okay let's dig in so hi everybody thanks for joining me on a Sunday evening all right so my name is hanjun I'm actually the sector science tutor at over marks all right so for today we are going to be covering all the term three and term 4 topics so that will be electrical systems digestive system transport system as well as human reproductive system now if you're wondering you're not going to go through the one to two topics yes all right uh it is already on YouTube so just go and find on the Obama YouTube channel uh we did one for media exams earlier this year okay so for today we'll only be focusing on these four topics now if you haven't already downloaded or printed out the materials for today please do so using this QR codes uh if not I think I think the Google Drive Link in the chats so we will start now with the first topic of electrical systems what do you need to know also before this right just to let you guys know uh try to stay to the end of this session because there will be a cartoon game and whoever's on top will have a chance to win one of the upper secondary curated notes okay which is worth like 40 or something so yes try your best to stay for the whole session if you can it's okay just leave you don't have to message me or tell me anything all right okay so electrical systems what do you need to know first of all there are three main components okay so there's electrical current potential difference and resistance let's examine what is current the definition of electric current is the flow of electrons in One Direction in a circuit okay so the analogy I like to use for all my students is think of a river all right in the river you have the flow of water okay that's exactly the same we call that current right oh we say oh the current of the kalang river very strong all right because we're referring to the flow of water so in an electric circuit it will be the flow of electrons a common misconception people will be like oh um current means electrons no it is not the same thing it is the flow of electrons all right now there's two models that we can use one is called the conventional current model and the second one is called the electron flow model what's the difference between these two conventional current model just says that oh okay it flows from the positive n to the negative end of your battery while electron flow says that it flows from the negative end to the positive n which one do we use in exams if they do not specify you always use conventional current which means that when you're tracing your current in the circuit always Trace from the positive n to the negative n all right we always use the conventional current model to measure current we will use okay MPS slsi unit and we always okay uh draw our ammeter which is a device to measure current in series what does this mean let's say you have a circuit right and then you have about okay and they're like oh how do we measure the current of this circuit we will draw our ammeter on the main wire that is what it means to be okay drawn in series which means when we are tracing our current it will pass through that ammeter back to the power source all right so we know for sure okay I've drawn this in series it is correct so that is electrical current now we'll go to the second one potential difference what is it another word for it is voltage all right so if you see your paper voltage potential difference they mean the exact same thing what is the definition it's a very long definition or you have to remember for me is that it is the energy needed to move a charge across two points of an electrical component what does that mean okay I'll break it down further for you okay so let me draw a very simple circuit for you same just one bulb in this socket if I connect my voltmeter over here essentially all I'm asking you right is that okay this point a and this is point B all I'm asking is what is the energy needed to move a charge from point A to point B all right so all you have to think about when you are answering any sort of potential difference or voltage questions right is where is my point a and where is my point B this means right if I draw my voltmeter like this I'm asking what is the voltage of the component between A and B for this particular circuit there's only one thing between A and B it is this box so whatever we measure right if the voltmeter says oh this is Five Books Okay it means that this bulb okay has a voltage of five volts all right so let's say I change the circuit now let's say I draw something like this okay we have two light bulbs all right and I draw and I connect a voltmeter like this where's my point a where's my point B point a is here point B is here I'm asking you all right so what is the energy needed to move a charge from point A over here all the way to point B over here and how many components does it pass through it passes through these two bulbs so I'm asking you what is the voltage of these two bulbs all right okay so all you have to do right is to figure out where is my point a and where is my point B okay whatever's in between point a point B all right is okay the voltage of whatever it is you're measuring which is why all right if you guys see in some questions you if you have any um circuit and then you have a voltmeter that's connected here okay I draw a voltmeter connected here all right what are they asking us for okay this is my point a this is my point B one is between point a point B as you can see here it is your power source so they're asking you what is the total potential difference of this socket okay what is the voltage or what is the potential difference of the power source okay so just take note this I know it's a bit confusing for some people all right so just um really all you have to do is remember okay figure out where it's point A minus point B okay and what is in between point A and B now the last component right will be resistance so that is a measure of opposition to current flow which means okay resistance is always opposite to current so when resistance goes up current has to come down when resistance goes down current has to come up so resistance and current are they have a inverse relationship this is important now because a lot of questions will ask you like oh at least if I vary the resistance how would that affect current so you have to know that there's an inverse relationship when recessive when resistance goes up current will go down all right so this is also why written here the greater the resistance the lower the current and how do we measure current we use ohms now there's two types of resistors that we can use one is a fixed resistor uh it just looks like a a box okay or rectangular box okay and the other one is a variable resistor which is the same thing but with the arrow passing through okay in this direction so you just need to know for fixed resistor right what is the function of a fixed resistor it just adds resistance to the Circuit so all it does is it has resistance okay but for variable resistor it has a slightly different function it varies the resistance okay so the resistance can go higher can go lower and ultimately that is going to affect the current so you guys must know all right what is the function of fixed as well as variable resistors it is uh somewhere probably in your textbook okay only common exams are not very lightly but it still could so it'll be good to know okay some functions of fixed and variable resistors now we are going to explore series versus parallel circuit so this is arguably one of the biggest parts of this topic all right so how first of all how do you identify if it's a series of parallel circuit okay series circuit right if you trace the current from the power source all the way back like from positive to negative and you will pass through all the wires okay so there's only one main wire but for parallel circuit when you trace it up okay you realize hey I didn't pass through all my wires all right there were branches okay there was stuff that's outside of the main wire so as long as we have branches right we consider it a parallel circuit okay it doesn't matter one branch two Branch three branch four Branch okay as long as you when you trace your current right you realize hey I couldn't Trace everything in one go okay it means it is a parallel circuit now uh you have to be aware of um these things in the table so first of all what happens when uh about blows in a series versus parallel circuit so for series let's say this about blue what's going to happen to the other Bob all right you need to remember that all other bumps will be affected okay all other bumps will blow which means that no about will be lit all right so if one goes down all of them will go down why because you see how you trace your current in order for the Bob to light cover the current has to go back to the power source but you see here a this one blue this one was like totally faulty so you took it out okay there's a hole all right so you can see the current gets stuck here it's like a roadblock the construction on the highway okay you can't go past this so the current will never be able to reach back to the power source all bulbs will be affected no box should be lit that is for series circuit how about parallel parallel RCR let's say I blow the first spot okay now one thing to understand about parallel circuits is that okay um because there are branches right okay the current will split what does it mean when the current split thing about it if I have a river okay this is your kalang River all right now we can split into smaller lakes or smaller Rivers okay like going to different directions so it's the same thing for a parallel circuit it can split so when you come back to this parallel circuit if let's say the first bought blue if you trace the current to the first Branch you're like hey you got stuck okay I couldn't manage to go back it's okay but can it go through the second branch yes as you can see here there's still a pathway for the current to go all the way back to the power source which means that this particular light bulb can remain lit so what I'm trying to say is in a parallel circuit right if one block blows in okay that particular branch all right the other bulbs in the other branches all right like this one or if I add another Branch here or as many branches as I want all the rest of the branches are unaffected okay so the bulbs in the other Loops what we mean lit okay now let's explore current in a series circuit right for current it is the same Trot which means uh if I put an ammeter here and I measure current and it tells me oh this is 10 amps wherever I move this emitter okay wherever I move it on the series circuit it will give me 10 amps so this represents total current take note okay if you have an Amazon on a series circuit it will always represent total current okay but for parallel circuit current is shared between the loops what does this mean it means okay the total current of a parallel circuit is split between the different branches so um let's say a first Branch if I put emitter here it gives me 10 amps and then the second Branch if I put anything here it gives me five amps the total current in this circuit will be 15 amps all right it will be split between the branches all right so um just take note of that uh then for voltage it's just the opposite so for voltage in a series circuit total voltage is the sum of voltages which means uh if I tell you this box here is five volts this one here is eight volts the total voltage will be 13 volts all right so that means your battery has a voltage of 13. but for parallel once again is the opposite so we always start with what you know power source let's say this battery is six volts okay six votes will be supplied to each branch so six volts is going to come here and six volts is Gonna Come here all right so each of these light bulbs will have six votes each okay it doesn't matter whether I have two branches or I have ten thousand branches okay as many branches as I want each branch will receive six volts okay so that's why I say the total voltage flows through each branch all right now the very last one we're going to talk about will be uh resistance so for series R is similar to potential difference which means if uh the total resistance is a sum of individual resistances so if here I have five ohms of resistance and here are five ohms of resistance my total resistance is my total resistance will be 10 ohms okay but for parallel it's slightly different there is a formula to determine total resistance now if you're lecture I've never seen this in my life okay it means that your school does not expect you to know this which means you can ignore myself for the next two minutes but if your school expects you to calculate resistance then you must know this formula okay it's a very important formula essentially right all you have to understand is that resistance in a parallel circuit right okay is that the more branches you add okay the lower the total resistance so it's an inverse relationship for series okay the higher the total the higher the number of like resistors we add okay the higher the total resistance but for parallel circuit is opposite the more you add up okay the lower the total resistance so I want to talk about how it relates to adding blocks so this is a very common question okay they say what happens if I add okay a light bulb in uh series okay if you add a light bulb in series it becomes dimmer okay but if you add a light bulb in parallel it becomes brighter white because in series okay the more Bobs you add the total resistance increases okay remember what's one of the first things that we mentioned today okay resistance is related to current so resistance and current have an inverse relationship so if total resistance increases total current will decrease okay and your bulb becomes dimmer all right but for parallel if you add more branches total resistance decreases so total current will increase and about becomes brighter okay so please take note of this now for Ohm's law once again not all of your schools will be testing Ohm's law but for those that are you have to be very familiar with the V equals II equation okay so for anything you have to be able to use because IR all right and use this I just have to move the things around so for example if you want um currently okay you just move become V over r or V1 resistance okay that will just be VV over I all right same for power for those schools that are testing power remember for me the equation for power okay power in what's will be electrical energy in joules over time in seconds your units are very important okay most of your schools will be testing questions where they say like oh in minutes so you have to remember the equation is in seconds so you have to convert your values back to seconds to use the power equation okay so we are nearing the end of this one okay let's talk about wiring in the main plug so any three pin plug in your house contains three types of wires all right you have your live neutral and Earth wire so what you need to know you need to know first of all position so which wire is which okay in both views this one and the cut open one what else you need to remember for me color okay the color of each wire as well as current and potential difference so in a live wire right okay there is current as well as potential difference okay in a neutral wire remember the name is neutral which means uh okay it's like it's like it doesn't really care okay it doesn't want to do anything okay so got current but no potential difference then last one okay um this is the wrong one this is your Earth wire sorry yeah Earth wire okay it's just a safety precaution it will have no current and no potential difference if you know your Appliance is working fine okay so uh for electrical dangerous and precautions all you have to do is memorize for me okay so what are some of the important dangers you have damaged wires wet conditions overloading and short circuit I don't think I have to really explain this okay memorize it for your exams okay you have to tell me what is the danger and what is the consequence so you have to tell me damaged wires okay can result in a electric shock wet conditions okay weapons also a shock then for overloading and short circuit it can cause a fire all right so link it to a consequence then for precautions three main precautions so first one of wiring what's important remember it's connected to the metal casing okay always is connected to the metal casing what does it do it conducts the current to the Earth okay then for fuse what is it it's just a small metallic wire connected to the live wire okay it's connected to the live wire because that is the one that is dangerous okay so the fuse is connected to the live wire what happens if the current is too high it will melt and break the circuit and the last one circuit breaker in your house also have what does it do is a car too high they will trip and break the circuit sorry what is going on okay yes and it will break the circuit okay okay so now I want you guys to take five minutes right to try this question so this is mainly for people who um have schools that are testing Ohm's law so V equals IR if your school is not testing this uh you all can just take a five minute break okay so for the benefit of those who need to learn Ohm's law okay can you try this question and I'll go through in five minutes okay all right I'm going to go through the question now in the interest of time so the figure below shows three resistors connected to a battery with a EMF of 10 volts okay I don't know why I say it's three resistance obviously two um so part a state the potential difference across the two ohm resistor now before we can even solve anything right let's figure out is this a series or a parallel circuit how do we figure out I told you just trace the current if when you trace up okay back to pulses if it passes through all the wires it's a series in the cut it's a parallel so if I'm tracing okay I'm like oh oh crap all right as you can see here there's some parts of the wires that did not um go through that tracing so this is definitely a parallel circuit so am I answering this question right we should be referring to on top all of the things about parallel circuits okay so over here uh what's essentially going on is that when the car is coming out of the power source at this point over here it's going to brush okay into Branch one and Branch two okay it's gonna draw back together and come back to the power source so for part a state the potential difference across the two ohm resistor remember it depends on your total voltage your total voltage is 10 volts which means that 10 volts is going to be supplied to each branch okay remember in a parallel circuit your total voltage is given to each and every Branch it doesn't matter about 50 branches every Branch will get the same amount as the total okay your power source so the answer for this is 10 volts now for Part B calculate the effective resistance between a b so you can see our way a is over here B is over here what did I mention about potential difference all we're asking is what is in between point a and point B so what's in between point a and point B okay you have two components you have the four ohm resistor as well as the 2 ohm resistor all right so basically this this question is asking and these are the only two components of this circuit so this part B is asking you right what is the total resistance of this entire circuit all right what is the formula for resistance for parallel circuits okay for Part B okay one over total resistance equals 1 over the resistance of Branch one okay which is four plus one over the resistance of Branch 2 which is 2 ohms all right so that is going to give you okay three over four but remember this is one over total resistance so my total resistance is going to be the flipped version which is four over three ohms okay so answer is four over three ohms all right you can do this four over three or you can leave it as 1.33 to three significant figures all right then for part C find the current okay flowing through point a so you're like okay where is Point a all right point a is over here okay on the left so that represents uh as you can see from the color coding that represents total current okay so it is on the yellow portion we're talking about total current before anything split okay on the red it's kind of Branch one the blue is current of Branch two okay so at Point a we're still asking what is the total current of the circuit how do we find it we have to use ohms more okay we have to use V equals to IR so for part C all right let me shrink this okay so for part C right first things first write out your vehicle's IR okay we are looking for current so we want I equals to V over R do we have total voltage yes our total voltage is the power source 10 volts okay 10 do we have total resistance yes we just found that from Part B okay which is 4 over 3. okay so 10 divided by 4 over 3 that is going to give me a answer of 7.5 amperes okay so Final Answer 7.5 and yes all right I hope you guys were able to solve this question because this is a very standard Ohm's law electricity parallel circuit question okay okay very good now we are going to go straight into the second topic of the day digestive system now uh first things first we need to figure out what's the three main nutrients what are the nutrients that we consume okay everything in life can be broken down into carbs proteins and fats what you need to know you need to know the function so for cars what does it do for our body it provides energy proteins growth and repair of damaged tissues fats insulation as well as energy important memorize this okay function of each of the nutrients all right next important thing they will ask you why do we need to digest why is it I can't just you know have these cups enter my cells directly okay and provide us with energy why do we bother digesting them into simpler molecules okay so for that right you need to remember okay that okay the reason why we digest is because these nutrients are two big to pass through okay the pause of the cell membrane okay ignore the back hand I think but yes it is too big to pass through the pause of your cell membrane okay so no matter how hard you try Okay fats proteins carbs they literally can't enter your cells okay so they can't okay do their functions all right they have to be broken down into simpler smaller molecules okay they can pass through the pulse of your cell membrane okay in order to be used by your cells okay so also remember for me your answers right you have to include okay the reason okay or the rationale behind why we digest food okay then uh so for chemical digestion okay we always involve okay digestive enzymes so you also need to remember some key characteristics of enzymes for example all enzymes in your body get digestive enzymes or any other type of enzyme all of them are made up of proteins they speed up the rate of reactions they are reused after a reaction and they are specific what is specificity of an enzyme this means if this enzyme is only for breaking down carbohydrates it will never be able to break down fats and proteins all right so for example if you see over here we have three classes of enzymes for three types of nutrients right we have carbs proteins and fats so we have three classes of enzymes we have carbohydrates proteases and lipasas each of these classes of enzymes will digest one type of nutrients so the first one is carbohydrates it breaks down your large carbohydrate molecules into simple sugars for example breaking down starch into male tools what is one example I want you guys to remember okay is a name in English so this is one type of carbohydrates and amylase breaks down starch into maltose so you see the word emulates later on when we are you know figuring out what happens in our organs but this is quite important so if you see the word emulates in your exams remember it is a carbohydrase it breaks down carbohydrates into simple sugars the next one we have protease is in the name what does it do it breaks down proteins into amino acids all right so amino acids others and products of protein digestion the last one we have live case uh it breaks down fats into two things fatty acids and glycerol all right so this is the only one that breaks it down into two different things why because if you look at the structure of fats okay you can see uh it's literally made up of two different things okay fatty acid as well as glycerol uh yes so yes it's broken down into two separate things now um some of your exams right will ask um there are something like oh okay they did an experiment all right and then the end product of digestion of that compound like compound X okay is acidic so they're asking is it carbohydrate protein or fat digestion and it's very simple the answer will always be fat digestion why remember fat is broken down into fatty acid and glycerol what is the name of this it literally says fatty acid okay the name has the word acid which means that fatty acid is a type of acid is it it is acidic all right so when you break down fats into fatty acids and glycerol okay the end product will be acidic the rest okay amino acids glucose Etc okay ask neutral all right so just take note if any exam you see it you conform to confirm is fat magician uh okay so what's the other main thing about this topic you need to remember what are the key processes that happen in each organ in your digestive tract all right that is five key organs from the mouth to the large intestine okay so for mouth what exactly happens here uh in the mouth one of the key things that happened is chewing what does chewing do increase surface area all right so that so I read enzymes okay can work more efficiently so always link back to increased surface area remember like when you're eating bread okay when you chew the bread okay it breaks down into smaller pieces of bread okay they have larger surface area Okay uh other enzymes in the mouth yes one specific enzyme you have salivary in Middle East so we just went through this amylase is a type of carbohydrates so in the mouth there is only carbohydrate digestion okay so your fats your proteins nothing will be digested in your mouth only carbohydrates because of the presence of salivary amylase all right now the second organ is your esophagus it is just a long tube that connects your mouth to your stomach okay you see this tube over here this tube is your esophagus you spell OE or you spell e for your esophagus doesn't matter it's just one is British English one is American English all right so esophagus what is one key process that happens here something called peristalsis it's just the contraction and relaxation of your muscles in the esophagus all right why is that important because it wants to push your food down you might be thinking oh but gravity will do the job right right if it's like it's like falling down it's like yes most of the time gravity helps but imagine you take a Big Mac okay and then you lie on your bed how is that Big Mac ball of food gonna go down your esophagus if you're lying flat down all right so um you still need some muscles okay in your esophagus to help push it down regardless of whether you're selling upright your line flat down or you're doing a handstand okay okay take note no digestion there is no digestion that takes place in the esophagus now for stomach what is important we have gastric juice that is made up of hydrochloric acid and proteases so the hydrochloric acid kills the bacteria in the food and your proteases that's what the protease does now okay it breaks down your proteins into amino acids so take note your stomach is very acidic because of the presence of hydrochloric acid all right um yes and it is also the reason why you don't get food poisoning after every meal because the acid is killing all the bacteria from your food so yes um what digestion happens in the stomach only protein why because gastric juice only contains proteases so no carbohydrates no fat digestion only protein in the stomach now we are on the fourth organ that is also intestine it is the main site of digestion which means okay main side means are all three nutrients will be digested here carbs proteins fats everything Japan together okay confirm will be digested in the small intestine so there's a misconception people think oh the summer is very digestion happens not really okay the main site of digestion is the small intestine there's a few juices that I need to remember the first one is called intestinal juice male function okay neutralization of acids all right when you go over level you all learned that okay actually there's no rules also got other enzymes but at your level you just need to remember one of the main functions of intestinal juice is to neutralize the acid from the stomach okay the bacteria cure already everything Q in the summer ID okay so when it comes to the small intestine we don't need an acidic environment anymore so we want to neutralize the acid then pancreatic juice uh contains your three key enzymes okay so your imylase to digest carbohydrates protease to digest fats and lipase to digest your you know proteins to digest proteins and lipase to digest fats all right so all three nutrients uh and then last one you have this thing called bile uh bile is not really a juice okay it is just something that helps in fat digestion so we'll come back to that a little bit later all right but it helps fat digestion it does not it is not an enzyme so take note bile is not an enzyme it does not digest the fat it just helps is also the site of absorption so at this point it's more that's enough we've digested everything down to the end products of digestion so you'll be small enough to be taken up into the bloodstream and enter our cells okay uh last one is your large intestine so here are once again no digestion everything ends at the small intestine okay whatever your body wants to digest it will digest there okay everything else no more okay it's gonna come out your body one way or another all right so what happens in the large intestine it is a side cause water reabsorption so take note in your large intestine okay there's no digestion but your body wants to take back as much water as possible okay water is precious to humans so it will always want to take more water all right so yes site of water be absorption okay so um this table is very important you have to be very very very very familiar with all the processes that happen at each organ okay so at the top okay you must be able to tell me okay stomach is protein digestion mouth is carbohydrate digestion small intestine is All Glass absorption etc etc okay important now last one I want to go back to bio so remember Bala okay it eats fat digestion through a process called Paris oh sorry sorry sorry emulsification okay if you're like Joe I've never heard this then ignore it again okay but if you have you're like sure I've heard of this but I forgot then yes please remember it okay emulsification is the process where bile breaks up very big fat globules so one big fat droplet into smaller fat droplets so essentially it is trying to increase surface area all right why is it important because remember for fat digestion specifically yeah in which organs can it occur in there's only one organ which fat digestion occurs and there is a small intestine you see it doesn't happen in the mouth it doesn't happen in esophagus it doesn't happen in the stomach it also doesn't happen in the large intestines it only happens in the small intestine which means that it has so little time to really like digest the fat so it needs a helper okay he needs like a mate okay and that is bile so it's helping to break up the fat Global into smaller fat droplets all right to increase service area for more efficient digestion okay so that wraps up for this topic now I'm gonna give you guys five minutes to attempt this question then I'll go straight again okay I'm gonna go through a question I also sorry we are running a little bit short time okay so part a label structures a b c d so a you can see is a tube that is connecting to the stomach okay I basically there's only one thing that's really like a tube in the digestive trap all right that would be your esophagus now Part B it is the one that I said is over here okay what is that that is your stomach all right then for part C uh oh okay I realized part C is pointing to the stomach okay then ignore that level Part B what is that that will be at the end of your entire digestive tract all right I didn't cover it but I'm pretty sure you went through in your school um that would be yeah all right so Part B name the organ in which that I absorption occurs that is your small intestine so recall small intestine is the main site of digestion as well as the site of absorption now for part C Sally is a large amount of butter describe what happens as it undergoes chemical digestion in the various parts of her digestive system to answer this question first of all you need to figure out what is butter right and butter is essentially made up of fats lots and lots of fats okay so this question is basically asking you trace fat digestion as it goes through the digestive organs recall where does fat digestion take place only one organ right the small intestine but you have to let the examiner know that you know okay that it can't take place in the other organs because lipase is not present so you have to tell me that as it goes from the mouth to the esophagus to the stomach all right as it passes through these organs there is no fat digestion so no butter digestion are basically because there are no lipasis present so that's the first part of your answer you have to tell me that okay actually is the butter goes through the mouth the esophagus the stomach but no fat digestion because no liposes are present to digest it then it enters the small intestine which is the site of fat digestion why because your pancreatic juice okay oops your pancreatic juice contains light pieces to digest facts into fatty acids plus glycerol myself okay so you tell me that in a small intestine all right there is fat digestion because okay there's lipase integrating juice to digest effects into fatty acids and glycerol all right so the end product and products of fat digestion your fatty acids and glycerol will be absorbed into your bloodstream okay if you want to go one step further if this is a four mark five mark question we also talk about bio okay why remember bile AIDS in fat digestion through emulsification of fats all right but let's say they just do two to three month question okay then whatever I return whatever I wrote over here is sufficient okay can very good so we are going to go into our third topic of today and that is transport system uh what's important you need to first of all memorize diffusion and osmosis Mass memorize definition free maximize them you do not take don't take your classmate to take it okay so remember diffusion net movement of molecules from a region of higher concentration to lower concentration think about it okay when someone sprayed deodorant after PE okay after a while the whole class can smell it why because the deodorant particles diffused across the classroom for osmosis it is only water molecules okay no other types of molecules only water molecules from a region of higher water okay you know this higher water potential two region of lower water potential okay don't use the term water concentration sorry I don't know why it was written like that okay say higher water potential to lower water potential now take Nona osmosis must have a partially permeable membrane not okay I'm talking about masks okay that Mark there must be a partially permeable membrane four osmosis to take place all right whether that be a risking tubing or whether that be a cell membrane all right doesn't matter as long as there is a partially performable membrane so next thing is how do plant and animal cells act in different types of solutions so there's three types of solutions hypertonic isotonic hypotonic all right um just remember okay so for hypertonic Solutions uh essentially right it is a solution with okay very oops very no water potential okay so for example it's concentrated sucrose solution concentrated syrup solution concentrated ribena okay very low water potential what's going to happen when you put a plant cell inside water molecules are moving out of the cell moving from the cell okay out of the cell into the concentrated solution what's going to happen the plant cell is going to become plus more lice then for hypotonic it's just the opposite okay it's very high water potential for example this still water okay very dilute sucrose solution dilute myelo wire whatever dilute anything now okay hypotonic it has high water potential so water is going to move from solution into cell so what water is going to move into yourself what's going to happen it's gonna start sweating and it becomes turgid isotonic is same water potential so no net movement no change okay so for animal cells are it's exactly the same thing all right exactly the same hypotonic means low water potential so water moves out of the animal cell okay what's going to happen it's gonna do like a it's going to look like a raisin okay we say that the cell becomes created okay the terms are important now we don't say plasmolize for animal cells we say cremated then for hypotonic it's high water potential solution so water molecules move from solution into cell now take note in animal cell the cell will burst and die all right it does not become turgid it dies all right why because they do not have a cell wall okay animal cells don't have a cell wall so when too much water enters the cell it's just going to burst think about it if you put too much water in a water balloon eventually it's also going to burst all right but for plant cells because there's a presence of a cell wall okay the cell wall is like the it's like the walls of your house okay um your house won't explode okay from too much water but for animal cells no cell wall so it will burst and die then that's one isotonic same no-nap movement no change what's next uh components of blood so remember in blood there's four main components red blood cell white blood cell platelet plasma okay you need to know how they look like uh yes okay so weight loss cells are always have a donut looking shape okay white blood cells have a irregular shape you will see as in you will know it when you see it and you will have a question on that later okay then playlist is very very small and plasma is just the fluid okay so plasma is not in itself all right four components of blood what you need to know you need to know the function so where blood cell transport oxygen return carbon dioxide main function is the transport of oxygen you also need to remember the three key features of red blood cells no nucleus contain hemoglobin and biconcave so far no nucleus and by concave this one and this one okay one and three it is to increase the surface area all right why because it wants to pack more oxygen molecules okay if not has been next to any trips but no we're like no how to pack as much oxygen as I can so I want no nucleus and I want a Bic concave shape to increase surface area then the second one is contain hemoglobin what is that it is just the substance that binds to oxygen okay it's like sticky so it binds to the oxygen all right make sure that oxygen doesn't fall off randomly okay then for white blood cell immune function what does it do five bacteria produce antibodies just memorize it okay let's form blood clots okay stop bleeding and last one plasma transport nutrients and waste substances so take note transport of oxygen is red blood cell transport everything else okay your nutrients like your glucose amino acids uh whatever okay it's plasma okay waste products like urea also plasma okay so red blood cell is transport oxygen all right so memorize it for me now for blood vessels you need to know there's three types of vessels capillaries veins and arteries the big one will be artery and vein in between those two you have capillaries okay you can see how thin and how small capillaries are all right so what you need to know you need to know the features of each type of blood vessel so for example all arteries carry blood away from the heart but veins carry blood towards the heart our capillaries it connects batteries and veins okay and the key function of capillaries is exchange of substances so all your oxygen and everything the waste products right go through capillaries to be exchanged between blood and body cells all right then you also need to know for arteries the blood that's flowing through it very high pressure how does it withstand the car high pressure it needs a thick muscle layer so they are interconnected all right therefore beans okay we don't need such a high pressure okay low pressure so we need a thinner muscle layer we don't need it to be so thick all right and last one is you're like sure what is a woman woman is just the hole in the center that allows the blood to flow through so if you see a cross section huh okay this is the muscle layer outside right this hole in the center okay virus inside this refers to the two months all right so Lumen size is obviously just opposite to your muscle layer size if you have a thick muscle layer like I do over here you have a very thin Lumen but if you have a very thin muscle layer so this is your muscle layer you will have a very wide lumen all right so this is uh narrow and this is white lumen all right so just remember for me Atria the blood need to be very high pressure thick muscle layer which also means it has narrow Lumen then for veins don't need so high pressure all right so thin muscle layer and white Lumen okay last one plant transport system uh um what you need to know uh place your company's in frame six okay so two types of transport vessels xylem and phloem so I love transport water and mineral salts phloem transports sugars from photosynthesis now take note specifically white sugar sucrose it transports sucrose so you're like sure but I thought glucose is the one that is produced in photosynthesis yes glucose is produced in photosynthesis it will be converted into sucrose for transport all right you like your wife I don't know as a plant okay so sucrose is the one that is transported okay then Direction xylem obviously because you take it out from the roots so um the water and mineral salts move from the roots to the rest of the plant remember phloem because photosynthesis happens in the leaves all right it um all these two growth is transported from the leaves to the rest of the plant what's important you need to know which is which when there's a cross section two main cross sections root and stem for the one that's most common is stem cross-section all right the one on the right um one way is just to memorize okay so the xylem is always the one in the center and the floor is the one outside same as the root cross section so xylem is the one in the center and floor Mr one outside now if you're my student you will know that I have a brilliant analogy for this okay which is that water is so precious to all living things all right we can only live what three days without water but you can live one week without food so water is 100 more important to us now if something is important to you do you keep it near to you or do you keep it far away from your Center you obviously keep it near to your center right like if you have your phone you keep your phone in your hand in your pocket you won't leave your phone at the edge of a copy time table all right so it's a safe it is precious you keep it near to our Center so your xylem is a one carrying water water is precious so the xylem vessel is always nearer to the center you can see a xylem vessel is nearer to the center in both the stem cross section and the root cross section okay so be very aware of that uh so yes now we are going to try this question um same now okay take five minutes to try it then we'll go through the question together okay I'm gonna go through the question now and once again please stop fighting in the chat okay or I'll be kicking you out of the zoo now uh for this question so we have five days of fresh potato all right immersed in Sugar Solutions of different concentrations uh then obviously there's some changes in the mess so either it reduces mass or increase in less uh and then there's a graph to show the differences of each potato strip so part A Name the process that causes the change in the mess of the potato discs the answer will always be osmosis so if you ever have any question exams okay potato strip La sweet potato strip like carrot strip whatever it is okay put in sugar solution just remember the answer is always osmosis all right it will be the movement of water molecules so part A answer osmosis now for Part B arrange the potato discs in ascending order of concentration of the sugar solution so from the least concentrated solution to the most concentrated solution how do we answer a question like this we need to think to ourselves what does it mean to put this strip in a let's say a very dilute solution all right remember we just went through this hypertonic hypotonic isotonic Solutions if it is a dilute solution okay does it have high or low water potential it has high water potential which means that the water molecules are going to move from solution to cell all right the water is going to move into the cell into the potato disk so water enters right the potato disc if it is a concentrated solution it has low water potential which means all right um the solution has low water potential which means that the water molecules are going to move from cell into the solution is going to move out of the cell into the solution so water leaves the cell all right so this is the cell dilute solution means water enters the cell concentrated solution means water leaves the cell so if water enters a cell what do you think is going to happen to the mass mass is going to increase for concentrated if water leaves the cell why do you think is going to happen to the mass mass is going to decrease all right so as you can see here if there is an increase in mass of the potato strip it has to have been put in a dilute solution all right so that all the water from the dilute solution enters the cell then you now you're asking how do I know like which like how do I know how diluted it is or how concentrated with this so the steeper the concentration gradient all right the more water molecules will move across think about it why do molecules even bother moving whether it's diffusion or osmosis you are trying to reach equilibrium trying to reach equal on both sides so if one oh sorry sorry wrong one if one has 100 to zero how many molecules must move across to make it equal okay 50 molecules have to move across to make it 50 50. but if the difference between two solutions is let's say only 10 and 0. how many molecules must move across to make it equal only five okay to make it five five so the more concentrated it is okay the more movement or the more dilute it is the more movement so the correct answer for Part B should be c d e a all right so potato strip C was put in the most dilute solution so the most amount of water enters it had the greatest increase in length all right similarly for a right it was put in the most concentrated solution so the most water left the cell so that was the greatest decrease in the mass all right so for part C explain what happened in potato disc seems so what caused such a great you know increase in mass of the potato strip all right so you to answer this question we might always talk about water potential and osmosis so you have to first of all tell Mia that the water potential of the cell set lower than the sugar solution lower than the water potential of the sugar solution so water potential is lower than the sugar solution so what what's going to happen all right water molecules oops water molecules are going to move from where to where move from okay sugar solution into the cell set through what remember all spouses has to take place through a partially permeable membrane so you have to tell me true The partially permeable cell membrane okay via osmosis right biosmosis so basically even if your English is very broken it doesn't matter because the teacher is going to market for the keywords okay so you can tell me your sources at the start of the sentence of the N or the sentence whatever all right so basically water molecules are moving from sugar solution into cell set through the partially permeable membrane via the process of osmosis okay I will answer questions at the end of the session okay because I'm afraid we're going to overrun the time a lot all right then you tell me that therefore the potato DC will increase in maths okay or you can tell me increase in Mass the greatest all right so take note for Bio always about King words okay now last topic reproductive system okay what's important I'm sorry I just I have to rush through some stuff okay you must know the location of the different organs if your school is not testing this you can just shut off your brain or you can leave the call okay but if you want to stay for the kahoot yeah you just um just chill all right so this topic you need to know the location of the organ so where is the ovary where's the fallopian tube like the uterus cervix and vagina then you need to know the function of each of these organs okay very important are the function is important same for male reproductive system you need to know where these organs are located and what is the main function of each of these organs okay also each of these are female and male reproductive system there's two views front view side view you must know both views okay uh puberty so what happens during puberty while you guys going through right now uh essentially in puberty your sex organs will mature and you can produce your sex cells so gametes is just another word for your sex cells what are your sex cells you have your sperm as well as your over your egg okay so once you go through puberty your body will start being able to produce and release these sex cells and then you also go through a series of physical changes so for boys but exactly is going through uh your sperms will be produced okay deepening of your voice facial and body hair development as well as Mark muscle development all right for girls what's the different physical changes okay you can start to release mature eggs okay you start menstruation your breasts begin to develop and your hips were widen now for both um across both genders you have growth spurt and you develop cubic and underarm path so yes remember for me what other physical changes we're going to go into menstrual cycle this okay technology menstrual cycle is not the same as menstruation so menstrual cycle refers to the whole cycle like it's a continuous process okay and part of your menstrual cycle is menstruation so menstruation takes place in day one to five all right so if a girl says she's referring to menstruation which is the discharge of your uterus lining okay through the vagina so you're discharging blood and dead tissue through the vagina that is menstruation okay that's day one to five now from day six onwards the sex hormone estrogen is going to repair and thicken that lining remember that all of the lining up has been shut off the body in day one to five so there's nothing left so D6 onwards your body is gonna start repairing and rebuilding that lining all right now for day 11 or 16 we call that the fertile period so this is the period that leads to the highest chance of pregnancy okay so take Nona different schools will have different dates so some schools will say 11 to 16 someone say 10 to 15 someone say 10 to 16. follow your school notes okay don't follow mine I mean if your school doesn't specify them for life but if uh if your school has a different range of the photo period please follow your school's notes okay okay uh and specifically on day 14 that is the day that ovulation happens which is when a mature egg or over is released from one over room okay can then after that day 17 onwards we don't need to grow the lining anymore it has already been repaired has grown to a sufficient thickness so progesterone another saxophone is going to maintain the lining okay one of my notes have so many errors okay so the lining maintain the thickness okay so progesterone primarily maintains the thickness of the lining all right but estrogen over here we pass and thickens the lining all right so slight difference okay but there are two main key hormones like okay each region and progesterone all right now uh last one both control methods same memorize it for me okay so you need to know how each of these birth control methods work okay so for example the key ones condom you need to know there's a male and a female version so the male one okay it's just a rubber tube okay that you put over the penis that prevents the deposition of sperm all right so it's like a plastic that it prevents any sperm from leaving and entering the female okay now for female the female condom is called diaphragm okay it also prevents sperm from entering so it's like an umbrella that stops IT okay then we have intrauterine device what does it do okay it is fitted okay into the wall of the uterus okay so that it prevents the fertilized egg from implanting itself in the wall okay so it physically blocks okay the uterus lining so even when fertilization takes place are you formula inside good right because I go can't imply itself in the uterus wall okay it's blocked by the iodine and last one is contraceptive pill it just stops ovulation okay it Alters like the chemicals and the hormones in your body all right then permanent important permanent means permanent okay no going back so for meal is called vasectomy you can't die from that then for females tubal ligation you can't die fallopian tubes okay very last one STIs three main STIs remember for me what they caused by Connor and syphilis is bacterial HIV is a virus okay then you remember the key symptoms so for gonorrhea burning sensation when you pee and pass being discharged for syphilis you have sauce and non-itchy rashes okay and last one HIV the virus causes AIDS okay why because it kills off all the white blood cells in your body okay so that is a key thing to take note now in the interest of time I'm just going to do this question on the spot with you guys okay so labor factors p q and R this is the front view of the female reproductive system P you can see I reverse it is pointing to this like Bean shaping like this is your ovary okay thank you over here it is the narrow opening that is called the cervix then ah okay is referring to this canal that is your vagina okay so must remember where each of these organs are now State one function of structure are so there's a few structure uh there's a few functions that you can talk about for um the vagina so one will be okay is the birth canal all right it's above Canal you can also say that it's the site of sperm deposition so this is where sperms are deposited all right then for part C so then essentially asking uh um all right what's happening here they say uh infertile okay so this movement carries out in vitro fertilization then where should this fertilize egg be implanted back in the woman so where thus as I could get implanted it is in the uterus lining so we just need to x out here okay left right doesn't matter okay um okay now uh we are done with this so I'm going to open a kahoot right now okay what is going on guys hold on let me okay sorry give me 10 seconds guys okay I've made one person the host okay I'm gonna message this person can this person please help me regulate the chat if you need to bet people just go in bed or if even better just like stop the chat altogether so like yes please okay please stop with these racist comments like is them sickening okay you guys are what already 14. uh for those who are still remaining I'm so sorry for what's happening in the chat we are going to proceed with the carpool now then for the ending please just um bend the chat if you can yeah sure you know you can win like 30 notes okay you know like she said it's worth 30 dollars okay sorry guys I'm a bit technically challenged uh hold on I'm setting up the the kahoot okay okay I got it I got it I got it oh no oh my gosh okay wait can the horse give me sharing abilities oh no sorry wait can the host just okay okay okay sorry yeah okay I'll see please please can I see my screen no okay I'm so sorry can you see it now okay great I'll start in 15 seconds uh so whoever haven't joined please join now okay I am starting now okay guys essentially right their questions just asking what happens if I increase the resistance right they say what happens if I increase the resistance of the real set all right remember resistance is inversely related to current so if you increase the resistance you will decrease the current so the ammeter reading decreases okay great all right so this doesn't just memorize only all right so remember fuse is always connected to the live wire foreign do it increases the surface area all right it has nothing to do with proteins and fats okay so by the time the food enters the esophagus it has a larger surface area thank you okay so basically they're asking which parts of the digestive system did the meat Patty digestion occur meat that is what is protein okay so protein wet stomach small intestine all right so the answer is one and three so which component of blood is involved in transform oxygen that will be your red blood cells all right sorry blood cells always looks like a donut here's a bicon cave shape that will be structure y thank you oh my gosh I oh my God I said this question wrongly uh it's D I'm so sorry to the 71 of your uh and to the 20 of y'all is wrong okay it's it's uh option b I'm so sorry I saw it wrongly this is my fault I'm sorry guys you still have two more questions to redeem ourselves okay so a vasectomy is a permanent method of birth control where you cut and tie the sperm ducts all right so all you have to do is you need to just figure out which of the structures is the sperm ducts and it will be the tube that's connected to your testis all right so that will be option A okay last question last question let's go great okay you guys know that because day 14 is the date of ovulation so that's when the mature over is released okay but even if you totally didn't think about that all right what's the photo period day 11 to 16. okay there's only one option that lies within the photo period there is day 14 here yay so let's take a look at the podium I'm so sorry guys I feel like so many of y'all should have gotten eight of it this is my fault yay okay very good so whoever um this short person is right can you please PM me um on telegram okay at h-a-n-j-u-n-n all right um just screenshot the page that says that you are sure all right so that I know that it's you okay um yes and then I'll contact you and you can get your curated notes okay so for everyone else thank you so much for joining me today I'm really very very very very sorry about what happened in the chat I didn't know that this was going on when I was like doing my talking and to those who participate participated in whatever was going on okay shame on you you should be very ashamed that you are talking all these racist things okay this should never have happened all right everyone else I hope it was enjoyable and productive session please study hard for your end of your exams okay yes that's all for three bye