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Discuss the possible origin of eukaryotic cell structures
Discuss the possible origin of eukaryotic cell structures, referring to the theory of endosymbiosis.
- One cell took in others
- In vacuoles / by endosymbiosis
- Kept them alive instead of digesting them
- One became the mitochondrion, and another the chloroplast
- Original cell respired anaerobically
- (prokaryotic) cell that respired aerobically became mitochondrion
- (prokaryotic) cell that photosynthesised became the chloroplast
- Symbiosis/mutualism benefits both/all cells involved
- Ribozomes sizes of mitochondria and chloroplasts evidence for symbiosis
- Presence/type of DNA in mitochondria and chloroplasts evidence for endosymbiosis
- Presence of two membranes is evidence for symbiosis.
Draw a diagram to show the ultra-structure of a generalised animal cell
Draw a diagram to show the ultra-structure of a generalised animal cell as seen in electron micrographs.
State one function of each of these organelles: Ribosome, RER, Lysosome, Golgoi Apparatus, Mitochondrion, Nucleus, Chloroplast, Nucleus
- Ribosome - Synthesises proteins
- Rough Endoplasmic Reticulum - Transports proteins from Ribosomes to other parts of the cell (such as Golgoi)
- Lysosome - Responsible for the cell's digestion/destruction of macromolecules, old cell parts, and microorganisms
- Golgoi Apparatus - the Golgi complex is the site of the modification, completion, and export of secretory proteins and glycoproteins - forms vesicles to export contents
- Mitochondrion - Site of second stage of aerobic respiration (ATP synthesis and Kreb's Cycle)
- Nucleus - Chromosones contain DNA - DNA arranged as genes which control all cell activities
- Chloroplast - Two stages of photosynthesis
State two similarities between prokaryotic and eukaryotic cells
- Cell Membranes
- Ribosomes
- Cytoplasm
- Nucleic Acids
State two differences between eukaryotic nucleus and prokaryotic nuclear material
- Eukaryotic - Nuclear Membrane, DNA in Chromosomes, DNA exclusively in nucleus
- Prokaryotic - No Membrane, DNA Loop, DNA and RNA in cytoplasm
Describe three differences between animal and plant cells
- Plant - Cellulose Cell Wall, Chlorophyll in Chloroplasts, Vacuole in Cell Sap
- Animal - No CCW, No CIC, Vesicles
State the composition and function of the plant cell wall
- Provide support (as water enters the cell osmotically the cell wall resists expansion and an internal pressure is created which provides turgidity for the plant)
- To give direct support to the cell and the plant as a whole by providing mechanical strength.
- To permit the movement of water through and along it and contribute to the movement of water in the plant as a whole in particular the cortex of the root,.
- Made of cellulose microfibrils embededded in an amorphous polysaccharide matrix
- Polymer of 10,000 beta-glucose molecules forming a long unbranched chain
- Many chains run parallel and have cross-linkages
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