Genetics
All the information your body needs to function is inside the nucleus
of every cell inside your body. The nucleus contains detailed
information for the cell of its role. The information is what we
call DNA. This blueprint, or DNA molecule, is the building block
of the entire body. Many DNA molecules are combined into a double
helix which is what typically see when DNA is displayed.
DNA strands are made up of combinations of four letters: G (Guanine),
A (Adenine), T (Thymine), and C (Cytosine). These letters combine
to make up pairs. A and T are always together and C and G are
always together. When the letters are combined into sentences,
they are called genes.
Genes order the cells to make protein molecules which enable the
cells to perform special functions as programmed. Some cells are
programmed to carry oxygen throughout the body while others determine
the color of the eyes.
Each of our 100 trillion cells has a job. The cell has
thousands of proteins which were designed to work together to make the
cell function.
Many of these traits are passed along from one generation to another.
Each parent passes along a random set of 23 chromosomes to a child (half
of the parent's 46). When the child is conceived, it takes the 23
chromosomes from each parent and has the perfect number of 46.
Each person has 22 pairs of autosomes (which get smaller in size
the further down the numbers you go) number which look the same in males
and females. The 23rd pair of chromosomes are different though.
Females have two X chromosomes, while males have one X and one Y
chromosome. Because each parent can pass along chromosomes from
either side of their DNA strand, no two children are exactly alike
(except for twins).
Children inherit different traits from the parents. Physical
traits and behavioral traits are both passed along. If both
parents have the same trait, chances are the child will have that trait.
Your environment can also play a part in your makeup.
Mutations can be an inherited trait from a parent and is in virtually
every cell of the body. Mutations that occur in an egg cell or
sperm cell or just after the egg is fertilized are the cause of genetic
disorders. These occur even if there is no family history of the
genetic disorder.
Mutations can occur after a person is born and are caused by
environmental reasons. This cannot be passed on to descendants.
Down syndrome is occurs when a person has an extra chromosome
21. They have 47 chromosomes in each cell.
Cancer cells have changes in their number of chromosomes. |
