1. Take out a piece of paper. Fold it in thirds
Take out a piece of paper. Fold it in thirds. Write observations at the top of one column, inferences at the top of the next, and predictions at the top of the last.

2. These two girls are twins. How could they look so different?

3. Independently and quietly, draw a model of how you think these twins came to be.

4. Our bodies are made up of over 37 trillion cells
How many cells do you think are in the human body? Hypothesize, and write down what you think!
Our bodies are made up of over 37 trillion cells

5. Each cell in our bodies contains genetic information called DNA that dictates many things, one of which is what we look like.

6. DNA is the genetic material that makes us who we are; what we look like, our strengths and weaknesses, our personality, etc. DNA, or deoxyribonucleic acid, is a long string like material called chromatin. To make all this information easier to store, the DNA is coiled into chromosomes.

7. DNA…
starts off as this…
then it coils to this!
Into a chromosome

8. DNA wraps around proteins to help condense it.
DNA double helix
DNA and histones
Chromatin
Supercoiled DNA
Chromatids
Centromere
This is a duplicated chromosome

9. Are there different types of chromosomes?
Humans and animals have 2 different types.
Sex chromosomes:
Either X or Y
Determine gender
Females are XX
Males are XY
Autosomes:
All other chromosomes in an organism

10. Humans….. ….have 2 sex chromosomes and 44 autosomes
How many total chromosomes are there?
How many pairs of chromosomes are there?

11. Every cell, except sex cells, have 2 copies of each autosome
Every cell, except sex cells, have 2 copies of each autosome. Where did they come from?
These copies are called homologous chromosomes.
They have the same size and shape.
They carry genes for the same traits.
How many pairs of homologous chromosomes do you have in your body cells?!

12. Diploid
Haploid
Have 2 sets of chromosomes (both chromosomes in a homologous pair)
Body cells
Have 1 set of chromosomes
Sex cells (gametes/sperm and egg cells)