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DNA
By: Mr. Hunter
Bellwork: Fill-In-The Blank. Write
the complete sentence.
• Inherited characteristics are
determined by _____ , which are
passed from one generation to the
next.
• Genes are parts of _____ , found in
the nucleus of the cell.
• Chromosomes are made of _____ and
_____ .
DNA
• What do you know about DNA?
• What do you want to know about
DNA?
Rosalind Franklin
• She used x-ray diffraction to make
images of DNA.
Watson and Crick
DNA
• DNA should be able to be
copied each time a cell
divides.
• DNA should be able to give
instructions for building and
maintaining cells.
DNA
• Double helix structure
• DNA is composed of nucleotides.
• Nucleotides: Adenine, Guanine,
Cytosine, Thymine
Nucleotides
Nucleotides are made of sugar,
phosphate group, and a nitrogenous
base.
Chargaff’s Rules
Mnemonic
MNEMONIC
Create a mnemonic device that will remind
you of the names of the bases and the
way the bases form pairs.
Example: Atoms are Tiny would help you
remember that adenine pairs with thymine.
DNA
• DNA strands are complimentary to
each other!
• For instance, the sequence CGAC will
bond to the sequence GCTG.
• This assists in DNA replication, which
occurs anytime a cell divides.
Write the Sentences and
• 1. What would the complimentary strand of
DNA be for a DNA strand with this
sequence: atgcccgggaaatt?
• 2. Briefly describe how each of the following
individuals contributed to DNA science:
Watson and Crick, Rosalind Franklin, and
Chargaff?
• 3. A nucleotide consists of a _____, _____,
and a ______ .
• 4. The shape of DNA is a ______ .
DNA
• 1. How does DNA differ in eukaryotic cells
differ from DNA in prokaryotic cells?
• 2. What is a gene?
• 3. Where is the DNA in your cells?
• 4. How does so much DNA fit into the
nucleus?
• 5. What is the name for stands of DNA
wound around proteins?
• 6. When do chromosomes become visible in
cells?
• 7. What are chromatids?
DNA-> PROTEIN
• List, describe, and draw a picture to
detail each step of protein formation.
Protein Synthesis
• RNA serves as a temporary copy of a DNA
sequence.
• 1. DNA strands separate. Free
nucleotides attach to one strand of DNA.
The nucleotides make up mRNA.
• *RNA has uracil instead of thymine.
• *It is called messenger RNA because it
leaves the nucleus of the cell.
Protein Synthesis
• 2. mRNA attaches to a ribosome.
(There are 10,000,000 ribosomes in
one human cell.)
• 3. tRNA (transfer RNA) carrying an
anticodon and amino acid affixes to
the ribosome. The process of
translation begins.
Protein Synthesis
• 4. Each codon on the mRNA matches an
anticodon on the tRNA. Codons and
anticodons are complimentary.
• 5. tRNA floats away and leaves its amino
acid behind.
• 6. The amino acids are assembled into
polypeptides (protein molecules).
• Transcription - Synthesis of mRNA
molecule.
• Translation - Synthesis of polypeptide
from amino acids.
• Codon - Base triplet on mRNA.
• Anticodon - Complementary triplet on
tRNA.
• Polypeptide - Protein molecule
DRAW THIS
DNA Protein
• You are a protein. Write a story of your
formation. Include the following words:
DNA, mRNA, tRNA, RNA, ribosome
Mutations
• Mutation: a change in the nucleotidebase sequence of a gene or DNA
molecule
• Insertion, deletion, substitution
Mutation Effects
• An improved trait
• No change
• A harmful trait
Mutations
• Occur in approximately one out of
every 10,000 base pairs. With cellular
proofing mechanisms, the final error
rate is as low as one in a billion.
• Mutations occur because of errors
when DNA is copied or mutagens
(radioactivity).
Example
Sickle Cell Anemia
Copy this!
• Human DNA consists of about 3 billion
base pairs. If you could print a book
with all the genetic information carried
in just one human cell, it would be
500,000 pages long!!!!!
Human Genome
• There are about 25,000 human genes,
and many genes code for multiple
proteins.
• In this and other ways, human genes
appear to be unique among
organisms.
Human Genome Project
• In 2003, the Human genome Project
had successfully mapped 99% of the 3
billion base pairs that make up a set of
human DNA. But the project has
raised new questions as well.
HUMAN GENOME PROJECT
• 3% of base pairs are used to make
proteins.
• 97% are regulatory sequences,
nonfunctioning genes, and sequences
with no known function.
CLONING
• Cloning is making an exact genetic
copy of DNA.
Why clone?
Medical Reasons
- Cloning animal models of disease
- Cloning stem cells for research
- “pharming” for drug production
Reviving Extinct Species
Why clone?
Reproducing a deceased pet
Cloning Humans
-to help an infertile couple have a child
-to replace a deceased child
Misconceptions
• Instant clones
Misconceptions
• Carbon Copies
What are the problems with
cloning?
• High failure rate
• Problems during later development
• Abnormal gene expression patterns
Genetic Engineering
What are the benefits?
• Eliminating genetic diseases
• Screening unborn babies
• Treating diseases
What are the risks?
• People can control possible traits in
organisms.
Questions to Ponder
• 1. This technology could allow a 60-year old
woman to have a baby. Do you think this
would be a positive or negative outcome of
the technology? Why?
• 2. During World War II, Nazis in Germany
conducted experiments to selectively breed
blond, blue-eyed men and women. This is
an example of eugenics that was
detrimental to society. Explain why.
DNA Extraction
http://learn.genetics.utah.edu/content/lab
s/extraction/