Group 1: OSMOSIS

Definition: Diffusion of water across a selectively permeable membrane (high to low concentration)

1 Factor that controls osmosis: concentration gradient-unequal distribution of particles

#3: water diffusing across a selectively permeable membrane the number of sugar molecules did not change on each side of the membrane but the number of water molecules on either side did change.

#4: water moves through or diffuses from different levels in concentration through the cellular membrane. almost all cells are subjected to osmosis because they are surrounded with water *** maintains homeostasis

#5: concentration of dissolved substances in the solution is the same as the concentration of dissolved substances inside the cell

Water moves at the same rate in and out of the cell

Group 2:

  1. Hypotonic: concentration of dissolved substances is lower in the solution outside the cell, than the concentration inside the cell.

Hypertonic: concentration of dissolved substances outside the cell is higher than the concentration inside the cell.

  1. hypotonic: cells experience osmosis. Cells are getting larger.

Hypertonic: experience osmosis that causes water to flow out. Cells are getting smaller.

  1. refer to picture on the board
  2. Isotonic stays the same.
    Hypotonic gets more water and has more concentration in the cell.
    Hypertonic has less concentration in the cell and loses water.

Group 3

  1. Passive Transport- movement of particles across the cell membranes by diffusion or osmosis; the cells use no energy to move the particles across the membrane.
  2. Facilitated Diffusion- passive transport of materials across a plasma membrane by transporting proteins embedded in the plasma membrane.
  3. Channel proteins form channels to allow only specific substances to flow through it. Carrier Proteins change shapes to allow a substance to pass through the plasma membrane.
  4. Demo= passive transport.

Group 4

  1. Active transport is the movement of materials through a membrane against a concentration gradient, requiring energy from a cell.
  2. Active transport occurs when a carrier protein first binds with a particle of the substance to be transported. Then the proper molecule binds with the protein, chemical energy allows cell to change the shape of the carrier protein, so the particle to be moved is released. [rubber band]
  3. Passive transport doesn’t use energy & active transport uses energy.
  4. Active transport is the materials being actively transported. This requires energy because it is not passive, less work for the cells. It occurs when unnecessary binding occurs.

Group 5:

  1. Endocytosis Process of cells taking in substances from low to high concentration

Exocytosis The expulsion or excretion of substances from an area of low concentration to an area of high concentration.

  1. Exoskeleton and Endoskeleton
  2. Surface area is how much material is in contact with the outside; Volume is the inner content
  3. DNA is needed to make proteins and a large cell would need a lot of proteins to transport materials and DNA can only make protein so fast.

Diffusion limits cell size because since diffusion is slow a large cell would have to wait for a long time for the nutrients to reach the mitochondria.

Surface area-to-volume limits cell size because when the surface area increases a little the volume increases a lot. This means there is little surface area to absorb all the necessary substances required to help the cell function.