Here, we will discuss how chromosomes are responsible for the similarities we inherit from our parents. A chromosome is a long DNA molecule with part or all of the genetic material of an organism. Most eukaryotic chromosomes include packaging proteins called histones which, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity.
Why we look somewhat like our
parents, but not exactly.
Think about the picture
Everyone in the class is
alike, but different.
How are we alike?
How are we different?
Click here and then on “Find out more
• The code for traits is contained in the nucleus of
each cell of our body.
• Inside the nucleus are chromosomes which are made of
DNA. This is the code to make you you.
DNA is a
• Click here for an animation showing the
relationship between cells, nuclei, chromosomes
– Then click on “What is DNA?”
– Then “Cellular Journey”
– Then Nucleus and
– Then “DNA Basics”
• Put the following items in order from
largest to smallest: chromosomes, DNA,
• Chromosomes are very small.
• Here is what they look like when you
see them through a microscope.
• Click here to see more about chromosomes.
Then click on “What are Chromosomes?
List three words that describe a chromosome.
• A karyotype is when
largest to smallest.
• They are also
grouped by the
and the banding
• List at least 3 chromosomes characteristics that are
used to make a karyotype. (What features of the
chromosomes do people look at to help them put the
chromosomes in the proper order?)
• Why do you think researchers and doctors would
rather look at a karyotype than at the chromosomes
smear as they appear through a microscope?
• Compare the karyotypes for a
male and a female.
A female A male
Compare the male and female karyotypes.
1. How are they alike?
2. How are they different?
3. How can you tell a female karyotype
from a male karyotype?
Body cells are all cells in the body,
except the egg and sperm
• Lung cells
• Liver cells
• Bone cells
• Nerve cells
• Skin cells
• Muscle cells, etc., etc., etc.
Where do we get new body
• Write where you think that we get new
• What do you think happens to the
number of chromosomes in these new
1. Before a body cell divides it copies every
one of the chromosomes.
2. When the body cell divides, each new
body cell gets a copy of each
3. The new body cell is exactly like the
original cell!! They have the same
number and same type of chromosomes.
Click here to see an
animation of this.
1. Look at this body cell. How many
chromosomes does it contain? _____
2. How many pairs of chromosomes? __
3. Sketch the body cells that will result after
this one divides. Draw
the new cell
of DNA is a
Scientists are finding out more
about DNA each day.
Human Genome Project:
• found the gene (code) for each
chromosome in our body
• don’t know exactly how each gene