1. What do I know about DNA? 4th period
DNA means deoxyribonucleic acid early 1900’s—not thought very important because so simple DNA is inherited from your parents—basis for genetics discovered in 1940’s Mutations mess up DNA & can cause birth defects or diseases discovered in 1970’s DNA is passed in sex cells discovered in 1950’s DNA makes up chromosomes-we have 20 something It’s twisty—like a twisted ladder—called a double helix Discovered 1951 nobel prize

2. What do I know about DNA? 5th period
DNA is found in the nucleus
You can identify a person by DNA analysis—unique for every person
Double helix structure
DNA is needed to make proteins
DNA controls everything happening in cell
Each child’s DNA comes from the parents
basis of genetics
parent’s got it from their parents
sex passes it on

3. DNA Structure and Replication Notes
November 11, 2018

4.
Who discovered dna?

5. Questions 4th period
Why do older women have more babies with birth defects? Why can blond mom and dad have red head kid?

6. DNA Structure Notes

7. Extract DNA from a strawberryhttps://www. youtube. com/watch
Pour DNA extract solution (dishwashing soap, NaCl, distilled water) into a sealable plastic bag with a strawberry. Seal … no leaks! Gently mash strawberry until it’s a smooth solution. (5 minutes) Line a funnel w/ cheesecloth, then filter mashed strawberry into a tube; mash juice but not chunks through cheesecloth. Throw out cloth; wash funnel. Gently layer (pour slowly down side of angled tube) cold alcohol onto top of strawberry solution. Watch 2 minutes as strands of DNA (chromosomes, each millions of nucleotides long!) rise into the top layer. Pull out some of the DNA with a plastic pipet, then add it to the class flask that is filled with alcohol (to make the DNA easier to see) Pour remaining solution down sink, rise tubes/stoppers & place in dish tray.

8. I. Functions of DNA = “Blueprint of Life”
Storing Information
Store the genes that code for basic instructions for cells and cell parts, physical traits, diseases, etc.
Eye color, blood type, skin color, diabetes, etc.
Copying Information
Before a cell divides, it must make a copy of every one of its genes
Process called DNA replication
Transmitting Information
Genes are transmitted from one generation to the next
DNA must be carefully sorted and passed along during mitosis and meiosis

9. II. Basics of DNA Structure
DNA - stands for deoxyribonucleic acid
B. double-stranded
C. 3-D model is called = double helix
Discovered by James Watson & Francis Crick (Received Nobel Prize 1962) with the help of Rosalind Franklin’s data

10. Long double helices of DNA, each millions of nucleotides long, form chromosomes. Each chromosome contains hundreds of genes. Humans cells have 46 chromosomes.

11. III. Nucleic Acid Structure
DNA is a type of molecule called a nucleic acid
The building blocks of DNA are known as nucleotides
All nucleotides have three “parts” in common:
Phosphate
Sugar (deoxyribose)
Nitrogen base

12. NUCLEOTIDE

13. B. Nitrogen Bases Four types: Adenine Guanine Cytosine Thymine
2. The order of these bases = the genetic code!

14. Complementary Base Pairing
A-T and C-G pairs are the only ones physically possible
Hydrogen bonds between nitrogen bases
2. Adenine and Thymine must form two hydrogen bonds to be stable while Guanine and Cytosine must form three hydrogen bonds

15. LET’S PRACTICE!
Write the complementary sequence of bases to this strand of DNA. A T C C G G A T

16. DNA Structure (more details)
Sugar/Phosphate “Backbone”
Sides of ladder
Covalent bond between
sugar and phosphate
Nitrogen Bases in center
Steps of ladder
Hydrogen bond between
Nitrogen bases
Double Helix
Twisted ladder
Anti-parallel
two strands of DNA run
in opposite directions

17. DNA is Anti-Parallel
The two strands of DNA run in opposite directions This allows for the bases to come in contact at the center of the molecule

19. DNA Replication Notes
November 11, 2018

20. I. DNA Replication Purpose All cells must divide to make new cells
Before cell division DNA is replicated so it can be passed to the new cell
This process of copying the DNA in the chromosomes is called DNA Replication
Without this process, new cells would have only half the DNA of their parents

21. Each new DNA molecule has one original “parent” strand and one new strand!

22. B. Process of DNA Replication
Occurs in the nucleus prior to any cell division
Enzyme is used to “unzip” or “unwind” the DNA into two single strands
Enzyme breaks hydrogen bonds between nitrogen bases
This occurs along several sections of the whole molecule of DNA
Enzyme

23. B. Process of DNA Replication (cont.)
Another enzyme, DNA polymerase, bonds a complementary nucleotide to each strand of template DNA
Nitrogenous bases pair up
A – T
C - G
Each strand is replicated in opposite directions, since DNA is anti-parallel
Process continues until the entire strand of DNA has been unzipped and replicated

25. B. Process of DNA Replication (cont.)
As a result, you create two new molecules of DNA that are identical to the original piece of parent DNA
Each DNA molecule has a new strand of DNA and an old strand of DNA (parent DNA)