1. Molecular Biology: DNA & Protein Synthesis
Ch. 8
Honors Biology

3. History of DNA Research
1) _________ (1928)- discovered harmless bacteria could be made harmful when mixed with another bacteria that causes disease through a process called “________________”

4. History of DNA Research
2) _______ (1944)- discovered ______ was responsible for transformation
3) ______________ (1952)- their studies supported Avery’s work by studying ____________ (a virus that infects bacteria)

5. Hershey & Chase Experiment

6. History of DNA Research
_______________ (1953)- first to develop a
3-D double helix model of _______

7. DNA Structure DNA is made up of ____________.
A nucleotide contains ____ parts:
1) ___________ group
2) _____________ group (deoxyribose)
3) ____________ (4 types)
- adenine (A)
- guanine (G) _________(double rings)
- cytosine (C)
- thymine (T) ____________ (single ring)

8. Purines & Pyrimidines
______________

9. Chargaff’s Rule _________(1949) discovered the
base-pairing rules for nitrogen bases:
1) ____ always pairs with___ (________)
____ always pairs with ___ (________)
2___________ in DNA= __________ in DNA
% (A+G) = % (C+T)
%__ = % ___ , % __ = % ____
Ex. If C is 30 %, then determine % for A, T, G.

10. DNA Structure

11. Double helix
DNA is a _________ composed of ____ long strands of nucleotides twisted and held together by ____________ in the center between the nitrogen bases. A ______________ backbone is on the outer part for each strand of DNA.
Purines base pair with ____________.

12. DNA vs. RNA DNA (Deoxy-ribonucleic Acid) _______ stranded
A, G, C,T (_________)
(A–T, C-G)
1 type
__________ sugar (Missing an oxygen)
RNA (Ribonucleic Acid)
_______ stranded
A, G, C, U (________)
(A-U, C-G)
3 types (mRNA, tRNA, rRNA)
________ sugar (No missing oxygen)

13. 3 Types of RNA 1) ______ (messenger RNA)
-copy the genetic information of _______
and carries it to ____________
2) ______ (transfer RNA)
- transfer ____________ to make ________
3)_______ (ribosomal RNA) - make up __________

14. DNA Replication (DNA -> DNA)
DNA makes an identical copy of itself.
takes place inside the ________ before _____ _________(during _______ of _________).
___________ unwinds DNA and ________ _____________ (enzyme) makes new strands of DNA.

15. DNA Replication (_________________)
(1 ____ strand and 1 ____strand in each DNA after it replicates.)

16. True or False. DNA is made up of nucleotides. DNA has a ribose sugar.
3. DNA is longer than mRNA.
4. Adenine pairs up with thymine in DNA.
5. Covalent bonds hold two nitrogen bases together.
6. DNA structure was discovered by Watson and Crick.
7. Adenine and Thymine are purines.

17. Molecular Biology
DNA --- RNA  Protein
________ ________

18. DNA

19. Transcription & Translation

20. 1. Transcription
- _______ is copied onto _____ because DNA cannot leave the nucleus
- occurs inside the _________.
Steps of Transcription
1) DNA molecule unwinds by enzymes (________)
2) An enzyme named _________ makes mRNA, a copy of DNA, using the base-pairing rule
3) _______ leaves nucleus and travels to
__________ for protein synthesis.

22. 2. mRNA modification
* occurs before __________________________ after ______________________.
During transcription, ________ are cleaved and removed, while _______ combine to form useful mRNA. Only ________ exit the nucleus.
initial mRNA 
introns (_____________________ = junk DNA) cleaved 
exons (___________________ = code for AA) combine 
final mRNA

23. 3.Translation/Protein Synthesis (mRNA -> Protein)
translate the ________ codes on ______ to make _______________.
occurs in ___________.
each protein is made up of ________________.
mRNA is translated in base triplets called
________ which represents an ____________.
3 nitrogen bases on mRNA(1 ________)
= 1 _____________
Use genetic code table to determine which
____________ each ________represents

25. Why a codon can not be one or two nitrogen bases long?
Not enough combinations to cover all __ amino acids.
1 nitrogen base long = __ amino acids
2 nitrogen bases long = __ a.a.
3 nitrogen bases long = __ a.a.
Having more than one codons (esp. the third letter of a codon) for each amino acid minimizes a mistake in transcription /translation.

26. Steps of Translation ______ leaves nucleus & travels to _________.
______ is attached to ribosome. _____ carries its specific _________and arrives at the ribosome when _______ contains a _______ codon (AUG).
3) tRNA’s _________ base-pair with mRNA’s ______ and releases its amino acid.
4) Amino acids form _________ bonds to combine in order to make a ________.
5) _______ continue moving down the ______ strand and transferring amino acids until a ______ codon is reached.
STOP codons: __________________
6) ______ is released from ribosomes. A _________ or a protein is formed.

27. Translation/Protein Synthesis

28. Codon Vs. Anticodon
Anticodon on ______ matches the codon on __________.

29. Transcription and Translation

30. Genetic Code All living things have ______ genetic code.
Ex. ACC in human codes for _______ amino acid as in ACC in your dog or an oak tree.
Different ______________-> different ___________-> distinct __________
The __________________ of different proteins determines the _________ characteristics of a living thing.

31. True or False A codon is found on tRNA.
Transcription occurs in the cytoplasm near the ribosomes.
Transcription precedes translation.
All living organisms have same genetic code.
Translation is also known as protein synthesis.

32. Mutation Definition: any change in _____ sequence
Mutations in ________cells are inheritable, but mutations in ______ cells are not.

33. What causes mutation? ___________ - any substance that causes mutation
– radiation (________________________), chemicals, high temperature

34. Types of Mutation DNA change ____________
- _______________ of one nitrogen base(s)
Ex. The big dog bit the man.
The big dog hit the man.

35. Types of Mutation b.____________ mutation
___________ or ___________ of nitrogen base(s)
Changes the ______________.
More fatal than __________________.
- A different _______ is produced & most likely it is NOT functional.
Ex. The big dog bit the man.
The xbi gdo gbi tth ema n. (insertion)
The bid ogb itt hem an (deletion)

36. Types of Mutation 2. Chromosomal mutation
-few of these mutations are passed on the next generation b/c the ___________ (fertilized egg) usually cannot survive. If the zygote lives and fully develops, the mature organism is often _________.
__________
ABCDE  ACDE
b. __________
ABCDE  ABABCDE
c. __________
ABCDE  ABDCE
d. ___________
ABCDE  ABCDEUVX
UVXYZ YZ

37. DNA and Protein Relationship
The mistakes in ________ will lead to mistakes in ___________ sequence.
This will result in _________________ and people could be ill because the defective proteins are not ___________.

38. Protein folding
* The length of proteins varies and the sequence of _________ determines how proteins ____ b/c some a.a. are attracted to each other and some repel.
*How proteins get folded determines its _____ ______ & its ________.

39. Why is your brain cell different from your skin cell even though they are from same original cell?
____________________
Cells become specialized in structure & function.
_____________________
Genes could be turned “on” and turned “off”.
Genes are ____________ = ____________ are made.
Different genes are ________ or ________ in different type of cells.

40. Lac Operon (in bacteria)
Has 3 genes that code for enzyme lactase.
_______ breaks down ______ sugar in milk.
________ – includes promoter, operator and gene(s) for a specific protein.
________ – helps RNA polymerase find where a gene starts.
________ – a DNA segment that turns the gene(s) “on” or “off”.

41. The Lac Operon (in bacteria) The ___________ IS bound to the __________. Transcription is blocked b/c RNA polymerase can’t bind to the ________. The genes are turned “______”

42. Regulation of Gene Expression
Lac operon (in bacteria)
__________ binds to the _____________ and the repressor comes off the ______________ site.
When the __________ is NOT bound to the _______ site, _______________ binds to promoter site and starts ________________.
The genes are turned “____” & expressed. _________ (enzyme protein) is produced.

43. Eukaryotic Gene Expression
More complex.
Needs _______ _________ in order for _____ ____________to start transcription.
Also enhancers and silencers can regulate the rate of transcription of gene.