Why we look somewhat like our
parents, but not exactly.
Think about the picture
matching activity.
Everyone in the class is
alike, but different.
How are we alike?
How are we different?
Click here and then on “Find out more
about Heredity!”
• 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.
Nucleus
Cell
Chromosome
DNA: One
section of
DNA is a
gene
• Click here for an animation showing the
relationship between cells, nuclei, chromosomes
and DNA.
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Then click on “What is DNA?”
Then “Cellular Journey”
Then Nucleus and
Then “DNA Basics”
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• Put the following items in order from
largest to smallest: chromosomes, DNA,
cell, nucleus
• Chromosomes are very small.
• Here is what they look like when you
see them through a microscope.
Chromosome
smear
•
Click here to see more about chromosomes.
Then click on “What are Chromosomes?
List three words that describe a chromosome.
a.
b.
c.
• A karyotype is when
chromosomes are
grouped from
largest to smallest.
• They are also
grouped by the
centromere position
and the banding
patterns.
• 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?)
a.
b.
c.
• 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
karyotype
A male
karyotype
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
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
cells?
• Write where you think that we get new
cells.
• What do you think happens to the
number of chromosomes in these new
cells?
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
chromosomes.
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 here:
One section
of DNA is a
gene
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
(code) works.