Many might think that an egg is made up of cells, when in actuality and egg itself is a cell. An egg has several main parts, including the egg shell (that acts as the cell membrane), the egg yolk and the egg white. There’s also a tiny white mass that is very important, it’s called the ovum, and it is the living part of the cell. If a hen lays an egg without mating with a cock then the ovum will not develop. If the hen does mate, then the egg will be fertile and it develops into a little chick. The egg being worked with in this experiment is not fertile (Lawrence Hall of Science 2009). The egg white is mostly water with a small amount of dissolved proteins known as albumin. The purpose of the egg white is to keep the embryo moist and cushioned during incubation. The yellow part in an egg is called the egg yolk. This is stored food for the embryo and fetus. The fetus consumes the yolk until it is almost gone, at hatching time (Lawrence Hall of Science 2009). An egg’s shell is its membrane. The shell is selectively permeable. This means that it determines what may enter and exit the cell(GT Biology Notes 09). When there are two different concentrations, a concentration gradient exists. When things move from a higher concentration to a lower concentration, it is known as diffusion. As long as diffusion is permitted to go on, equilibrium will be reached. Equilibrium is when two areas have reached equal concentration levels. The egg in this lab will have water and substances diffusing though it in and out. The direction, in which things diffuse, depends on the type of solution the egg is placed in. A hypertonic solution isa solution that is outside the cell and it has lower free water molecule concentration than cytosol. Water diffuses out of the cell and the cell shrinks. A hypotonic solution is a solution that is outside the cell and it has a higher free water molecule concentration than cytosol. The water diffuses into the cell and the cell...
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