1. People and Terms YOU need to know!

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

3. Where can we find DNA? DNA up close! chromosome cell nucleus
Double stranded DNA molecule
DNA up close!
Individual Nucleotides

4. Messages from the inside?
DNA (Deoxyribonucleic Acid) is the genetic information of all living organisms stored in units called genes
A gene is a sequence of DNA that codes for a protein
These proteins make up our traits!!!

5. What about those alleles we learned about last time?
Our traits (genes) are inherited by our ancestors, but how do those traits tell our bodies to look the way we look? It’s a code!
(Like the Braille activity we did!) = CODE

6. Rosalind Franklin
Took x-ray of what is now known as the DNA double helix
Shared the Nobel Prize for aiding in discovery of the double helix of DNA

7. The Structure of DNA
Using the information found by Rosalind Franklin, Watson & Crick developed the double helix model of DNA in 1953
The double helix consists of a backbone made of sugars and phosphates and alternating bases called nucleotides

9. Nucleotides A nucleotide is the monomer of DNA
Nucleotides are small molecules made up of three parts
A ribose (sugar)
A phosphate group
A nitrogenous group

10. DNA’s Four Nucleotides
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
Phosphate group
Deoxyribose

11. Base Pairing Adenine always binds with Thymine (A-T)
Cytosine always binds with Guanine (C-G)

12. Rungs of the Ladder are pairs of nitrogenous bases
This is one example of the ladder being “untwisted”
and how the bases are paired together

13. Let’s put it all together!
Nucleotide
Hydrogen bonds
Sugar-phosphate backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)

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

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

16. Chromosome
Chromatin

17. Chromatid ½ of a chromosome 2 chromatids = 1 chromosome
TWO appear during the
process of mitosis = SISTERS!

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

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

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

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

23. Mom
Dad
Homologous Pair
Dad
Mom

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

25. *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

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

27. 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??

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

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

30. Any questions??