FINAL REVISION | Gr. 12 Life Sciences Paper 1

Hi everyone, welcome to the live lesson. I knew I had to squeeze in one of these lastminute.com sessions for everyone out there. Thank you for joining the live. I'm going to try and do as much as possible in this live because I know a lot of you've got so many different questions and you've got work to do tonight so I'm not going to make this a very very long live. I'm going to try and be as quick and precise as possible and get to everyone's questions as quickly as possible. Remember there is a chat alongside that you can ask all the questions that you want. I'm going to try and answer them as many as possible. If you know people that want to join the live or have been waiting for me to go live then share the link with them now. Make sure that your quality is set to the highest as fast as we can just because it means you'll be able to read what I'm writing and read the questions that we'll go over together. A lot of the questions I'm going to use today are some of the ones that I included in my prediction video so if you haven't gone and watched the prediction video I suggest you go and do that after this. If you can't stay for the full length of this video that's okay. When we're done it will be uploaded automatically and then you can come back and watch it as many times as you need and you want to hear me explain things and of course I have the full library of all my other YouTube videos as well so don't stress everybody. Okay whilst everyone is joining the live and a couple more people will I'm just going to tell you some of the things that we're going to cover today because I'm pretty sure you're keen to just hear some of the general items. I'm going to cover things like the eye, specifically accommodation. I'm going to do the semicircular canals so that's for balance. I'm going to cover geotropism. I'm going to cover a female menstrual cycle graph question and then I'm going to do like a reflex spinal nervous system question as well for you guys. That's basically what we're going to cover. That means we've covered the big four things. If we have enough time I might even squeeze in a little bit of endocrine just as a top tip to me from you from me to you is endocrine is often understudied everyone so I suggest that you go home and you well you're already home probably and make sure that you are covering it as much as possible. Okay so without further ado because I don't want to any more time I'm going to share my screen with you and we can get into it. Right okay I think you can all see my screen. Okay so this is our live lesson everybody. I'm just holding a little oros for energy. Okay right so without further ado I am going to dive into our first question and I want to start off with a section that I think many of us don't study enough which is going to be the geotropic section. I think plant hormones don't get enough attention and I think we're going to underestimate it a little bit tomorrow. Okay so let's dive in. So this is a past paper question. I took this particular question from the Eastern Cape September in 2023. It says an investigation was conducted and this bit right here is important to us to determine the influence of external stimulus on the direction of growth in plants. Everybody that's the aim so in your exam tomorrow always highlight that part of the sentence. We had the following procedure. We had germinating seeds that were pinned onto wet tissue as shown in the diagram. The disc was placed vertically in an upright position in a dark room. Seedlings were gently sprayed with water daily. After four days the discs were turned in a position shown in diagram two. After a week observations were made. Direction of growth of the young stem and root were recorded. So let's move this up so we can see the rest of this question. Okay so this is before basically as we start at the beginning and this is after. In other words four days after they have moved it around and so essentially diagram one is showing us the initial and then diagram two is showing us how they've turned the disc clockwise and kept it stationary. In other words they are turning it and stopping and turning it and stopping. It's not continuously revolving which is an important thing to remember. Okay so let's go into the effects of this. Now I kind of already know it's going to be geotropism because they've removed the light so there's no light affecting the outcome of this. Okay so it says state the pattern of distribution of the growth hormone at a and b. So first of all remember the growth hormone they are talking about is the auxins right and now what you need to be able to do is tell the the pattern of distribution of the growth hormone at a and b meaning there's a difference between auxins in a shoot and different distribution of auxins in a root. Okay so when they say state the pattern of distribution what they mean is where is it collecting and where is it distributing to. So if a is the shoot that means it's going to be in the apical bud and that means it is going to be moving downwards right because you make it at the top. Then if you look at b it is made at the apical root. I suppose you could also call it an apical bud as well and that is also moving downwards and what I mean by moving downwards is that it's diffusing from the tip down. So another way to write this as well I'm just going to write it on the side here is that when we talk about shoots and auxins, auxins we're going to move towards gravity basically for both of these. Okay essentially they also want to know is it equal is it even and it's only one word it's only one mark everybody so don't overthink this they're not trying to fool you they're not trying to ask you very complicated questions here they just want to know what is the pattern of distribution of the growth hormone. In other words it's starting at the top and it's evenly distributing down lower. In the root it's starting at the bottom and it's not distributing up essentially okay it's not going up that's the point because auxins don't move away from gravity they move towards it. So don't feel like it's wrong if you repeat yourself twice is what I'm trying to get at that's what they're trying to confuse you with and yes they will try and confuse you. Okay next question explain one reason why the disc was kept in the dark room you may remember that from earlier and essentially everybody remember when we use an explain question tomorrow please remember that you must give a statement and then you must follow it with a reason that's for two marks if it's out of three marks then you must give two reasons one statement and two reasons. So why was the disc kept in the dark room? So hold on let's get rid of that little box there we go. The statement and reason that we're going to put there is we are going to say to remove the light stimulus and then the second tick after that would be so that only I'm going to squeeze this in gravity will affect the growth it's as simple as that we put it in a dark room so that no phototropism is occurring only geotropism is occurring. Okay then it says for number three draw a neat diagram to show the direction of growth of the young shoot and root in diagram two after a week so I'm not going to redraw the whole thing but I'm going to go a little bit closer so you can see it. If this is the distribution of the auxins and we've got to pay close attention this side here is the root this side here is the shoot okay you got to pay close attention to which side is which. If they have moved it and now they're saying they're going to leave it in this position for a week what you should then draw is the root going down and the shoot coming up that's basically the sketch that you would have made you would have just redrawn the bean and then or the seed and you would have had the root and shoot coming out making sure that you orientated yourself with which one is which. If you're asking yourself ma'am why did they even rotate it in the first place it's to see whether or not you are spatially aware which means did you make a note of the fact that the bean was in this position first and then did you notice it revolved and is now in this position it just makes sure that you're paying attention to where the root is before and after and the shoot is it's as simple as that everyone. Okay so that's all you would need to do now just to make sure that you get three marks please always assume that a diagram must have a heading it must be drawn in pencil and I suggest I strongly suggest including a label. In actual fact even though this is out of three marks I would label it with at least two labels and a heading and I would label the shoot and the root I would or I would use the letters a and b because they also use the letters a and b up in the top part of the diagram so I would label which one is a and which one is b. Okay right and then last but not least the big one right they always like to end a question off with a very chunky seven to six mark explanation and now what you are going to do is you are going to be perfect in this answer tomorrow if you do this you will always get your full marks it says explain the direction of growth of the young root okay after it was placed in the position shown in diagram two so remember we're only talking about diagram two so we must refer to the fact that in diagram two after it was placed in the position shown in that so in other words after time has happened what's going to happen you are going to explain why the root over here is actually going to turn and bend downwards all right so how do we get full marks for this so let me give you some bullet points that you would include so number one you need to tell me where are the auxins so the auxins are going to move towards gravity on the lower side of the root okay remember they're attracted to gravity and you can include that and you can say as auxins are um positively geotropic which means they move no yes yes they are they move sorry i'm just clarifying my mind they move towards gravity okay so auxins move towards gravity on the lower side of the root as auxins are positively geotropic next point um these cells on the lower side with the high let me put you a con concentration of auxins do not elongate that's important so they do not elongate because remember they're not going to get long and if you can't remember what that means remember cell elongation is when a cell goes from this to this okay so they're not going to do that the ones on the causing the root to bend towards sorry i'm writing this very quickly gravity okay now a good rule of thumb to get all your marks is to tell me where are the auxins in there so where are they okay they're moving towards gravity they're moving to the lower side which has the higher concentration so it's always tell me where are they moving to tell me where that is that's the higher concentration tell me what's happening on the opposite side once you've told me that there is a high concentration on this side and a low concentration on that side tell me what's happening with the cells one side the cells are elongating the other side is not elongating because the one side side elongates it causes the root to bend and in this case it's bending towards gravity if it was light of course it would be bending towards the light and so you've got to really really really really know your geotropic explanations everybody and there's no reason why you wouldn't get seven out of seven for this okay so that is geotropism in a nutshell there are many different ways they could ask you this tomorrow and they haven't asked geotropism in a while so it makes me feel like they might ask it and they might even they've been loving the questions also a lot lately when they like cut the tip off as well that's another one that i've seen a lot of so i think uh oh my screen is frozen i think that if you guys want to prepare as much as possible for your exam for tomorrow i think you need to also be prepared what happens when you cut the tip off of the shoot or the root okay so i'm just going to pause for two seconds and ask you uh sorry everybody i've closed my page i will come back into it don't stress everybody i'm just gonna stop screwing my screen sharing my screen for a minute if there's any questions you want to ask me about geotropism please do that now while i just refresh my page that we can go back in again and that we can have a lesson together and i can see the chat so i can of course see what you want to know about geotropism a quick response to this one question i can see here yes this video will be uploaded when i'm done so if you want to come back and watch it you don't have to watch it all now you can watch it later um so geo what happens when you cut the tip off of a shoot or a root is you remove the auxins which means there will be no geotropism there will be no phototropism there will be no bending basically and when you also cut the tip off it stimulates lateral growth which means it stimulates side branches or lateral roots geotropism so this question says the geotropism is only to do with gravity yes um but you do need to know that um shoots are negatively geotropic positively phototropic which means they grow towards the light away from the ground and then roots are the opposite roots are negatively phototropic positively geo which means they grow towards the ground away from light and that's what keeps plants above ground and their roots below ground okay and for some of you who wanted to know where this is from this question is from the eastern cape prelim paper or the september paper back in 2023 okay apical dominance everybody i can like recap that very quickly for all of you i just want to see if i have joined back to my live let's just see here if i've connected again okay yes i have let me share my screen again with you okay so geo apical dominance is very simple um it is what allows trees to have this appearance and so essentially that's because the apical bud is at the top here and that's where auxins are made in their highest concentration so you just have a really high concentration at the top of a tree and as it diffuses down it gets further and further away which means it gets a lower amount and because there's less and less auxins it allows for lateral branches to grow out so apical dominance in a nutshell stops lateral branches or side branches from growing why if they ask you why is apical dominance important to plants it's important to plants because of photosynthesis you don't want the top of your tree those leaves and branches to compete for light with the ones at the bottom because if you imagine a tree being a square and not a triangle it means that the sunlight can only get to the top part of the tree it can't get into those deeper layers but when it is a triangle you're able to get a really nice even distribution of light all the way over it and that's what apical dominance is all right i think i'm going to leave it there and i'm going to move on to our next section which i know you're all waiting in baited breath here is a female reproductive question now i just want to also warn everybody that i feel personally that matrix spend too much time studying the female reproductive system and when when it actually comes down to it the whole question is easy except for one question maybe out of five marks and you've spent too many hours worrying about it and not worrying about the other topics and i think that you kind of shoot yourself in the foot a little bit so i am going to do this question because i do think there will be some kind of graph question tomorrow um and i think as i suggested it might be a fsh question um maybe even linking to estrogen and how they work together or should i say how they're linked to one another um but yeah um let's let's dive into this because i know you're going to have a lot of female reproductive questions and i want to get to them with enough time to move on to the others so let's dive into this question unfortunately i can't remember which paper i got this from but this is a nsc final november paper that i did get this from so it says the graph below shows the levels of two hormones that are secreted by the pituitary gland during the menstrual cycle so they've already given you two clues as to what these are so we know that there are pituitary hormones and in terms of the female reproductive system there are only two and that is fsh and lh now on the graph a lot of metrics struggle to tell the difference between which one is which right so um i have a very very simple method of telling the difference and i'm going to start with the easier one of the two to identify here when you are looking for lh lh peaks once and once only and it peaks near or around day 14 so looking at this diagram there's only one hormone that's peaking around day 14 and that's going to be hormone b over here so that is definitely a hundred percent lh now the next hormone which you would go oh obviously ma'am it's fsh because that's the leftover one but i just want you to know something that bothers me and that metrics don't get right and that is is that if this wasn't lh and fsh let's say it was fsh and estrogen i know a lot of you can't tell the difference between fsh and estrogen because if i drew in estrogen not even that actually i'm going to draw better let me draw better okay that would be estrogen and so a lot of people can't tell the difference between which one is which especially if it's fsh and estrogen so how do you know which one is which well fsh is always going to peak first do you see how there's a peak here and the other line that i drew in and read there which would represent estrogen peaks second so the very first hormone that peaks the very very very first hormone is always going to be fsh it's never going to be any other hormone then if we move on to knowing why it's also fsh is because it peaks again on ovulation day because it helps with ovulation and the corpus luteum it also helps with the negative feedback so that we start making progesterone and we don't make any more eggs because we don't want any more eggs so how do i know if it's fsh because it peaks first and it peaks twice it peaks first and it peaks on day 14 estrogen will never peak on day 14 as you can see here it peaks early and then it peaks after ovulation okay so let's get into the questions that go along with this diagram first things first it says state two functions of hormone b so you had to correctly identify what lh is i don't think a lot of people know the second one as much as they do the first but first of all the two functions are ovulation which i think most metrics know but i think the second one is where people struggle just remember the word is luteinized luteinizing hormone what other structure has the word luteal in well the corpus luteum so it's there for formation i'm sorry it's there for ovulation and the formation of the corpus oh i always spell luteum wrong there we go luteum okay just keep that in your mind guys because a lot of people know the one and not the other okay next question which i really liked because it's often a question that we see in these final exams they speak about like what's stopping pregnancy i said in my prediction video that maybe they might have something about the fallopian tubes being blocked another question that i think might come up not directly linked to this question but linked to reproduction is about the amnion the amniotic fluid and so like they might even do something where like women don't make enough amniotic fluid and then they're going to ask you questions like well if she doesn't have enough amniotic fluid you know what's the problem what's wrong with the baby you know it's not gonna be able to maintain its body temperature it's not going to be a shock absorber those kinds of things um so if we move into the next one you can see it says explain why a female who is struggling to get pregnant a may be given pills containing hormone a as a treatment now remember it's an explanation question and i always say this statement and then a reason but now it's our it's out of three marks so you've got to give two reasons so make a statement what does that mean ma'am it means say what hormone a does make that statement so what does hormone a do i'm going to move this over so i can put this in hormone a is going to stimulate a follicle right so she's going to take these pills so she can stimulate a follicle now let's follow on the reasons with this now then because that follicle is going to develop an ovum and then of course that ovum will secrete oh i can't fit in the word secrete there let me just move this over a bit secrete um estrogen and what do we use estrogen for or we use estrogen remember to grow back the lining of the uterus okay so why is she given it well you tell me what fsh does a statement fsh stimulates the release of a follicle or the development of a follicle next reason well we need that follicle to turn into an ovum and that ovum is going to make estrogen so that the ovarian cycle i mean excuse me so that the uterine cycle can grow back the endometrium so that she can actually get pregnant because there's no point in making an egg if it has nowhere to go it has to go to endometrium and you can only grow the endometrium back with the estrogen okay let's move on now it says explain why a female who's struggling to get pregnant for the next one will have her levels of hormone b constantly monitored now that means everybody that you need to understand that we're talking about lh now if she wants to be pregnant right doesn't she need to know when she's ovulated so why remember this is explained so as always a statement and a reason so why will her levels be monitored so to establish if she has ovulated as this whoops hormone peaks on ovulation day and therefore i can't fit this all in sorry everybody without writing all over the place increasing the chances of fertilization so statement we want to establish that she's ovulated because it will be the peak on her ovulation day tick therefore increasing the chances of fertilization or you could say therefore increasing the chances of the egg cell meeting the sperm cell something like that okay right um then i'm just going to move this up now because i need as much room as possible it says for number three explain how the levels of hormone a on days zero to five will differ in a pregnant female so if we go back up here right remember everyone hormone a is fsh if you are pregnant are you going to make fsh no no because you're already pregnant right you don't need to be pregnant twice you can't you want babies at two different stages so how will the levels from uh from day zero to five differ so how will they differ so i'm going to answer it down here i'm going to say they will not rise as a ovum has already been fertilized um so as to prevent two babies at different stages that's what we want to say different stages so pregnant woman don't make fsh they're already pregnant they don't want to make another follicle because if they make another follicle they will be pregnant with potentially two babies at two different stages one could be four months the other one could be four weeks and we don't want that so that's how the levels of hormone a will differ fsh will differ okay coolio now um i just want to remove some of this i want to move it to the side just to get my little eraser is so small let's make the eraser bigger there we go okay so i want to do this very last one because i think this is the one you all dread describe and that's for five marks so do you know your ovarian hormones your ovarian hormones remember are estrogen and progesterone right so now they're asking you to describe the secretion of those hormones and then their roles for five marks so i'm just going to bullet point it to this little window is irritating me okay so number one the ovarian hormone let's start off with estrogen so you must always tell me where estrogen comes from so estrogen from the graphene follicle next point will regrow and maintain the um endometrium sorry i couldn't think of the word okay progesterone from the i'm just going to put you a cl short for corpus luteum will make the endometrium vascular and glandular let me just move this up a little bit maintaining the endometrium okay so describe this secretion that means that you need to say where they came from which we've done so from the graphene follicle and then the role in the menstrual cycle so the role in the menstrual cycle for estrogen is to regrow and maintain the endometrium again progesterone comes from the corpus luteum which makes the endometrium vascular and glandular also maintaining the lining so we've got about five marks some of them are double ticks for example i would say we would go one two three four and five something like that that's probably where they would put the ticks on that one so that is the ovarian hormone cycle it's not so scary guys um i'm just going to look at your questions quickly while i take a quick little break and have a look um and i'm also checking my laptop power um i'm just having a look uh everybody for those of you asking me for a scope you should go and watch my prediction video and also the scope of the exam in terms of the actual mark allocations is in your exam guidelines everybody should have that and everyone has access to that um i'm just reading some other questions so yash asked doesn't the corpus luteum also release estrogen from day 14 to day 28 as well it does but it's very minimal it's very minimal but yes it does you're not wrong it does i'm just focusing on its progesterone um can you write in point form i wouldn't write in point form but i would like fake it so in other words you can pretend to write in full sentences whilst still writing in point form does that make sense like you write a sentence full stop and then just start the next sentence on the next line why do i not suggest writing it like i did now because sometimes um the memo gives a tick for like a connector word almost like a conjunction or like a word that's joining the one idea to the other and if you don't write in full sentences you might miss that okay um what somebody asked here what is the who's this what is the negative feedback between fsh and progesterone so it's a very simple negative feedback as estrogen increases sorry progesterone beg your pardon as progesterone increases fsh decreases but i just want you to that progesterone doesn't cause fsh to go down it's actually estrogen fsh goes down as estrogen goes up what keeps fsh down is progesterone because remember progesterone is the pregnancy hormone so if you want to stay pregnant and you don't want to make another follicle you'll have high progesterone and low fsh but who pushed fsh down first that would be estrogen estrogen would push fsh down allowing it progesterone to increase and when progesterone is at its peak along with some estrogen it keeps fsh down so that if we do get pregnant we stay pregnant um somebody asked here if i say thicker instead of saying vascular and glandular am i correct no you're not you do need to say vascular and glandular they don't mean the same thing thickness does not indicate if it has lots of blood vessels it just means that it could be the tissue could be thicker it doesn't mean there's any blood vessels or glands inside somebody else asked here is lh only released on the 14th day generally speaking yes on the 14th day some woman it's on the 13th or the 16th but you'll know it because it's the only one that somewhere in the middle um somebody asked here is it advisable to write as much as we know um sometimes if the question has like this one up here i just want to bring your attention you see this one up here where it says state two up there if you write more than two we will only mark the first two if however this one we did this long one we did now for five marks this one at the end if you write like everything you know you run the risk of not convincing your market that you know what you're talking about and so they might not be very lenient they might think that you're just putting everything down and then waiting for us to tell for us to figure it out this is the rule of thumb this is a beautiful piece of advice i would give any metric writing tomorrow when you write a long explanation question for your marker tomorrow are you painting them a picture with your words or are you letting them guess or imply what you or infer if you want to be really fancy what you're actually saying so i need you to be very literal tomorrow i don't want you to think they know that you know you must pretend they don't know anything and you must tell them from beginning to end for example when we did these explanation questions tell me what estrogen does tell me where it's made and tell me what it does and where is it secreted to i need you to really paint a picture i need to be able to imagine this if you put everything down i might think that you don't know what you're talking about and you're just waiting for me to find the okay please also remember for tomorrow's exam that all of you have gone over spermatogenesis and eugenesis and only only write the exam guideline answer don't write what's in your textbook don't write what's in your teacher notes and this of course is my note because i write my note based off of the guideline so only the exam guideline for eugenesis and spermatogenesis so i'm going to do one last question which i think is actually a really good question what causes the corpus luteum to degenerate if fertilization doesn't occur is it that lh is low and lh maintains the corpus luteum yes so if you don't fall pregnant there is nothing maintaining the corpus luteum after fertilization happens a chemical reaction occurs where the zygote sends a signal to continue producing lh now it only does this for a short period of time and it's the time in which you have the embryo attaching to the wall of the uterus or should i say the endometrium because another one that metrics don't know which i want you to know now is the placenta takes over the job of the corpus luteum the corpus luteum disintegrates about month three so it's completely gone in month three of pregnancy and after that the placenta takes over and secretes large volumes of progesterone so i just want you to know that okay i have a question here from jess saying difference between corpus callosum and corpus luteum the corpus callosum is in the brain corpus luteum is in the female reproductive system okay let's move on everybody um i'm just going to do a quick little highlight reel of the eye and this one is a mixture if i look carefully between oh it's not a mixture i beg your pardon is it no this is um accommodation i'm just going to give you the highlight reel so what you're looking at here is accommodation and can you see how the lens is getting thinner here and it's getting fatter here and so this is far vision and this is close vision and essentially what you need to be able to do tomorrow is explain accommodation and what's happening to the lens remember that you have these i'm just going to put your sus ligaments so they are the suspensory ligaments and they are attached to these muscles over here which are the ciliary muscles now when we talk about um accommodation i want you to know that if one is contracting the other is relaxing what do you mean by that ma'am well if the ciliary muscle is relaxing then the suspensory ligament is contracting or the better word is pulling taut like it's being pulled on and so if one is relaxing the other one is contracting and so that's what's happening when we look at close vision and that's so that we increase refraction what is refraction bending light why must we bend light because the more light you bend the clearer your vision everybody this far away one is just the opposite you can see the suspensory ligaments are like slack look how loose they are here which means that the ciliary muscle is contracting and the ligaments are relaxing and so that's what makes the lens fatter and less light is refracted and that's because when you look far away you don't need to see as much detail um they won't ask you to draw the structure of the eye they may ask you to label it um they may also ask you a question it's not in this picture but they may also ask you about the papillary mechanism which remember you've got circular muscles and you've got radial muscles and the circular muscles are the muscles that make the pupil smaller and the radial ones are the ones that make it bigger and so you need to know that if i'm going into bright light the circular muscles make it smaller if i'm going into dark light the radial muscles open up the pupil to let more light in and that is the papillary mechanism it's about four marks most of the time i'm not really too stressed about the eye everybody um i wouldn't be concerned if i was you to be honest i think the hardest question that matrix get is just because they don't know what lens you're supposed to put in front of the eye so if you have myopia which is what i have means i can't see far away i need a convex lens like this one which is exactly what my glasses are right now it's a convex lens so it goes in a lot of metrics don't know that so please know how to correct the visual impairments and i also mentioned this in my prediction video please know about astigmatism please please please please how to identify it in a picture how to treat it and what causes it those three main things okay now i actually want to pop over to the ear and i'm just gonna move this picture over a smidge and then i'm going to zoom in on it okay um i'm not just going to do this one i'm just going to list a whole bunch of things that i have emphasized to my own metrics about the ear which is as follows please don't just know ossicles please also know the names of all the ossicle bones which are from biggest to smallest the hammer the anvil and the stirrup please know the name of those three bones don't just know ossicles please note that the hammer is the largest then the anvil is the middle small middle size and the stirrup uh is the smallest you don't need to know the latin names you can just use the everyday names please also know the function of the ossicles that they are there for amplification please know that they are amplifying a mechanical movement and converting it into a pressure wave in the perilymph in the cochlea which is what we can see here right so there is the oval window which is exactly where the stirrup that's the smallest bone let me make this bigger sorry it's not very big the smallest bone knocks against sound is going to go in through the perilymph go around inside the cochlea and it's going to stimulate remember the organ of corti that is the receptor you use for hearing right you're going to stimulate that it's going to send an impulse via the vestibular nerve to your cerebrum and you're going to interpret hearing that's the five six mark situation but then we also have these other components let's not forget what the round window does the round window is for excess reverberations or vibrations to leave the cochlea so you don't hear an echo the next thing that we must learn which is what's in this picture here is these guys here these semi-circular canals so let's go through all the possibilities semi-circular canals what are they for they are there for speed and direction okay so they're telling you what direction your head is going is it going up down left right forward back they love to ask this question when someone's running or someone is moving through space and so again what are you going to do you are going to talk about how you are stimulating the cristae at the bottom and the base which is this thing over here and how it's being stimulated by the fluid moving and stimulating it that then sends a message to the cerebellum remember this is all about the cerebellum and the cerebellum is going to send a message to your muscles of the body to maintain your posture and your balance and it does both remember the utricle and saccule which sits over here you've got one here and one there they are responsible the utricle and saccule they are responsible for posture so are you upright or are you lying down that's why you have two because one is at a right angle to the other to tell you if you're lying down or upright and yeah basically you also need to know the name of that receptor which is the maculae this one up here is the cristae must know those it's really important and again this can't they can't ask that many questions difficult questions on the ear they can literally just ask you something about hearing like balance or hearing itself and then everything else is going to be like label the diagram what is the function of this why are the ossicles arranged from biggest to smallest amplification what is the purpose of the round window gets rid of excess sound waves what part of the brain does the cochlea communicate with the cerebrum so there's a lot of content knowledge recall it's not as much as you would think when it comes to explaining the ear everybody okay Nathan wants to know why are there semi-semicircular canals at right angles they're at right angles so that you have one for every movement of plane of movement so you've got to have one going up and down you have to go one left and right and one forward and backward that's how we move we move in a three-dimensional space okay all right and I think I'm going to run out of battery soon everybody so I just want to make that very clear so I'm going to call this live very soon but I want to just do a couple more questions in the background for you please put them in the chat now about anything you want me to quickly answer or revise for you please put that in the chat so somebody wants to know uh for Rosa wants to know do we have to draw any structures tomorrow please be prepared to draw a graph please be prepared to draw a pie chart okay I always threaten this one and people think that I'm like being funny about it every year but please be prepared for a pie chart a graph and if they are going to make you draw anything tomorrow it will never be something complicated it'll be like a sperm cell an egg cell or um like the the what the root or the shoot looks like after geo and phototropism have taken place and they're not going to ask you to draw like the whole ear they're not going to ask you to draw the whole eye um they might ask you in a very unique circumstance to maybe draw um I don't think they can't no they can't make you draw anything else egg cell sperm cell photo and geotropism results like of that it's about it guys and graphs obviously graphs you've got to be prepared for a histogram a bar graph a line graph and of course a pie chart if my screen is blurry it's actually not my screen everybody it is actually your screen um I'm streaming at a pretty high quality so it just means that you need to change your settings in order to be able to see everything um I think I did make a mistake did I make a mistake I'm trying to read what's here ma'am can you do long type of lens to correct them okay so I actually did that already I spoke about it I have myopia which by the way everybody you're supposed to know what myopia is I don't have to call it short-sightedness you need to know both so I have short-sightedness what correct short-sightedness a convex lens convex if I am long-sighted which means I can see far away or I have hypermetropia I have a con hold on rewind rewind sorry I have myopia myopia means I have a concave lens that's the lens in my glasses if I want to see uh if I have far vision which means I have long-sightedness I have a convex lens in my glasses yes that's why sometimes if you've noticed some people have that extra like window in their glasses and it's like it bulges out and that's because it is convex make sure I say that um no please don't say that the round window releases pressure because it doesn't I'm going back to my picture now to see what you're referring to but I swapped the lenses do you mean what you use to fix the lenses or what the lenses are doing I'm just you can reply to me I won't I'm not going to go off just yet um somebody asked you to use a pen or pencil for graphs you always use a pencil for drawing and a pen for labeling um I do I do have a pie chart video I do actually um if you go if you want to see a question with a pie chart you can go into my question playlist um on youtube um the metric question playlist and you'll see if you look just look at the thumbnails there is an actual picture of a pie chart and I can't remember what the topic was I don't know if it was for eyes or something like that but you'll see it if you'll see the pie chart I'll be in it and then there's like a pie chart next to me as one of the graphics um that's a past paper question with a pie chart so you can more than welcome to go and watch that and I'll show you how to plot it and how to calculate everything um calculations that's a good one you must be able to calculate percentage increase and percentage decrease everybody which is a very simple formula it is initial minus final over initial multiplied by a hundred I'll say it again initial minus final divided by initial times by a hundred and that will give you your percentage increase or decrease it'll be a positive number uh or a negative number depending if it's you know increasing or decreasing and by the way if you are a member everybody it does also mean that you have access to um my study guide I'm just seeing I do see um Tallulah has a good little point for me that I'm just clarifying for myself because I'm just going back and what I said to just make sure that if I do need to fix an explanation I will do so now I'm just gonna go back and see that's why it looks like I'm looking all over the screen is because I'm just going back in time to see what I'd said about the eye because I don't want to make a mistake as people watch this and obviously if I go too quickly it's possible and I don't want to do that um we spoke about accommodation and we did the lenses when you have myopia or short-sightedness your eye is too long to cornea it's too flat eye is too short it's far away oh I think I know what you're talking about you're talking about my accommodation explanation we are on the same patch don't use stress so if I'm looking for near vision near your ceciliary muscles they contract suspensory slacking oh I'm with you I'm with you Tallulah okay I'll share my screen quickly so we everyone knows what we're talking about so let me just open that up before I go everybody I want to clarify this I made this mistake earlier and it is an important one for me to fix before we go these two are what I want to swap around so this is close vision and this is far vision there we go so it's about the shape of the lens okay and so it's all about the shape the most important thing I want to teach you today um if