2.3 eukaryotic cells

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2.3 eukaryotic cells

  1. 1. 2.3 Eukaryotic Cells Topic 2 Cells
  2. 2. Eukaryotic Cells 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. 2.3.2 Annotate the diagram from 2.3.1 with the functions of each named structure. 2.3.3 Identify structures from 2.3.1 in electron micrographs of liver cells.
  3. 3. Eukaryotic 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.
  4. 4. Eukaryotic 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.
  5. 5. A Generalised Animal Cell
  6. 6. A Generalised Animal Cell Ref: Advanced Biology, Roberts,Riess
  7. 7. Parts of a Generalised Animal Cell You should know the function of the following parts: – Ribosomes • Site of protein synthesis – Rough Endoplasmic Reticulum • Transportation of proteins synthesised by the attached ribosomes – Lysosome • Small vesicles containing digestive enzymes – Golgi Apparatus • Packaging of proteins into vesicles – Mitochondrion • Site of aerobic respiration – Nucleus • Contains the chromosomes (genetic information) for the cell • Controls the activities of the cell
  8. 8. Mitochondria Double membrane: – Outer membrane and Inner membrane. Inner membrane is folded forming cristae The interior contains an organic matrix containing chemical compounds.
  9. 9. Rough Endoplasmic Reticulum and Ribosomes A membrane system of flattened parallel cavities which are interconnected and covered with ribosomes. An intracellular transport system
  10. 10. Golgi Apparatus Consists of a stack of flattened cavities which package substance produced by the cell into vesicles. These vesicles can fuse with the cell membrane (exocytosis) or become lysosomes (digestive vesicles).
  11. 11. Golgi Apparatus Ref: Advanced Biology Roberts etal.
  12. 12. Prokaryotic vs Eukaryotic Feature Prokaryotic Cells Eukaryotic Cells Type of Genetic material A naked loop of DNA Chromosomes consisting of strands of DNA wrapped around associated proteins (Histones) Location of genetic material In the cytoplasm in a region called the nucleoid In the nucleus, inside a nuclear membrane (nuclear envelope) Mitochondria Not present (mesosome used instead) Always present Ribosomes Smaller sized (70S) Larger sized (80S) Organelles No membrane bound organelles Many are present eg: ER, Golgi Apparatus, lysosome S = svedburg units. A measure of the size of organelles
  13. 13. Plant vs Animal Cells
  14. 14. Plant vs Animal Cells Plant and animal cells have many similarities because they are both eukaryotic. They also have some differences: Feature Animal Plant Cell Wall Not present Present (made of cellulose) Chloroplasts Not present Present in plant cells that photosynthesise Carbohydrate Storage Glycogen Starch Vacuole Not usually present. If present they are small Large and permanent
  15. 15. Plant Cell Walls The main component of plant cell walls is cellulose. Cellulose molecules are arranged in bundles called microfibrils. The function of the plant cell wall is to provide strength and support the plant. The microfibrils are laid down in a criss-cross way across the cytoplasm. These give the cell great tensile strength They also allow high pressure to be built up as a result of Osmosis. This is called Turgor Pressure.
  16. 16. IBO guide: 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 2.3.1 with the functions of each named structure.
  17. 17. IBO guide: 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.
  18. 18. IBO guide: 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.

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