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DNA: The Genetic Material of Life
All cells contain genetic information that is located within the nucleus of a cell, but just
what is that genetic material of life?
Within the nucleus, the genetic material of a cell is organized into threadlike structures
called ____________ and each chromosome contains many different _______ that are
the units of genetic information which determine specific characteristics of an individual.
Each living thing has a specific number of chromosomes within the nucleus of every one
of its cell. Humans have _____ chromosomes, dogs have _____, and mice have ____.
However, all chromosomes are made up of the same chemical called
______________________________________(____). DNA is the genetic material that
provides a cell with all of the information needed to perform all the functions
(ex. Growth, repair, making new cell parts, and reproduction)
DNA has a structure known as a _______________ (it looks like a ladder that has been
twisted). The sides of a DNA molecule are made of ________ (5-carbon deoxyribose)
and ____________ molecules. In between, there are ________ _____ that pair together.
DNA has 4 nitrogen bases that combine in different ways to produce the genetic code.
The nitrogen bases are:
A – ______________ and T – ________________;
G – ______________ and C – ________________;
Adenine and Thymine always pair up and Guanine and Cytosine always pair up.
Every sequence of 3 nitrogen bases (a codon) is like a ‘word’ and those sequences
combine to give a ‘story’ which is the genetic blueprint for a molecule.
The genetic blueprints (stories) that are formed are the genes that determine specific
characteristics (hair colour, height, flower colour ….)
The genetic code is made up of ~_______ billion nitrogen bases arranged on ~________
genes on 46 chromosomes of a human being
**Initial thoughts were ~6 billion bases on 100,000 genes
Genetic Variation:
Humans have _______ chromosomes (23 pairs). One chromosome from each pair comes from
your _________ and the other from your __________. Each chromosome carries the same genes
but the information on the genes may be slightly __________, therefore you are a combination of
the genes of both your parents. The characteristics that you end up with depend on the ________
of each gene you receive. The DNA contained in your chromosomes is __________ and no one
else has exactly the same DNA (except identical twins)
DNA and Cancer:
DNA can be exposed to harmful chemicals that get into the nucleus of a cell. Any of these can
cause the order of the nitrogen bases to change which results in a change in the genetic code called a _______________. Sometimes mutations can be beneficial but they are usually neutral.
Cancer is one example of a mutation that is damaging to a cell. Cancer is a group of diseases
that are associated with ______________ and _______________ cell division. When mutations
occur to the genes that control cell division, cancer can result. Substances that cause mutations
are called _____________________ (ex. Viruses that cause leukemia, radiation that causes skin
cancer and chemicals such as those in cigarettes that may cause lung cancer).
Cancer cells reproduce too quickly and this can crowd out or damage healthy cells. They cannot
carry out specific functions of healthy cells because they don’t specialize. Normal cells
specialize as they grow to perform specific functions. Cancer cells don’t do this and therefore
they use the resources of the body to reproduce but don’t do the ___________ as normal cells do.