1. Terms YOU need to know!

2. What is the difference?
Chromosome
DNA
Chromatin
Gene
Chromatid

3. Chromatin DNA and proteins in a non-structured form
The term Chromatin = when the cell is not reproducing (Interphase)

4. Made up of DNA and proteins
Chromosome
Made up of DNA and proteins

5. Chromosome
Chromatin

6. Chromatid ½ of a chromosome 2 chromatids = 1 chromosome
TWO appear during the
process of mitosis =
sister chromatids

7. Contains hereditary information
DNA
Contains hereditary information
Found in chromosomes

8. Gene
“Instructions”
Many genes within DNA
Why we are who
we are!

10. What does homologous mean?
Homo = the same
Hetero = different

11. Homologous The same!! We get ½ our chromosomes from
… and ½ our chromosomes from

12. Karyotype
Mom
Dad
Homologous Pair
Dad
Mom

13. Who you callin' a diploid??
Haploid vs. Diploid
Who you callin' a diploid??

14. *Total number of homologous pairs of chromosomes in a cell*
Haploid
*Total number of homologous pairs of chromosomes in a cell*
What is the haploid number
of human cells? 23

15. Sperm and egg! = reproductive cells
Gametes
Sperm and egg! = reproductive cells
ARE HAPLOID! 23 15

16. Total number of chromosomes in a cell
Diploid
Total number of chromosomes in a cell
What is the diploid
number of human cells? 46

17. All other cells!
ARE DIPLOID! 46 17

18. Haploid vs. Diploid The reference to haploid cells is 1N
The reference to diploid cells is 2N
If N = 23 for humans (haploid)
Then 2N ( 2 x 23 ) = 46 (diploid)
Get it??

19. Sex chromosomes vs. Autosomes
Sex chromosomes = this is what determines our sex (duh!)
Autosomes = all the other chromosomes

20. Humans have 1 pair of sex chromosomes and 22 pairs of autosomes
X and Y (male)
X and X (female)

21. Any questions??

22. So Why Meiosis? Pg. 153 What is the purpose of meiosis?
Define the following key words:
Gamete
Crossing-over
Genetic Recombination
Independent Assortment
3. Why is crossing-over important in the creation of new gametes? Think of the BIG picture
4. List TWO ways that you see meiosis is different from mitosis