The document provides an overview of DNA structure and function, explaining that DNA contains the genetic code for all living things and is made up of nucleotides containing nitrogenous bases that pair up in the DNA double helix. It describes how DNA is replicated through the process of transcription to make mRNA and then translated to synthesize proteins. The document also discusses mutations that can occur in DNA through errors in replication or recombination and their potential effects.
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?
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. DNAmRNAprotein
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. DNAmRNAamino 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
DNAmRNAProtein
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
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
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!!!
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
71. Test Your DNA knowledge
DNA Practice EOC
exam questions
Answers to DNA
questions
Editor's Notes
DNA fingerprinting info (explain to students)The chemical structure of everyone's DNA is the same. Only difference between people (or any animal) is the order of the base pairs. There are so many millions of base pairs in each person's DNA that every person has a different sequence.Using these sequences, every person could be identified solely by the sequence of their base pairs. However, because there are so many millions of base pairs, the task would be very time-consuming. DNA finger printing uses the short, repeating segments of human DNA for comparisonThese patterns do not, however, give an individual "fingerprint," but they are able to determine:If samples are from the same person, related people, or non-related people. Scientists use a small number of sequences of DNA that are known to vary among individuals a great deal, and analyze those to get a certain probability of a match.
Explain what a DNA finger print is…click on interactive activity