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LEQ: Why are most cells microscopic?. Reading: 5.1, 5.5 Activator – identify small everyday objects in your life. What are the advantages to being small? Why are these things small? Record the thoughts of your group in your journal. Key terms: surface area, volume.
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LEQ: Why are most cells microscopic? • Reading: 5.1, 5.5 • Activator – identify small everyday objects in your life. What are the advantages to being small? Why are these things small? Record the thoughts of your group in your journal. • Key terms: surface area, volume
UNIT CONCEPT Cells have distinct phases of growth, reproduction, and the potential for specialization in multicellular organisms.
Cells need surface area to acquire resources for chemical reactions • Diffusion depends on surface area and volume • How do cells acquire more surface area? • compartments (volume) for chemical reactions? • ,
Volume increases faster than surface area. Limitations: • concentration is inversely related to volume • Surface area to volume ratio
Surface area increases while total volume remains constant 5 1 1 Total surface area [Sum of the surface areas (height width) of all boxes sides number of boxes] 150 750 6 Total volume [height width length number of boxes] 1 125 125 Surface-to-volume (S-to-V) ratio [surface area ÷ volume] 6 1.2 6
Simple cells can only perform so many different reactions efficiently
Summary: • Which has a larger surface are to volume ratio – a tennis ball or a soccer ball? Explain your answer. • What limits the maximum size of a cell? Some single celled organisms have been found to consist of cells over 4 mm long. Speculate – what sorts of adaptations should biologists look for to explain how they maintain homeostasis?