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6.2 Water and Diffusion. Martin a.k.a. Tha ’ Boss!. THE POLAR WATER MOLECULE. I. WATER AND IT’S IMPORTANCE. Water dissolves things Water can help transport things into organisms Blood and sap (mainly H 2 O) transport things in animals and trees. I. WATER AND IT’S IMPORTANCE.
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6.2 Water and Diffusion Martin a.k.a. Tha’ Boss!
I. WATER AND IT’S IMPORTANCE • Water dissolves things • Water can help transport things into organisms • Blood and sap (mainly H2O) transport things in animals and trees.
I. WATER AND IT’S IMPORTANCE • A. Water is Polar • Hydrogen side has a net “positive” charge • Oxygen side has a net “negative” charge • This gives the molecule a positive and negative end • Allows it to attract other positive or negative ions • Such as Na+ or Cl- • Polar molecule: a molecule with an unequal distribution of charge (has a positive end and negative end)
I. WATER AND IT’S IMPORTANCE • A. Water is Polar • Polar molecules attract polar molecules • hydrogen bonds: opposite charges between hydrogen and oxygen • Occurs between water molecules • Water can creep up thin tubes in a motion called “capillary action” • Used in plants to get water to leaves
I. WATER AND IT’S IMPORTANCE • B. Water resists temperature changes • Very important in helping maintain homeostasis • Good insulator for humans • Humans made mainly of animal cells, and cell are over 70-90% water
II. DIFFUSION • A. Early observations: “Brownian motion” • First observed in grains of pollen suspended in water (using a microscope) • Robert Brown noticed that the pollen was “constantly” moving in a random nature with no explanation • Can be seen in gases, liquids, and some solids
II. DIFFUSION • B. The Process of Diffusion • Diffusion: the net movement of dissolved particles (solutes) from higher concentration to lower concentration • Caused by “Brownian motion” • Is a very slow process
II. DIFFUSION • B. The Process of Diffusion • 3 Things that affect how fast diffusion occurs • Concentration (most important factor) • Temperature • Pressure • Increase in any of the above, will increase how fast diffusion of solutes will happen
II. DIFFUSION • C. The Results of Diffusion • Molecules will reach a “homeostasis” point • However, molecules will be equally moving in a cell, and equally moving out at the same rate • Dynamic equilibrium: point in which there is continuous movement of materials in and out of a cell, but no net change in concentration
II. DIFFUSION • D. Diffusion in Living Systems • Concentration gradient: differences in concentrations across space • Diffusion occurs in all living things to move things in and out of their cells • Cells are most surrounded by water. Cells are mostly water inside as well • Oxygen also diffuses into the air sacs in the lungs (part of the reason why we breathe)