1. Deoxyribonucleic acid
DNA
Deoxyribonucleic acid

2. DNA! Makes up chromosomes
Contains genes: chunks of DNA that code for certain traits

3. Watson and Crick Discovered structure of DNA in 1953
long, twisted, double stranded.
Received Nobel prize for medicine in 1963

6. Rosalind Franklin: X-ray images of DNA
She did not receive the Nobel Prize because she was ineligible (she died in 1958).

7. NUCLEOTIDES: -building blocks of DNA
-made of a nitrogenous base (A, T, C, or G), sugar (deoxyribose), and phosphate.

8. The Bases
A = Adenine
T = Thymine
C = Cytosine
G = Guanine

9. DNA Backbone
The DNA backbone is a strand of alternating sugars and phosphates.
The nitrogenous bases (A,T,C, & G) attach at the sugar site.

10. DNA Rungs
The rungs of the DNA strand consist of the base pairs and are attached only to the sugar (deoxyribose).
Adenine only pairs with thymine. (A & T)
Cytosine only pairs with guanine. (C & G)

11. DNA Replication- occurs during interphase
DNA Replication- occurs during interphase. DNA unwinds and each half strand creates a new DNA molecule from loose nucleotides in the nucleus.
Step 1: Double strand unwinds, and is unzipped by an enzyme (DNA polymerase)

12. Step 2: Loose nucleotides join up with their matching base pairs on both separated strands. Enzymes called DNA polymerases attach the loose nucleotides.
Replication

13. Replication
Result: Two chains formed, each with one old strand and one new strand.

14. DNA Replication Enzymes(DNA Polymerases) unzip the DNA molecule
Each (half) strand is now a template for a new strand
DNA Polymerase joins complementary nucleotides to the template strand
DNA polymerase also proofreads for mistakes
Video

15. Do You Remember Ribosomes??
Protein
Synthesis-
creation of
proteins
from your
amino acids
according to
your DNA

16. Protein Synthesis
Transcription- to read and write a copy(called RNA) of a section of DNA code for building a protein. Occurs in the nucleus.
Translation- to translate the RNA code into building proteins from amino acids. Occurs at the ribosomes.

17. 3 main differences between RNA and DNA
RNA is like DNA, a long sequence of nucleotides.
3 main differences between RNA and DNA
The sugar is RIBOSE not deoxyribose
RNA is single stranded
RNA contains URACIL(U) instead of Thymine (T)

19. Types of RNA RNA is involved in protein synthesis. 2 main kinds of RNA
1. Messenger RNA (mRNA)- carries genetic messages from nucleus to ribosomes. Length= many letters= one gene
2. Transfer RNA (tRNA)- carries amino acids from cytoplasm to ribosomes. Length= 3 letters

20. Messenger RNA
Genes(sections of DNA) contain instructions for assembling amino acids. The instructions are carried in messenger RNA(mRNA) with the complementary base:
C in DNA is carried by G in mRNA.
G in DNA is carried by C in mRNA
T in DNA is carried by A in mRNA
A in DNA is carried by U in mRNA(*RNA has Uracil instead of Thymine)
The messenger RNA are messengers from DNA to the rest of the cell.

21. Transcription
Video

22. mRNA leaves the nucleus to find a ribosome to give its code to and translation begins.

23. Translation- translating the RNA code into building proteins from amino acids. Occurs at the ribosomes.
Amino Acids- the building blocks of protein molecules. We get them from digesting the protein(meat, etc) we eat
Codon – a set of 3 nitrogen bases on the mRNA that codes for creation of one amino acid. Ex. GCA codes for the amino acid alanine

24. Section 12-3

25. Note that the code for the mRNA codon is complementary to the code for the DNA codon. There will be one more complementary switch back to the original letters on the tRNA codon (sometimes referred to as the anticodon).

26. Transfer RNA(tRNA)
During the construction of a protein, a 2nd type of RNA molecule transfers each amino acid to the ribosome as it is specified by coded messages in mRNA.
These RNA molecules are known as transfer RNA. tRNA codons are sometimes called anticodons.

28. Translation (In the cytoplasm) mRNA molecule attaches to a ribosome
As each codon moves through the ribosome, the proper amino acid is brought into the ribosome by tRNA.
The amino acid is connected to the growing polypeptide(protein) chain.
video

29. Main Point DNA Transcription and Translation is
DNA  mRNA  tRNA  Protein
Video

30. Transcription is DNA converted to mRNA in nucleus
Translation is mRNA moving into the cytoplasm, where the code makes the protein molecule on the ribosomes

31. Genetic Mutations
Gene Mutations- errors in 1 or more nucleotides in the duplicated DNA sequence. May occur during replication or protein synthesis.
Chromosome Mutations- changes in the number or structure of chromosomes. Extra or lost chromosomes and added or deleted sections of chromosomes.