Topic 1

skeletal muscle fibers are larger/have many nuclei/are not typical cells fungal hyphae are (sometimes) not divided up into individual cells unicellular organisms can be considered acellular because they are larger than a typical cell/carry out all functions of life some tissues/organs contain large amounts of extracellular material e.g. vitreous humor of eye/ mineral deposits in bone/ xylem in trees/other example statement of cell theory/all living things/most tissues are composed entirely of true cells

name of component: 1 max e.g. plant cell wall/cellulose/interstitial matrix/basement membrane/glycoprotein/bone matrix; functions: 3 max EITHER e.g. (plant cell wall) strengthens/supports the cell/plant (against gravity); prevents the entry of pathogens; maintains the shape of plant cells; allows turgor pressure/high pressure to develop inside the cell; prevents excessive entry of water to the cell; OR helps cells to stick together/adhere; needed to hold cells/tissues together / example of cells/tissues holding together; forms interstitial matrix / forms basement membrane to support single layers of cells; e.g. around a blood capillary; forms (part of the) filtration membrane in the glomerulus;

small cells have larger ratio (than larger cells)/ratio decreases as size increases surface area/membrane must be large enough to absorb nutrients/oxygen/substances needed surface area/membrane must be large enough to excrete/pass out waste products need for materials is determined by (cell) volume cell size is limited (by SA/Volume ratio)/cells divide when they reach a certain size reference to diffusion across/through membrane/surface area

differentiation is development in different/specific ways cells carry out specialized functions/become specialized example of a differentiated cell in a multicelluar organism cells have all genes/could develop in any way some genes are switched on/expressed but not others position/hormones/cell-to-cell signals/chemicals determine how a cell develops a group of differentiated cells is a tissue

stem cells are undifferentiated cells; embryo cells are stem cells; stem cells can differentiate in many/all ways / are pluripotent/totipotent; differentiation involves expressing some genes but not others; stem cells can be used to repair/replace tissues/heal wounds;

lysosome: hydrolysis/digestion/break down of materials (macromolecules) Golgi apparatus: synthesis/sorting/transporting/secretion of cell products rough endoplasmic reticulum: site of synthesis of proteins (to be secreted)/ intracellular transport of polypeptides to Golgi apparatus nucleus: controls cells activities/mitosis/replication of DNA/transcription of DNA (to RNA)/directs protein synthesis mitochondrion: (aerobic) respiration/generates ATP

Award 1 mark per difference plant cells have cell walls, animals do not have plastids/ chloroplasts, animals do not have a large central vacuole, animals do not store starch, animal cells store glycogen have plasmodesmata, animal cells do not animal cells have centrioles, plant cells do not have cholesterol in the cell membrane, plant cells do not plant cells are generally have a fixed shape/ more regular whereas animal cells are more rounded

P: prokaryotic cells; E: eukaryotic cells DNA: P: naked/loop of DNA; E: associated with protein/histones/nucleosomes/DNA in chromosomes location of DNA: P: in cytoplasm/nuceloid/no nucleus; E: within a nucleus/nuclear membrane membrane bound organelles: P: none; E: present ribosomes: P: 70S ; E: 80S plasma membrane: P & E: same structure within both groups cell wall: P: peptidoglycan/not cellulose/not chitin; E: cellusose/chitin/not peptidoglycan respiratory structures: P: no mitochondria; E: mitochondria pili: P: pili present E: pili absent; plasmids: P: plasmids (sometimes) present E:plasmids absent; flagella: P: flagella solid E: flagella flexible/membrane-bound;