How is a human sample analyzed to determine the blood type?
Blood is a complex mixture of cells, enzymes, proteins, and inorganic substances. Under-
standing the different components of blood allows a scientist to use the components in sim-
plex tests are performed in a crime laboratory.done one site at the crime scene, or more com-
▪ Students will be able to distinguish between antigens and antibodies, and the uses of these
two components in blood typing.
▪ Students will be able to apply genetic inheritance of blood typing using Punnet squares.
Blood is primarily made up of a fluid portion, called plasma, and three types of
cells – erythrocytes, leukocytes, and platelets.
Proteins found in blood are made from amino acids linked together through a
Serology, the study of the proteins found in blood, used in forensics will focus
on the antigen / antibody protein connection to determine blood typing.
▪ Protein synthesis, DNA, chromosomes, genes, human reproduction
Saferstein, 8 edition, pg. 328-346
Model 1 : The Mixture Known as Blood
Other common Percentage Facts worth
names used found knowing
in whole blood
Plasma - 55% - a clear yellowish fluid that sits on top
can be milky in color after a fatty meal,
due to the fat molecules being
suspended Erythrocytes - Red blood - 45% - percentage of blood made up
cells called the hematocrit commonly
- shaped like a shallow bowl,
called a biconcave disc
- has NO nucleus, extruded out
- can change shape, allowing it to
squeeze through very small
- contains hemoglobin, the
protein that carries oxygen
- have antigens on their surface, a protein
with a specific shape that determines the