Unit 2 Cells 2.3 Eukariotic cells IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.1 Draw and label a diagram of the ultrastructure of a liver cell as an example of an animal cell. The diagram should show free ribosomes, rough endoplasmic reticulum (rER), lysosome, Golgi apparatus, mitochondrion and nucleus. The term Golgi apparatus will be used in place of Golgi body, Golgi complex or dictyosome. 2.3.2 Annotate the diagram from 2.3.1with the functions of each named structure. 2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells. 2.3.4 Compare prokaryotic and eukaryotic cells. Differences should include: Naked DNA versus DNA associated with proteins DNA in cytoplasm versus DNA enclosed in a nuclear envelope No mitochondria versus mitochondria 70S versus 80S ribosomes eukaryotic cells have internal membranes that compartmentalize their functions. 2.3.5 State three differences between plant and animal cells. 2.3.6 Outline two roles of extracellular components. The plant cell wall maintains cell shape, prevents excessive water uptake, and holds the whole plant up against the force of gravity. Animal cells secrete glycoproteins that form the extracellular matrix. This functions in support, adhesion and movement. Assessment statements IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko Introduction Eukaryotic organisms have cells that contain a nucleus. Animals, plants, fungi and protoctist all have eukaryotic cells. They all have organelles which can only be fully appreciated while observed with an electron microscope. Note that the image on the left is a highly schematic illustration. It compares some possible structures of both animal and plant cells. IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.1 Draw and label a diagram of the ultrastructure of a liver cell as an example of an animal cell. The diagram should show : Free ribosomes Rough endoplasmic reticulum (rER), Lysosome, Golgi apparatus, Mitochondrion Nucleus. The term Golgi apparatus will be used in place of Golgi body, Golgi complex or dictyosome. IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.2 Annotate the diagram from 2.3.1with the functions of each named structure. Cell organelle Structure Function (free) ribosome made of two subunits, both made of protein and RNA free ribosomes make proteins that are used in the cell site of protein synthesis (see Topic 3.5) IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.2 Annotate the diagram from 2.3.1with the functions of each named structure. Cell organelle Structure Function rough endoplasmic reticulum - RER RER is membrane with ribosomes attached. RER makes proteins that are exported via exocytosis in order to be used outside the cell free ribosomes make proteins that are used in the cell site of protein synthesis (see Topic 3.5) IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.2 Annotate the diagram from 2.3.1with the functions of each named structure. Cell organelle Structure Function lysosome contains hydrolytic enzymes e.g. lysozymes which can break down substances in the cell fuses with and digests old cell organelles and material taken in via endocytosis intracellular digestion); it also can burst and cause autolysis of a cell IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.2 Annotate the diagram from 2.3.1with the functions of each named structure. Cell organelle Structure Function Golgi apparatus stack of flattened, membrane-bound sacs, forming an extensive network in the cell intracellular transport, processing and packaging of proteins IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.2 Annotate the diagram from 2.3.1with the functions of each named structure. Cell organelle Structure Function mitochondrion the link reaction and the Krebs cycle take place in the matrix; the electron transport chain is found on the cristae of the inner membrane Involved in the release of energy from inorganic molecules IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.2 Annotate the diagram from 2.3.1with the functions of each named structure. Cell organelle Structure Function nucleus largest cell organelle contains DNA controls the activity of the cell by transcribing certain genes and not others (see Topic 3.5) IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells. Golgi apparatus An electron micrograph of a liver cell IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells. Endoplasmic reticulum Mitochondrium IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells. Lysosomes Nucleus IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.4 Compare prokaryotic and eukaryotic cells. Feature Similarities Differences Prokaryotes Eukaryotes Genetic material Naked DNA DNA associated with proteins Circular DNA Linear DNA DNA found in cytoplasm (nucleoid area) DNA enclosed in nuclear envelope Protein synthesis 70S (mass and size) 80S(mass and size) Respiration no mitochondria but uses plasma membrane and mesosomes Mitochondria Ultrastructure no internal membranes present compartmentalise the cell into areas with different functions The differences should include: Naked DNA versus DNA associated with proteins DNA in cytoplasm versus DNA enclosed in a nuclear envelope No mitochondria versus mitochondria 70S versus 80S ribosomes Eukaryotic cells have internal membranes that compartmentalize their functions IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko Protein synthesis 70S (mass and size) 80S(mass and size) Extra info Svedberg unit (symbol S, sometimes Sv) is a non-SI unit for sedimentation rate. It is often used to reflect the rate at which a molecule travels to the bottom of a test tube under the centrifugal force of a centrifuge. IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.4 Compare prokaryotic and eukaryotic cells. Feature Plant cell Animal cell cell wall cellulose cell wall and plasma membrane only plasma membrane chloroplast present in photosynthetic cells absent vacuole large, permanent vacuole, filled with cell sap small, temporary vacuoles may be present reserve food carbohydrate stored as starch and also plant oils carbohydrate storage as glycogen and some stored as animal fat IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.6 Outline two roles of extracellular components. Extracellular components are found associated with both plant and animal cells. Cellulose is the best known example of an extracellular component in plant cells. Bone, cartilage and connective tissue are examples of tissues with a very important extracellular component in animal cells. Link to explicative video IB Biology SFP - Mark Polko

IB Biology SFP - Mark Polko 2.3.6 Outline two roles of extracellular components. The cell wall is a non-living secretion (an extracellular component) of the cell and it serves several purposes: • The cell wall provides support and mechanical strength for the cell and in turn the tissues of the plant as a whole. It determines the shape of the cell. • As the plant cell takes up water, the intra-cellular pressure increases. The cell wall will limit the amount of expansion and prevent the plant cell from bursting. The cell will continue to take in water due to osmosis but the same amount of water will be expelled due to the pressure of the cell wall. The cell is now turgid and mechanically quite stable. Many plants depend to a large extend on turgor to keep them upright. • Cellulose is a carbohydrate and plants can use the cell wall for carbohydrate storage. • The cell wall provides a barrier for pathogens (disease causing organisms). Plant cells store specific proteins in the cell wall that recognise pathogens and start a ‘defense response’ to them. IB Biology SFP - Mark Polko

Unit 2 Cells 2.3 Eukariotic cells IB Biology SFP - Mark Polko