1. Chapter 4 Genes and DNA
Section 1+2
Pages

2. What does DNA look like? Pieces of the Puzzle: DNA
DNA must be able to be

3. Nucleotides: Subunits of DNA
A nucleotide consists of a ______, a ______, and a _____. Nucleotides are identical except for their base.
There are 4 bases: A_____, T_____, G_____, and C______
All four bases have a different _____.

4. Chargaff’s Rules
Guanine and Cytosine always occur in _____ _______ in DNA, as do Adenine and Thymine

5. Franklin’s Discovery
Used X Ray diffraction to make images of DNA molecules
Suggested the ____ shape of DNA

6. Watson and Crick’s Model
After seeing Franklin’s image, Watson and Crick concluded that DNA must look like a ____, ______ ______.
This helped explain how DNA is ______ and how it ______ in the cell.

7. DNA’s Double Structure
Double Helix, two sides of the ladder are made of alternating _____ parts and ________ parts.
The rungs of the ladder are made of a pair of bases:
A______-T______
G______-C______

8. Animated DNA

9. Making Copies of DNA
Pairing the bases allows the cell to _______ or make copies of DNA
The pairs are _____________ since they always pair A-T and G-C

10. How are copies made?
During replication, a DNA molecule is _____ ____ the _______, where _____ meet.
The bases on each side of the molecule are used as a _________ for the new strand.
As the bases on the original molecule are exposed, _________ ________ are added to each side of the ladder.
Two DNA molecules are formed.
Half of each of the molecules is old DNA, half is the new DNA

11. Unraveling DNA
DNA is often wound around ______, coiled into strands, and bundled up even more.
Cell’s without a nucleus the DNA forms ______ ______ within the cell.
Cell’s with a nucleus the DNA and proteins are bundled into __________.

12. When are copies made? DNA is copied …
The job of ________, ________ and __________ the DNA is done by proteins within the cell.

13. Unraveling DNA The structure of DNA allows it to hold ________.
The ______ of the bases is the code that carries the information.
A gene consists of
Humans have over ______ genes.
2003 Human Genome Project

14. Unraveling DNA- Quiz Where is the DNA in your cells?
How does so much DNA fit into the nucleus?
What is the name for strands of DNA wound around proteins?
When do chromosomes become visible in cells?
What are chromatids? In
It is C
When the
Two

15. Genes and Proteins
DNA code is read like a book, from one end to the other and in one direction.
Bases form the alphabet of the code.
Groups of __ bases are code for the ____ _____ profile. (example: AGC)
A long string of amino acids forms a ______.
Each gene is

16. Proteins and Traits
Proteins are found _______ cells and cause most of the _______ that you see among organisms.
Proteins act as _______ ________ and ________ for many processes within the cell.
A single organism may have _______ of genes that code for thousands of proteins.

17. Help from RNA RNA (ribonucleic acid) a molecule
Helps in the process of

18. Making of a Protein
Step 1: A copy is made of one side of the DNA segment where a particular gene is located. This copy is transferred to the _________.

19. Making of a Protein
Step 2: This mirror like copy of a DNA segment is called messenger RNA (mRNA).
Messenger RNA..

20. Making of a Protein
Step 3: Each group of ____ bases on the mRNA segment codes for ___ amino acid.

21. Making of a Protein
Step 4: The mRNA segment is fed through the _______. A ribosome is a cell organelle composed of ____ and _______.

22. Making of a Protein Step 5: Molecules of
transfer RNA (tRNA) deliver amino acids from the cytoplasm to the ribosome.
Transfer RNA (tRNA) transfers

23. Making of a Protein Step 6: The _____ _____ are dropped off
at the ribosome.

24. Making of a Protein
Step 7: The amino acids are joined to make a ______. Usually, one protein is produced for each _____.

25. Animated mRNA

26. How is RNA different from DNA?
RNA: one strand
contains ______ instead of thymine
A, G, C, U
DNA: two strands
A, G, C, T

27. Changes in Genes
Mutation: a change in the nucleotide-base sequence of a gene or DNA molecule
Either __________, ________ or ___________
Causes an ___________, __________ or _____________
If the mutation occurs on the sex cells, the mutation can be passed to the _______ _________
Mutations happen _______
Mutagens are any physical or chemical agent that can cause the mutation (examples: UV radiation, X rays, cigarette smoke)
Examples are

28. Example of Substitution
Sickle Cell Anemia- affects red blood cells. When _______ is substituted for _______ _______ in a blood protein. The change in shape isn’t good for the cell to carry oxygen and clot in vessel (very painful).

29. Genetics
Genetic Engineering: Manipulate individual genes to create new products, such as foods, drug or fabrics
Genetic Identification: DNA is your unique fingerprint, only identical twins share DNA
Clone:
Selective breeding: A technique to produce offspring with desirable traits.
Inbreeding:
Hybridization:

30. Web sites….. DNA and Genetics:
Genetics: