1. From Peas and fruit flies to humans…

3. What is a genome???
 All the genetic information (genes) that
make up an organism

4. What makes us
human?
 Analyze human
chromosome…
 Karotype
 Picture of all the chromosomes
in an organism
 Autosomes
○ CHROMOSOMES 1-44 (pairs 1-
22)
○ Autosomal chromsomes
 Sex chromosomes
○ Determine a person’s sex (male
XY or female XX)
○ Chromosome 45 and 46 (set 23)

8. DNA
StructureAcid
Deoxyribonucleic
 DNA is a polymer made
up of many monomers
called nucleotides
 Nucleotide contains:
 5-carbon sugar called
deoxyribose
 RNA contains
RIBOSE sugar
instead
 Phosphate group
 One Nitrogenous
base (there are 4
types)

11. What are these Nitrogenous
bases???
 Make up the “steps” of the DNA
ladder
 One Step= A Purine + A
Pyrimidine
 Purines
 Double ring structure
 Adenine
 Guanine
 Pyrimidines
 Single-ring structure
 Cytosine
 Thymine (in DNA only)
 Uracil (in RNA only)

12. Nucleic Acids
 RNA  DNA
 Single Strand  Double strand
 Ribose sugar  Deoxyribose sugar
 A=U  A=T
 G=C  G=C
 Uracil is the
nitrogenous
base used
instead of
THYMINE

14. DNA Review
The 2 Fates of DNA
Protein Synthesis
DNA Replication
(when cell is doing is
(if cell enters cell
normal job-in G1
division…S-phase)
phase of cell cycle)

17. DNA Facts
 All living things have DNA
 Prokaryotes-DNA in cytoplasm,
simple
○ Contain extra DNA called
PLASMIDS
 Eukaryotes-DNA in nucleus,
complex
 DNA codes for the same 20 amino
acids in ALL living things
 It is the UNIVERSAL code...all
organisms have the same A,T,G
and C bases and the same 20
a.a., just arranged differently

18. 5
The DNA backbone
PO4
 Putting the DNA
backbone together base
5 CH2
 refer to the 3 and 5 ends O
4 1
of the DNA C
3
○ the last trailing carbon O
2
–O P O
Sounds trivial, but…
O base
this will be 5 CH2
IMPORTANT!! O
4 1
3 2
OH
3

19. Anti-parallel
strands
 Nucleotides in DNA
backbone are bonded from
phosphate to sugar 5 3
between 3 & 5 carbons
 DNA molecule has
“direction”
 complementary strand runs
in opposite direction
3 5

20. Bonding in DNA
hydrogen
bonds
5 3
3
5
….strong or weak bonds?
How do the bonds fit the mechanism for copying DNA?

21. Base pairing in DNA
 Purines
 adenine (A)
 guanine (G)
 Pyrimidines
 thymine (T)
 cytosine (C)
 Pairing
 A:T
○ 2 bonds
C:G
○ 3 bonds

22. Copying DNA
 Replication of DNA
 base pairing allows
each strand to serve
as a template for a
new strand
 new strand is 1/2
parent template &
1/2 new DNA
○ semi-conservative
copy process

23. Let’s meet
the team…
DNA Replication
 Large team of enzymes coordinates replication

24. Important Enzymes
 DNA Helicase
 Unzips original DNA strand
 DNA Polymerase
 Adds nucleotides to the
unzipped sides
 DNA Ligase
 Attaches/glues DNA
fragments together on one
of the new copies

25. How does DNA replicate
itself?
 Template mechanism
 What is a template???
 Like the negative of a photograph
 DNA Replication
 Process of copying the DNA molecule
○ What phase of the CELL CYCLE?
 S-phase….
 2 strands of double helix separate (Unzips)
 Each strand acts as a negative for making the
new complementary strand
 Nucleotides line up one by one following base
pairing rules
 Enzymes (DNA Polymerase and DNA Ligase)
link nucleotides together to form 2 new DNA
strands called the daughter strands

27. Fate #2: Protein Synthesis
 You already know about this…central
dogma of Biology
 Just need to know your key players…

28. The Protein Synthesis Team
 DNA
 mRNA
 tRNA
 rRNA
 Codons
 Anticodons
 Amino acids
 Proteins
 Introns
 Exons

30.  DNAmRNAprotein
 DNA TRANSCRIBES to
mRNA
 Process is called
transcription
 mRNA TRANSLATES to
proteins
 Process is called
translation
 mRNA actually makes
amino acids, which come
together to make proteins

31. DNAmRNAamino acids/polypeptide chain
(Proteins)
 DNA codes for an RNA strand
 The every 3 bases on the RNA
strand code for a specific amino
acid
 CODON: three sequential bases
that code for a specific a.a. (20
a.a. total)
 Amino acid are strung together to
make a protein (primary structure)
 Change DNA will change RNA
which will change amino
acids, which change protein

33.  Transcription
DNAmRNAProtein
 Different form of the same
message
 DNA makes single
stranded RNA (U replaces
T)
 RNA leaves nucleus
 Translation
 Translate from nucleic acid
language to amino acid
language
 Uses codons, 3-base
“word” that codes for
specific a.a.
○ “code” for an amino acid
 Several codons make a
“sentence” that translates
to a polypeptide (protein)

34. Start Stop
Codons Codons
 AUG  UAA
 UGA
 UAG

35. Three Types of RNA
 mRNA
 tRNA
 rRNA

36. Three Types of RNA… #1
 mRNA (messanger RNA)
 RNA transcribed from DNA template
 Modified in nucleus before if exits
○ RNA splicing: process in which Introns are removed and
exons re joined together to make a continuous coding
mRNA molecule
 Introns
○ Internal non-coding regions of DNA and mRNA
○ Space fillers/jibberish
○ They are cut out of mRNA before it is allowed to leave the
nucleus
○ Process is called RNA splicing (processing)
 Exons (MOST important part of DNA)
○ Coding region of DNA and mRNA that will be translated
(Expressed)
○ VERY important part of mRNA…it is carrying the message
from DNA (def can’t cut this out)

37. Three Types of RNA…#2
 tRNA (transfer RNA)
 The interpreter
 Translate 3-letter base
codes into amino acids
 Carries anti-codon on
one end (three letters
opposite of what is on
mRNA)
 Carries amino acid on
other end
 Anti-codon recognizes
codon and attaches

38. Three Types of RNA…#3
 rRNA (ribosomal RNA)
 Found in ribosome
 Ribosome composed of 2
subunits:
○ Small subunit for mRNA to
attach
○ Large Subunit for two tRNAs to
attach
 “P” site: holds the tRNA
carrying the growing
polypeptide chain
 “A” site: holds the tRNA that
is carrying the next a.a. to be
added to the chain
 When stop codon
(UAA, UAG, UGA) is
reached, translation ends and
polypeptide is released

47. Mutations
 Occur when there is an error in DNA
replication
 Def: Change in genetic material
 Mutagens
 Physical or chemical agents that cause
mutations
○ Ex: high energy radiation (x-ray or UV)
○ Ex. Chemicals (that are similar to DNA but
cause incorrect base pairing)

48.  Mutation
 Any change in the nucleotide sequence of
DNA
 Large or small
 2 Main types
 Point Mutation
○ Base Substitutions
 Frameshift Mutation
 Insertions or deletions

49. Base Substitution
 Replacement of one base or nucleotide with
another
 Usually do not change amino acid
 Sometimes causes a change in the protein
made
 Silent Mutation
 When a substitution does not cause a change in the
protein expressed by a gene
 Remember some codons represent the same amino
acid
 Example: GAA and GAG both code for Glu

50.  Point Mutation
A point mutation is a simple change in one base of
the gene sequence. This is equivalent to changing
one letter in a sentence, such as this example,
where we change the 'c' in cat to an 'h':
Original: The fat cat ate the wee rat.
Point Mutation: The fat hat ate the wee rat.

51. Insertion or Deletion
 Nucleotide is removed or added
 More disastrous
 mRNA is read as triplet codes
 Adding/removing bases changes these three
letter codes
 Codons downstream from insertion/deletion will
be regrouped and probably code for a non-
working protein
 Result: FRAMESHIFT MUTATION
 Shift the “reading” frame of the genetic message

52. Frameshift mutation
 Original: The fat cat ate the wee rat.
 Frame Shift: The fat caa tet hew eer at.

54. Chromosomal Mutations
 Involve changes in the number or
structure of the chromosome

55. Chromosomal Disorders
 Mechanics of meiosis (where we separate
chromosomes) is usually pretty good
 But nobody’s perfect…mistakes happen….
 Most common problem…
 Nondisjunction: when homologous
chromosomes fail to separate properly
 Literally means “not coming apart”
 If this occurs, ABNORMAL #s of chromosomes
may find their way into gametes and a disorder
of chromosome number may result

56. Nondisjunction
 If one of the gametes with an ABNORMAL
# ends up getting fertilized, MAJOR
problems!!!
 Trisomy: “three bodies”
○ Occurs when an autosomal chromosome fails to
separate during meiosis
 When do chrm separate?
- Anaphase I and Anaphase 2
○ One gamete ends up with an extra copy of a
chromosome and then the fertilized zygote ends
up with 3 copies of a chrm instead of 2
○ Example: Downs Syndrome

59. Chromosomal Mutations
 May change location of
genes on chromosome
 Include:
 Deletions: loss of part of
chromosome
 Duplications: produce
extra copies of parts of
chromosome
 Inversions: reverse
direction of chromosome
 Translocation: when one
chromosome breaks off
and attaches to another

61. Mutations
 NOT always harmful
 Some alter a protein in a beneficial
way that may help species in a
specific environment
 If mutation is present in organisms
gametes, it may be passed off to off-
spring
 Mutations are the ULTIMATE source
for GENETIC DIVERSITY!!!

62. What is biotechnology?
 Here are some hints…

63. Biotechnology
 Manipulation of living organisms or their
parts to produce useful products
 Main use is to improve human health
and food production
 Seedless fruits
 Make insulin

64. Genetic engineering
 The transfer of genes or pieces of DNA
from one organism into another
organism
 New DNA is a combination of pieces from
two different organisms…called
recombinant DNA
 Used to introduce new characteristics
into organisms and populations
 Gentically Modified Organisms GMOs

65. How to make recombinant
DNA
 Use DNA from complex organism (human) and
transfer to a simple organism (bacteria)
 Uses a PLASMID
 Small circular DNA in bacteria
 It is called a VECTOR when used in genetic
engineering

68. Genetic Engineering
 Positive/benefits  Negatives/Cons
 Make medicine like  Unknown long term
insulin and vaccines effects if ingested by
plentiful and humans
inexpensive  Harm native, natural
 Improves crop plants species
like corn and rice  Cross pollination
○ Grow faster and between GMOs and
stronger wild plants resulting in
○ Resist disease and unwanted hybrids
insects (mockingjays!)
○ Genes can be added  ***Decreases genetic
to add more vitamins
variation
to plants

69.  The chemical structure of everyone's
DNA Fingerprinting DNA is the same.
 Only difference is order of base pairs
 Too many bases to analyze every
 Not like the single one, so scientists analyze
groups /segments of bases
fingerprint on your  These patterns do not, however, give an
hand individual "fingerprint," but they are able
to determine:
 Used to determine  If samples are from the same person,
the paternity of a related people, or non-related people.
child and in  There are a few small fragments in
humans that scientists KNOW vary
forensics (the CSI greatly from individual to individual
stuff you see on TV)  They analyze those segments and get a
certain probability of a match

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71. Test Your DNA knowledge
 DNA Practice EOC
exam questions
 Answers to DNA
questions