hi everyone and welcome to miss cestric biology in this video i'm going to be going through eukaryotic cells for a level biology so first of all let's have a look at what are the organelles that you need to know the structure and function of for this topic the cell surface membrane the nucleus mitochondria chloroplasts golgi apparatus and the vesicles lysosomes ribosomes rough endoplasmic reticulum and the smooth endoplasmic reticulum so rer and scr and the cell wall and the cell vacuole so for each of these i'll go through the structure and function with a diagram in the level of detail that you need for a level biology now if you want to have a go at testing yourself pause now and have a go if not i'm going to go through what all of these labels are on the cell so first of all there is our cell surface membrane we have an example there of the rough endoplasmic reticulum so those circles on the outside that make it rough are the ribosomes then we have the golgi apparatus the cytoplasm a lysosome ribosome a centrosome now that's not actually on the aqa or the a level specification but i've included that there just so you can see that structure and that is involved in cell division the smooth endoplasmic reticulum and a mitochondrion and if that was pointing to pleural it'd be mitochondria but the singular is mitochondrion so same again for the plant cell pause if you want to test yourself if not we're going straight into it so we're starting over here with the smooth endoplasmic reticulum so you can't see any of those ribosome on the outside that's how we know it's a smooth it's then pointing to those dots on the outside and those are the ribosomes on the outside of the rough endoplasmic reticulum we've got then the nucleus the nuclear envelope and the pores the rough endoplasmic reticulum or rer goldie apparatus and here we have some golgi vesicles coming off the golgi apparatus cytoplasm mitochondrion the vacuole chloroplast cell wall and finally the plasma membrane so let's get into each of those structures starting with the nucleus so the structures that you need to know about are the nuclear envelopes so this is the plasma membrane on the outside of the nucleus and it's a double membrane there are holes within it which we call pores the liquid within or this granular jelly-like substance is the nucleoplasm the nucleus is where you find the chromosomes and inside there's a nucleolus and this here is where the rrna production happens so that is where the rna to make ribosomes occurs so the function of the nucleus is it's the site of dna replication it's also the site of transcription which is the first stage in protein synthesis where mrna is created and it's where all of the genetic information is contained for the cell so the next structure is the endoplasmic reticulum and you can have either rough which means it's got ribosomes on the outside or smooth and in both cases it's folded membranes called systony and as we said the rough ones have ribosomes on the outside and because they have ribosomes on the outside of that rer that means that is where protein synthesis happens because protein synthesis happens on ribosomes the smooth endoplasmic reticulum that is where synthesis of lipids and carbohydrates happen and also they can be stored there the golgi apparatus and vesicles these look very similar to the smooth endoplasmic reticulum but they're often more curved in appearance so we can see here it looks a bit more semi-circular so again it is folded membranes to make these cysteine a and you have these vesicles pinching off and that will then be carrying a finished product that has been made and some of those products then are linked to the function column here so in the golgi you can have carbohydrates being added to the proteins which are first of all passed into the golgi from the ribosomes and we then call them glycoproteins meaning carbohydrate attached to a protein you could have secretory enzymes being produced carbohydrates in general we have the proteins and carbohydrates being modified transported and even storing lipids as well as modifying them you can create lysosomes which are vesicles that contain these enzymes molecules can be labeled for the destination that they're going to so that could mean you're adding on a receptor for example and the finished products are transported to the cell surface membrane to then be released to wherever they need to go in these golgi vesicles so lysosomes we briefly talked about there but lysosomes are bags of or sacks of digestive enzymes and those enzymes are able to hydrolyze things such as phagocytes and they will completely break down dead cells whether that is a phagocyte or your own body cells and we call that auto lysis exocytosis will then happen which is when we have the release of enzymes to the outside of the cell to destroy material and it can also digest worn out organelles so they can then be reused so it's not just pathogens that get digested by the enzymes from lysosomes it's also dead cells dead organelles or not dead organelles but as i said worn out organelles the mitochondria so this is the site of aerobic respiration anaerobic respiration happens in the cytoplasm but most atp is made in aerobic respiration so this organelle has two membranes it's a double membrane organelle the inner membrane is folded to make these cristy and the fluid within that is called the mitochondrial matrix and it also has its own loops of dna and that is because that dna will code for the enzymes required for respiration ribosomes come as two subunits so we have a smaller and a larger subunit and there's two types of ribosomes depending on whether they're found in eukaryotic cells or prokaryotic cells eukaryotic cells will have larger ribosomes which we describe as being ats and prokaryotic cells such as bacteria will have smaller ribosomes which we describe as 70s and ribosomes are made up of rrna and proteins and the function of a ribosome is protein synthesis vacuoles you do not find in animal cells but within the plant cells vacuoles are fluid filled they just have a single membrane around the outside and we call that membrane the tonoplast and the function of the vacuole is to help give the cell structural support it pushes from the inside out so it helps to make the cell turgid it's also a temporary store of sugars and amino acids and sometimes the pigments that may um color the petals to attract pollinators are found within the vacuole as well chloroplasts is another organelle only found in the plants not animals it's very similar to a mitochondria so again you've got a double membrane you also have folded membranes but this isn't the inner membrane this is additional membranes called thylakoid membranes and those can stack up to make what we call a granum and this is going to be the site of the light dependent reactions in photosynthesis the fluid on the inside is called the stroma and that contains the enzymes required for photosynthesis in the light independent reactions so that's the function of chloroplasts it's the site of photosynthesis and the reason it's green is all of the chlorophyll pigment embedded within the membrane of the thylakoids cell walls are not found in animals but they are found in plants and fungi but they're made up of different substances the plant cell wall is made up of cellulose and those cellulose polymers bond together with many many hydrogen bonds to make fibrils or microfibrils and that then goes towards making the cellulose fiber which provides structural strength fungi have chitin instead of cellulose and that's a nitrogen containing polysaccharide the cell wall though whatever it's made of the function is to provide structural strength the plasma membrane now this is found in all organisms and the plasma membrane controls what can enter and exit the cell but also organelles if it's an organelle which is membrane bound so these are found as i said in all cells i have that phospholipid bilayer and within that phospholipid bilayer you have proteins embedded you also have receptors which could be glycoproteins or glycolipids you have cholesterol as well but the function is to control what can enter and exit either the organelle or the cell so that is it for what you need to know about the eukaryotic cells structure and function organelles for a level biology if you found it helpful please give this video a thumbs up you