Download Cell Differentiation - David Brotherton CCCMC

Biology
Lesson 6: Cell Differentiation
Objective: 1.1.3
Just as organelles have shapes and structures related to their functions, cells are also specialized.
Cell Differentiation: The proces that produces specailized cells with different structures and functions.
Genes: Sections of DNA (i.e. nucleotides/rungs fo the DNA ladder) that code for specifc traits.
Sequence for Eukaryotes
The fertilization of a female sex cell (egg) by a male sex cell (sperm) to form a fertilzied egg (Zygote).
 The zygote’s DNA serves as the instructions for the development of the entire organism.
 As the zygote grows by repeated cell division, all the new cells receive the same DNA.
 Although almost all cells contain a complete copy of the DNA, only a portion of that information
is needed at any given time. During cell division, cells use certain parts of the DNA strand and
ignore others.
 Once differentiation has begun, it can not be changed (i.e. a mucsle cell can’t become a liver cell).
However, for a period of time as an embryo develops, the type of cell to be produced can be
altered.
Stem Cells:The unspecialized cells that have the capacity to differintiate into many types of
specialized cells.
Types:
Embryonic Stem Cells: Found in embryos and umbilical cords.
Adult Stem Cells: An exmaple for humans is bone marrow cells, which differentiate to
become either blood or bone cells.
Gene Expression: The process by which the information in genes is used to make proteins.
 Not all genes are expressed or make proteins at a given time.
Ex: The gene that codes for hemoglobin, which carries oxygen in the blood is expressed in blood
cells but not in the pancrease.
Gene Regulation: A complex mechanism that determines whether a gene is turned on or off in a cell.
Ex: Genes associated with the production of reproductive hormones are not turned on until
puberty in humans and genes that control the growth of bone are turned off at maturity.
Key Words:
Gene
Cell differentiation
Zygote
Stem cell
Gene Expression
Gene Regulation