Biology book chapter 1

• Active Transport


  A mechanism by which cells move substances into the cell against their concentration gradient, requiring energy input to accomplish.
• Moving Substances by Active Transport

  Uptake: moving substances into the cell (e.g., ions, sugars, amino acids). Efflux: removing substances from the cell (e.g., toxin removal)
• The Importance of Active Transport

  Regulation of cell homeostasis, cellular survival, maintaining cellular concentration gradients, regulation of cell signaling, maintenance of nerve function
• Surface Area to Volume Ratio


  The amount of surface area a cell has compared to its volume.
• Importance of Surface Area to Volume Ratio

  Affects cellular transport, energy consumption, and growth and development.
• As living organisms get bigger, their surface area to volume ratio get smaller. Gases and food molecules no longer reach cells inside organisms by simple diffusion.
• Adaptation for exchanging materials


  Features that help organisms secure food, water, shelter, and protection, such as specialized mouthparts, roots, stems, seeds, and pollen.
• What is a unique adaptation of the Australian Fitzroy river turtle?

  It can breathe underwater.
• How does the Australian Fitzroy river turtle facilitate underwater breathing?

  It has two large sacs lined with finger-like folds that provide a large surface area.
• What is the primary function of fish gills?

  To exchange oxygen and carbon dioxide between blood and the water.
• What process do fish use to obtain oxygen from water?

  They exchange oxygen and carbon dioxide between blood and the water in which they swim.
• What are the adaptations of the Australian Fitzroy river turtle and fish for respiration?

  • Australian Fitzroy river turtle:
  • Can breathe underwater
  • Has two large sacs lined with finger-like folds for increased surface area
  • Fish:
  • Exchange oxygen and carbon dioxide between blood and water