This document provides an overview of key concepts from chapters 5-8 regarding DNA, genes, and genetics. It begins with a review of DNA and RNA structure, including nucleotides, sugars, and bases. It then summarizes experiments that identified DNA as the genetic material, such as Griffith's experiments and Avery's work. Subsequent sections discuss DNA replication, transcription, translation, gene expression, mutations, and factors that can cause mutations. The document utilizes questions and diagrams to reinforce major topics and concepts from these chapters on molecular genetics.

1. CH. 8
IDENTIFYING DNA AS THE GENETIC MATERIAL

2. CH. 5 & 6 REVIEW
•ANSWER THE FOLLOWING
QUESTIONS:
•1. What macromolecule group
does DNA & RNA belong in?
•2. What monomer do we use to
assemble the macromolecule
group from question #1.

3. CH. 5 & 6 REVIEW
•ANSWER THE FOLLOWING
QUESTIONS:
•3. What is a nucleotide?
•4. What would a nucleotide for
DNA contain?
•5. What would a nucleotide for
RNA contain?

4. • Ch. 8.1 – Identifying DNA as the Genetic Material
• Griffith finds a “transforming principle.” - NOTES

5. • Ch. 8.1 – Identifying DNA as the Genetic
Material
• Griffith finds a “transforming principle.”-
QUESTION & ANSWER:
• 1. What was “transformed” in Griffith’s
experiment?
• That the R bacteria in the presence of the dead
S bacteria became pathogenic.
• 2. Explain how the results support the
experimenters conclusion.
• The mice dying when they shouldn’t have
means that the S bacteria must have contained
some information that was able to change the
harmless bacteria t deadly bacteria.

6. • Ch. 8.1 – Identifying DNA as the Genetic Material
• Avery Identifies DNA as the transforming principle - NOTES

7. • Ch. 8.1 – Identifying DNA as the Genetic
Material
• Avery Identifies DNA as the transforming
principle – QUESTION & ANSWERS:
• 1. How did Avery and his group identify the
transforming principle?
• 1st identifying the 2 components: proteins &
DNA
• Used enzymes to break down the protein & the
R-bacteria were still transformed to S bacteria
killing the mice.
• Only when an enzyme to break down DNA did
the transformation failed to occur.

8. • Ch. 8.1 – Identifying DNA as the Genetic Material
• Hershey & Chase confirm that DNA is the genetic material – NOTES

9. • Ch. 8.1 – Identifying DNA as the Genetic Material
• Hershey & Chase confirm that DNA is the genetic material –
QUESTIONS & ANSWERS:
• 1. Summarize how Hershey & Chase confirmed that DNA is the
genetic material.
• A: They labeled the protein of bacteriophages with radioactive sulfur
and their DNA with radioactive phosphorus. The bacteriophages
were allowed to infect bacteria.
• 2. Summarize why the bacteriophage was an excellent choice for
research to determine whether genes are made of DNA or proteins?
• A: A bacteriophage consists of little more than a protein coat
surrounding DNA. The protein coat is left behind when the viral DNA
enters a bacterium.
• 3. Explain how the results support their conclusions.
• A: That the phage’s DNA had entered the bacteria, but the protein
had not, convincing scientists that the genetic material is DNA & not
protein.

10. •Review
•1. What did Hersey &
Chase know about
bacteriophages that led
them to use these viruses
in their DNA experiments?

11. •ANSWER:
•That bacteriophages are
made up of a protein
coat surrounding DNA.

12. • 8.2 – Structure of DNA
•DNA is composed of 4 types of
nucleotides (monomer):
•Nucleotide composed of:
•Phosphate group
•5 carbon sugar
•Nitrogen base

13. • DNA is composed of 4 types of nucleotides con’t.
• Nucleotide in DNA is composed of:
• Phosphate group
• Deoxyribose sugar
• Nitrogen base
• Cytosine = C
• Thymine = T
• Adenine = A
• Guanine = G
• Nucleotide in RNA is composed of:
• Phosphate group
• Ribose sugar
• Nitrogen base
• Cytosine = C
• Uracel = U (replaces thymine)
• Adenine = A
• Guanine = G
• Letter abbreviations refer both to the base & to the nucleotides that contain
that base

14. • DNA is composed of 4 types of nucleotides
con’t.
• CHARGAFF’S RULE:
• A = T
• G = C
• QUESTION:
• What is the only difference among the 4 DNA
nucleotides?
• Which part of a DNA molecule carries the
genetic instructions that are unique for each
individual; the sugar-phosphate backbone or
the nitrogen-containing bases? Explain.

15. ANSWER TO QUESTIONS
•1. THE 4 NITROGEN BASES.
•2. THE NITROGEN BASES,
BECAUSE THE REMAINING
PARTS OF THE NUCLEOTIDE
ARE IDENTICAL.

16. •Watson & Crick Developed an accurate
model of DNA - NOTES

17. •Watson & Crick Developed an accurate
model of DNA – QUESTION & ANSWER:
•What bases are considered pyrimidines &
purines?
• Pyrimidines = T & C
• Purines = A & G
•How did the Watson & Crick Model
explain Chargaff’s rules?
• The pyrimidine – thymine a single ringed
base pairs with a purine – adenine a double
ringed base so that the double helix will be

18. •Nucleotides always pair in the same way.
•DNA nucleotides of a single strand are
joined together by covalent bonds
connecting the sugar of one nucleotide
to the phosphate of the next nucleotide.
•Alternating sugars & phosphates form
the sides of a double helix sort of like a
twisted ladder.
•DNA double helix is held together by
hydrogen bonds between the
bases in the middle.

19. •Nucleotides always pair in the same way –
QUESTIONS & ANSWERS:
•What sequence of bases would pair with
the following sequence: T T A C G C G A C
•A A T G C G C T G

20. •8.3 – DNA Replication
•Replication copies the genetic
information
•Watson & Crick’s experiments
showed that one strand of DNA is
used as a template to build the other
strand
•Guarantees that each strand of
DNA is identical.

21. • Proteins carry out the process of replication
• How :
• DNA is unzipped at numerous places (H bonds
broken)
• Free floating nucleotides pair with the exposed
bases (template strands)
• DNA polymerase bonds the nucleotides together
to form the new strands that are complementary
to the template strand (original strand).
• Creates 2 identical molecules of DNA.
• Each DNA molecule has an original & a new
strand.
• Why DNA replication is called semiconservative
replication.

22. • DNA Replication

23. •Replication is fast & accurate
•Replication is fast because the DNA
strand is opened at hundreds of
different points & allowing nucleotides
to be added at many spots at the same
time.
•Proofreading is carried out at the same
time that nucleotides are added.
•DNA polymerase can detect errors &
make corrections.
•Pg. 238, fig. 8.9 shows this process

24. • 8.4 TRANSCRIPTION
• RNA carries DNA’s instructions
• Central Dogma
• Information flows from DNA to RNA to
proteins
• Transcription converts a DNA message into
an intermediate molecule, called RNA.
• Translation interprets an RNA message into
a string of amino acids, called a
polypeptide.
• Either a single polypeptide or many
polypeptides working together make up a

25. •RNA carries DNA’S instructions con’t.
•Prokaryotic cells:
•Replication, transcription, and
translation all occur in the cytoplasm at
approximately the same time.
•Eukaryotic cells:
•Replication, transcription, and
translation occur in different locations.
• Replication & transcription – nucleus
• Translation – occurs in the cytoplasm

26. •RNA carries DNA’s instructions con’t.
•RNA acts as an intermediate link between
DNA in the nucleus & protein synthesis in
the cytoplasm.
•Gets used then destroyed.
•RNA is single stranded, contains ribose
sugar & has uracil instead of thymine
•A (DNA) = U (RNA)
•T (DNA) = A (RNA)
•G (DNA) = C (RNA)
•C (DNA) = G (RNA)

27. •Transcription makes 3 types of RNA
•Transcription is the process of copying
a sequence of DNA to produce a
complementary strand of RNA.
•Part of the chromosome, called a
gene, is transferred into an RNA
message.
•Transcription is catalyzed by RNA
polymerase.

28. •Transcription produces 3 major types of
RNA molecules
•mRNA (messenger RNA) – an
intermediate message that is translated
to form a protein
•rRNA (ribosomal RNA) – forms part of
ribosomes, a cell’s protein factories
•tRNA (transfer RNA) – brings amino acids
from the cytoplasm to a ribosome to
help make the growing protein.
•Pg. 241, Fig. 8.11 visualizes transcription

29. • Transcription vs. replication
• Similarities
• Happen in nucleus of eukaryotic cells
• Need enzymes to begin the process
• Unwind the DNA double helix
• Complementary base pairing to the DNA strand
• Regulated by the cell
• Differences
• Replication makes sure each new cell will have one complete
set of genetic instructions & occurs only once during each
round of the cell cycle.
• Transcription could make hundreds or thousands of copies of
certain proteins or the rRNA or tRNA molecules needed to
make proteins based on the demands of the cell, using a single
stranded complementary mRNA strand.

30. • 8.5 TRANSLATION
• Amino acids are coded by mRNA base sequences
• Translation is the process that converts, or
translates, an mRNA message into a
polypeptide.
• Could be 1 or more polypeptides to make up
a protein
• Language of nucleic acids:
• DNA – uses 4 nucleotides = A, G, C, & T
• RNA – uses r nucleotides = A, G, C, & U
• Language of proteins uses 20 amino acids

31. • Triplet Code
• Genetic code uses codons, which is read in groups of 3
nucleotide bases
• Codon is a 3 nucleotide sequence that codes for a particular
amino acid, referred to as the reading frame.
• First 2 nucleotides are usually the most important in coding for
an amino acid
• Start codon – signals the start of translation and the amino
acid is methionine
• 3 stop codons – signal the end of the amino acid chain.
• If reading frame is changed, changes protein or even can
prevent a protein from being made.
• Almost all organisms, including viruses, follows the genetic
code.
• This allows scientists to insert a gene from 1 organism into
another organism to make a functional protein.

32. • GENETIC CODE

33. • Genetic Code

34. • DETERMINE WHAT AMINO ACID SEQUENCES
ARE CREATED FROM THE FOLLOWING STRINGS
OF NUCLEOTIDES
•1) A U G A C C A A C A G C
•A) methionine(start), threonine,
asparagine, serine
•2) A U G C C C C A A U G A
•A) methionine(start), proline,
glutamine, stop

35. •Amino acids are linked to become a protein
•Review:
•mRNA is a short lived molecule that
carries instructions from DNA in the
nucleus to the cytoplasm
•mRNA message is read in groups of 3
nucleotides called codons
•How it translates the codon into an amino
acid requires the use of rRNA & tRNA
molecules

36. • Amino acids are linked to become a protein
• Ribosomes are made of a combination of rRNA & proteins &
they catalyze the reaction that forms the bonds between amino
acids.
• Ribosomes have a large & small subunit that fit together & pull
the mRNA strand through.
• Small unit holds the mRNA strand & the large subunit holds
onto the growing protein
• tRNA carries amino acids from the cytoplasm to the ribosome
• Has an L shape to the tRNA molecule, one end of the L is
attached to the specific amino acid & the other end of the
L, is called the anticodon, which recognizes a specific codon.
• Anticodon is a set of 3 nucleotides that is complementary
to an mRNA codon.
• PG. 246, Fig. 8.16 Translation
• Read pg. 247

37. • 8.6 – GENE EXPRESSION & REGULATION
• mRNA processing
• Important part of gene regulation in eukaryotic cells
is RNA processing.
• mRNA that is produced by transcription needs to be
edited
• Exons are nucleotide segments that code for parts
of the protein.
• Introns are nucleotide segments that are located
between the exons
• Introns are removed from mRNA before it leaves
the nucleus.
• Exons are joined back together

38. • TRANSLATION

39. • 8.7 MUTATIONS
• Some mutations affect a single gene & others affect the entire
chromosome
• Mutation is a change in an organism’s DNA
• Types of gene mutations:
• Point mutation – a mutation in which one nucleotide is
substituted for another.
• DNA polymerase could find & correct mistake, if not may
permanently change an organism’s DNA
• Frameshift mutation – involves the insertion or deletion of a
nucleotide in the DNA sequence
• Affects the polypeptide more than a point mutation
(substitution)
• Causes the reading frame from point of insertion or
deletion to change the remaining amino acids

40. •MUTATIONS
•ORIGINAL NUCLEOTIDE SEQUENCE:
•A U G C C G U U A A C G C G A U C C G G
•READS:
•MUTATED NUCLEOTIDE SEQUENCE:
•A U G C A C G U U A A C G C G A U C C G G
•READS:

41. • Types of chromosomal mutations:
• Gene duplication:
• During crossing over chromosomes do not align & the
chromosomal segments are different sizes. The
chromosome receiving the larger segment would
have part of the chromosome that is duplicated.
• Gene deletion:
• During crossing over chromosomes do not align & the
chromosomal segments are different sizes. The
chromosome receiving the smaller segment would
have part of the chromosome that is deleted.
• Translocation:
• A piece of one chromosome moves to a non-
homologous chromosome.

42. • Mutations may or may not affect phenotype.
• Phenotype – Collection of all of an organism’s physical
characteristics.
• Ex: black hair, blue eyes, attached ear lobes.
• Chromosomal mutations
• Usually have big affect on organisms
• Ex: may break a gene causing it not to function
• Ex: may create a new hybrid gene with a new function
• Ex: may cause a gene to be more or less active
• Gene mutations – could have a bad affect, no affect, or create a
beneficial mutation
• Could change the active site for an enzyme & now it cannot
accept the substrate
• Could affect how protein folds & possibly destroying the
protein’s function
• Could create a premature stop, making protein nonfunctional

43. • Impact on offspring
• Mutations can happen in body cells & in germ cells.
• Body cell mutations only affect that individual
• Germ cell mutations may be passed to offspring
• Can be source of genetic variations, which is the basis
of natural selection.
• Will affect the phenotype of offspring
• Could be harmful & the offspring do not develop
properly or could die before reproducing
• Could be mutations not well suited to environment
& the alleles will be removed from the population
• Could be a mutation that is well suited to
environment & the alleles will be increased in the
population
• http://staff.tuhsd.k12.az.us/gfoster/standard/bmut.htm

44. •Mutations can be caused by several
factors
•Mutagens – agents in the environment
that can change DNA.
•Speed up the rate of replication errors
•Break DNA strands
•Cause cancer
•Types of mutagens:
•UV light
•Industrial chemicals