospholipids form bilayer and this is called or referred to as lipid bilayer or phospholipid bilayer now your outer part of the layer is going to be the head or the hydrophilic side of this lipid this is the water loving side and on the inside of the layer is going to be your hydrophobic or your water hating side it's going to be safely on the interior these phospholipid bilayers are super important because they make up our cell membranes they're protective layer of our cell membranes specifically because they have the hydrophobic and hydrophilic side so for most organisms and most viruses this is going to make up major part of your cells so the final lipid that we're going to learn about are our steroids steroid is any compound with specific four ring structure now steroids apply to various types of chemicals one important steroid is cholesterol cholesterol is important because it is precursor to the synthesis of other steroids such as testosterone estrogen vitamin and cortisol another common steroid is aldosterone aldosterone maintains fluid balance in your body by promoting reabsorption of excess sodium and excreting potassium the last thyroid want to touch on is cortisol cortisol is important because it has anti-inflammatory effects on the body related to cortisone is classification of drugs man-made drugs called corticosteroids these are type of anti-inflammatory drugs just like cortisone anti-inflammatory these are given to patients for treatment like rheumatoid arthritis lupus vasculitis things like this that have that that causes too much inflammation in the body so in my opinion as far as the atit's exam goes there's not too much you need to know about steroids the most important thing is that what is unique to them is that four-ring structure so if you see the four-wing structure you're going to need to identify it as steroid but also know some of the high-yield types of steroids from my research through various books that have review questions i've seen aldosterone cortisol vitamin testosterone and estrogen and think testosterone estrogen and what's other progesterone progesterone is also one of those high-yield steroids so guys am going to cut this short right here know that we still have to finish our macro molecules we went over carbohydrates we went over lipids but we still need to go over the proteins and the nucleic acids i'm going to stop right here because am actually feeling little sick and have feeling that i'm going to be out for the next couple days so will upload part two and the first thing that we'll jump into is the proteins and then the nucleic acids and then we'll continue from there but hope you enjoy this video if you are still watching this video to the end please give me thumbs up and happy study guys